:Glyphosate

Glyphosate was first synthesized in 1950 by Swiss chemist Henry Martin, who worked for the Swiss company Cilag. The work was never published.{{cite book | editor-last1 = Nandula | editor-first1 = Vijay K. | title = Glyphosate Resistance in Crops and Weeds: History, Development, and Management | first1 = Gerald M. | last1 = Dill | first2 = R. Douglas | last2 = Sammons | first3 = Paul C. | last3 = Feng | first4 = Frank | last4 = Kohn | first5 = Keith | last5 = Kretzmer | first6 = Akbar | last6 = Mehrsheikh | first7 = Marion | last7 = Bleeke | first8 = Joy L. | last8 = Honegger | first9 = Donna | last9 = Farmer | first10 = Dan | last10 = Wright | first11 = Eric A. | last11 = Haupfear | name-list-style = vanc | chapter = Glyphosate: Discovery, Development, Applications, and Properties | chapter-url = http://media.johnwiley.com.au/product_data/excerpt/10/04704103/0470410310.pdf | date = 2010 | publisher =John Wiley & Sons, Inc.| location =Hoboken, NJ| isbn = 978-0-470-41031-8 }}{{rp|1}} Early studies found it to be a weak chemical chelating agent.{{cite journal|title=Comments for Mertens et al. (2018), Glyphosate, a chelating agent—relevant for ecological risk assessment?|first1=John T.|last1=Swarthout|first2=Marian S.|last2=Bleeke|first3=John L.|last3=Vicini|journal=Environmental Science and Pollution Research International|date=June 16, 2018|volume=25|issue=27|pages=27662–3|doi=10.1007/s11356-018-2506-0|pmc=6132386|pmid=29907899|bibcode=2018ESPR...2527662S }}

Glyphosate was independently discovered in the United States at Monsanto in 1970. About 100 derivatives of aminomethylphosphonic acid had been prepaared as potential water-softening agents. Two were found to have weak herbicidal activity, and John E. Franz, a chemist at Monsanto, was asked to try to make analogs with stronger herbicidal activity. Glyphosate was the third analog he made.{{rp|1–2}}{{cite journal | vauthors = Alibhai MF, Stallings WC | title = Closing down on glyphosate inhibition – with a new structure for drug discovery | journal =Proceedings of the National Academy of Sciences of the United States of America| volume = 98 | issue = 6 | pages = 2944–46 | date = Mar 2001 | pmid = 11248008 | pmc = 33334 | doi = 10.1073/pnas.061025898 | bibcode = 2001PNAS...98.2944A | jstor = 3055165 | doi-access = free }}{{cite journal|title=Monsanto's John E. Franz Wins 1990 Perkin Medal|journal=Chemical & Engineering News|date=12 March 1990|volume=68|issue=11|pages=29–30|doi=10.1021/cen-v068n011.p029 }} Franz received the National Medal of Technology of the United States in 1987 and the Perkin Medal for Applied Chemistry in 1990 for his discoveries.{{cite web | url = http://www.uspto.gov/about/nmti/recipients/1987.jsp | title = The National Medal of Technology and Innovation Recipients – 1987 | publisher = The United States Patent and Trademark Office| access-date = 2012-11-29 }}{{cite journal | title = People: Monsanto Scientist John E. Franz Wins 1990 Perkin Medal For Applied Chemistry | journal =The Scientist| vauthors = Stong C | date = May 1990 | volume = 4 | issue = 10 | pages = 28 | url = http://classic.the-scientist.com/?articles.view/articleNo/11141/|archive-url=https://web.archive.org/web/20140416133120/http://classic.the-scientist.com/?articles.view/articleNo/11141/title/People--Monsanto-Scientist-John-E--Franz-Wins-1990-Perkin-Medal-For-Applied-Chemistry/|url-status=dead|archive-date=2014-04-16 }}{{cite web|title=SCI Perkin Medal|url=https://www.sciencehistory.org/sci-perkin-medal|website=Science History Institute|access-date=24 March 2018|date=May 31, 2016}}

Monsanto developed and patented the use of glyphosate to kill weeds in the early 1970s and first brought it to market in 1974 under the Roundup brandname.{{cite web | url=https://monsanto.com/app/uploads/2017/06/back_history.pdf | title=History of Monsanto's Glyphosate Herbicides | publisher=Monsanto| access-date=20 December 2015 | archive-date=August 7, 2018 | archive-url=https://web.archive.org/web/20180807095908/https://monsanto.com/app/uploads/2017/06/back_history.pdf | url-status=dead }} While its initial patent{{cite patent| country = US| number = 3799758 | status = application| title = N-phosphonomethyl-glycine phytotoxicant compositions | pubdate = 1974-03-26| fdate = 1971-08-09| pridate = 1971-08-09| invent1 = John E. Franz| assign1 = Monsanto Company}} expired in 1991, Monsanto retained exclusive rights in the United States until its patent{{cite patent| country = US| number = 4405531 | status = application| title = Salts of N-phosphonomethylglycine| pubdate = 1983-09-20| fdate = 1982-03-08| pridate = 1975-11-10| invent1 = John E. Franz| assign1 = Monsanto Company}} on the isopropylamine salt expired in September 2000.{{cite web |url=http://www.frost.com/prod/servlet/market-insight-print.pag?docid=JEVS-5N2CZG |title=The Glyphosate Market: A 'Roundup' |last1=Fernandez |first1=Ivan |date=2002-05-15 |website=Frost & Sullivan|access-date=2015-03-10 |archive-url=https://web.archive.org/web/20160304085158/http://www.frost.com/prod/servlet/market-insight-print.pag?docid=JEVS-5N2CZG |archive-date=2016-03-04}}

In 2008, scientists at the United States Department of Agriculture Agricultural Research Service (USDA ARS) described glyphosate as a "virtually ideal" herbicide.{{citation |first1=Stephen O. |last1=Duke |first2=Stephen B. |last2=Powles |name-list-style=vanc |date=2008 |url=http://naldc.nal.usda.gov/download/17918/PDF |format=PDF |title=Glyphosate: a once-in-a-century herbicide: Mini-review |journal=Pest Management Science|volume=64 |issue=4 |pages=319–25 |doi=10.1002/ps.1518 |pmid=18273882 |access-date=April 13, 2014 |archive-date=July 2, 2019 |archive-url=https://web.archive.org/web/20190702211642/https://naldc.nal.usda.gov/download/17918/PDF |url-status=dead |url-access=subscription }} In 2010 Powles stated: "glyphosate is a one in a 100-year discovery that is as important for reliable global food production as penicillin is for battling disease."{{cite journal | vauthors = Powles SB | title = Gene amplification delivers glyphosate-resistant weed evolution | journal =Proceedings of the National Academy of Sciences of the United States of America| volume = 107 | issue = 3 | pages = 955–56 | date = January 2010 | pmid = 20080659 | pmc = 2824278 | doi = 10.1073/pnas.0913433107| bibcode = 2010PNAS..107..955P | doi-access = free }}

As of April 2017, the Canadian government stated that glyphosate was "the most widely used herbicide in Canada", at which date the product labels were revised to ensure a limit of 20% POEA by weight.{{cite web|url=https://www.canada.ca/en/health-canada/services/consumer-product-safety/reports-publications/pesticides-pest-management/fact-sheets-other-resources/request-special-review-glyphosate-herbicides-containing-polyethoxylated-tallowamine/frequently-asked-questions.html|title=Frequently Asked Questions on the Re-evaluation of Glyphosate|publisher=Pest Management Regulatory Agency of Canada|date=28 Apr 2017|access-date=10 May 2018}}{{failed verification|date=October 2020}} Health Canada's Pest Management Regulatory Agency found no risk to humans or the environment at that 20% limit, and that all products registered in Canada at that time were at or below that limit.

File:Glyphosate Dissociation V.1.svg

Glyphosate is a derivative of aminophosphonic acid and the amino acid glycine. Both the phosphonic acid and carboxylic acid moieties can ionised (deprotonated) and the amine group can be protonated. Consequently the substance exists as a series of rapidly interchanging zwitterions. It was originally synthesized by the reaction of chloromethylphosphonate with glycine. Its name is a contraction of its constituents: glycine and a phosphonate.{{cite book|url = https://books.google.com/books?id=gbHeBwAAQBAJ&q=industrial+synthesis+glyphosate&pg=PA384|title = Survey of Industrial Chemistry|author = Chenier, Philip J.|page = 384|year = 2012|publisher = Springer Science+Business Media|edition = 3rd|isbn = 978-1461506034}}

:{{chem2|(HO)2P(O)CH2Cl + H2NCH2COOH → (HO)2P(O)CH2NHCH2COOH + HCl}}

The main degradation path for glyphosate is hydrolysis to aminomethylphosphonic acid.{{cite web | url = http://www.cdpr.ca.gov/docs/emon/pubs/fatememo/glyphos.pdf | title = Environmental Fate of Glyphosate | vauthors = Schuette J | publisher = Department of Pesticide Regulation, State of California | access-date = June 4, 2012 | archive-url = https://web.archive.org/web/20120420013222/http://www.cdpr.ca.gov/docs/emon/pubs/fatememo/glyphos.pdf | archive-date = April 20, 2012 | url-status = dead }}

Two main approaches are used to synthesize glyphosate industrially, both of which proceed via the Kabachnik–Fields reaction. The first is to react iminodiacetic acid and formaldehyde with phosphorous acid (sometimes formed in situ from phosphorus trichloride using the water generated by the Mannich reaction of the first two reagents). Decarboxylation of the hydrophosphonylation product gives the desired glyphosate product. Iminodiacetic acid is usually prepared on-site by various methods depending on reagent availability.

File:Glyphosate synthesis from iminodiacetic acid.svg approach to glyphosate synthesis]]

The second uses glycine in place of iminodiacetic acid. This avoids the need for decarboxylation but requires more careful control of stoichiometry, as the primary amine can react with any excess formaldehyde to form bishydroxymethylglycine, which must be hydrolysed during the work-up to give the desired product.

File:Glyphosate synthesis from dimethyl phosphite.svg

This synthetic approach is responsible for a substantial portion of the production of glyphosate in China, with considerable work having gone into recycling the triethylamine and methanol solvents. Progress has also been made in attempting to eliminate the need for triethylamine altogether.{{cite journal|title = Study on a New Synthesis Approach of Glyphosate | vauthors = Zhou J, Li J, An R, Yuan H, Yu F | journal = J. Agric. Food Chem.|year = 2012|volume = 60|issue = 25|pages = 6279–85|doi = 10.1021/jf301025p| pmid = 22676441 }}

Technical grade glyphosate is a white powder which, according to FAO specification, should contain not less than 95% glyphosate. Formaldehyde, classified as a known human carcinogen,

{{cite book |last1=International Agency for Research on Cancer |title=IARC Monographs on the Evaluation of Carcinogenic Risks to Humans Volume 88: Formaldehyde, 2-Butoxyethanol and 1-tert-Butoxypropan-2-ol. |date=2006 |publisher=IARC/WHO |location=Lyon |url=http://monographs.iarc.fr/ENG/Monographs/vol88/index.phpExit|isbn=978-9283212881 }}

{{cite book |last1=National Toxicology Program |title=Report on Carcinogens |date=June 2011 |publisher=Department of Health and Human Services, Public Health Service, National Toxicology Program |edition= 12th }}

and N-nitrosoglyphosate, have been identified as toxicologically relevant impurities.{{cite book |last1=FAO |title=FAO specifications and evaluations for agricultural pesticides: glyphosate |date=2014 |publisher=. Food and Agriculture Organization of the United Nations |page=5 |url=http://www.fao.org/fileadmin/templates/agphome/documents/Pests_Pesticides/Specs/Glypho_2014.pdf}} The FAO specification limits the formaldehyde concentration to a maximum of 1.3 g/kg glyphosate. N-Nitrosoglyphosate, "belonging to a group of impurities of particular concern as they can be activated to genotoxic carcinogens",{{cite journal |last1=European Food Safety Authority |title=Conclusion on the peer review of the pesticide risk assessment of the active substance glyphosate |journal= EFSA Journal|date=2015 |volume=13 |issue=11:4302 |page=10 |doi=10.2903/j.efsa.2015.4302 |doi-access=free }} should not exceed 1 ppm.

{{Main|Glyphosate-based herbicides}}

File:Roundup herbicide logo.jpg is the earliest formulation]]

Glyphosate is marketed in the United States and worldwide by many agrochemical companies in diverse strengths and with diverse adjuvants, under dozens of tradenames.Farm Chemicals International [http://www.farmchemicalsinternational.com/crop-protection-database/#//product/brief/203900 Glyphosate entry in Crop Protection Database]{{cite web | url = http://www.weeds.iastate.edu/mgmt/2001/glyphosate%20review.htm#Glyphosate%20Products | series = ISU Weed Science Online | title = Glyphosate: a Review | last1 = Hartzler | first1 = Bob | publisher =Iowa State University Extension| access-date = August 26, 2012 | archive-url = https://web.archive.org/web/20180518051215/http://www.weeds.iastate.edu/mgmt/2001/glyphosate%20review.htm#Glyphosate%20Products | archive-date = May 18, 2018 | url-status = dead }}{{cite web | url = http://www.invasive.org/gist/products/handbook/14.Glyphosate.pdf | title = Glyphosate | vauthors = Tu M, Hurd C, Robison R, Randall JM | date = November 1, 2001| work = Weed Control Methods Handbook | publisher = The Nature Conservancy }} As of 2010, more than 750 glyphosate products were on the market.National Pesticide Information Center. Last updated September 2010 [http://npic.orst.edu/factsheets/glyphogen.html Glyphosate General Fact Sheet] In 2012, about half of the total global consumption of glyphosate by volume was for agricultural crops, with forestry comprising another important market.[https://www.monsanto.ca/products/Documents/vision_label_en.pdf monsanto.ca: "Vision Silviculture Herbicide"] {{Webarchive|url=https://web.archive.org/web/20160407094242/http://www.monsanto.ca/products/Documents/vision_label_en.pdf |date=April 7, 2016 }}, 03-FEB-2011 Asia and the Pacific was the largest and fastest growing regional market.{{cite news|url=https://www.reuters.com/article/2014/04/30/research-and-markets-idUSnBw306202a+100+BSW20140430|title=Press Release: Research and Markets: Global Glyphosate Market for Genetically Modified and Conventional Crops 2013–2019|date=30 April 2014|work=Reuters|url-status=dead|archive-url=https://web.archive.org/web/20150924200327/https://www.reuters.com/article/2014/04/30/research-and-markets-idUSnBw306202a+100+BSW20140430|archive-date=September 24, 2015|df=mdy-all}} As of 2014, Chinese manufacturers collectively are the world's largest producers of glyphosate and its precursorsChina Research & Intelligence, June 5, 2013. [http://www.shcri.com/agricultural-chemicals/14-research-report-on-global-and-china-glyphosate-industry-2013-2017.html Research Report on Global and China Glyphosate Industry, 2013–2017] {{Webarchive|url=https://web.archive.org/web/20160303222042/http://www.shcri.com/agricultural-chemicals/14-research-report-on-global-and-china-glyphosate-industry-2013-2017.html |date=March 3, 2016 }} and account for about 30% of global exports. Key manufacturers include Anhui Huaxing Chemical Industry Company, BASF, Bayer CropScience (which also acquired the maker of glyphosate, Monsanto), Dow AgroSciences, DuPont, Jiangsu Good Harvest-Weien Agrochemical Company, Nantong Jiangshan Agrochemical & Chemicals Co., Nufarm, SinoHarvest, Syngenta, and Zhejiang Xinan Chemical Industrial Group Company.

Glyphosate is an acid molecule, so it is formulated as a salt for packaging and handling. Various salt formulations include isopropylamine, diammonium, monoammonium, or potassium as the counterion. The active ingredient of the Monsanto herbicides is the isopropylamine salt of glyphosate. Another important ingredient in some formulations is the surfactant polyethoxylated tallow amine (POEA). Some brands include more than one salt. Some companies report their product as acid equivalent (ae) of glyphosate acid, or some report it as active ingredient (ai) of glyphosate plus the salt, and others report both. Given that each salt has its own molecular weight, the acid equivalent is a more accurate method of expressing and comparing concentrations.

