respirator

File: Medico peste.jpg]]

The history of protective respiratory equipment can be traced back as far as the first century, when Pliny the Elder ({{circa|23 AD}}–79) described using animal bladder skins to protect workers in Roman mines from red lead oxide dust.{{cite wikisource | title=Naturalis_Historia/Liber_XXXIII#XL|wslanguage=la}} In the 16th century, Leonardo da Vinci suggested that a finely woven cloth dipped in water could protect sailors from a toxic weapon made of powder that he had designed.{{cite web |date=11 September 2001 |title=Women in the US Military – History of Gas Masks |url=http://chnm.gmu.edu/courses/rr/s01/cw/students/leeann/historyandcollections/collections/photopages/phesgasmasks.html |archive-url=https://web.archive.org/web/20110512042523/http://chnm.gmu.edu/courses/rr/s01/cw/students/leeann/historyandcollections/collections/photopages/phesgasmasks.html |archive-date=12 May 2011 |access-date=18 April 2010 |publisher=Chnm.gmu.edu}}

Alexander von Humboldt introduced a primitive respirator in 1799 when he worked as a mining engineer in Prussia.{{Cite web|url=https://books.google.com/books?id=LW1oAAAAcAAJ|title=Ueber die unterirdischen Gasarten und die Mittel ihren Nachtheil zu vermindern|website=WorldAtlas|year=1799|language=en|access-date=2020-03-27|last1=Humboldt|first1=Alexander von}}

Julius Jeffreys first used the word "respirator" as a mask in 1836.{{cite journal|author=David Zuck|date=1990|title=Julius Jeffreys: Pioneer of humidification|url=http://kora.matrix.msu.edu/files/21/120/15-78-188-22-1990-Zuck-JeffreysResp.pdf|journal=Proceedings of the History of Anaesthesia Society|volume=8b|pages=70–80|access-date=16 August 2020|archive-date=4 November 2021|archive-url=https://web.archive.org/web/20211104215545/http://kora.matrix.msu.edu/files/21/120/15-78-188-22-1990-Zuck-JeffreysResp.pdf|url-status=live}}

File:John Stenhouse's mask.png

In 1848, the first US patent for an air-purifying respirator was granted to Lewis P. Haslett{{cite book|last=Christianson|first=Scott|title=Fatal Airs: The Deadly History and Apocalyptic Future of Lethal Gases that Threaten Our World|publisher=ABC-CLIO|year=2010|isbn=9780313385520|author-link=Scott Christianson}} for his 'Haslett's Lung Protector,' which filtered dust from the air using one-way clapper valves and a filter made of moistened wool or a similar porous substance.{{cite patent |country=US |number=6529A |status=patent |title=Lung Protector |pubdate=1849-06-12 |gdate=1849-06-12 |inventor=Lewis P. Haslett |url=https://worldwide.espacenet.com/patent/search/family/002066829/publication/US6529A?q=US6529A }} {{Webarchive|url=https://web.archive.org/web/20210308054414/https://worldwide.espacenet.com/patent/search/family/002066829/publication/US6529A?q=US6529A |date=8 March 2021 }} Hutson Hurd patented a cup-shaped mask in 1879 which became widespread in industrial use.{{Cite patent|title=Improvement in inhaler and respirator|gdate=1879-08-26|url=https://patents.google.com/patent/US218976A/en}}

Inventors in Europe included John Stenhouse, a Scottish chemist, who investigated the power of charcoal in its various forms, to capture and hold large volumes of gas. He built one of the first respirators able to remove toxic gases from the air, paving the way for activated charcoal to become the most widely used filter for respirators.{{Cite book|last=Britain|first=Royal Institution of Great|url=https://archive.org/details/bub_gb_tfkAAAAAYAAJ|page=[https://archive.org/details/bub_gb_tfkAAAAAYAAJ/page/n63 53]|title=Notices of the Proceedings at the Meetings of the Members of the Royal Institution, with Abstracts of the Discourses|date=1858|publisher=W. Nicol, Printer to the Royal Institution|language=en}} Irish physicist John Tyndall took Stenhouse's mask, added a filter of cotton wool saturated with lime, glycerin, and charcoal, and in 1871 invented a 'fireman's respirator', a hood that filtered smoke and gas from air, which he exhibited at a meeting of the Royal Society in London in 1874.{{Cite journal|last=Tyndall|first=John|date=1873|title=On Some Recent Experiments with a Fireman's Respirator|journal=Proceedings of the Royal Society of London|volume=22|pages=359–361|jstor=112853|bibcode=1873RSPS...22R.359T|issn=0370-1662}} Also in 1874, Samuel Barton patented a device that 'permitted respiration in places where the atmosphere is charged with noxious gases, or vapors, smoke, or other impurities.'{{Cite web|url=http://67.225.133.110/~gbpprorg/invention/development.html|title=Gas Mask Development (1926)|website=67.225.133.110|access-date=2020-03-27|archive-date=27 February 2021|archive-url=https://web.archive.org/web/20210227141330/http://67.225.133.110/~gbpprorg/invention/development.html|url-status=live}}{{cite patent |country=US |number=148868A |status=patent |title=Respirator |pubdate=1874-03-24 |gdate=1874-03-24 |inventor=Samuel Barton |url=https://worldwide.espacenet.com/patent/search/family/002218281/publication/US148868A?q=US148868A }} {{Webarchive|url=https://web.archive.org/web/20210308180749/https://worldwide.espacenet.com/patent/search/family/002218281/publication/US148868A?q=US148868A |date=8 March 2021 }}

In the 1890s, the German surgeon Johannes Mikulicz began using a "mundbinde" ("mouth bandage") of sterilized cloth as a barrier against microorganisms moving from him to his patients. Along with his surgical assistant Wilhelm Hübener, he adapted a chloroform mask with two layers of cotton mull. Experiments conducted by Hübener showed that the "mouth bandage" or "surgical mask" (German: Operationsmaske, as Hübener called it) blocked bacteria.{{cite journal |last1=Lowry |first1=H. C. |title=Some Landmarks in Surgical Technique |journal=The Ulster Medical Journal |year=1947 |volume=16 |issue=2 |pages=102–113 |pmid=18898288 |pmc=2479244 }}Schlich T, Strasser BJ. Making the medical mask: surgery, bacteriology, and the control of infection (1870s–1920s). Medical History. 2022;66(2):116-134. doi:10.1017/mdh.2022.5

File:How a Man may Breath Safely in a Poisonous Atmosphere b10154140 010 tif zw12z649n.tiff

{{excerpt|Wu Lien-teh|Pneumonic plague|only=paragraphs|paragraphs=1-2}}

{{excerpt|Gas mask|World War I|only=paragraphs|paragraphs=1-2}}

{{excerpt|N95 respirator|Early US respirator standards}}

In the 1970s, the successor to the United States Bureau of Mines and NIOSH developed standards for single-use respirators, and the first single-use respirator was developed by 3M and approved in 1972.{{cite web|url=https://www.fastcompany.com/90479846/the-untold-origin-story-of-the-n95-mask|title=The untold origin story of the N95 mask|work=Fast Company |date=24 March 2020 |publisher=Fast Company and Mansueto Ventures, LLC|access-date=9 April 2020|archive-date=19 May 2020|archive-url=https://web.archive.org/web/20200519041831/https://www.fastcompany.com/90479846/the-untold-origin-story-of-the-n95-mask|url-status=live |last1=Wilson |first1=Mark }} 3M used a melt blowing process that it had developed decades prior and used in products such as ready-made ribbon bows and bra cups; its use in a wide array of products had been pioneered by designer Sara Little Turnbull.{{Cite web|url=https://designmuseumfoundation.org/ask-why/|title=Ask Why: Sara Little Turnbull|last1=Rees|first1=Paula|last2=Eisenbach|first2=Larry|date=2020|website=Design Museum Foundation|access-date=2020-04-01|df=mdy-all|archive-date=20 July 2020|archive-url=https://web.archive.org/web/20200720125822/https://designmuseumfoundation.org/ask-why/|url-status=live}}

{{excerpt|N95 respirator|Approval of Part 84 and replacement of 30 CFR 11}}

==== Continuing mesothelioma litigation ====

{{see also|Toxic tort}}

File:30 cfr part11 label.png label, with asbestos approval]]

NIOSH certifies B Readers, people qualified to testify or provide evidence in mesothelioma personal injury lawsuits,{{cite journal | url=https://larc.cardozo.yu.edu/cgi/viewcontent.cgi?article=1644&context=faculty-articles | title=Fraud and Abuse in Mesothelioma Litigation | volume=31 | issue=33 | date=2004 | last1=Brickman | first1=Lester | journal=Tul. L. Rev. | pages=47–48}} in addition to regulating respirators. However, since 2000, the increasing scope of claims related to mesothelioma started to include respirator manufacturers to the tune of 325,000 cases, despite the primary use of respirators being to prevent asbestos and silica-related diseases. Most of these cases were not successful, or reached settlements of around $1000 per litigant, well below the cost of mesothelioma treatment.