Adjuvant loading refers to the amount of adjuvant{{cite web | url = http://www.invasive.org/gist/products/handbook/14.Glyphosate.pdf | title = Glyphosate | vauthors = Tu M, Randall JM | date = 2003-06-01 | work = Weed Control Methods Handbook | publisher = The Nature Conservancy }}{{cite web | url = http://extension.psu.edu/pests/weeds/control/adjuvants-for-enhancing-herbicide-performance | title = Adjuvants for Enhancing Herbicide Performance | vauthors = Curran WS, McGlamery MD, Liebl RA, Lingenfelter DD | year = 1999 | publisher =Penn State Extension }} already added to the glyphosate product. Fully loaded products contain all the necessary adjuvants, including surfactant; some contain no adjuvant system, while other products contain only a limited amount of adjuvant (minimal or partial loading) and additional surfactants must be added to the spray tank before application.{{cite web | url = http://agdev.anr.udel.edu/weeklycropupdate/?p=96 | title = Glyphosate Formulations | vauthors = VanGessel M | work = Control Methods Handbook, Chapter 8, Adjuvants: Weekly Crop Update | publisher = University of Delaware Cooperative Extension | access-date = August 27, 2012 | archive-url = https://web.archive.org/web/20100613014135/http://agdev.anr.udel.edu/weeklycropupdate/?p=96 | archive-date = June 13, 2010 | url-status = dead }}

Products are supplied most commonly in formulations of 120, 240, 360, 480, and 680 g/L of active ingredient. The most common formulation in agriculture is 360 g/L, either alone or with added cationic surfactants.Alberta Agriculture and Rural Development. April 26, 2006. [http://www1.agric.gov.ab.ca/$department/deptdocs.nsf/all/faq8069 Quick Guide to Glyphosate Products – Frequently Asked Questions] {{Webarchive|url=https://web.archive.org/web/20170726123020/http://www1.agric.gov.ab.ca/$department/deptdocs.nsf/all/faq8069 |date=July 26, 2017 }}

For {{Convert|360|g/L}} formulations, European regulations allow applications of up to {{Convert|12|L/ha}} for control of perennial weeds such as couch grass. More commonly, rates of {{Convert|3|L/ha}} are practiced for control of annual weeds between crops.{{cite web|url=http://e-phy.agriculture.gouv.fr/|title=e-phy|website=e-phy.agriculture.gouv.fr}}

Glyphosate interferes with the shikimate pathway, which produces the aromatic amino acids phenylalanine, tyrosine and tryptophan in plants and microorganisms{{cite journal | vauthors = Funke T, Han H, Healy-Fried ML, Fischer M, Schönbrunn E | title = Molecular basis for the herbicide resistance of Roundup Ready crops | journal =Proceedings of the National Academy of Sciences of the United States of America| volume = 103 | issue = 35 | pages = 13010–15 | date = Aug 2006 | pmid = 16916934 | pmc = 1559744 | doi = 10.1073/pnas.0603638103 | bibcode = 2006PNAS..10313010F| jstor = 30050705 | doi-access = free }} – but does not exist in the genome of animals, including humans.{{cite journal | vauthors = Maeda H, Dudareva N | title = The shikimate pathway and aromatic amino Acid biosynthesis in plants | journal =Annual Review of Plant Biology| volume = 63 | pages = 73–105 | year = 2012 | issue = 1 | pmid = 22554242 | doi = 10.1146/annurev-arplant-042811-105439 | quote = The AAA pathways consist of the shikimate pathway (the prechorismate pathway) and individual postchorismate pathways leading to Trp, Phe, and Tyr.... These pathways are found in bacteria, fungi, plants, and some protists, but are absent in animals. Therefore, AAAs and some of their derivatives (vitamins) are essential nutrients in the human diet, although in animals Tyr can be synthesized from Phe by Phe hydroxylase....The absence of the AAA pathways in animals also makes these pathways attractive targets for antimicrobial agents and herbicides. }}{{cite journal | last=Casida | first=John E. | title=Organophosphorus Xenobiotic Toxicology | journal=Annual Review of Pharmacology and Toxicology | publisher=Annual Reviews | volume=57 | issue=1 | date=2017-01-06 | issn=0362-1642 | doi=10.1146/annurev-pharmtox-010716-104926 | pages=309–327| pmid=28061690 | doi-access=free }} It blocks this pathway by inhibiting the enzyme 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS), which catalyzes the reaction of shikimate-3-phosphate (S3P) and phosphoenolpyruvate to form 5-enolpyruvyl-shikimate-3-phosphate (EPSP).{{cite journal | vauthors = Steinrücken HC, Amrhein N | title = The herbicide glyphosate is a potent inhibitor of 5-enolpyruvyl-shikimic acid-3-phosphate synthase | journal =Biochemical and Biophysical Research Communications| volume = 94 | issue = 4 | pages = 1207–12 | date = Jun 1980 | pmid = 7396959 | doi = 10.1016/0006-291X(80)90547-1 }} Glyphosate is absorbed through foliage and minimally through roots, meaning that it is only effective on actively growing plants and cannot prevent seeds from germinating. After application, glyphosate is readily transported around the plant to growing roots and leaves and this systemic activity is important for its effectiveness. Inhibiting the enzyme causes shikimate to accumulate in plant tissues and diverts energy and resources away from other processes, eventually killing the plant. While growth stops within hours of application, it takes several days for the leaves to begin turning yellow.{{cite book | first1 = Bertold | last1 = Hock | first2 = Erich F. | last2 = Elstner | name-list-style = vanc | title = Plant Toxicology, Fourth Edition | url = https://books.google.com/books?id=pWqBJpWnK4EC&pg=PA292 | year= 2004 | publisher=CRC Press | isbn = 978-0-203-02388-4 | pages = 292–96 }} Glyphosate may chelate Co2+ which contributes to its mode of action.{{cite journal | last1=Shick | first1=J. Malcolm | last2=Dunlap | first2=Walter C. | title=Mycosporine-Like Amino Acids and Related Gadusols: Biosynthesis, Accumulation, and UV-Protective Functions in Aquatic Organisms | journal=Annual Review of Physiology | publisher=Annual Reviews | volume=64 | issue=1 | year=2002 | issn=0066-4278 | doi=10.1146/annurev.physiol.64.081501.155802 | pages=223–262| pmid=11826269 }}{{cite journal | last1=Kishore | first1=Ganesh M. | last2=Shah | first2=Dilip M. | title=Amino Acid Biosynthesis Inhibitors as Herbicides | journal=Annual Review of Biochemistry | publisher=Annual Reviews | volume=57 | issue=1 | year=1988 | issn=0066-4154 | doi=10.1146/annurev.bi.57.070188.003211 | pages=627–663| pmid=3052285 }}{{cite journal | last1=Bentley | first1=Ronald | last2=Haslam | first2=E. | title=The Shikimate Pathway — A Metabolic Tree with Many Branches | journal=Critical Reviews in Biochemistry and Molecular Biology | publisher=Taylor & Francis | volume=25 | issue=5 | year=1990 | issn=1040-9238 | doi=10.3109/10409239009090615 | pages=307–384 | pmid=2279393 | s2cid=1667907}}

File:EPSPreactionII.svg

Under normal circumstances, EPSP is dephosphorylated to chorismate, an essential precursor for the amino acids mentioned above.Purdue University, Department of Horticulture and Landscape Architecture, Metabolic Plant Physiology Lecture notes, [http://www.hort.purdue.edu/rhodcv/hort640c/aromat/ar00007.htm Aromatic amino acid biosynthesis, The shikimate pathway – synthesis of chorismate] {{Webarchive|url=https://web.archive.org/web/20071219165155/http://www.hort.purdue.edu/rhodcv/hort640c/aromat/ar00007.htm |date=December 19, 2007 }}. These amino acids are used in protein synthesis and to produce secondary metabolites such as folates, ubiquinones, and naphthoquinone.

X-ray crystallographic studies of glyphosate and EPSPS show that glyphosate functions by occupying the binding site of the phosphoenolpyruvate, mimicking an intermediate state of the ternary enzyme–substrate complex.{{cite journal | vauthors = Schönbrunn E, Eschenburg S, Shuttleworth WA, Schloss JV, Amrhein N, Evans JN, Kabsch W | title = Interaction of the herbicide glyphosate with its target enzyme 5-enolpyruvylshikimate 3-phosphate synthase in atomic detail | journal =Proceedings of the National Academy of Sciences of the United States of America| volume = 98 | issue = 4 | pages = 1376–80 | date = Feb 2001 | pmid = 11171958 | pmc = 29264 | doi = 10.1073/pnas.98.4.1376 | bibcode = 2001PNAS...98.1376S | doi-access = free }}[http://www.ebi.ac.uk/pdbe-srv/PDBeXplore/ligand/?ligand=GPJ Glyphosate bound to proteins] in the Protein Data Bank Glyphosate inhibits the EPSPS enzymes of diverse species of plants and microbes, although rates vary.{{cite journal | last1 = Schulz | first1 = A. | last2 = Krüper | first2 = A. | last3 = Amrhein | first3 = N. | name-list-style = vanc | year = 1985 | title = Differential sensitivity of bacterial 5-enolpyruvylshikimate-3-phosphate synthases to the herbicide glyphosate | journal =FEMS Microbiology Letters| volume = 28 | issue = 3| pages = 297–301 | doi=10.1111/j.1574-6968.1985.tb00809.x| doi-access = free }}{{cite journal | vauthors = Pollegioni L, Schonbrunn E, Siehl D | title = Molecular basis of glyphosate resistance-different approaches through protein engineering | journal = The FEBS Journal| volume = 278 | issue = 16 | pages = 2753–66 | date = Aug 2011 | pmid = 21668647 | pmc = 3145815 | doi = 10.1111/j.1742-4658.2011.08214.x }}

File:Glyphosate USA 2019.png

Glyphosate is effective in killing a wide variety of plants, including grasses and broadleaf and woody plants. By volume, it is one of the most widely used herbicides.{{cite web|url=http://npic.orst.edu/factsheets/glyphotech.html|publisher=National Pesticide Information Center|title=Glyphosate technical fact sheet (revised June 2015)|year=2010|access-date=September 1, 2015|archive-url=https://web.archive.org/web/20150828151524/http://npic.orst.edu/factsheets/glyphotech.html|archive-date=August 28, 2015|url-status=bot: unknown}} In 2007, glyphosate was the most used herbicide in the United States agricultural sector, with 180 to 185 million pounds ({{convert|180000000|to|185000000|lb|t|abbr=off|disp=output only}}) applied, the second-most used in home and garden with 5 to 8 million pounds ({{convert|5000000|to|8000000|lb|t|abbr=off|disp=output only}}) and 13 to 15 million pounds ({{convert|13000000|to|15000000|lb|t|abbr=off|disp=output only}}) in non-agricultural settings. It is commonly used for agriculture, horticulture, viticulture, and silviculture purposes, as well as garden maintenance (including home use). It has a relatively small effect on some clover species and morning glory.{{cite web | first1 = Stevan Z. | last1 = Knezevic | name-list-style = vanc | publisher =University of Nebraska Extension Integrated Weed Management Specialist | date = February 2010 | url = http://elkhorn.unl.edu/epublic/live/g1484/build/ | archive-url = https://archive.today/20100615033810/http://elkhorn.unl.edu/epublic/live/g1484/build/ | archive-date=June 15, 2010| url-status = dead | title = Use of Herbicide-Tolerant Crops as Part of an Integrated Weed Management Program}}

File:Roundup-in-apple-orchard.jpg

Glyphosate and related herbicides are often used in invasive species eradication and habitat restoration, especially to enhance native plant establishment in prairie ecosystems. The controlled application is usually combined with a selective herbicide and traditional methods of weed eradication such as mulching to achieve an optimal effect.{{ cite journal | first1 = Priscilla A. | last1 = Nyamai | first2 = Timothy S. | last2 = Prather | first3 =John M. | last3 = Wallace | name-list-style = vanc | year = 2011 | title = Evaluating Restoration Methods across a Range of Plant Communities Dominated by Invasive Annual Grasses to Native Perennial Grasses | journal =Invasive Plant Science and Management| volume = 4 | issue = 3 | pages = 306–16 | doi = 10.1614/IPSM-D-09-00048.1 | s2cid = 84696972 }}

In many cities, glyphosate is sprayed along the sidewalks and streets, as well as crevices in between pavement where weeds often grow. However, up to 24% of glyphosate applied to hard surfaces can be run off by water.{{cite journal |vauthors=Luijendijk CD, Beltman WH, Smidt RA, van der Pas LJ, Kempenaar C | url = http://www.wageningenur.nl/upload_mm/f/d/9/042e8dca-ba43-4687-99f0-fa082db417f1_Nota_353_totaal.pdf | title = Measures to reduce glyphosate runoff from hard surfaces | journal =Plant Research International B.V.| location = Wageningen | date = May 2005}} Glyphosate contamination of surface water is attributed to urban and agricultural use.{{cite journal | vauthors = Botta F, Lavison G, Couturier G, Alliot F, Moreau-Guigon E, Fauchon N, Guery B, Chevreuil M, Blanchoud H | title = Transfer of glyphosate and its degradate AMPA to surface waters through urban sewerage systems | journal =Chemosphere| volume = 77 | issue = 1 | pages = 133–39 | date = Sep 2009 | pmid = 19482331 | doi = 10.1016/j.chemosphere.2009.05.008 | bibcode = 2009Chmsp..77..133B }} Glyphosate is used to clear railroad tracks and get rid of unwanted aquatic vegetation. Since 1994, glyphosate has been used in aerial spraying in Colombia in coca eradication programs; Colombia announced in May 2015 that by October, it would cease using glyphosate in these programs due to concerns about human toxicity of the chemical.BBC. May 10, 2015. [https://www.bbc.com/news/world-latin-america-32677411 Colombia to ban coca spraying herbicide glyphosate]

Glyphosate is also used for crop desiccation to increase harvest yield and uniformity.{{cite web | url = https://monsanto.com/app/uploads/2017/06/agronomic-benefits-of-glyphosate-in-europe.pdf | title = The agronomic benefits of glyphosate in Europe | publisher = Monsanto Europe SA | date = February 2010 | access-date = 2013-06-02 | archive-date = September 4, 2017 | archive-url = https://web.archive.org/web/20170904155703/https://monsanto.com/app/uploads/2017/06/agronomic-benefits-of-glyphosate-in-europe.pdf | url-status = dead }} Glyphosate itself is not a chemical desiccant; rather crop desiccants are so named because application just before harvest kills the crop plants so that the food crop dries from normal environmental conditions ("dry-down") more quickly and evenly.{{cite web |last1=MacLean |first1=Amy-Jean |title=Desiccant vs. Glyphosate: know your goals |url=https://www.portageonline.com/ag/desiccant-vs-glyphosate-know-your-goals |website=PortageOnline.com |publisher=Golden West|access-date=19 August 2016 |archive-url=https://web.archive.org/web/20190731205820/https://www.portageonline.com/ag/desiccant-vs-glyphosate-know-your-goals |archive-date=31 July 2019 |language=en}}{{refn|In agriculture, the term desiccant is applied to an agent that promotes dry down. "True desiccants" are not chemical desiccants either, rather the distinction is whether an agent is a contact herbicide such as Diquat and sodium chlorate that rapidly kill the above-ground portion of the plant as it dries out over a few days,{{cite web |title=Crop Desiccation |url=https://saifood.ca/crop-desiccation/ |website=Sustainable Agricultural Innovations & Food |publisher=University of Saskatchewan|access-date=31 July 2019 |archive-url=https://web.archive.org/web/20190731214944/https://saifood.ca/crop-desiccation/ |archive-date=31 July 2019 |language=en-CA |date=25 October 2016}} or an agent such as glyphosate that is absorbed systemically and translocated to the root, a process that can take days to weeks.}} Because glyphosate is systemic, excess residue levels can persist in plants due to incorrect application and this may render the crop unfit for sale.{{cite web|last1=Sprague|first1=Christy|title=Preharvest herbicide applications are an important part of direct-harvest dry bean production| url=http://msue.anr.msu.edu/news/preharvest_herbicide_applications_are_an_important_part_of_direct_harvest_d|website=Michigan State University|date=August 20, 2015 |publisher=Michigan State University Extension, Department of Plant, Soil and Microbial Sciences|access-date=20 August 2015}} When applied appropriately, it can promote useful effects. In sugarcane, for example, glyphosate application increases sucrose concentration before harvest.{{cite web |last1=Gravois |first1=Kenneth |title=Sugarcane Ripener Recommendations |url=https://www.lsuagcenter.com/topics/crops/sugarcane/harvesting_and_processing/sugarcane-ripener-recommendations--glyphosate |website=LSU AgCenter|publisher=Louisiana State University, College of Agriculture |archive-url=https://web.archive.org/web/20180920175015/https://www.lsuagcenter.com/topics/crops/sugarcane/harvesting_and_processing/sugarcane-ripener-recommendations--glyphosate |archive-date=20 September 2018 |date=14 August 2017}} In grain crops (wheat, barley, oats), uniformly dried crops do not have to be windrowed (swathed and dried) prior to harvest, but can easily be straight-cut and harvested. This saves the farmer time and money, which is important in northern regions where the growing season is short, and it enhances grain storage when the grain has a lower and more uniform moisture content.{{cite web |title=Pre-harvest Management of Small Grains |url=https://blog-crop-news.extension.umn.edu/2017/07/pre-harvest-management-of-small-grains.html |website=Minnesota Crop News |publisher=University of Minnesota Extension|archive-url=https://web.archive.org/web/20190527142012/https://blog-crop-news.extension.umn.edu/2017/07/pre-harvest-management-of-small-grains.html |archive-date=27 May 2019 |language=en |date=18 July 2017}}{{cite web |last1=Fowler |first1=D.B. |title=Harvesting, Grain Drying and Storage – Chapter 23 |url=https://www.usask.ca/agriculture/plantsci/winter_cereals/winter-wheat-production-manual/chapter-23.php |website=Winter Wheat Production Manual |publisher=University of Saskatchewan|archive-url=https://web.archive.org/web/20181209105427/https://www.usask.ca/agriculture/plantsci/winter_cereals/winter-wheat-production-manual/chapter-23.php |archive-date=9 December 2018|language=en|access-date=2017-05-03}}

{{Main|Genetically modified crops|Genetically modified organism|Genetically modified food|Genetically modified food controversies}}

Some micro-organisms have a version of 5-enolpyruvoyl-shikimate-3-phosphate synthetase (EPSPS) resistant to glyphosate inhibition. A version of the enzyme that was both resistant to glyphosate and that was still efficient enough to drive adequate plant growth was identified by Monsanto scientists after much trial and error in an Agrobacterium strain called CP4, which was found surviving in a waste-fed column at a glyphosate production facility.{{cite journal | vauthors = Green JM, Owen MD | title = Herbicide-resistant crops: utilities and limitations for herbicide-resistant weed management | journal =Journal of Agricultural and Food Chemistry| volume = 59 | issue = 11 | pages = 5819–29 | date = Jun 2011 | pmid = 20586458 | pmc = 3105486 | doi = 10.1021/jf101286h }}{{cite book | vauthors = Rashid A | title = Introduction to Genetic Engineering of Crop Plants: Aims and Achievements | year = 2009 | publisher = I K International | isbn = 978-93-80026-16-9 | pages = 259 }}{{rp|56}} This CP4 EPSPS gene was cloned and transfected into soybeans. In 1996, genetically modified soybeans were made commercially available.{{cite web | url = https://monsanto.com/company/history/ | title = Company History | work = Web Site | publisher = Monsanto Company | access-date = June 27, 2017 | archive-date = November 5, 2018 | archive-url = https://web.archive.org/web/20181105125639/https://monsanto.com/company/history/ | url-status = dead }} Current glyphosate-resistant crops include soy, maize (corn), canola, alfalfa, sugar beets, and cotton, with wheat still under development.