One reason is due to the fact that respirator manufacturers are not allowed to modify a respirator once it is certified by NIOSH. In one case, a jury ruled against 3M for a respirator that was initially approved for asbestos, but was quickly disapproved once OSHA permissible exposure limits for asbestos changed. Combined with testimony that the plaintiff rarely wore a respirator around asbestos, the lack of evidence, and the limitation of liability from static NIOSH approval, the case was overturned.{{cite journal | first1=Victor E. | last1=Schwartz | first2=Cary | last2=Silverman | first3=Christopher E. | last3=Appel. | title=Respirators to the Rescue: Why Tort Law Should Encourage, Not Deter, the Manufacture of Products that Make Us Safer. | journal=Am. J. Trial Advoc. | volume=33 | issue=13 | date=2009 | url=https://www.shb.com/-/media/files/professionals/s/silvermancary/respiratorstotherescue.pdf |pages=48–51}}

Nonetheless, the costs of litigation reduced the margins for respirators, which was blamed for supply shortages for N95 respirators for anticipated pandemics, like avian influenza, during the 2000s.

China normally makes 10 million masks per day, about half of the world production. During the COVID-19 pandemic, 2,500 factories were converted to produce 116 million daily.{{cite web|url=https://www.voanews.com/a/science-health_coronavirus-outbreak_world-depends-china-face-masks-can-country-deliver/6186071.html|title=World Depends on China for Face Masks But Can Country Deliver?|last1=Xie|first1=John|date=19 March 2020|website=Voice of America|publisher=Voice of America|language=en|url-status=live|archive-url=https://web.archive.org/web/20200321094219/https://www.voanews.com/science-health/coronavirus-outbreak/world-depends-china-face-masks-can-country-deliver|archive-date=21 March 2020}}

During the COVID-19 pandemic, people in the United States, and in a lot of countries in the world, were urged to make their own cloth masks due to the widespread shortage of commercial masks.{{Cite web |last=Dwyer |first=Colin |date=April 3, 2020 |title=CDC Now Recommends Americans Consider Wearing Cloth Face Coverings In Public |website=NPR |url=https://www.npr.org/sections/coronavirus-live-updates/2020/04/03/826219824/president-trump-says-cdc-now-recommends-americans-wear-cloth-masks-in-public}}

{{see also|2020–2025 H5N1 outbreak}}

{{excerpt|N95 respirator|Among dairy workers|hat=no}}

{{clear}}

File:N95-respirator-protection-types-508.jpg

All respirators have some type of facepiece held to the wearer's head with straps, a cloth harness, or some other method. Facepieces come in many different styles and sizes to accommodate all types of face shapes.

A full facepiece covers the mouth, nose and eyes and if sealed, is sealed round the perimeter of the face. Unsealed versions may be used when air is supplied at a rate which prevents ambient gas from reaching the nose or mouth during inhalation.

Respirators can have half-face forms that cover the bottom half of the face including the nose and mouth, and full-face forms that cover the entire face. Half-face respirators are only effective in environments where the contaminants are not toxic to the eyes or facial area.

An escape respirator may have no component that would normally be described as a mask, and may use a bite-grip mouthpiece and nose clip instead. Alternatively, an escape respirator could be a time-limited self-contained breathing apparatus.

For hazardous environments, like confined spaces, atmosphere-supplying respirators, like SCBAs, should be used.

A wide range of industries use respirators including healthcare & pharmaceuticals, defense & public safety services (defense, firefighting & law enforcement), oil and gas industries, manufacturing (automotive, chemical, metal fabrication, food and beverage, wood working, paper and pulp), mining, construction, agriculture and forestry, cement production, power generation, painting, shipbuilding, and the textile industry.{{Cite web|url=https://www.bls.gov/iif/oshwc/osh/os/osnr0014.txt|title=Respirator use and practices|website=U.S. Bureau of Labour Statistics|access-date=29 March 2020|archive-date=17 October 2020|archive-url=https://web.archive.org/web/20201017155428/https://www.bls.gov/iif/oshwc/osh/os/osnr0014.txt|url-status=live}}

Respirators require user training in order to provide proper protection.

File:Обучение использованию СИЗОД (проверка правильности одевания избыточным давлением).jpg

Each time a wearer dons a respirator, they must perform a seal check to be sure that they have an airtight seal to the face so that air does not leak around the edges of the respirator. (PAPR respirators may not require this because they don't necessarily seal to the face.) This check is different than the periodic fit test that is performed using testing equipment. Filtering facepiece respirators are typically checked by cupping the hands over the facepiece while exhaling (positive pressure check) or inhaling (negative pressure check) and observing any air leakage around the facepiece. Elastomeric respirators are checked in a similar manner, except the wearer blocks the airways through the inlet valves (negative pressure check) or exhalation valves (positive pressure check) while observing the flexing of the respirator or air leakage. Manufacturers have different methods for performing seal checks and wearers should consult the specific instructions for the model of respirator they are wearing. Some models of respirators or filter cartridges have special buttons or other mechanisms built into them to facilitate seal checks.{{cite web |title=Filtering out Confusion: Frequently Asked Questions about Respiratory Protection, User Seal Check (2018) |url=https://www.cdc.gov/niosh/docs/2018-130/pdfs/2018-130.pdf |website=NIOSH |access-date=8 December 2021}}{{harvnb|ANSI Z88.2|2015}}

{{excerpt|Respirator fit test|only=paragraphs|paragraphs=1-2}}

{{excerpt|N95 respirator|Contrast with surgical mask|hat=no}}

File:3M Surgical N95 Respirator.png 1860 surgical N95, with a non-surgical 3M 8210 in the background]]

{{excerpt|N95 respirator|In healthcare|only=paragraphs|paragraphs=1-2}}

{{clear}}

== Respirator selection ==

Air-purifying respirators are respirators that draw in the surrounding air and purify it before it is breathed (unlike air-supplying respirators, which are sealed systems, with no air intake, like those used underwater). Air-purifying respirators filter particulates, gases, and vapors from the air, and may be negative-pressure respirators driven by the wearer's inhalation and exhalation, or positive-pressure units such as powered air-purifying respirators (PAPRs).

According to the NIOSH Respirator Selection Logic, air-purifying respirators are recommended for concentrations of hazardous particulates or gases that are greater than the relevant occupational exposure limit but less than the immediately dangerous to life or health level and the manufacturer's maximum use concentration, subject to the respirator having a sufficient assigned protection factor. For substances hazardous to the eyes, a respirator equipped with a full facepiece, helmet, or hood is recommended. Air-purifying respirators are not effective during firefighting, in oxygen-deficient atmosphere, or in an unknown atmosphere; in these situations a self-contained breathing apparatus is recommended instead.{{Cite journal|title=NIOSH respirator selection logic|url=https://www.cdc.gov/niosh/docs/2005-100/default.html|last=Bollinger|first=Nancy|date=2004-10-01|website=U.S. National Institute for Occupational Safety and Health|pages=5–16|language=en-us|doi=10.26616/NIOSHPUB2005100|access-date=2020-04-20|doi-access=free|archive-date=15 July 2020|archive-url=https://web.archive.org/web/20200715045859/https://www.cdc.gov/niosh/docs/2005-100/default.html|url-status=live}}

: Main Article: Mechanical filter respirator (and regulatory ratings)

File:What it Means to be NIOSH-Approved - A look into N95 Certification Testing.webm

Mechanical filters remove contaminants from air in several ways: interception when particles following a line of flow in the airstream come within one radius of a fiber and adhere to it; impaction, when larger particles unable to follow the curving contours of the airstream are forced to embed in one of the fibers directly; this increases with diminishing fiber separation and higher air flow velocity; by diffusion, where gas molecules collide with the smallest particles, especially those below 100 nm in diameter, which are thereby impeded and delayed in their path through the filter, increasing the probability that particles will be stopped by either of the previous two mechanisms; and by using an electrostatic charge that attracts and holds particles on the filter surface.

There are many different filtration standards that vary by jurisdiction. In the United States, the National Institute for Occupational Safety and Health defines the categories of particulate filters according to their NIOSH air filtration rating. The most common of these are the N95 respirator, which filters at least 95% of airborne particles but is not resistant to oil.