In 2023, 91% of corn, 95% of soybeans, and 94% of cotton produced in the United States were from strains that were genetically modified to be tolerant to multiple herbicides, including dicamba, glufosinate, and glyphosate.{{cite web|title=Adoption of Genetically Engineered Crops in the U.S.|url=http://www.ers.usda.gov/data-products/adoption-of-genetically-engineered-crops-in-the-us/recent-trends-in-ge-adoption.aspx|website=Economic Research Service|publisher=USDA|access-date =26 March 2024}}

File:Landscape company Oklahoma.jpg company in Oklahoma applying a weed control product that contains glyphosate]]

Glyphosate has four ionizable sites, with pKa values of 2.0, 2.6, 5.6 and 10.6.P. Sprankle, W. F. Meggitt, D. Penner: Adsorption, mobility, and microbial degradation of glyphosate in the soil. In: Weed Sci. 23(3), p. 229–234, as cited in [https://www.inchem.org/documents/ehc/ehc/ehc159.htm Environmental Health Criteria 159]. Therefore, it is a zwitterion in aqueous solutions and is expected to exist almost entirely in zwitterionic forms in the environment. Zwitterions generally adsorb more strongly to soils containing organic carbon and clay than their neutral counterparts.{{cite web |title = PubChem Compound Summary for CID 3496, Glyphosate | publisher = National Center for Biotechnology Information | access-date = June 16, 2022 | url = https://pubchem.ncbi.nlm.nih.gov/compound/Glyphosate}} Glyphosate strongly sorbs onto soil minerals, and, with the exception of colloid-facilitated transport, its soluble residues are expected to be poorly mobile in the free porewater of soils. The spatial extent of ground and surface water pollution is therefore considered to be relatively limited. Glyphosate is readily degraded by soil microbes to aminomethylphosphonic acid (AMPA, which like glyphosate strongly adsorbs to soil solids and is thus unlikely to leach to groundwater). Though both glyphosate and AMPA are commonly detected in water bodies, a portion of the AMPA detected may actually be the result of degradation of detergents and other aminophosphonates rather than degradation of glyphosate.{{cite journal | vauthors = Botta F, Lavisonb G, Couturier G, Alliot F, Moreau-Guigon E, Fauchon N, Guery B, Chevreuil M, Blanchoud H | year = 2009 | title = Transfer of glyphosate and its degradate AMPA to surface waters through urban sewerage systems | journal = Chemosphere | volume = 77 | issue = 1| pages = 133–139 | doi=10.1016/j.chemosphere.2009.05.008 | pmid=19482331| bibcode = 2009Chmsp..77..133B}} The proportion of AMPA from non-glyphosate sources is claimed to be higher in Europe compared to USA.{{cite journal | last=Schwientek | first=M. | last2=Rügner | first2=H. | last3=Haderlein | first3=S.B. | last4=Schulz | first4=W. | last5=Wimmer | first5=B. | last6=Engelbart | first6=L. | last7=Bieger | first7=S. | last8=Huhn | first8=C. | title=Glyphosate contamination in European rivers not from herbicide application? | journal=Water Research | volume=263 | date=2024 | doi=10.1016/j.watres.2024.122140 | page=122140}} Glyphosate does have the potential to contaminate surface waters due to its aquatic use patterns and through erosion, as it adsorbs to colloidal soil particles suspended in runoff. Detection in surface waters (particularly downstream from agricultural uses) has been reported as both broad and frequent by the United States Geological Survey (USGS) researchers,{{cite journal |last1=Battaglin |first1=W.A. |last2=Meyer |first2=M.T. |last3=Kuivila |first3=K.M. |last4=Dietze |first4=J.E. |title=Glyphosate and Its Degradation Product AMPA Occur Frequently and Widely in U.S. Soils, Surface Water, Groundwater, and Precipitation |journal=JAWRA Journal of the American Water Resources Association |date=April 2014 |volume=50 |issue=2 |pages=275–90 |doi=10.1111/jawr.12159|bibcode=2014JAWRA..50..275B |s2cid=15865832 }} although other similar research found equal frequencies of detection in urban-dominated small streams.{{cite journal |last1=Mahler |first1=Barbara J. |last2=Van Metre |first2=Peter C. |last3=Burley |first3=Thomas E. |last4=Loftin |first4=Keith A. |last5=Meyer |first5=Michael T. |last6=Nowell |first6=Lisa H. |title=Similarities and differences in occurrence and temporal fluctuations in glyphosate and atrazine in small Midwestern streams (USA) during the 2013 growing season |journal=Science of the Total Environment |date=February 2017 |volume=579 |pages=149–58 |doi=10.1016/j.scitotenv.2016.10.236|pmid=27863869 |bibcode=2017ScTEn.579..149M |doi-access=free }} Rain events can trigger dissolved glyphosate loss in transport-prone soils.{{cite journal |last1=Richards |first1=Brian K. |last2=Pacenka |first2=Steven |last3=Meyer |first3=Michael T. |last4=Dietze |first4=Julie E. |last5=Schatz |first5=Anna L. |last6=Teuffer |first6=Karin |last7=Aristilde |first7=Ludmilla |last8=Steenhuis |first8=Tammo S. |title=Antecedent and Post-Application Rain Events Trigger Glyphosate Transport from Runoff-Prone Soils |journal=Environmental Science & Technology Letters |date=23 April 2018 |volume=5 |issue=5 |pages=249–54 |doi=10.1021/acs.estlett.8b00085|bibcode=2018EnSTL...5..249R }} The mechanism of glyphosate sorption to soil is similar to that of phosphate fertilizers, the presence of which can reduce glyphosate sorption.{{cite journal | vauthors = Muniraa S, Farenhorsta A, Flatena D, Grant C | year = 2016 | title = Phosphate fertilizer impacts on glyphosate sorption by soil | journal = Chemosphere | volume = 153 | pages = 471–77 | doi=10.1016/j.chemosphere.2016.03.028| pmid = 27035384 | bibcode = 2016Chmsp.153..471M| hdl = 1993/31877 | hdl-access = free }} Phosphate fertilizers are subject to release from sediments into water bodies under anaerobic conditions, and similar release can also occur with glyphosate, though significant impact of glyphosate release from sediments has not been established.{{cite journal | vauthors = Kanissery RG, Welsh A, Sims GK | s2cid = 31227173 | year = 2014 | title = Effect of soil aeration and phosphate addition on the microbial bioavailability of 14C-glyphosate | journal = Journal of Environmental Quality| volume = 44 | issue = 1| pages = 137–44 | doi = 10.2134/jeq2014.08.0331 | pmid = 25602328 }} Limited leaching can occur after high rainfall after application. If glyphosate reaches surface water, it is not broken down readily by water or sunlight.{{cite journal | vauthors = Borggaard OK, Gimsing AL | title = Fate of glyphosate in soil and the possibility of leaching to ground and surface waters: a review | journal = Pest Management Science | volume = 64 | issue = 4 | pages = 441–56 | date = Apr 2008 | doi = 10.1002/ps.1512 | pmid = 18161065 | doi-access = free }}

The half-life of glyphosate in soil ranges between 2 and 197 days; a typical field half-life of 47 days has been suggested. Soil and climate conditions affect glyphosate's persistence in soil. The median half-life of glyphosate in water varies from a few to 91 days. At a site in Texas, half-life was as little as three days. A site in Iowa had a half-life of 141.9 days. The glyphosate metabolite AMPA has been found in Swedish forest soils up to two years after a glyphosate application. In this case, the persistence of AMPA was attributed to the soil being frozen for most of the year.{{cite journal | vauthors = Torstensson NT, Lundgren LN, Stenström J | title = Influence of climatic and edaphic factors on persistence of glyphosate and 2,4-D in forest soils | journal = Ecotoxicology and Environmental Safety | volume = 18 | issue = 2 | pages = 230–39 | date = Oct 1989 | pmid = 2806176 | doi = 10.1016/0147-6513(89)90084-5 | bibcode = 1989EcoES..18..230T }} Glyphosate adsorption to soil, and later release from soil, varies depending on the kind of soil.{{cite journal | vauthors = Albers CN, Banta GT, Hansen PE, Jacobsen OS | title = The influence of organic matter on sorption and fate of glyphosate in soil—comparing soils and humic substances | journal = Environmental Pollution | volume = 157 | issue = 10 | pages = 2865–70 | date = Oct 2009 | pmid = 19447533 | doi = 10.1016/j.envpol.2009.04.004 | bibcode = 2009EPoll.157.2865A }}{{cite journal | url = http://www.academyjournal.net/asj/index.php/TSPN/article/viewArticle/193 | title = Does phosphate affect soil sorption and degradation of glyphosate? – A review | vauthors = Ole K, Borggaard OK | journal = Trends in Soil Science and Plant Nutrition | volume = 2 | issue = 1 | year = 2011 | pages = 17–27 }}{{Dead link|date=December 2019 |bot=InternetArchiveBot |fix-attempted=yes }} Glyphosate is generally less persistent in water than in soil, with 12- to 60-day persistence observed in Canadian ponds, although persistence of over a year has been recorded in the sediments of American ponds. The half-life of glyphosate in water is between 12 days and 10 weeks.{{cite journal | vauthors = Sparling DW, Matson C, Bickham J, Doelling-Brown P | year = 2006 | title = Toxicity of glyphosate as Glypro® and LI700 to red-eared slider (Trachemys scripta elegans) embryos and early hatchlings | journal = Environmental Toxicology and Chemistry | volume = 25 | issue = 10 | pages = 2768–74 | doi = 10.1897/05-152.1 | pmid = 17022419 | s2cid = 12954689 }}

According to the National Pesticide Information Center fact sheet, glyphosate is not included in compounds tested for by the Food and Drug Administration's Pesticide Residue Monitoring Program, nor in the United States Department of Agriculture's Pesticide Data Program. The U.S. has determined the acceptable daily intake of glyphosate at 1.75 milligrams per kilogram of body weight per day (mg/kg/bw/day) while the European Union has set it at 0.5.{{cite web | last = European Commission| date = 2017 | url = http://ec.europa.eu/food/plant/pesticides/eu-pesticides-database/public/?event=activesubstance.detail&language=EN&selectedID=1438 | title = EU Pesticides database: Glyphosate| access-date = 29 August 2018}}

Pesticide residue controls carried out by EU Member States in 2016 analysed 6,761 samples of food products for glyphosate residues. 3.6% of the samples contained quantifiable glyphosate residue levels with 19 samples (0.28%) exceeding the European maximum residue levels (MRLs), which included six samples of honey and other apicultural products (MRL = 0.05 mg/kg) and eleven samples of buckwheat and other pseudo‐cereals (MRL = 0.1 mg/kg). Glyphosate residues below the European MRLs were most frequently found in dry lentils, linseeds, soya beans, dry peas, tea, buckwheat, barley, wheat and rye.{{cite journal |last1=European Food Safety Authority |title=The 2016 European Union report on pesticide residues in food |journal= EFSA Journal|date=July 2018 |volume=16 |issue=7 |page=67 |doi=10.2903/j.efsa.2018.5348 |pmid=32625983 |pmc=7009629 |doi-access=free }} In Canada, a survey of 7,955 samples of food found that 42.3% contained detectable quantities of glyphosate and only 0.6% contained a level higher than the Canadian MRL of 0.1 mg/kg for most foods and 4 mg/kg for beans and chickpeas. Of the products that exceeded MRLs, one third were organic products. Health Canada concluded based on the analysis "that there was no long-term health risk to Canadian consumers from exposure to the levels of glyphosate".{{cite journal |last1=Kolakowski |first1=Beata M. |last2=Miller |first2=Leigh |last3=Murray |first3=Angela |last4=Leclair |first4=Andrea |last5=Bietlot |first5=Henri |last6=van de Riet |first6=Jeffrey M. |title=Analysis of Glyphosate Residues in Foods from the Canadian Retail Markets between 2015 and 2017 |journal=Journal of Agricultural and Food Chemistry |date=6 May 2020 |volume=68 |issue=18 |pages=5201–5211 |doi=10.1021/acs.jafc.9b07819|pmid=32267686 |doi-access=free }}

Glyphosate is the active ingredient in herbicide formulations containing it. However, in addition to glyphosate salts, commercial formulations of glyphosate contain additives (known as adjuvants) such as surfactants, which vary in nature and concentration. Surfactants such as polyethoxylated tallow amine (POEA) are added to glyphosate to enable it to wet the leaves and penetrate the cuticle of the plants.

The acute oral toxicity for mammals is low,{{cite journal | vauthors = Van Bruggen AC, He MM, Shin K, Mai V, Jeong KC, Finckh MR, Morris JG | title = Environmental and health effects of the herbicide glyphosate | journal = Sci. Total Environ. | volume = 616–17 | pages = 255–68 | date = March 2018 | pmid = 29117584 | doi = 10.1016/j.scitotenv.2017.10.309 | bibcode = 2018ScTEn.616..255V }} but death has been reported after deliberate overdose of concentrated formulations.{{cite journal |vauthors= Sribanditmongkol P, Jutavijittum P, Pongraveevongsa P, Wunnapuk K, Durongkadech P |title= Pathological and toxicological findings in glyphosate-surfactant herbicide fatality: a case report |journal= The American Journal of Forensic Medicine and Pathology |volume= 33 |issue=3 |pages= 234–37 |date= Sep 2012 |doi= 10.1097/PAF.0b013e31824b936c |pmid= 22835958 |s2cid= 3457850 }} The surfactants in glyphosate formulations can increase the relative acute toxicity of the formulation.{{cite journal |vauthors= Bradberry SM, Proudfoot AT, Vale JA |s2cid= 5636017 |title= Glyphosate poisoning |journal = Toxicological Reviews |volume= 23 |issue=3 |pages= 159–67 |year= 2004 |pmid= 15862083 |doi= 10.2165/00139709-200423030-00003}}{{Citation| title = Glyphosate: Human Health and Ecological Risk Assessment | publisher= Syracuse Environmental Research Associates, Inc.(SERA) |access-date = 2018-08-20| url = https://www.fs.fed.us/r5/hfqlg/publications/herbicide_info/2003_glyphosate.pdf}} Glyphosate is less toxic than 94% of herbicides, and is also less toxic than household chemicals such as table salt or vinegar.{{cite web |last1=Wallace |first1=John |last2=Lingenfelter |first2=Dwight |title=Glyphosate (Roundup): Understanding Risks to Human Health |url=https://extension.psu.edu/glyphosate-roundup-understanding-risks-to-human-health |website=extension.psu.edu |publisher=Pennsylvania State University Extension |access-date=12 July 2024 |language=en}}

In a 2017 risk assessment, the European Chemicals Agency (ECHA) wrote: "There is very limited information on skin irritation in humans. Where skin irritation has been reported, it is unclear whether it is related to glyphosate or co-formulants in glyphosate-containing herbicide formulations." The ECHA concluded that available human data was insufficient to support classification for skin corrosion or irritation.{{Cite web|url=https://echa.europa.eu/documents/10162/2f8b5c7f-030f-5d3a-e87e-0262fb392f38|title=Committee of Risk Assessment Opinion proposing harmonised classification and labelling at EU level of glyphosate (ISO); N-(phosphonomethyl)glycine}} Inhalation is a minor route of exposure, but spray mist may cause oral or nasal discomfort, an unpleasant taste in the mouth, or tingling and irritation in the throat. Eye exposure may lead to mild conjunctivitis. Superficial corneal injury is possible if irrigation is delayed or inadequate.

The consensus among national pesticide regulatory agencies and scientific organizations is that labeled uses of glyphosate have demonstrated no evidence of human carcinogenicity. The Joint FAO/WHO Meeting on Pesticide Residues (JMPR),{{cite book |last1=Boobis |first1=Alan R. |title=Pesticide residues in food 2016, Joint FAO/WHO Meeting on Pesticide Residues, 9–13 May 2016 |date=2016 |publisher=WHO/FAO |location=Rome |isbn=978-92-5-109246-0 |pages=19–28 |url=https://www.who.int/foodsafety/areas_work/chemical-risks/JMPR_2016_Report_May.pdf}} the European Commission, the Canadian Pest Management Regulatory Agency, the Australian Pesticides and Veterinary Medicines Authority{{Cite book| publisher = SAGE Publications, Inc.| isbn = 978-1-4129-6987-1| last1 = Guston| first1 = David| last2 = Ludlow| first2 = Karinne| title = Encyclopedia of Nanoscience and Society| chapter = Australian Pesticides and Veterinary Medicines Authority| location = Thousand Oaks, CA| date = 2010| chapter-url = http://sk.sagepub.com/reference/nanoscience/n22.xml}} and the German Federal Institute for Risk Assessment{{Cite web| title = The BfR has finalised its draft report for the re-evaluation of glyphosate – BfR| access-date = 2018-08-18| url = https://www.bfr.bund.de/en/the_bfr_has_finalised_its_draft_report_for_the_re_evaluation_of_glyphosate-188632.html}} have concluded that there is no evidence that glyphosate poses a carcinogenic or genotoxic risk to humans. The United States Environmental Protection Agency (EPA) has classified glyphosate as "not likely to be carcinogenic to humans."{{Cite web| last = US EPA| first = OCSPP| title = EPA Releases Draft Risk Assessments for Glyphosate| work = US EPA| format = Announcements and Schedules| access-date = 2018-08-18| date = 2017-12-18| url = https://www.epa.gov/pesticides/epa-releases-draft-risk-assessments-glyphosate}}{{cite book |last1=Cancer Assessment Review Committee, HED, Office of Pesticides Program, US EPA |title=Evaluation of the Carcinogenic potential of Glyphosate, Final Report |date=October 1, 2015 |publisher=US EPA |location=Washington |pages=77–78 |url=http://src.bna.com/eAi}} One international scientific organization, the International Agency for Research on Cancer, classified glyphosate in Group 2A, "probably carcinogenic to humans" in 2015.