Other categories filter 99% or 99.97% of particles, or have varying degrees of resistance to oil.{{cite journal | last1 = Metzler | first1 = R | last2 = Szalajda | first2 = J | title = NIOSH Fact Sheet: NIOSH Approval Labels - Key Information to Protect Yourself | journal = DHHS (NIOSH) Publication No. 2011-179 | year = 2011 | url = https://www.cdc.gov/niosh/docs/2011-179/pdfs/2011-179.pdf | issn = 0343-6993 | access-date = 10 September 2017 | archive-date = 20 July 2018 | archive-url = https://web.archive.org/web/20180720182756/https://www.cdc.gov/niosh/docs/2011-179/pdfs/2011-179.pdf | url-status = live }}

In the European Union, European standard EN 143 defines the 'P' classes of particle filters that can be attached to a face mask, while European standard EN 149 defines classes of "filtering half masks" or "filtering facepieces", usually called FFP masks.{{cite web |title=A Guide to Respiratory Protective Equipment |url=https://www.hsa.ie/eng/Publications_and_Forms/Publications/Chemical_and_Hazardous_Substances/Respiratory%20Protective%20Equipment.pdf |website=hsa.ie |access-date=12 July 2024 |archive-date=30 June 2024 |archive-url=https://web.archive.org/web/20240630012837/https://www.hsa.ie/eng/Publications_and_Forms/Publications/Chemical_and_Hazardous_Substances/Respiratory%20Protective%20Equipment.pdf |url-status=live }}

According to 3M, the filtering media in respirators made according to the following standards are similar to U.S. N95 or European FFP2 respirators, however, the construction of the respirators themselves, such as providing a proper seal to the face, varies considerably. (For example, US NIOSH-approved respirators never include earloops because they don't provide enough support to establish a reliable, airtight seal.) Standards for respirator filtration the Chinese KN95, Australian / New Zealand P2, Korean 1st Class also referred to as KF94, and Japanese DS.{{Cite web|url=https://multimedia.3m.com/mws/media/1791500O/comparison-ffp2-kn95-n95-filtering-facepiece-respirator-classes-tb.pdf|title=Technical Bulletin: Comparison of FFP2, KN95, and N95 and Other Filtering Facepiece Respirator Classes|date=January 2020|publisher=3M Personal Safety Division|access-date=3 April 2020|archive-date=14 April 2020|archive-url=https://web.archive.org/web/20200414004708/https://multimedia.3m.com/mws/media/1791500O/comparison-ffp2-kn95-n95-filtering-facepiece-respirator-classes-tb.pdf|url-status=live}}

File:Respirator canister with ESLI for asid gases -1.JPG canister, type BKF (БКФ), for protection against acid gases. It has a transparent body and a special sorbent that changes color upon saturation. This color change may be used for timely replacement of respirators' filters (like an end-of-service-life indicator, ESLI).|alt=]]

{{Main|Chemical cartridge|NIOSH air filtration rating#Chemical cartridge and canister classifications|Gas mask}}

Chemical cartridges and gas mask canisters remove gases, volatile organic compounds (VOCs), and other vapors from breathing air by adsorption, absorption, or chemisorption. A typical organic vapor respirator cartridge is a metal or plastic case containing from 25 to 40 grams of sorption media such as activated charcoal or certain resins. The service life of the cartridge varies based, among other variables, on the carbon weight and molecular weight of the vapor and the cartridge media, the concentration of vapor in the atmosphere, the relative humidity of the atmosphere, and the breathing rate of the respirator wearer. When filter cartridges become saturated or particulate accumulation within them begins to restrict air flow, they must be changed.The document describes the methods used previously and currently used to perform the timely replacement of cartridges in air purifying respirators.{{Primary source inline|reason=Unambiguous original research|date=January 2025}}

If the concentration of harmful gases is immediately dangerous to life or health, in workplaces covered by the Occupational Safety and Health Act the US Occupational Safety and Health Administration specifies the use of air-supplied respirators except when intended solely for escape during emergencies.OSHA standard [http://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=STANDARDS&p_id=12716 29 CFR 1910.134] {{Webarchive|url=https://web.archive.org/web/20140924184743/https://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=STANDARDS&p_id=12716 |date=24 September 2014 }} "Respiratory Protection" NIOSH also discourages their use under such conditions.{{cite book|last=Bollinger|first=Nancy|title=NIOSH Respirator Selection Logic|url=https://www.cdc.gov/niosh/docs/2005-100/|series=DHHS (NIOSH) Publication No. 2005-100|year=2004|publisher=National Institute for Occupational Safety and Health|location=Cincinnati, Ohio|pages=32|display-authors=etal|doi=10.26616/NIOSHPUB2005100|access-date=10 September 2017|archive-date=23 June 2017|archive-url=https://web.archive.org/web/20170623115207/https://www.cdc.gov/niosh/docs/2005-100/|url-status=live}}

{{excerpt|NIOSH air filtration rating|Chemical cartridge and canister classifications|only=paragraph|hat=no}}

File:Atemluftfilter Einwegmaske.jpg

{{Excerpt|Mechanical filter (respirator)|Filtering facepiece respirators|Filtering facepiece|only=paragraph}}

File:Police officer wearing half-mask respirator.jpg officer wearing a 3M elastomeric respirator with P100-standard particulate filters in the aftermath of the 2007 New York City steam explosion|alt=Head-only portrait of a male police officer wearing a navy blue peaked cap emblazoned with the New York City coat of arms and navy uniform shirt with gold collar insignia identifying him as a member of the 112th Precinct. His nose and mouth are covered by a gray rubber respirator with bright pink filters.]]

{{Excerpt|Elastomeric respirator|paragraphs=1-2|files=0}}

{{excerpt|Powered air-purifying respirator|files=0}}

These respirators do not purify the ambient air, but supply breathing gas from another source. The three types are the self contained breathing apparatus, in which a compressed air cylinder is worn by the wearer; the supplied air respirators, where a hose supplies air from a stationary source; and combination supplied-air respirators, with an emergency backup tank.{{Cite web|url=https://www.osha.gov/SLTC/etools/respiratory/respirator_selection_airvsatmos_resp.html|title=Respirator Selection: Air-purifying vs. Atmosphere-supplying Respirators|website=U.S. Occupational Safety and Health Administration|access-date=2020-04-09|archive-date=17 April 2020|archive-url=https://web.archive.org/web/20200417114028/https://www.osha.gov/SLTC/etools/respiratory/respirator_selection_airvsatmos_resp.html|url-status=live}}

{{excerpt|Self-contained breathing apparatus|only=paragraphs}}

{{excerpt|Supplied-air respirator|only=paragraphs}}

File:Escape-filter_Fluchtfilter_Dräger-Parat-3200-02.jpg escape respirator. This model has no hood, and instead comes with noseclips to ensure the wearer breathes only through the filter.]]

{{excerpt|Smoke hood|only=paragraph}}

{{excerpt|Self-contained breathing apparatus|Continuous-flow|only=paragraphs}}

{{excerpt|Self-contained self-rescue device|only=paragraphs}}

{{US respirator topics}}

{{further|30 CFR 11}}

In 1992, NIOSH published a draft report on the effectiveness of respirator regulations under the then-current 30 CFR 11. Particulate respirators back then were mainly classified as either DM, DFM, or HEPA.{{harvnb|NIOSH|1992}}

Assigned protection factors (APF) are predicated on the assumption that users are trained in the use of their respirators, and that 100% of users exceed the APF."NIOSH has concluded that APFS based on APF definitions from Myers et al. and the Guy Committee are derived from WPF data that were obtained after each test subject has been properly fitted and trained"... {{harvnb|NIOSH|1992|p=34}} This "simulated workplace protection factor" (SWPF) was said to be problematic:

{{blockquote|By inference, these data are equally at odds with the protection factors established by OSHA for various types of respirator, which were based on QNFT [quantitative fit testing] data obtained by the Los Alamos National Laboratory in the 1970s. Until recently, the SWPFs gathered during QNFT were more or less assumed to translate directly into the protection afforded by a particular respirator, or class of respirators, while worn in the workplace.{{break}}{{break}}

Apparently this is now a questionable assumption which has thrown the entire concept of fit testing into doubt.Quote from: {{citation| title=Open Forum: Respirator Testing-Old Values |date= May 1989 |publisher=Ind. Safety and Hyg. News}}}}

The ideal assumption of all respirator users exceeding the APF is termed the zero control failure rate by NIOSH. The term control failure rate here refers to the number of respirator users, per 100 users, that fail to reach the APF.{{harvnb|NIOSH|1992|p=52}} The risk of user error affecting the failure rate, and the studies quantifying it, was, according to NIOSH, akin to the study of contraception failure rates.{{harvnb|NIOSH|1992|p=51}}

This is despite there being a "reasonable expectation, of both purchasers and users, [that] none of the users will receive less protection than the class APF (when the masks are properly selected, fit tested by the employer, and properly worn by the users)". NIOSH expands on the methods for measuring this error in Chapter 7 of the draft report.