{{As of|2020}}, the evidence for long-term exposure to glyphosate increasing the risk of human cancer remains inconclusive.{{cite journal|vauthors = Agostini LP, Dettogni RS, Dos Reis RS, Stur E, Dos Santos E, Ventorim DP, Garcia FM, Cardoso RC, Graceli JB, Louro ID|title= Effects of glyphosate exposure on human health: Insights from epidemiological and in vitro studies|url=https://pubmed.ncbi.nlm.nih.gov/31972943/|journal=Sci Total Environ|volume=705|page=135808|date=2020|doi= 10.1016/j.scitotenv.2019.135808|pmid= 31972943|bibcode= 2020ScTEn.70535808A|s2cid= 210883035}} There is weak evidence human cancer risk might increase as a result of occupational exposure to large amounts of glyphosate, such as in agricultural work, but no good evidence of such a risk from home use, such as in domestic gardening.{{cite web |publisher=Cancer Research UK| title=Food Controversies – Pesticides and organic foods|url=http://www.cancerresearchuk.org/about-cancer/causes-of-cancer/diet-and-cancer/food-controversies#food_controversies4 |date=2016 |access-date=28 November 2017}}{{cite journal|vauthors=Donato F, Pira E, Ciocan C, Boffetta P|title=Exposure to glyphosate and risk of non-Hodgkin lymphoma and multiple myeloma: an updated meta-analysis|journal=Med Lav|volume=111|pages=63–73|date=2020|issue=1|pmid=32096774|pmc=7809965}}

Although some small studies have suggested an association between glyphosate and non-hodgkin lymphoma, subsequent work confirmed the likelihood this work suffered from bias, and the association could not be demonstrated in more robust studies.{{cite journal |vauthors=Boffetta P, Ciocan C, Zunarelli C, Pira E |title=Exposure to glyphosate and risk of non-Hodgkin lymphoma: an updated meta-analysis |journal=Med Lav |volume=112 |issue=3 |pages=194–199 |date=June 2021 |pmid=34142676 |pmc=8223940 |doi=10.23749/mdl.v112i3.11123 |type=Meta-analysis}}{{cite journal |vauthors=Álvarez F, Arena M, Auteri D, Binaglia M, Castoldi AF, Chiusolo A, Crivellente F, Egsmose M, Fait G, Ferilli F, Gouliarmou V, Nogareda LH, Ippolito A, Istace F, Jarrah S, Kardassi D, Kienzler A, Lanzoni A, Lava R, Linguadoca A, Lythgo C, Mangas I, Padovani L, Panzarea M, Parra Morte JM, Rizzuto S, Romac A, Rortais A, Serafimova R, Sharp R, Szentes C, Terron A, Theobald A, Tiramani M, Vianello G, Villamar-Bouza L |title=Peer review of the pesticide risk assessment of the active substance glyphosate |journal=EFSA J |volume=21 |issue=7 |pages=e08164 |date=July 2023 |pmid=37502013 |pmc=10369247 |doi=10.2903/j.efsa.2023.8164 |type=Review |display-authors=5}}{{Cite web |date=2023-08-25 |orig-date= |title=Peer Review Report on Glyphosate (AIR V) Part 3 of 6: Report of Pesticide Peer Review TC 80 |url=https://open.efsa.europa.eu/study-inventory/EFSA-Q-2020-00140 |archive-format= |access-date=2023-11-16 |pages=59–78 |language=en |publication-place=EFSA|quote= The available epidemiological studies currently do not provide sufficient indication that glyphosate exposure is associated with any cancer-related health effect.}}

Amongst mammals, glyphosate is considered to have "low to very low toxicity". The LD₅₀ of glyphosate is 5,000 mg/kg for rats, 10,000 mg/kg in mice and 3,530 mg/kg in goats. The acute dermal LD₅₀ in rabbits is greater than 2,000 mg/kg. Indications of glyphosate toxicity in animals typically appear within 30 to 120 minutes following ingestion of a large enough dose, and include initial excitability and tachycardia, ataxia, depression, and bradycardia, although severe toxicity can develop into collapse and convulsions.

A review of unpublished short-term rabbit-feeding studies reported severe toxicity effects at 150 mg/kg/day and "no observed adverse effect level" doses ranging from 50 to 200 mg/kg/day.{{cite journal | vauthors = Kimmel GL, Kimmel CA, Williams AL, DeSesso JM | title = Evaluation of developmental toxicity studies of glyphosate with attention to cardiovascular development | journal = Critical Reviews in Toxicology | volume = 43 | issue = 2 | pages = 79–95 | year = 2013 | pmid = 23286529 | pmc = 3581053 | doi = 10.3109/10408444.2012.749834 }} Glyphosate can have carcinogenic effects in nonhuman mammals. These include the induction of positive trends in the incidence of renal tubule carcinoma and haemangiosarcoma in male mice, and increased pancreatic islet-cell adenoma in male rats. In reproductive toxicity studies performed in rats and rabbits, no adverse maternal or offspring effects were seen at doses below 175–293 mg/kg/day.

Large quantities of glyphosate-based herbicides may cause life-threatening arrhythmias in mammals. Evidence also shows that such herbicides cause direct electrophysiological changes in the cardiovascular systems of rats and rabbits.{{cite journal | vauthors = Gress S, Lemoine S, Séralini GE, Puddu PE | s2cid = 17936407 | title = Glyphosate-based herbicides potently affect cardiovascular system in mammals: review of the literature | journal = Cardiovascular Toxicology | volume = 15 | issue = 2 | pages = 117–26 | date = April 2015 | pmid = 25245870 | doi = 10.1007/s12012-014-9282-y }}

In many freshwater invertebrates, glyphosate has a 48-hour LC₅₀ ranging from 55 to 780 ppm. The 96-hour LC₅₀ is 281 ppm for grass shrimp (Palaemonetas vulgaris) and 934 ppm for fiddler crabs (Uca pagilator). These values make glyphosate "slightly toxic to practically non-toxic".

The antimicrobial activity of glyphosate has been described in the microbiology literature since its discovery in 1970 and the description of glyphosate's mechanism of action in 1972. Efficacy was described for numerous bacteria and fungi.Abraham William Wildwood. [http://www.patentbuddy.com/Patent/7771736 Glyphosate formulations and their use for inhibition of 5-enolpyrovylshikimate-3-phosphate synthase], US Patent 7, 771, 736 B2; 2010 Glyphosate can control the growth of apicomplexan parasites, such as Toxoplasma gondii, Plasmodium falciparum (malaria), and Cryptosporidium parvum, and has been considered an antimicrobial agent in mammals.{{cite journal | vauthors = Roberts CW, Roberts F, Lyons RE, Kirisits MJ, Mui EJ, Finnerty J, Johnson JJ, Ferguson DJ, Coggins JR, Krell T, Coombs GH, Milhous WK, Kyle DE, Tzipori S, Barnwell J, Dame JB, Carlton J, McLeod R | title = The shikimate pathway and its branches in apicomplexan parasites | journal = The Journal of Infectious Diseases | volume = 185 | issue = Suppl 1 | pages = S25–36 | date = Feb 2002 | pmid = 11865437 | doi = 10.1086/338004 | doi-access = free }} Inhibition can occur with some Rhizobium species important for soybean nitrogen fixation, especially under moisture stress.{{cite journal | vauthors = Zablotowicz RM, Reddy KN | title = Impact of glyphosate on the Bradyrhizobium japonicum symbiosis with glyphosate-resistant transgenic soybean: a minireview | journal = Journal of Environmental Quality | volume = 33 | issue = 3 | pages = 825–31 | year = 2004 | pmid = 15224916 | doi = 10.2134/jeq2004.0825 | bibcode = 2004JEnvQ..33..825Z }}

File:Glyphosate degradation.svg

When glyphosate comes into contact with the soil, it can be bound to soil particles, thereby slowing its degradation.{{cite journal | title = Influence of repeated applications of glyphosate on its persistence and soil bioactivity | year = 2003 | vauthors = Andréa MM, Peres TB, Luchini LC, Bazarin S, Papini S, Matallo MB, Savoy VL | journal = Pesquisa Agropecuária Brasileira | volume = 38 | issue = 11 | pages = 1329–35 | doi = 10.1590/S0100-204X2003001100012 | doi-access = free }} Glyphosate and its degradation product, aminomethylphosphonic acid are considered to be much more benign toxicologically and environmentally than most of the herbicides replaced by glyphosate.{{cite journal | vauthors = Cerdeira AL, Duke SO | title = Effects of glyphosate-resistant crop cultivation on soil and water quality | journal = GM Crops | volume = 1 | issue = 1 | pages = 16–24 | date = January 2010 | pmid = 21912208 | doi = 10.4161/gmcr.1.1.9404 | s2cid = 38119904 | url = http://ainfo.cnptia.embrapa.br/digital/bitstream/item/47350/1/2010AP03-2.pdf }} A 2016 meta-analysis concluded that at typical application rates glyphosate had no effect on soil microbial biomass or respiration.{{cite journal | last1 = Nguyen | first1 = Duy B. | last2 = Rose | first2 = Michael T. | last3 = Rose | first3 = Terry J. | last4 = Morris | first4 = Stephen G. | last5 = van Zwieten | first5 = Lukas | name-list-style = vanc | title = Impact of glyphosate on soil microbial biomass and respiration: A meta-analysis | journal = Soil Biology and Biochemistry | volume = 92 | year = 2016| pages = 50–57 | issn = 0038-0717 | doi = 10.1016/j.soilbio.2015.09.014 | bibcode = 2016SBiBi..92...50N }} Some species of earthworms are affected, some are not. Some avoid treated soil.{{cite book |last1=Rose|first1=Michael T. |last2=Cavagnaro |first2=Timothy R. |last3=Scanlan |first3=Craig A. |last4=Rose |first4=Terry J.|last5=Vancov |first5=Tony |last6=Kimber |first6=Stephen |last7=Kennedy |first7=Ivan R. |last8=Kookana |first8=Rai S. |last9=Van Zwieten |first9=Lukas |series=Advances in Agronomy | name-list-style = vanc |title=Impact of Herbicides on Soil Biology and Function |volume=136 |year=2016 |pages=168 |doi=10.1016/bs.agron.2015.11.005 |hdl=2440/110451 |isbn=978-0128046814}}

In 2007, the EPA selected glyphosate for further screening through its Endocrine Disruptor Screening Program (EDSP). Selection for this program is based on a compound's prevalence of use and does not imply particular suspicion of endocrine activity.{{cite journal | author = United States Environmental Protection Agency | journal = Federal Register | volume = 72 | issue = 116 | pages = 33486–503 | date = 18 June 2007 | title = Draft List of Initial Pesticide Active Ingredients and Pesticide Inerts to be Considered for Screening under the Federal Food, Drug, and Cosmetic Act | url = http://www.epa.gov/endo/pubs/draft_list_frn_061807.pdf }} On June 29, 2015, the EPA released the Weight of Evidence Conclusions of the EDSP Tier 1 screening for glyphosate, recommending that glyphosate not be considered for Tier 2 testing. The Weight of Evidence conclusion stated "...there was no convincing evidence of potential interaction with the estrogen, androgen or thyroid pathways."{{cite web |author= United States Environmental Protection Agency |title= Memorandum: EDSP Weight of Evidence Conclusions on the Tier 1 Screening Assays for the List 1 Chemicals |url= http://www2.epa.gov/sites/production/files/2015-06/documents/glyphosate-417300_2015-06-29_txr0057175.pdf |archive-url= https://web.archive.org/web/20160116111524/http://www.epa.gov/sites/production/files/2015-06/documents/glyphosate-417300_2015-06-29_txr0057175.pdf |archive-date= 16 January 2016 |date= 29 June 2015 }} A review of the evidence by the European Food Safety Authority published in September 2017 showed conclusions similar to those of the EPA report.{{cite journal |title=Peer review of the pesticide risk assessment of the potential endocrine disrupting properties of glyphosate |journal= EFSA Journal|date=September 2017 |volume=15 |issue=9 |doi=10.2903/j.efsa.2017.4979|pmid= 32625644|doi-access=free |author1= European Food Safety Authority |pages= e04979|pmc= 7010201}}

Some studies have found causal relationships between glyphosate and increased or decreased disease resistance.{{cite book |doi=10.1007/978-1-4020-5799-1_15 |chapter=Interactions of Synthetic Herbicides with Plant Disease and Microbial Herbicides |title=Novel Biotechnologies for Biocontrol Agent Enhancement and Management |series=NATO Security through Science Series |year=2007 | vauthors = Duke SO, Wedge DE, Cerdeira AL, Matallo MB | isbn = 978-1-4020-5797-7 | pages = 277–96 |publisher=Springer |location=Dordrecht | editor1-first = Maurizio | editor1-last = Vurro | editor2-first = Jonathan | editor2-last = Gressel }} Exposure to glyphosate has been shown to change the species composition of endophytic bacteria in plant hosts, which is highly variable.{{cite journal | vauthors = Rosenblueth M, Martínez-Romero E | title = Bacterial endophytes and their interactions with hosts | journal = Molecular Plant-Microbe Interactions | volume = 19 | issue = 8 | pages = 827–37 | date = Aug 2006 | pmid = 16903349 | doi = 10.1094/MPMI-19-0827 | doi-access = free }}

Glyphosate-based formulations may contain a number of adjuvants, the identities of which may be proprietary.{{cite web |url=http://www2.epa.gov/pesticide-registration/pesticide-registration-manual |title=Pesticide Registration Manual | Pesticide Registration | US EPA |date=March 4, 2013 |access-date=March 7, 2014 |archive-date=April 14, 2016 |archive-url=https://web.archive.org/web/20160414065403/https://www.epa.gov/pesticide-registration/pesticide-registration-manual |url-status=dead }} Surfactants are used in herbicide formulations as wetting agents, to maximize coverage and aid penetration of the herbicide(s) through plant leaves. As agricultural spray adjuvants, surfactants may be pre-mixed into commercial formulations or they may be purchased separately and mixed on-site.{{cite web |title=Adjuvants for Enhancing Herbicide Performance |url=https://extension.psu.edu/adjuvants-for-enhancing-herbicide-performance |website=extension.psu.edu |publisher=Penn State Extension |access-date=15 August 2018 |language=en}}

Polyethoxylated tallow amine (POEA) is a surfactant used in the original Roundup formulation and was commonly used in 2015.{{cite web|title=Measuring POEA, a Surfactant Mixture in Herbicide Formulations|url=http://toxics.usgs.gov/highlights/glyphosate_poea.html|publisher=U.S. Geological Survey|access-date=May 29, 2015|archive-date=October 7, 2015|archive-url=https://web.archive.org/web/20151007051906/http://toxics.usgs.gov/highlights/glyphosate_poea.html|url-status=dead}} The percentage of POEA varies. A 1997 US government report said that Roundup is 15% POEA while Roundup Pro is 14.5%. Since POEA is more toxic to fish and amphibians than glyphosate alone, POEA is not allowed in aquatic formulations.Gary L. Diamond and Patrick R. Durkin February 6, 1997, under contract from the United States Department of Agriculture. [http://www.fs.fed.us/foresthealth/pesticide/pdfs/Surfactants.pdf Effects of Surfactants on the Toxicity of Glyphosate, with Specific Reference to RODEO] As of 2000, at least 58 studies existed on the effects of Roundup on a range of organisms.{{cite book |doi=10.1007/978-1-4612-1156-3_2 |year=2000 | vauthors = Giesy JP, Dobson S, Solomon KR |chapter=Ecotoxicological Risk Assessment for Roundup® Herbicide | isbn = 978-0-387-95102-7 | volume = 167 | pages = 35–120 | chapter-url = https://books.google.com/books?id=7iTdm5ii4NYC&pg=PA35|title=Reviews of Environmental Contamination and Toxicology |publisher=Springer |location=New York, NY }} This review concluded that "...for terrestrial uses of Roundup minimal acute and chronic risk was predicted for potentially exposed non-target organisms".{{cite web |title=Ecotoxicological Risk Assessment for Roundup Herbicide |url=https://www.usask.ca/toxicology/jgiesy/pdf/publications/JA-228.pdf |access-date=May 9, 2019 |archive-date=August 7, 2019 |archive-url=https://web.archive.org/web/20190807140955/https://www.usask.ca/toxicology/jgiesy/pdf/publications/JA-228.pdf |url-status=dead }}

Overall, there is no conclusive evidence on glyphosate's effect on human health.{{cite journal |vauthors=Gillezeau C, van Gerwen M, Shaffer RM, Rana I, Zhang L, Sheppard L, Taioli E |title=The evidence of human exposure to glyphosate: a review |journal=Environ Health |volume=18 |issue=1 |pages=2 |date=January 2019 |pmid=30612564 |pmc=6322310 |doi=10.1186/s12940-018-0435-5 |bibcode=2019EnvHe..18....2G |type=Review |doi-access=free }}{{cite journal |vauthors=Peillex C, Pelletier M |title=The impact and toxicity of glyphosate and glyphosate-based herbicides on health and immunity |journal=J Immunotoxicol |volume=17 |issue=1 |pages=163–174 |date=December 2020 |pmid=32897110 |doi=10.1080/1547691X.2020.1804492 |s2cid=221541734 |url=|doi-access=free |hdl=20.500.11794/66510 |hdl-access=free }}

Acute toxicity and chronic toxicity are dose-related. Skin exposure to ready-to-use concentrated glyphosate formulations can cause irritation, and photocontact dermatitis has been occasionally reported. These effects are probably due to the preservative benzisothiazolin-3-one. Severe skin burns are very rare. Inhalation is a minor route of exposure, but spray mist may cause oral or nasal discomfort, an unpleasant taste in the mouth, or tingling and irritation in the throat. Eye exposure may lead to mild conjunctivitis. Superficial corneal injury is possible if irrigation is delayed or inadequate. Death has been reported after deliberate overdose. Ingestion of Roundup ranging from 85 to 200 ml (of 41% solution) has resulted in death within hours of ingestion, although it has also been ingested in quantities as large as 500 ml with only mild or moderate symptoms.{{cite journal | vauthors = Talbot AR, Shiaw MH, Huang JS, Yang SF, Goo TS, Wang SH, Chen CL, Sanford TR | s2cid = 8028945 | title = Acute poisoning with a glyphosate-surfactant herbicide ('Roundup'): a review of 93 cases | journal = Human & Experimental Toxicology | volume = 10 | issue = 1 | pages = 1–8 | date = January 1991 | pmid = 1673618 | doi = 10.1177/096032719101000101 | bibcode = 1991HETox..10....1T }} Adult consumption of more than 85 ml of concentrated product can lead to corrosive esophageal burns and kidney or liver damage. More severe cases cause "respiratory distress, impaired consciousness, pulmonary edema, infiltration on chest X-ray, shock, arrhythmias, renal failure requiring haemodialysis, metabolic acidosis, and hyperkalaemia" and death is often preceded by bradycardia and ventricular arrhythmias. While the surfactants in formulations generally do not increase the toxicity of glyphosate itself, it is likely that they contribute to its acute toxicity.