Qualitative fit testing with isoamyl acetate, irritant smoke, and saccharin were proposed as alternatives to quantitative fit testing in the 1980s, but doubts were raised as to its efficacy.{{harvnb|NIOSH|1992|pp=35-36}}

With regards to the effectiveness of fit testing in general, others have said: {{blockquote|First of all, it is unfortunate that fit testing results apparently cannot be used as a reliable indication of respirator performance in the workplace. Life would be simpler if the converse were to continue to be true...{{break}}{{break}}

In my opinion, we are left with respirator fit testing, whether qualitative or quantitative, playing the role as a means of obtaining the best possible fit of a given respirator on a given person at a given time. We should not make any representation as to the ultimate efficiency in the workplace.}}

With regards to fit test protocols, it was noted by NIOSH that "time pressures" resulted in the exclusion of intense exercises meant to simulate workplace use:{{harvnb|NIOSH|1992|p=37}} {{blockquote|Part of the original test procedure called for test subjects to be stressed by treadmill, while undergoing a quantitative respirator leak evaluation. The purpose of this stressing was to simulate actual workplace use of the respirators. We accordingly abandoned the "stress" portion of the exercises, and substituted a period to be spent in a hot humid chamber, to work up a sweat, as a substitute for physical activity.{{citation |last=Douglas |first=D. D. |title=Respirator Studies for the National Institute for Occupational Safety and Health, July 1, 1974-June 30, 1975, Los Alamos Scientific Laboratory Progress Report LA-6386-PR |publisher=Office of Scientific and Technical Information|location=Los Alamos, New Mexico |pages=35–36 |date=August 1976}}}}

Neither exercise was included in the OSHA fit test protocols. Put another way, it has been said: {{blockquote|The exercise time limits are very short. The required exercises are sedentary and do not replicate movements of workers that may occur in workplaces.{{citation |first=W. H. |last=Revoir |title=Comments on OSHA's Proposal to Modify Existing Provisions for Controlling Employee Exposure to Toxic Substances Found in 29 CFR 1910.1000(3) and 29 CFR 1910.134(a)(1). Comments submitted to OSHA |date=1990-05-30 |page=20}}}}

In spite of the requirement to fit test by OSHA, the following observations of noncompliance with respirator regulations were made by NIOSH and OSHA:{{harvnb|NIOSH|1992|p=45-46}}

• Almost 80% of negative-pressure respirator wearers were not receiving fit testing.
• Over 70% of 123,000 manufacturing plants did not perform exposure-level monitoring, when selecting respirators to use in the plants.
• Noncompliance increased to almost 90% for the smallest plants.
• 75% of manufacturing plants did not have a written program.
• 56% of manufacturing plants did not have a professional respirator-program administrator (i.e., qualified individual supervising the program).
• Almost 50% of wearers in manufacturing plants did not receive an annual examination by a physician.
• Almost 50% of wearers in manufacturing plants did not receive respirator-use training.
• 80% of wearers in manufacturing plants did not have access to more than one facial-size mask, even though nearly all reusable masks were available in at least three sizes.

These noncompliance errors make up what NIOSH calls the program protection factor:{{harvnb|NIOSH|1992|p=47}}{{blockquote|...NIOSH has concluded that all respirator workplace studies reported in the 1980s and early 1990s are respirator-performance studies, not respirator program evaluation studies. That is, they evaluate workplace protection factors, not program protection factors.

WPF studies frequently are conducted primarily to demonstrate "adequate protection" from a particular make and model respirator. Thus, in effect, WPF studies generally are designed and conducted to measure only respirator performance in the most favorable light possible. This is done to avoid reducing or "biasing" (i.e., systematically distorting) the observed respirator protection resulting from poorly-performed or inadequately-performed respirator program elements that are typically found in actual programs. A major objective in respirator-performance (WPF) studies is to minimize the effects of human errors, even though these errors may typically occur in actual workplace use of respirators...

}}

File:Part 11 respirator final air-purifying APFs (1992) - illustration - page 137.jpg

APFs may be based on the filtration performance from one or two manufacturers that barely pass the regulation. When the DM and DFM respirator filter standards at the time were found to have an unacceptably high filter leakage, NIOSH proposed lowering the APF for DM respirators from 10 to 2. On this scale, 1 is a completely ineffective respirator. Some respirator manufacturers, like 3M, complained that DM and DFM respirators with superior filtration, that would normally receive an APF well above 2, were being "held hostage" by poorly-performing respirators.{{harvnb|NIOSH|1992|p=127}} While NIOSH acknowledged the predicament poorly-performing respirators were having on superior respirators in the same class, they concluded that the APFs, for respirator classes like DFM halfmask respirators, should be lowered to at least 6, despite APFs of 6 through 10 being allowed previously for DFM halfmasks.{{harvnb|NIOSH|1992|p=128}}