Glyphosate products for aquatic use generally do not use surfactants, and aquatic formulations do not use POEA due to aquatic organism toxicity.{{cite web |title=SS-AGR-104 Safe Use of Glyphosate-Containing Products in Aquatic and Upland Natural Areas |url=https://edis.ifas.ufl.edu/pdffiles/AG/AG24800.pdf |publisher=University of Florida |access-date=13 August 2018 |archive-date=March 8, 2021 |archive-url=https://web.archive.org/web/20210308112508/https://edis.ifas.ufl.edu/pdffiles/AG/AG24800.pdf |url-status=dead }} Due to the presence of POEA, such glyphosate formulations only allowed for terrestrial use are more toxic for amphibians and fish than glyphosate alone.{{cite journal|vauthors=Mann RM, Hyne RV, Choung CB, Wilson SP|title=Amphibians and agricultural chemicals: Review of the risks in a complex environment|journal=Environmental Pollution|year=2009|volume=157|issue=11|pages=2903–27|doi=10.1016/j.envpol.2009.05.015|pmid=19500891|bibcode=2009EPoll.157.2903M |url=http://hdl.cqu.edu.au/10018/35613}}{{Dead link|date=December 2023 |bot=InternetArchiveBot |fix-attempted=yes }} The half-life of POEA (21–42 days) is longer than that for glyphosate (7–14 days) in aquatic environments.{{cite journal | vauthors = Mesnage R, Defarge N, Spiroux de Vendômois J, Séralini GE | title = Potential toxic effects of glyphosate and its commercial formulations below regulatory limits | journal = Food Chem. Toxicol. | volume = 84 | pages = 133–53 | year = 2015 | pmid = 26282372 | doi = 10.1016/j.fct.2015.08.012 | s2cid = 12725778 | author-link4 = Gilles-Éric Séralini | url = https://kclpure.kcl.ac.uk/portal/en/publications/potential-toxic-effects-of-glyphosate-and-its-commercial-formulations-below-regulatory-limits(e185bac2-4db2-4568-b1d2-f258ed2fe7f3).html }} Aquatic organism exposure risk to terrestrial formulations with POEA is limited to drift or temporary water pockets where concentrations would be much lower than label rates.

Some researchers have suggested the toxicity effects of pesticides on amphibians may differ from those of other aquatic fauna because of their lifestyle; amphibians may be more susceptible to the toxic effects of pesticides because they often prefer to breed in shallow, lentic, or ephemeral pools. These habitats do not necessarily constitute formal water-bodies and can contain higher concentrations of pesticide compared to larger water-bodies.{{cite journal | vauthors= Govindarajulu PP | year = 2008 | title = Literature Review of Impacts of Glyphosate Herbicide on Amphibians: What Risks can the Silvicultural Use of this Herbicide Pose for Amphibians in BC?|publisher=British Columbia, Ecosystems Branch, Ministry of Environment| citeseerx = 10.1.1.314.3577 }} Studies in a variety of amphibians have shown the toxicity of GBFs containing POEA to amphibian larvae. These effects include interference with gill morphology and mortality from either the loss of osmotic stability or asphyxiation. At sub-lethal concentrations, exposure to POEA or glyphosate/POEA formulations have been associated with delayed development, accelerated development, reduced size at metamorphosis, developmental malformations of the tail, mouth, eye and head, histological indications of intersex and symptoms of oxidative stress. Glyphosate-based formulations can cause oxidative stress in bullfrog tadpoles.

A 2003 study of various formulations of glyphosate found, "[the] risk assessments based on estimated and measured concentrations of glyphosate that would result from its use for the control of undesirable plants in wetlands and over-water situations showed that the risk to aquatic organisms is negligible or small at application rates less than 4 kg/ha and only slightly greater at application rates of 8 kg/ha."{{cite journal | vauthors = Solomon KR, Thompson DG | title = Ecological risk assessment for aquatic organisms from over-water uses of glyphosate | journal = Journal of Toxicology and Environmental Health, Part B | volume = 6 | issue = 3 | pages = 289–324 | year = 2003 | pmid = 12746143 | doi = 10.1080/10937400306468 | bibcode = 2003JTEHB...6..289S | s2cid = 42770586 }}

A 2013 meta-analysis reviewed the available data related to potential impacts of glyphosate-based herbicides on amphibians. According to the authors, the use of glyphosate-based pesticides cannot be considered the major cause of amphibian decline, the bulk of which occurred prior to the widespread use of glyphosate or in pristine tropical areas with minimal glyphosate exposure. The authors recommended further study of per-species and per-development-stage chronic toxicity, of environmental glyphosate levels, and ongoing analysis of data relevant to determining what if any role glyphosate might be playing in worldwide amphibian decline, and suggest including amphibians in standardized test batteries.{{cite journal | vauthors = Wagner N, Reichenbecher W, Teichmann H, Tappeser B, Lötters S | title = Questions concerning the potential impact of glyphosate-based herbicides on amphibians | journal = Environmental Toxicology and Chemistry | volume = 32 | issue = 8 | pages = 1688–700 | date = Aug 2013 | pmid = 23637092 | doi = 10.1002/etc.2268 | s2cid = 36417341 }}

Several studies have not found mutagenic effects,ToxNet. [http://toxnet.nlm.nih.gov/cgi-bin/sis/search/a?dbs+hsdb:@term+@DOCNO+3432 Glyposate]. National Library of Medicine. so glyphosate has not been listed in the United States Environmental Protection Agency or the International Agency for Research on Cancer databases.{{Citation needed|date=December 2019|reason=removed citation to predatory publisher content}} Various other studies suggest glyphosate may be mutagenic.{{Citation needed|date=December 2019|reason=removed citation to predatory publisher content}} The IARC monograph noted that glyphosate-based formulations can cause DNA strand breaks in various taxa of animals in vitro.

A 2013 systematic review by the German Institute for Risk Assessment (BfR) examined more than 1000{{cite web|url=http://www.bfr.bund.de/en/press_information/2014/03/glyphosate__no_more_poisonous_than_previously_assumed__although_a_critical_view_should_be_taken_of_certain_co_formulants-188898.html|title=Glyphosate: no more poisonous than previously assumed, although a critical view should be taken of certain co-formulants – BfR|website=Bfr.bund.de}} epidemiological studies, animal studies, and in vitro studies. It found that "no classification and labelling for carcinogenicity is warranted" and did not recommend a carcinogen classification of either 1A or 1B.{{rp|34–37, 139}} It provided the review to EFSA in January 2014 which published it in December 2014.Renewal Assessment Report: Glyphosate. Volume 1. Report and Proposed Decision. December 18, 2013. German Institute for Risk Assessment, page 65. Downloaded from http://dar.efsa.europa.eu/dar-web/provision {{Webarchive|url=https://web.archive.org/web/20090130105523/http://dar.efsa.europa.eu/dar-web/provision |date=January 30, 2009 }} (registration required){{cite web | url=https://www.scribd.com/doc/238082730/Glyphosate-RAR-01-Volume-1-2013-12-18-San#scribd | title=Glyphosate RAR 01 Volume 1 2013-12-18 San | publisher=Hungry4Pesticides | work=Renewal Assessment Report | date=18 December 2013 | access-date=27 March 2015}}{{cite web|archive-url=https://web.archive.org/web/20151014145339/http://www.bfr.bund.de/cm/349/frequently-asked-questions-on-the-health-assessment-of-glyphosate.pdf|archive-date=October 14, 2015|publisher=Bundesinstitut für Risikobewertung|date=15 January 2014|url=http://www.bfr.bund.de/cm/349/frequently-asked-questions-on-the-health-assessment-of-glyphosate.pdf|title=Frequently asked questions on the health assessment of glyphosate|url-status=dead|df=mdy-all}}

In November 2015, EFSA published its conclusion in the Renewal Assessment Report (RAR), stating it was "unlikely to pose a carcinogenic hazard to humans".{{cite journal | year = 2015 | title = Conclusion on the peer review of the pesticide risk assessment of the active substance glyphosate | journal = EFSA Journal| volume = 13 | issue = 11| page = 4302 | doi = 10.2903/j.efsa.2015.4302 | doi-access = free | author1 = European Food Safety Authority (EFSA) }} The EU was largely informed by this report when it made its decision on the use of glyphosate in November 2017.{{cite news|last1=Nelson|first1=Arthur|title=EU report on weedkiller safety copied text from Monsanto study|url=https://www.theguardian.com/environment/2017/sep/15/eu-report-on-weedkiller-safety-copied-text-from-monsanto-study|newspaper=The Guardian|access-date=September 30, 2017|date=September 14, 2017}}

EFSA's decision and the BfR report were criticized in an open letter published by 96 scientists in November 2015 saying that the BfR report failed to adhere to accepted scientific principles of open and transparent procedures.{{cite news |url=http://www.dw.com/en/independent-scientists-warn-over-monsanto-herbicide/a-18886833 | title=Independent scientists warn over Monsanto herbicide| publisher=DW| date=December 1, 2015| access-date=December 9, 2015}}{{cite letter |recipient=Vytenis Andriukaitis | url = http://db.zs-intern.de/uploads/1448884347-151127_Portier_et_al_EFSA-Glyphosate-Letter.pdf | last = Portier | first = Christopher J. | display-authors=et al | subject=Open letter: Review of the Carcinogenicity of Glyphosate by EFSA and BfR | date = November 27, 2015 | access-date = December 9, 2015 }} The BfR report included unpublished data, lacked authorship, omitted references, and did not disclose conflict-of-interest information.

In July 2023, EFSA re-evaluated after three years of assessment the putative impact of glyphosate on the health of humans, animals and the environment. As a result, no critical areas of concern were identified that would otherwise prevent glyphosate's registration renewal in the EU.{{cite journal |last1=Alvarez |first1=Frenando |last2=Arena |first2=Maria |display-authors=1|title=Peer review of the pesticide risk assessment of the active substance glyphosate |journal=EFSA Journal |date=July 2023 |volume=7 |issue=21 |pages=e08164 |doi=10.2903/j.efsa.2023.8164|pmid=37502013 |pmc=10369247 }}{{Cite web |date=2023-07-06 |title=Glyphosate: no critical areas of concern; data gaps identified {{!}} EFSA |url=https://www.efsa.europa.eu/en/news/glyphosate-no-critical-areas-concern-data-gaps-identified |access-date=2023-07-06 |website=www.efsa.europa.eu |language=en}}{{cite web | title=Supporting documents for EFSA-Q-2020-00140 | website=Open EFSA | url=https://open.efsa.europa.eu/study-inventory/EFSA-Q-2020-00140 | access-date=25 August 2023}}

In March 2015, the International Agency for Research on Cancer (IARC), an intergovernmental agency forming part of the World Health Organization of the United Nations, published a summary of their forthcoming monograph on glyphosate, and classified glyphosate as "probably carcinogenic in humans" (category 2A) based on epidemiological studies, animal studies, and in vitro studies. It noted that there was "limited evidence" of carcinogenicity in humans for non-Hodgkin lymphoma.{{cite web | title = Press release: IARC Monographs Volume 112: evaluation of five organophosphate insecticides and herbicides | date = March 20, 2015 | url = http://www.iarc.fr/en/media-centre/iarcnews/pdf/MonographVolume112.pdf | publisher = International Agency for Research on Cancer, World Health Organization}}{{cite web | first1 = Michael | last1 = Specter | name-list-style = vanc | work = New Yorker | date = 10 April 2015 | url = http://www.newyorker.com/news/daily-comment/roundup-and-risk-assessment | title = Roundup and Risk Assessment | quote = 'Probable' means that there was enough evidence to say it is more than possible, but not enough evidence to say it is a carcinogen," Aaron Blair, a lead researcher on the IARC's study, said. Blair, a scientist emeritus at the National Cancer Institute, has studied the effects of pesticides for years. "It means you ought to be a little concerned about" glyphosate, he said.}} The IARC classifies substances for their carcinogenic potential, and "a few positive findings can be enough to declare a hazard, even if there are negative studies, as well." Unlike the BfR, it does not conduct a risk assessment, weighing benefits against risk.{{cite web | url = https://www.nytimes.com/2015/03/28/business/energy-environment/decades-after-monsantos-roundup-gets-an-all-clear-a-cancer-agency-raises-concerns.html | title = Weed Killer, Long Cleared, Is Doubted | first = Andrew | last = Pollack | name-list-style = vanc | date = 27 March 2015 | work = New York Times}}

The BfR responded that IARC reviewed only a selection of what they{{who|date=October 2020}} had reviewed earlier, and argued that other studies, including a cohort study called Agricultural Health Study, do not support the classification.{{cite web | url = http://www.bfr.bund.de/cm/343/loest-glyphosat-krebs-aus.pdf | title = Löst Glyphosat Krebs aus? (announcement 007/2015)|date=23 March 2015|publisher=German Institute for Risk Assessment | language = de}} The IARC report did not include unpublished studies, including one completed by the IARC panel leader.{{Cite news|url=https://www.motherjones.com/environment/2017/06/monsanto-roundup-glyphosate-cancer-who/|title=A scientist didn't disclose important data – and let everyone believe a popular weedkiller causes cancer | last = Butler | first = Kiera | name-list-style = vanc |date=June 15, 2017|work=Mother Jones|access-date=2017-06-19|language=en-US}} The agency's international protocol dictates that only published studies be used in classifications of carcinogenicity,{{cite web | url = http://monographs.iarc.fr/ENG/Preamble/index.php | title = Preamble to the IARC Monographs | year = 2006 | publisher =International Agency for Research on Cancer}} since national regulatory agencies including the EPA have allowed agrochemical corporations to conduct their own unpublished research, which may be biased in support of their profit motives.{{cite web | first1 = Sharon | last1 = Lerner| name-list-style = vanc | url = https://theintercept.com/2015/11/03/epa-used-monsanto-funded-research/| title = EPA used Monsanto's Research to Give Roundup A Pass | date=3 November 2015 | website=The Intercept|language=en-US}}

A 2017 review done by personnel from EFSA and BfR argued that the differences between the IARC's and EFSA's conclusions regarding glyphosate and cancer were due to differences in their evaluation of the available evidence. The review concluded that "Two complementary exposure assessments ... suggests that actual exposure levels are below" the reference values identified by the EFSA "and do not represent a public concern."

In contrast, a 2016 analysis by Christopher Portier, a scientist advising the IARC in the assessment of glyphosate and advocate for its classification as possibly carcinogenic, concluded that in the EFSA's Renewal Assessment Report, "almost no weight is given to studies from the published literature and there is an over-reliance on non-publicly available industry-provided studies using a limited set of assays that define the minimum data necessary for the marketing of a pesticide", arguing that the IARC's evaluation of probably carcinogenic to humans "accurately reflects the results of published scientific literature on glyphosate".{{cite journal | vauthors = Portier CJ, Armstrong BK, Baguley BC, Baur X, Belyaev I, Bellé R, Belpoggi F, Biggeri A, Bosland MC, Bruzzi P, Budnik LT, Bugge MD, Burns K, Calaf GM, Carpenter DO, Carpenter HM, López-Carrillo L, Clapp R, Cocco P, Consonni D, Comba P, Craft E, Dalvie MA, Davis D, Demers PA, De Roos AJ, DeWitt J, Forastiere F, Freedman JH, Fritschi L, Gaus C, Gohlke JM, Goldberg M, Greiser E, Hansen J, Hardell L, Hauptmann M, Huang W, Huff J, James MO, Jameson CW, Kortenkamp A, Kopp-Schneider A, Kromhout H, Larramendy ML, Landrigan PJ, Lash LH, Leszczynski D, Lynch CF, Magnani C, Mandrioli D, Martin FL, Merler E, Michelozzi P, Miligi L, Miller AB, Mirabelli D, Mirer FE, Naidoo S, Perry MJ, Petronio MG, Pirastu R, Portier RJ, Ramos KS, Robertson LW, Rodriguez T, Röösli M, Ross MK, Roy D, Rusyn I, Saldiva P, Sass J, Savolainen K, Scheepers PT, Sergi C, Silbergeld EK, Smith MT, Stewart BW, Sutton P, Tateo F, Terracini B, Thielmann HW, Thomas DB, Vainio H, Vena JE, Vineis P, Weiderpass E, Weisenburger DD, Woodruff TJ, Yorifuji T, Yu IJ, Zambon P, Zeeb H, Zhou SF | display-authors = 1 | title = Differences in the carcinogenic evaluation of glyphosate between the International Agency for Research on Cancer (IARC) and the European Food Safety Authority (EFSA) | journal = Journal of Epidemiology and Community Health | volume = 70 | issue = 8 | pages = 741–45 | date = August 2016 | pmid = 26941213 | pmc = 4975799 | doi = 10.1136/jech-2015-207005 }}

In October 2017, an article in The Times revealed that Portier had received consulting contracts with two law firm associations representing alleged glyphosate cancer victims that included a payment of US$160,000 to Portier.{{Cite news|url=https://www.faz.net/1.5248763|title=Herbizid: Der dramatische Kampf um die Deutungshoheit von Glyphosat|last=Grossarth|first=Jan|work=FAZ.NET|access-date=2019-01-06|language=de|issn=0174-4909}}{{Cite news|url=https://www.thetimes.com/uk/law/article/weedkiller-scientist-was-paid-120-000-by-cancer-lawyers-v0qggbrk6|title=Weedkiller scientist was paid £120,000 by cancer lawyers|last=Webster|first=Ben |date=2017-10-18|work=The Times|access-date=2019-01-06|language=en|issn=0140-0460}} The IARC final report was also found to have changed compared to an interim report, through the removal of text saying certain studies had found glyphosate was not carcinogenic in that study's context, and through strengthening a conclusion of "limited evidence of animal carcinogenicity," to "sufficient evidence of animal carcinogenicity".{{Cite news|url=https://www.reuters.com/investigates/special-report/who-iarc-glyphosate/|title=Glyphosate: WHO cancer agency edited out|last=Kelland|first=Kate|website=Reuters|language=en|access-date=2019-01-06}}

In a 1993 review, the EPA, considered glyphosate to be noncarcinogenic and relatively low in dermal and oral acute toxicity.{{cite web | url = https://www3.epa.gov/pesticides/chem_search/reg_actions/reregistration/fs_PC-417300_1-Sep-93.pdf | title = Registration Decision Fact Sheet for Glyphosate (EPA-738-F-93-011) | year = 1993 | work = R.E.D. FACTS | publisher = United States Environmental Protection Agency }} The EPA considered a "worst case" dietary risk model of an individual eating a lifetime of food derived entirely from glyphosate-sprayed fields with residues at their maximum levels. This model indicated that no adverse health effects would be expected under such conditions. In 2015, the EPA initiated a review of glyphosate's toxicity and in 2016 reported that glyphosate is likely not carcinogenic.{{cite journal | first1 = Daniel | last1 = Cressey | name-list-style = vanc | url = http://www.nature.com/news/widely-used-herbicide-linked-to-cancer-1.17181 | title = Widely used herbicide linked to cancer | journal = Nature | date = March 25, 2015 | doi = 10.1038/nature.2015.17181 | s2cid = 131732731 | doi-access = free }}{{cite news |last=Charles|first=Dan | name-list-style = vanc |date=17 September 2016|title=EPA Weighs In On Glyphosate, Says It Doesn't Cause Cancer|url=https://www.npr.org/sections/thesalt/2016/09/17/494301343/epa-weighs-in-on-glyphosate-says-it-doesnt-cause-cancer|newspaper=NPR|access-date=19 September 2016}} In August 2019, the EPA announced that it no longer allowed labels claiming glyphosate is a carcinogen, as those claims would "not meet the labeling requirements of the Federal Insecticide, Fungicide, and Rodenticide Act" and misinform the public.{{cite web |title=EPA Takes Action to Provide Accurate Risk Information to Consumers, Stop False Labeling on Products |url=https://www.epa.gov/newsreleases/epa-takes-action-provide-accurate-risk-information-consumers-stop-false-labeling |publisher=US EPA |access-date=28 October 2019 |language=en |date=8 August 2019}}

In 2017, evidence collected in a lawsuit brought against Monsanto by cancer patients revealed company emails which appeared to show a friendly relationship with a senior EPA official.{{cite web |last1=Charles |first1=Dan |title=Emails Reveal Monsanto's Tactics To Defend Glyphosate Against Cancer Fears |url=https://www.npr.org/sections/thesalt/2017/03/15/520250505/emails-reveal-monsantos-tactics-to-defend-glyphosate-against-cancer-fears |website=NPR |date=March 15, 2017 |access-date=May 14, 2019}}

Monsanto called the IARC report biased and said it wanted the report to be retracted.{{cite web|url=https://www.reuters.com/article/us-monsanto-herbicide-idUSKBN0MK2GF20150324#TWrEqcrkJiYtdXgJ.97|title=Monsanto seeks retraction for report linking herbicide to cancer|last1=Gillam|first1=Carey|date=24 March 2015|work=Reuters|name-list-style=vanc}} In 2017, internal documents from Monsanto were made public by lawyers pursuing litigation against the company,{{Cite web|url=http://baumhedlundlaw.com/pdf/monsanto-documents/72-Document-Details-Monsantos-Goals-After-IARC-Report.pdf|title=Glyphosate: IARC (Monsanto shared document)|date=February 23, 2015|website=Baum Hedlund Law|access-date=2018-06-03}} who used the term "Monsanto papers" to describe the documents.{{cite web|url=https://www.baumhedlundlaw.com/toxic-tort-law/monsanto-roundup-lawsuit/monsanto-secret-documents/|title=Monsanto Papers: Secret Documents|publisher=Baum, Hedlund, Aristei & Goldman, PC|access-date=2019-10-31}} This term was later used also by Leemon McHenry{{Cite journal|last=McHenry|first=Leemon B.|date=2018|title=The Monsanto Papers: Poisoning the scientific well|journal=International Journal of Risk & Safety in Medicine|url=https://content.iospress.com/articles/international-journal-of-risk-and-safety-in-medicine/jrs180028|volume=29|issue=3–4|pages=193–205|doi=10.3233/JRS-180028|issn=1878-6847|pmid=29843257|s2cid=44179710 |url-access=subscription}} and others.{{Cite web|url=https://www.industrydocuments.ucsf.edu/chemical/collections/roundup-litigation-documents/|title=Chemical Industry Documents Library|language=en-US|access-date=2019-11-02}} The documents indicated Monsanto had planned a public relations effort to discredit the IARC report, and had engaged Henry Miller to write a 2015 opinion piece in Forbes Magazine challenging the report. Miller did not reveal the connection to Forbes, and according to the New York Times, when Monsanto asked him if he was interested in writing such an article, he replied "I would be if I could start from a high-quality draft" provided by the company.{{Cite news|url=https://www.nytimes.com/2017/08/01/business/monsantos-sway-over-research-is-seen-in-disclosed-emails.html|title=Monsanto Emails Raise Issue of Influencing Research on Roundup Weed Killer|last=Hakim|first=Danny|date=2017-08-01|work=The New York Times|access-date=2019-10-26|language=en-US|issn=0362-4331}} Once this became public, Forbes removed his blog from their site.

Two journalists from Le Monde won the 2018 European Press Prize for a series of articles on the documents, also titled Monsanto Papers. Their reporting described, among other things, Monsanto's lawyers' letters demanding that IARC scientists turn over documents relating to Monograph 112, which contained the IARC finding that glyphosate was a "probable carcinogen"; several of the scientists condemned these letters as intimidating.{{cite web|website=European Press Prize|url=https://www.europeanpressprize.com/article/monsanto-papers/|author1=Stéphane Foucart|author2=Stéphane Horel|title= The Investigative Reporting Award 2018 Winner: Monsanto Papers|access-date=31 March 2019|quote=[T]he non-American scientists who had been members of the IARC panel on glyphosate all received the same letter. Sent by Monsanto’s law firm, Hollingsworth, the letter told them to hand over all the files related to their work on Monograph 112.}}

In March 2015, the California Office of Environmental Health Hazard Assessment (OEHHA) announced plans to have glyphosate listed as a known carcinogen based on the IARC assessment. In 2016, Monsanto started a case against OEHHA and its acting director, Lauren Zeise,{{Cite news|title = Monsanto Sues California Over Herbicide Classification|url = https://www.nytimes.com/2016/01/22/business/monsanto-sues-california-over-herbicide-classification.html|newspaper = The New York Times|date=2016-01-21|access-date=2016-01-25|issn = 0362-4331|agency = Reuters}} but lost the suit in March 2017.{{Cite news|title=Monsanto loses cancer label lawsuit, accused of ghostwriting study|url = http://www.bizjournals.com/stlouis/news/2017/03/14/monsanto-loses-cancer-label-lawsuit-accused-of.html|newspaper = St. Louis Business Journal|date=2017-03-14|access-date=2017-06-28}}

Glyphosate was listed as "known to the State of California to cause cancer" in 2017, requiring warning labels under Proposition 65.{{Cite web|url=https://oehha.ca.gov/proposition-65/crnr/glyphosate-listed-effective-july-7-2017-known-state-california-cause-cancer|title=Glyphosate Listed Effective July 7, 2017, as Known to the State of California to Cause Cancer |website=oehha.ca.gov|language=en|access-date=2017-07-07}} In February 2018, as part of an ongoing case, an injunction was issued prohibiting California from enforcing carcinogenicity labeling requirements for glyphosate until the case was resolved. The injunction stated that arguments by a US District Court Judge for the Eastern District of California "[do] not change the fact that the overwhelming majority of agencies that that have examined glyphosate have determined it is not a cancer risk."{{cite news |title=Federal judge rules against California's attorney general over glyphosate |url=http://www.agweek.com/business/agriculture/4460533-federal-judge-rules-against-californias-attorney-general-over |access-date=14 August 2018 |publisher=AgWeek|date=14 June 2018|language=en}} In August 2019, the EPA also said it no longer allowed labels claiming glyphosate is a carcinogen, as those claims would "not meet the labeling requirements of the Federal Insecticide, Fungicide, and Rodenticide Act" and misinform the public.

On March 15, 2017 the European Chemicals Agency (ECHA) announced recommendations proceeding from a risk assessment of glyphosate performed by ECHA's Committee for Risk Assessment (RAC). Their recommendations maintained the current classification of glyphosate as a substance causing serious eye damage and as a substance toxic to aquatic life. However, the RAC did not find evidence implicating glyphosate to be a carcinogen, a mutagen, toxic to reproduction, nor toxic to specific organs.{{cite web|url=https://echa.europa.eu/-/glyphosate-not-classified-as-a-carcinogen-by-echa|title=Glyphosate not classified as a carcinogen by ECHA |website=echa.europa.eu}} In 2022, the agency reiterated these findings in a later review and stated on cancer risk that, "Based on a wide-ranging review of scientific evidence, the committee again concludes that classifying glyphosate as a carcinogen is not justified."{{cite web |title=Glyphosate: no change proposed to hazard classification|url=https://echa.europa.eu/sk/-/glyphosate-no-change-proposed-to-hazard-classification |website=echa.europa.eu |publisher=European Chemicals Agency |access-date=26 May 2023 |language=sk-SK}}

{{seealso|Herbicide resistance}}

In the 1990s, no glyphosate-resistant weeds were known to exist. In 2005 a slow upward trend began, resistant weeds appearing rarely around the world. Another inflection point occurred in 2011 and resistance accelerated globally.

:{{cite journal|issue=2|year=2017|publisher=John Wiley & Sons, Inc.|pages=48–60|last=Carvalho|volume=6|first=Fernando|journal=Food and Energy Security|issn=2048-3694|s2cid=89994510|doi=10.1002/fes3.108|title=Pesticides, environment, and food safety|doi-access=free}}

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:{{cite journal|issue=1|year=2016|publisher=Springer Science and Business Media LLC|last1=Peterson|volume=15|first1=John|last2=Antoniou|first2=Michael|last3=Blumberg|first3=Bruce|last4=Carroll|first4=Lynn|last5=Colborn|first5=Theo|last6=Everett|first6=Lorne|last7=Hansen|first7=Michael|last8=Landrigan|first8=Philip|last9=Lanphear|first9=Bruce|last10=Mesnage|first10=Robin|last11=Vandenberg|first11=Laura|last12=vom Saal|first12=Frederick|last13=Welshons|first13=Wade|last14=Benbrook|first14=Charles|journal=Environmental Health|issn=1476-069X|s2cid=10631819|doi=10.1186/s12940-016-0117-0|title=Concerns over use of glyphosate-based herbicides and risks associated with exposures: a consensus statement|page=19 |pmid=26883814 |pmc=4756530 |bibcode=2016EnvHe..15...19M |doi-access=free }}

:

:These reviews cite this research.

:

:{{cite journal|issue=1|year=2016|publisher=Springer Science and Business Media LLC|volume=28|last=Benbrook|first=Charles|journal=Environmental Sciences Europe|issn=2190-4707|s2cid=1660085|doi=10.1186/s12302-016-0070-0|title=Trends in glyphosate herbicide use in the United States and globally|page=3 |pmid=27752438 |pmc=5044953 |doi-access=free }}

By 2014, glyphosate-resistant weeds dominated herbicide-resistance research. At that time, 23 glyphosate-resistant species were found in 18 countries. "Resistance evolves after a weed population has been subjected to intense selection pressure in the form of repeated use of a single herbicide."{{cite news| url=https://www.nytimes.com/2010/05/17/opinion/17mon3.html?ref=opinion | work=The New York Times | title=Resisting Roundup | date=May 16, 2010 |access-date=March 24, 2016}}

According to Ian Heap, a weed specialist, who completed his PhD on resistance to multiple herbicides in annual ryegrass (Lolium rigidum) in 1988{{cite book | title=Resistance to herbicides in annual ryegrass (Lolium Rigidum) | publisher=Department of Agronomy, University of Adelaide | date=1988 | author=Heap, Ian Michael | location=Adelaide}} – the first case of an herbicide-resistant weed in Australia{{cite web | url=http://www.agannex.com/weeds/history-of-herbicide-resistance | title=History of herbicide resistance Herbicide resistance: Then, now, and the years to come | date=June 2015 | access-date=24 March 2016 | author=King, Carolyn | archive-date=July 3, 2015 | archive-url=https://web.archive.org/web/20150703010649/http://www.agannex.com/weeds/history-of-herbicide-resistance | url-status=dead }} – by 2014 Lolium rigidum was the "world’s worst herbicide-resistant weed" with instances in "12 countries, 11 sites of action, 9 cropping regimens" and affecting "over 2 million hectares."{{cite book |doi=10.1007/978-94-007-7796-5_12 |chapter=Herbicide Resistant Weeds |title=Integrated Pest Management |pages=281–301 |year=2014 |last1=Heap |first1=Ian |publisher=Springer |location=Dordrecht |isbn=978-94-007-7795-8 }} Annual ryegrass has been known to be resistant to herbicides since 1982. The first documented case of glyphosate-resistant L. rigidum was reported in Australia in 1996 near Orange, New South Wales.{{citation |url=http://www.weeds.iastate.edu/mgmt/2003/glyresistance.shtml |series=Weed Science Online |title=Are Roundup Ready Weeds in Your Future II |first=Bob |last=Hartzler |name-list-style=vanc |date=January 29, 2003 |access-date=March 24, 2016 |work=Iowa State University (ISU) |archive-date=March 5, 2016 |archive-url=https://web.archive.org/web/20160305021727/http://www.weeds.iastate.edu/mgmt/2003/glyresistance.shtml |url-status=dead }}{{cite journal | vauthors = Powles SB, Lorraine-Colwill DF, Dellow JJ, Preston C | year = 1998 | title = Evolved Resistance to Glyphosate in Rigid Ryegrass (Lolium rigidum) in Australia | journal = Weed Science | volume = 46 | issue = 5 | pages = 604–07 | jstor = 4045968 | doi = 10.1017/S0043174500091165 | s2cid = 83591923 }}Glyphosate Resistance in Crops and Weeds: History, Development, and Management. Editor, Vijay K. Nandula. John Wiley & Sons, 2010 {{ISBN|978-1118043547}} In 2006, farmers associations were reporting 107 biotypes of weeds within 63 weed species with herbicide resistance.{{Cite web|url=http://southeastfarmpress.com/glyphosate-resistant-weeds-reality-cotton-growers/ |title=Glyphosate resistance is a reality that should scare some cotton growers into changing the way they do business |publisher=Southeastfarmpress.com |access-date=2010-08-22|date=February 10, 2006 }} In 2009, Canada identified its first resistant weed, giant ragweed, and at that time 15 weed species had been confirmed as resistant to glyphosate.{{Cite web|author=Lori |url=http://www.uoguelph.ca/news/2009/05/u_of_g_research_19.html |title=U of G Researchers Find Suspected Glyphosate-Resistant Weed |publisher=Uoguelph.ca |date=2009-05-07 |access-date=2010-08-22}}{{cite web |url=http://weedscience.org/Summary/MOA.aspx?MOAID=12 | title = List of Herbicide Resistant Weeds by Herbicide Mode of Action – Weeds Resistant to EPSP synthase inhibitors (G/9) | publisher=Herbicide Resistance Action Committee|website=The International Survey of Herbicide Resistant Weeds | year=2020 | access-date=22 November 2020 | vauthors = Heap I}} As of 2010, in the United States {{convert|7|to|10|e6acre|e6ha|abbr=off}} of soil were afflicted by herbicide-resistant weeds, or about 5% of the 170 million acres planted with corn, soybeans, and cotton, the crops most affected, in 22 states.{{Cite news|url=https://www.nytimes.com/2010/05/04/business/energy-environment/04weed.html|title=U.S. Farmers Cope With Roundup-Resistant Weeds | vauthors = Neuman W, Pollack A | date = 4 May 2010 | work = The New York Times | pages = B1 | access-date = 4 May 2010 | location = New York }} In 2012, Charles Benbrook reported that the Weed Science Society of America listed 22 herbicide-resistant species in the U.S., with over {{convert|5.7|e6ha|e6acre|abbr=on}} infested by GR weeds and that Dow AgroSciences had carried out a survey and reported a figure of around {{convert|40|e6ha|e6acre|sigfig=1|abbr=on}}.{{cite journal |doi=10.1186/2190-4715-24-24 |title=Impacts of genetically engineered crops on pesticide use in the U.S. – the first sixteen years |journal=Environmental Sciences Europe |volume=24 |pages=24 |year=2012 |last1=Benbrook |first1=Charles M |issue=1 |doi-access=free }} The International Survey of Herbicide Resistant Weeds database lists species that are resistant to glyphosate.

In response to resistant weeds, farmers are hand-weeding, using tractors to turn over soil between crops, and using other herbicides in addition to glyphosate.

Monsanto scientists have found that some resistant weeds have as many as 160 extra copies of a gene called EPSPS, the enzyme glyphosate disrupts.{{cite web | title = With BioDirect, Monsanto Hopes RNA Sprays Can Someday Deliver Drought Tolerance and Other Traits to Plants on Demand | work = MIT Technology Review | url = http://www.technologyreview.com/featuredstory/540136/the-next-great-gmo-debate | access-date = 2015-08-31}}

File:Amaranthus palmeri.jpg (Amaranthus palmeri)]]

In 2004, a glyphosate-resistant variation of Palmer amaranth was found in the U.S. state of Georgia.{{cite journal |doi=10.1614/WS-06-001R.1 |title= Glyphosate-resistant Palmer amaranth (Amaranthus palmeri) confirmed in Georgia |year=2006 |vauthors=Culpepper AS, Grey TL, Vencill WK, Kichler JM, Webster TM, Brown SM, York AC, Davis JW, Hanna WW |s2cid= 56236569 | journal =Weed Science | volume = 54 | issue = 4 | pages = 620–26 | jstor = 4539441 }} In 2005, resistance was also found in North Carolina.{{cite web | url = http://www.cals.ncsu.edu/agcomm/magazine/winter09/cotton.html | title = Cotton versus the monster weed| last= Hampton |first = Natalie |date = Winter 2009|website = College of Agriculture and Life Science|publisher = North Carolina State University}} The species can quickly become resistant to multiple herbicides and has developed multiple mechanisms for glyphosate resistance due to selection pressure.{{cite journal |last1=Ward |first1=Sarah M. |last2=Webster |first2=Theodore M. |last3=Steckel |first3=Larry E. |title=Palmer Amaranth (Amaranthus palmeri): A Review |journal=Weed Technology|date=20 January 2017 |volume=27 |issue=1 |pages=12–27 |doi=10.1614/WT-D-12-00113.1|s2cid=84142912 |doi-access=free }}

File:Canadese fijnstraal plant Conyza canadensis.jpg]]

Conyza bonariensis (also known as hairy fleabane and buva) and C. canadensis (known as horseweed or marestail) are other weed species that have lately developed glyphosate resistance.{{cite journal |doi=10.1590/S0100-83582007000300017 |title=Buva (Conyza bonariensis) resistente ao glyphosate na região sul do Brasil |trans-title=Conyza bonariensis biotypes resistant to the glyphosate in southern Brazil |language=pt |year=2007 |vauthors=Vargas L, Bianchi MA, Rizzardi MA, Agostinetto D, Dal Magro T |journal=Planta Daninha |volume=25 |issue=3 |pages=573–78|doi-access=free }}{{cite journal |doi=10.1614/WS-05-010R |title=Assessment of two nondestructive assays for detecting glyphosate resistance in horseweed (Conyza canadensis) |year=2005 |vauthors=Koger CH, Shaner DL, Henry WB, Nadler-Hassar T, Thomas WE, Wilcut JW |s2cid=198128423 | journal =Weed Science| volume = 53 | issue = 4 | pages = 438–45 | jstor = 4047050}}{{cite journal | vauthors = Ge X, d'Avignon DA, Ackerman JJ, Sammons RD | title = Rapid vacuolar sequestration: the horseweed glyphosate resistance mechanism | journal = Pest Management Science | volume = 66 | issue = 4 | pages = 345–48 | date = Apr 2010 | pmid = 20063320 | pmc = 3080097 | doi = 10.1002/ps.1911 }} A 2008 study on the current situation of glyphosate resistance in South America concluded "resistance evolution followed intense glyphosate use" and the use of glyphosate-resistant soybean crops is a factor encouraging increases in glyphosate use.{{cite journal | vauthors = Vila-Aiub MM, Vidal RA, Balbi MC, Gundel PE, Trucco F, Ghersa CM | title = Glyphosate-resistant weeds of South American cropping systems: an overview | journal =Pest Management Science| volume = 64 | issue = 4 | pages = 366–71 | date = Apr 2008 | pmid = 18161884 | doi = 10.1002/ps.1488 }} In the 2015 growing season, glyphosate-resistant marestail proved to be especially problematic to control in Nebraska production fields.{{cite news|last1=Jhala|first1=Amit|title=Post-Emergence Herbicide Options for Glyphosate-Resistant Marestail in Corn and Soybean|url=http://cropwatch.unl.edu/controlling-glyphosate-resistant-marestail|access-date=17 August 2015|agency=Nebraska Extension|publisher=CropWatch|date=4 June 2015 | name-list-style = vanc }}

File:Lolium perenne Engels raaigras doorgeschoten plant.jpg]]

Glyphosate-resistant ryegrass (Lolium) has occurred in most of the Australian agricultural areas and other areas of the world. All cases of evolution of resistance to glyphosate in Australia were characterized by intensive use of the herbicide while no other effective weed control practices were used. Studies indicate resistant ryegrass does not compete well against nonresistant plants and their numbers decrease when not grown under conditions of glyphosate application.{{cite journal | title = A Decade of Glyphosate-Resistant Lolium around the World: Mechanisms, Genes, Fitness, and Agronomic Management |year=2009 |vauthors=Preston C, Wakelin AM, Dolman FC, Bostamam Y, Boutsalis P |s2cid=85725624 | journal =Weed Science| volume = 57 | issue = 4 | pages = 435–41 | doi = 10.1614/WS-08-181.1 }}

Glyphosate-resistant Johnson grass (Sorghum halepense) has been found in Argentina as well as Arkansas, Louisiana, and Mississippi.{{cite journal |last1=Peerzada |first1=Arslan Masood |last2=Ali |first2=Hafiz Haider |last3=Hanif |first3=Zarka |last4=Bajwa |first4=Ali Ahsan |last5=Kebaso |first5=Lynda |last6=Frimpong |first6=David |last7=Iqbal |first7=Nadeem |last8=Namubiru |first8=Halima |last9=Hashim |first9=Saima |last10=Rasool |first10=Ghulam |last11=Manalil |first11=Sudheesh |last12=van der Meulen |first12=Annemieke |last13=Chauhan |first13=Bhagirath Singh |display-authors=1|title=Eco-biology, impact, and management of Sorghum halepense (L.) Pers. |journal=Biological Invasions|date=16 March 2017 |volume=25 |issue=4 |pages=955–973 |doi=10.1007/s10530-017-1410-8|s2cid=17096998 |url=https://espace.library.uq.edu.au/view/UQ:547820/UQ547820_OA.pdf }}

Use of glyphosate and other herbicides like 2,4-D to clear milkweed along roads and fields may have contributed to a decline in monarch butterfly populations in the Midwestern United States.{{cite web |url=http://weedcontrolfreaks.com/2014/02/are-herbicides-responsible-for-the-decline-in-monarch-butterflies/ |title=Are herbicides responsible for the decline in Monarch butterflies? |last1=Kniss |first1=Andrew |name-list-style=vanc |date=2014-02-10 |website=Control Freaks |access-date=2016-06-16 |quote=The evidence seems clear that the number of milkweed plants through this region has indeed declined. The cause for the milkweed decline, though, is a little less certain. |archive-date=August 29, 2016 |archive-url=https://web.archive.org/web/20160829045127/http://weedcontrolfreaks.com/2014/02/are-herbicides-responsible-for-the-decline-in-monarch-butterflies/ |url-status=dead }} Along with deforestation and adverse weather conditions,{{cite news |url=https://www.washingtonpost.com/news/wonk/wp/2014/01/29/the-monarch-butterfly-population-just-hit-a-record-low-heres-why/ |title=Monarch butterflies keep disappearing. Here's why. |last=Plumer |first=Brad | name-list-style = vanc |date=January 29, 2014 |newspaper=The Washington Post |access-date=2016-06-16}} the decrease in milkweed contributed to an 81% decline in monarchs.{{cite journal |doi=10.1111/j.1752-4598.2012.00196.x |title=Milkweed loss in agricultural fields because of herbicide use: Effect on the monarch butterfly population |journal=Insect Conservation and Diversity|volume=6 |issue=2 |pages=135–44 |year=2013 |last1=Pleasants |first1=John M |last2=Oberhauser |first2=Karen S |s2cid=14595378 |url=http://osf.io/wmj6e | name-list-style = vanc }}{{cite journal |doi=10.1016/s0261-2194(00)00024-7 |title=Occurrence of common milkweed (Asclepias syriaca) in cropland and adjacent areas |journal=Crop Protection|volume=19 |issue=5 |pages=363–66 |year=2000 |last1=Hartzler |first1=Robert G |last2=Buhler |first2=Douglas D |bibcode=2000CrPro..19..363H | name-list-style = vanc |url=https://lib.dr.iastate.edu/agron_pubs/32 }} The Natural Resources Defense Council (NRDC) filed a suit against the EPA in 2015, in which it argued that the agency ignored warnings about the potentially dangerous impacts of glyphosate usage on monarchs.{{cite web | title = NRDC Sues EPA Over Demise of Monarch Butterfly Population | url = http://www.nbcnews.com/science/environment/nrdc-sues-epa-over-demise-monarch-butterfly-population-n314371 | year = 2015 | work = NBC }}

Glyphosate was first approved for use in the 1970s, and as of 2010 was labelled for use in 130 countries.{{rp|2}}

In 2017 Vandenberg et al. cited a 100-fold increase in the use of glyphosate-based herbicides from 1974 to 2014, the possibility that herbicide mixtures likely have effects that are not predicted by studying glyphosate alone, and reliance of current safety assessments on studies done over 30 years ago. They recommended that current safety standards be updated, writing that the current standards "may fail to protect public health or the environment."{{cite journal|url= |title=Is it time to reassess current safety standards for glyphosate-based herbicides?|vauthors=Vandenberg LN, Blumberg B, Antoniou MN, Benbrook CM, Carroll L, Colborn T, Everett LG, Hansen M, Landrigan PJ, Lanphear BP, Mesnage R, vom Saal FS, Welshons WV, Myers JP|date=June 2017|journal=J Epidemiol Community Health|volume=71|issue=6|pages=613–18|doi=10.1136/jech-2016-208463|pmid=28320775|pmc=5484035}}

A vote on the relicensing of glyphosate in the EU stalled in March 2016. Member states France, Sweden, and the Netherlands objected to the renewal.{{cite news|url=https://www.theguardian.com/environment/2016/mar/08/eu-vote-on-controversial-weedkiller-licence-postponed-glyphosate|title=Vote on controversial weedkiller's European licence postponed|author=Arthur Nelson|newspaper=The Guardian|date=2016-03-08}} A vote to reauthorize on a temporary basis failed in June 2016{{cite news|url=https://www.theguardian.com/environment/2016/jun/06/recall-of-monsantos-roundup-likely-as-eu-refuses-limited-use-of-glyphosate|title=Recall of Monsanto's Roundup likely as EU refuses limited use of glyphosate|agency=Reuters|date=2016-06-06}} but at the last minute the license was extended for 18 months until the end of 2017.{{cite news|url=https://www.theguardian.com/business/2016/jun/29/controversial-chemical-roundup-weedkiller-escapes-immediate-ban|title=Controversial chemical in Roundup weedkiller escapes immediate ban|author=Arthur Nelson|newspaper=The Guardian|date=2016-06-29}}

On 27 November 2017, in the EU Council a majority of eighteen member states voted in favor of permitting the use of glyphosate for five more years. A qualified majority of sixteen states representing 65% of EU citizens was required to pass the law.

[https://www.nrc.nl/nieuws/2017/11/28/roundup-omstreden-bestrijdingsmiddel-glyfosaat-blijft-nog-zeker-vijf-jaar-te-gebruiken-in-eu-14259800-a1582828 'EU votes for five more years usage of herbicide glyphosate']. NRC Handelsblad {{in lang|nl}}, 28 November 2017. The German Minister of Agriculture, Christian Schmidt, unexpectedly voted in favor while the German coalition government was internally divided on the issue which usually results in Germany abstaining.[https://www.nrc.nl/nieuws/2017/11/28/gesprek-cdu-spd-onder-druk-door-onkruidverdelger-a1582937 'Talks CDU-SPD under pressure because of herbicide'] {{in lang|nl}}. NRC Handelsblad, 28 November 2017.

In December 2018, attempts were made to reopen the decision to license the weed-killer. These were condemned by Conservative MEPs, who said the proposal was politically motivated and flew in the face of scientific evidence.{{cite news |title= Move to re-open Glyphosate case attacked by Conservative MEPs |url= http://conservativeeurope.com/news/move-to-re-open-glyphosate-case-attacked-by-conservative-meps |work= Conservative Europe |date= 6 December 2018 |access-date= January 30, 2019 |archive-date= January 30, 2019 |archive-url= https://web.archive.org/web/20190130162344/http://conservativeeurope.com/news/move-to-re-open-glyphosate-case-attacked-by-conservative-meps |url-status= dead }}

In March 2019, the European Court of Justice (ECJ) ordered the European Food Safety Authority (EFSA) to release all carcinogenicity and toxicity pesticide industry studies on glyphosate to the general public.[https://sustainablepulse.com/2019/03/07/european-court-of-justice-orders-eu-regulators-to-publicly-release-secret-industry-glyphosate-studies/ ‘European Court of Justice orders public release of industry glyphosate studies’], 7 March 2019.

The assessment process for an approval of glyphosate in the European Union was scheduled to begin in December 2019. France, Hungary, the Netherlands and Sweden were to jointly assess the application dossiers of the producers. The draft report of the assessment group was then to be peer-reviewed by the EFSA before the then-current approval expired in December 2022.{{cite web |last1=European Commission |title=Glyphosate Current status of glyphosate in the EU |url=https://ec.europa.eu/food/plant/pesticides/glyphosate_en |access-date=October 29, 2019|date=July 12, 2017 }}

The date was subsequently pushed back, partially due to very high interest and input in the participation process, with the European Food Safety Authority (EFSA) even calling it an "unprecedented number".{{Cite web |date=10 May 2022 |title=Glyphosate: EFSA and ECHA update timelines for assessments |url=https://www.efsa.europa.eu/en/news/glyphosate-efsa-and-echa-update-timelines-assessments |access-date=28 May 2022 |website=European Food Safety Authority}} Because the EFSA had to review all these 2400 comments and almost 400 responses, the process was expected to take longer. The created document was under extra review by the specially formed Glyphosate Renewal Group (GRG) and the Assessment Group on Glyphosate (AGG), the panel consisting of the four mentioned member states. With their responses then being scheduled for September 2022, the consultations with member states were supposed to be held by the very end of 2022.{{Cite web |date=11 May 2022 |title=Glifosato: La EFSA pospone su evaluacion ante la avalancha de comentarios recibidos |url=https://www.agrodigital.com/2022/05/11/glifosato-la-efsa-pospone-su-evaluacion-ante-la-avalancha-de-comentarios-recibidos/ |access-date=28 May 2022 |website=Agrodigital}}{{Cite web |last=Case |first=Philip |date=11 May 2022 |title=EU delays glyphosaterenewal decision until 2023 |url=https://www.fwi.co.uk/news/farm-policy/eu-delays-glyphosate-renewal-decision-until-2023 |access-date=28 May 2022 |website=Farmers Weekly}} This would allow to finish the final assessment by mid-2023 and pass it on to further legislature to decide.

In November 2023, glyphosate received a 10 year renewed authorization for use in the EU from the European Commission.{{Cite web |date=2023-11-16 |title=No qualified majority reached by Member States to renew or reject the approval of glyphosate |url=https://ec.europa.eu/commission/presscorner/detail/en/statement_23_5792 |access-date=2023-11-16 |website=European Commission |language=en}}

In April 2014, the legislature of the Netherlands passed legislation prohibiting sale of glyphosate to individuals for use at home; commercial sales were not affected.Staff, Sustainable Pulse. Apr 4 2014 [http://sustainablepulse.com/2014/04/04/dutch-parliament-bans-glyphosate-herbicides-non-commercial-use Dutch Parliament Bans Glyphosate Herbicides for Non-Commercial Use]

In June 2015, the French Ecology Minister asked nurseries and garden centers to halt over-the-counter sales of glyphosate in the form of Monsanto's Roundup. This was a nonbinding request and all sales of glyphosate remained legal in France until 2022, when it was planned to ban the substance for home gardening.{{cite news | url = https://www.reuters.com/article/france-monsanto-idUSL5N0Z00H120150614?type=companyNews | title = French minister asks shops to stop selling Monsanto Roundup weedkiller | newspaper = Reuters | date = June 14, 2015 }} However, subsequently the French parliament decided to not to impose a definitive date for such a ban.

French parliament does not vote for a date to terminate glyphosate:

[https://www.lemonde.fr/planete/article/2018/05/29/l-assemblee-nationale-ne-vote-pas-de-date-pour-la-fin-du-glyphosate_5306106_3244.html Rejet à l’Assemblée de l’inscription dans la loi de la date de sortie du glyphosate] In January 2019, "the sale, distribution, and use of Roundup 360 [wa]s banned" in France. Exemptions for many farmers were later implemented, and a curb of its use by 80% for 2021 is projected.{{Cite web|url=https://www.france24.com/en/20190116-weedkiller-roundup-banned-france-after-court-ruling|title=Weedkiller Roundup banned in France after court ruling|date=2019-01-16|website=France 24|language=en|access-date=2019-01-16}}{{cite news|newspaper=Reuters|title=French court cancels Monsanto weedkiller permit on safety grounds|date=15 January 2019|access-date=16 January 2019|url=https://www.reuters.com/article/us-bayer-monsanto-france/french-court-cancels-monsanto-weedkiller-permit-on-safety-grounds-idUSKCN1P91F6}}

In March 2019, the Austrian state of Carinthia outlawed the private use of glyphosate in residential areas while the commercial application of the herbicide is still permitted for farmers. The use of glyphosate by public authorities and road maintenance crews was already halted a number of years prior to the current ban by local authorities.[https://diepresse.com/home/wirtschaft/economist/5598237/Kaernten-verbietet-ab-28-Maerz-Glyphosat-fuer-Private "Kärnten verbietet ab 28. März Glyphosat für Private"] (in German). Die Presse. Retrieved 29 April 2019.

In June 2019, Deutsche Bahn and Swiss Federal Railways announced that glyphosate and other commonly used herbicides for weed eradication along railway tracks will be phased out by 2025, while more environmentally sound methods for vegetation control are implemented.Briner M (July 2018). [https://www.aargauerzeitung.ch/wirtschaft/schluss-mit-glyphosat-sbb-wollen-unkraut-anders-vernichten-132845313 Schluss mit Glyphosat: SBB wollen Unkraut anders vernichten] {{Webarchive|url=https://web.archive.org/web/20190627064202/https://www.aargauerzeitung.ch/wirtschaft/schluss-mit-glyphosat-sbb-wollen-unkraut-anders-vernichten-132845313 |date=June 27, 2019 }} Aargauer Zeitung (in German). Retrieved 26 June 2019.Schlesiger Ch (June 2019). [https://www.wiwo.de/unternehmen/dienstleister/unkrautvernichter-deutsche-bahn-will-kuenftig-auf-glyphosat-verzichten-/24456436.html Deutsche Bahn will künftig auf Glyphosat verzichten] Wirtschaftswoche (in German). Retrieved 26 June 2019.

In July 2019, the Austrian parliament voted to ban glyphosate in Austria.[https://orf.at/stories/3128905/ Nationalrat stimmt für Glyphosatverbot], Austrian parliament votes to forbid Glyphosphat & water is a public good necessary for the existence of a human, orf.at, 2019-07-02 However, the ban was never brought into effect due to a legal defect rendering it unable to be promulgated.{{cite news |last=Murphy |first=Francois |url=https://www.reuters.com/article/business/environment/austrian-leader-blocks-ban-on-weedkiller-glyphosate-citing-technicality-idUSKBN1YD11Y/ |title=Austrian leader blocks ban on weedkiller glyphosate, citing technicality |work=Reuters |date=December 9, 2019 |access-date=January 11, 2025 |url-access=registration}}

In September 2019, the German Environment Ministry announced that the use of glyphosate would be banned from the end of 2023. The use of glyphosate-based herbicides would be reduced starting from 2020.{{cite news |last1=Rinke |first1=Andreas |title=Germany to ban use of glyphosate from end of 2023 |url=https://www.reuters.com/article/us-germany-glyphosate/germany-to-ban-use-of-glyphosate-from-end-of-2023-sources-idUSKCN1VP0TY |work=Reuters|date=September 4, 2019}} As of April 2024, a partial ban was reported to be in effect.{{cite news |title=German cabinet approves restricted use of herbicide glyphosate |url=https://www.reuters.com/world/europe/german-cabinet-approves-restricted-use-herbicide-glyphosate-2024-04-24/ |work=Reuters |date=April 24, 2024 |access-date=January 11, 2025 |url-access=registration |quote=...[glyphosate] is also prohibited in some arable farming.}}

A full ban on the use of glyphosate in Luxembourg entered into force on 1 January 2022. The ban was annulled by the Administrative Court of Luxembourg in April 2023.{{cite news |last=Zeimetz |first=Claude |url=https://today.rtl.lu/news/luxembourg/a/2049532.html |title=Luxembourg's glyphosate ban lacks legal basis |date=April 6, 2023 |work=RTL |access-date=January 11, 2025}}

In September 2013, the Legislative Assembly of El Salvador approved legislation to ban 53 agrochemicals, including glyphosate; the ban on glyphosate was set to begin in 2015,Staff, Centralamericadata.com. September 6, 2013 [http://en.centralamericadata.com/en/article/home/El_Salvador_Use_of_53_Chemicals_Banned El Salvador: Use of 53 Chemicals Banned]Staff, Centralamericadata.com. November 27, 2013 [http://en.centralamericadata.com/en/article/home/El_Salvador_Confirmation_to_Be_Given_on_Ban_of_Agrochemicals El Salvador: Confirmation to Be Given on Ban of Agrochemicals]Legislative Assembly of El Salvador. November 26, 2013

[http://www.asamblea.gob.sv/noticias/archivo-de-noticias/analizan-observaciones-del-ejecutivo-al-decreto-que-contiene-la-prohibicion-de-53-agroquimicos-que-danan-la-salud/ Analizan observaciones del Ejecutivo al decreto que contiene la prohibición de 53 agroquímicos que dañan la salud] {{Webarchive|url=https://web.archive.org/web/20150531075642/http://www.asamblea.gob.sv/noticias/archivo-de-noticias/analizan-observaciones-del-ejecutivo-al-decreto-que-contiene-la-prohibicion-de-53-agroquimicos-que-danan-la-salud |date=May 31, 2015 }} [https://translate.google.com/translate?sl=auto&tl=en&js=y&prev=_t&hl=en&ie=UTF-8&u=http%3A%2F%2Fwww.asamblea.gob.sv%2Fnoticias%2Farchivo-de-noticias%2Fanalizan-observaciones-del-ejecutivo-al-decreto-que-contiene-la-prohibicion-de-53-agroquimicos-que-danan-la-salud%2F&edit-text= English translation by Google] but was later rescinded.{{cite news |url=https://www.rfi.fr/en/business-and-tech/20230920-glyphosate-where-is-it-banned-or-restricted |title=Glyphosate: where is it banned or restricted? |date=September 20, 2023 |work=Radio France Internationale |agency=Agence France-Presse |access-date=January 10, 2025 |quote=Colombia and El Salvador both banned glyphosate and then overturned the decision...}}

In the United States, the state of Minnesota preempts local laws that attempt to ban glyphosate. In 2015 there was an attempt to pass legislation at the state level that would repeal that preemption.{{cite web | first1=Robyn | last1=Moore | title=Herbicide a growing problem | website=The Citizen | publisher=Press Publications | date=2021-08-08 | url=http://www.presspubs.com/citizen/news/herbicide-a-growing-problem/article_09362c4a-e475-11e4-8a7b-7b5484fd9d09.html | access-date=2021-08-09}} As of January 2018, glyphosate is not banned at either the federal or state level in the US. However, numerous local governments in various states have enacted restrictions or bans on the use of glyphosate in their respective jurisdictions.{{cite web |url=https://www.texasorganicresearchcenter.org/organic-research-page/Glyphosate-Where-is-it-Restricted-or-Banned-in-the-United-States_vq13273.htm |title=Glyphosate – Where is it Restricted or Banned in the United States? |website=Texas Organic Research Center |access-date=January 11, 2025}} In addition, the state of California attempted to enforce a requirement for a Prop 65 carcinogen warning label on glyphosate containers, but was permanently enjoined from doing so by a federal court.{{cite web |url=https://natlawreview.com/article/ninth-circuit-finds-glyphosate-prop-65-warning-unconstitutional |title=Ninth Circuit Finds Glyphosate Prop 65 Warning Unconstitutional |website=The National Law Review |date=November 14, 2023 |access-date=January 11, 2025}}

In May 2015, the President of Sri Lanka banned the use and import of glyphosate, effective immediately.Staff, Colombo Page. May 22, 2015 [http://www.colombopage.com/archive_15B/May22_1432308620CH.php Sri Lankan President orders to ban import of glyphosate with immediate effect] {{Webarchive|url=https://web.archive.org/web/20150630213502/http://www.colombopage.com/archive_15B/May22_1432308620CH.php |date=June 30, 2015 }}Sarina Locke for the Australian Broadcasting Corporation. Updated May 27, 2015 [http://www.abc.net.au/news/2015-05-27/toxicologist-worries-glyphosate-ban-based-on-bad-science/6500720 Toxicologist critical of 'dodgy science' in glyphosate bans] However, in May 2018 the Sri Lankan government decided to re-authorize its use in the plantation sector.{{cite web | title = Glyphosate ban lifted for tea, rubber industries: Navin | url = http://www.dailymirror.lk/article/Glyphosate-ban-lifted-for-tea-rubber-industries-Navin-149402.html | work = Daily Mirror | date = 2018-05-02 }} The ban was fully revoked in August 2022.{{cite journal |last1=Dorlach |first1=Tim |last2=Gunasekara |first2=Sandya |date=November 13, 2023 |title=The politics of glyphosate regulation: lessons from Sri Lanka's short-lived ban |url= |journal=Global Health |volume=19 |issue=1 |publisher=PubMed |pages=10 |doi=10.1186/s12992-023-00981-2 |pmc=10644602 |pmid= 37957659 |doi-access=free |access-date= |name-list-style=vanc}}

In May 2015, Bermuda blocked importation on all new orders of glyphosate-based herbicides for a temporary suspension awaiting outcomes of research.{{cite news | title = Health Minister: importation of roundup weed spray suspended | url = http://www.todayinbermuda.com/news/health/item/1471-health-minister-importation-of-roundup-weed-spray-suspended | publisher = Bermuda Today | date = 11 May 2015 | archive-url = https://web.archive.org/web/20150602094518/http://www.todayinbermuda.com/news/health/item/1471-health-minister-importation-of-roundup-weed-spray-suspended | archive-date = June 2, 2015 | url-status = dead }} In 2016, the Bermudian government banned all glyphosate concentrates with a strength of over 2 per cent.{{cite news |last=Neil |first=Scott |url=https://www.royalgazette.com/environment/news/article/20200703/roundup-settlement-prompts-farmer-to-demand-ban/ |title=Roundup settlement prompts farmer to demand ban |work=The Royal Gazette |date=July 3, 2020 |access-date=January 11, 2025}}

In May 2015, Colombia announced that it would stop using glyphosate by October 2015 in the destruction of illegal plantations of coca, the raw ingredient for cocaine. Farmers have complained that the aerial fumigation has destroyed entire fields of coffee and other legal produce. The glyphosate ban in Colombia was subsequently lifted.

In April 2019, Vietnam's Ministry of Agriculture and Rural Development banned the use of glyphosate throughout the country.{{cite news | title = Việt Nam bans weed killer ingredient glyphosate | url = http://vietnamnews.vn/society/518568/viet-nam-bans-weed-killer-ingredient-glyphosate.html | publisher = Viet Nam News | date = 11 April 2019}}

In August 2020, Mexican President Andrés Manuel López Obrador announced that glyphosate would be gradually phased out of use in Mexico by late 2024.{{cite web |title=Mexico to phase out use of herbicide glyphosate |url=https://www.reuters.com/article/us-mexico-herbicide-idUSKCN25902N |website=Reuters |access-date=3 March 2021 |date=13 August 2020}} However in March 2024, the Mexican government postponed the ban, and did not set a new date for its implementation.{{cite news |last=Enciso L |first=Angelica |url=https://www.jornada.com.mx/noticia/2024/03/27/politica/mantendra-mexico-el-uso-de-glifosato-en-su-agricultura-345 |title=Mantendrá México el uso de glifosato en su agricultura |trans-title=Mexico will maintain the use of glyphosate in its agriculture |date=March 27, 2024 |work=La Jornada |lang=es-mx |access-date=January 10, 2025}}

Thailand's National Hazardous Substances Committee decided to ban the use of glyphosate in October 2019Reuters (October 25, 2019). [https://www.reuters.com/article/us-thailand-chemicals-usa/u-s-protests-thailands-chemical-ban-would-hurt-crop-exports-idUSKBN1X41JQ U.S. protests Thailand's chemical ban would hurt crop exports] but reversed the decision in November 2019.{{cite news |title=Thailand reverses ban of chemicals use in pesticides |url=https://www.reuters.com/article/us-thailand-chemicals/thailand-reverses-ban-of-chemicals-use-in-pesticides-idUSKBN1Y1128 |access-date=12 December 2019 |work=Reuters |date=27 November 2019 |language=en}}

After a court ruling in 2018, glyphosate was temporarily banned in Brazil. This decision was later overturned, causing major criticism by the federal agency of health (Anvisa). This comes, as the latest evaluations declared glyphosate as noncarcinogenic. Since all carcinogenic agrichemicals are automatically banned in the country, this allowed the continuous use.{{Cite web |last=Spring |first=Jake |date=26 February 2019 |title=Brazil health officials find weed-killer glyphosate non-cancerous |url=https://www.reuters.com/article/us-brazil-agriculture-glyphosate-idUSKCN1QF1J1 |access-date=28 May 2022 |website=Reuters}}

In New Zealand, glyphosate is an approved herbicide for killing weeds, with the most popular brand being Roundup.{{Cite web|url=https://www.mpi.govt.nz/food-safety-home/safe-levels-of-chemicals-in-food/fertilisers-pesticides-hormones-and-medicines-in-food/glyphosate-in-food/|title=Glyphosate in food | MPI – Ministry for Primary Industries. A New Zealand Government Department.|first=Ministry for Primary|last=Industries|website=www.mpi.govt.nz|date=July 13, 2021 }}{{Cite web|url=https://www.epa.govt.nz/everyday-environment/gardening-products/glyphosate/|title=Glyphosate | EPA|website=www.epa.govt.nz}} Genetically modified crops designed to resist glyphosate are absent in New Zealand. Crops applied with glyphosate must be regulated under the HSNO Act 1996 and ACVM Act 1997.{{cite web|url=https://www.epa.govt.nz/assets/Uploads/Documents/Hazardous-Substances/Glyphosate-call-for-information/Glyphosate-call-for-information-summary-report-may22.pdf |title=Glyphosate in Aotearoa New Zealand |date=11 May 2022 |last=New Zealand Government}} Legal status for glyphosate use in New Zealand is approved for commercial and personal use. In 2021, exports of New Zealand honey were found to contain traces of glyphosate, causing some concern to Japanese importers.{{Cite web|url=https://www.rnz.co.nz/news/country/434807/japan-warns-it-will-block-nz-honey-shipments-if-glyphosate-limits-breached|title=Japan warns it will block NZ honey shipments if glyphosate limits breached|date=January 20, 2021|website=RNZ }}{{Cite web|url=https://thespinoff.co.nz/business/01-06-2021/glyphosate-is-farmings-favourite-weed-killer-can-nz-learn-to-live-without-it|title=Glyphosate is farming's favourite weed killer. Can NZ learn to live without it?|first=Nick|last=Stringer|date=June 1, 2021|website=The Spinoff}}

{{See also|Monsanto legal cases#Roundup}}

Since 2018, in a number of court cases in the United States, plaintiffs have argued that their cancer was caused by exposure to glyphosate in glyphosate-based herbicides produced by Monsanto/Bayer. Defendant Bayer has paid out over $9.6 billion in judgements and settlements in these cases. Bayer has also won at least 10 cases, successfully arguing that their glyphosate-based herbicides were not responsible for the plaintiff's cancer.{{Cite web |date=December 23, 2023 |title=Bayer wins latest Roundup cancer trial, ending losing streak |url=https://www.reuters.com/legal/bayer-wins-latest-roundup-cancer-trial-ending-losing-streak-2023-12-23/ |website=Reuters}}

In 2016, a lawsuit was filed against Quaker Oats in the Federal district courts of both New York and California after trace amounts of glyphosate were found in oatmeal. The lawsuit alleged that the claim of "100% natural" was false advertising.{{Cite news| issn = 0362-4331| last = Strom| first = Stephanie| title = Quaker Oats' 100% Natural Claim Questioned in Lawsuit| work = The New York Times| access-date = 2018-08-13| date = 2017-12-21| url = https://www.nytimes.com/2016/05/02/business/quaker-oats-100-natural-claim-questioned-in-lawsuit.html}} That same year General Mills dropped the label "Made with 100% Natural Whole Grain Oats" from their Nature Valley granola bars after a lawsuit was filed that claimed the oats contained trace amounts of glyphosate.{{Cite web| title = General Mills drops '100% Natural' on Nature Valley granola bars after lawsuit| work = USA Today| access-date = 2018-08-25| url = https://www.usatoday.com/story/money/nation-now/2018/08/24/general-mills-drops-100-percent-natural-nature-valley/1082709002/}}

United States companies have cited trade issues with glyphosate being dumped into western world market areas by Chinese companies, and a formal dispute was filed in 2010.{{cite web | url = https://www.usitc.gov/trade_remedy/731_ad_701_cvd/investigations/2010/Glyphosate%20from%20China/Preliminary/conference_04-22-2010.pdf | title = In the Matter of: Glyphosate From China | date = 2010-04-22 | publisher = United States International Trade Commission }}{{cite news |last1=Hoskins |first1=Tim |title=Glyphosate maker complains of Chinese dumping |url=https://agupdate.com/iowafarmertoday/news/state-and-regional/glyphosate-maker-complains-of-chinese-dumping/article_b260291c-1d8d-56a9-8fd3-d460c89c8565.html |access-date=29 December 2023 |publisher=Iowa Farmer Today |date=15 April 2010}}

Glyphosate has become a locus of campaigning and misinformation by anti-GMO activists because of its association with genetically-modified glyphosate-resistant crops.{{cite web |publisher=Science-Based Medicine |first=Bellamy |last=Jann |title=Monsanto gets injunction against California's mandated cancer warning for glyphosate |date=20 July 2020 |url=https://sciencebasedmedicine.org/monsanto-gets-injunction-against-californias-mandated-cancer-warning-for-glyphosate/}}

The US politician Robert F. Kennedy Jr. has incorporated glyphosate into his anti-vaccination rhetoric, falsely claiming that both glyphosate and vaccines may be contributing to the American obesity epidemic. Stephanie Seneff has also falsely claimed that it may have a role in autism and in worsening concussion.{{cite web |publisher=Science-Based Medicine |vauthors=Gorski DH |title=Quoth RFK Jr.: Vaccines and glyphosate are responsible for the obesity epidemic! |date=24 February 2020 |url=https://sciencebasedmedicine.org/quoth-rfk-jr-vaccines-and-glyphosate-are-responsible-for-the-obesity-epidemic/}}

{{div col|colwidth=20em|small=yes}}

• 2,4-Dichlorophenoxyacetic acid
• Ammonium sulfamate
• Atrazine
• Environmental impact of pesticides
• Health effects of pesticides
• Integrated pest management
• Monsanto legal cases
• Pesticide regulation in the United States
• Regulation of pesticides in the European Union
• Séralini affair

{{div col end}}

{{Reflist}}

{{Commons category}}

• {{PPDB|373|Name=Glyphosate}}
• {{PPDB|1062|Name=Glyphosate trimesium}}
• {{PPDB|2395|Name=Glyphosate, isopropylamine salt}}
• {{PPDB|2396|Name=Glyphosate, potassium salt}}

{{Herbicides}}

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