ANSI suggested additional contaminant monitoring by employers to allow for the use of DM and DFM respirators, when the mass median aerodynamic diameter of dusts in contaminated workplaces is such that DM and DFM respirators could work. However, NIOSH pointed out that the poor adherence to OSHA regulations on exposure-level monitoring by employers, as well as lack of expertise in interpreting the collected data, would likely result in more workers being put at risk.{{harvnb|NIOSH|1992|pp=132-133}} In addition, NIOSH pointed out that the ANSI recommendations would effectively mandate the use of expensive Part 11 HEPA filters under Part 11 regulations,{{harvnb|NIOSH|1992|p=135}} due to lack of adherence to exposure-level monitoring rules.{{harvnb|NIOSH|1992|p=136}}

{{further|Hierarchy of hazard controls}}

File:NIOSH’s “Hierarchy of Controls infographic” as SVG.svg outbreak)]]

The Hierarchy of Controls, noted as part of the Prevention Through Design initiative started by NIOSH with other standards bodies, is a set of guidelines emphasizing building in safety during design, as opposed to ad-hoc solutions like PPE, with multiple entities providing guidelines on how to implement safety during development{{cite web|url=https://www.cdc.gov/niosh/docs/2014-123/pdfs/2014-123_v2.pdf|title=The State of the National Initiative on Prevention through Design|date=May 2014|publisher=NIOSH|access-date=3 June 2024|archive-date=3 June 2024|archive-url=https://web.archive.org/web/20240603035524/https://www.cdc.gov/niosh/docs/2014-123/pdfs/2014-123_v2.pdf|url-status=live}} outside of NIOSH-approved respirators. US Government entities currently and formerly involved in the regulation of respirators follow the Hierarchy of Controls, including OSHA and MSHA.{{cite web|url=https://www.uaf.edu/mapts/tools/15_Respiratory_Program_Requirements.pdf|title=Summary of Key MSHA Requirements for a Respiratory Protection Program|access-date=3 June 2024|archive-date=16 June 2024|archive-url=https://web.archive.org/web/20240616204739/https://www.uaf.edu/mapts/tools/15_Respiratory_Program_Requirements.pdf|url-status=live}}

However, some HOC implementations, notably MSHA's, have been criticized for allowing mining operators to skirt engineering control noncompliance by requiring miners to wear respirators instead if the permissible exposure limit (PEL) is exceeded, without work stoppages, breaking the hierarchy of engineering controls. Another concern was fraud related to the inability to scrutinize engineering controls,{{cite web|url=https://democrats-edworkforce.house.gov/imo/media/doc/scott_adams_comment_letter_to_dol_on_msha_proposed_silica_rule.pdf|title=RE: Lowering Miners' Exposure to Respirable Crystalline Silica and Improving Respiratory Protection (RIN 1219-AB36)|date=11 September 2023}}{{cite web|url=https://www.safetyandhealthmagazine.com/articles/24515-mshas-proposed-rule-on-silica-has-shortcomings-lawmakers-say|title=MSHA's proposed rule on silica has 'shortcomings,' lawmakers say|date=21 September 2023|access-date=3 June 2024|archive-date=5 June 2024|archive-url=https://web.archive.org/web/20240605172058/https://www.safetyandhealthmagazine.com/articles/24515-mshas-proposed-rule-on-silica-has-shortcomings-lawmakers-say|url-status=live}} unlike NIOSH-approved respirators, like the N95, which can be fit tested by anyone, are subject to the scrutiny of NIOSH, and are trademarked and protected under US federal law.{{cite web|url=https://www.cdc.gov/niosh/npptl/usernotices/counterfeitResp.html|title=Counterfeit Respirators / Misrepresentation of NIOSH Approval|date=23 May 2024 |publisher=NIOSH}} NIOSH also noted, in a 2002 video about TB respirator use, that "engineering controls, like negative pressure isolation rooms may not control the TB hazard completely. The use of respirators is necessary".{{cite wikisource |title=TB Respiratory Protection - Administrators Review |publisher=NIOSH |year=2002}}

{{see also|N95 respirator#Later history}}

With regards to people complying with requirements to wear respirators, various papers note high respirator non-compliance across industries,{{cite journal |url=https://doi.org/10.1093/occmed/kqr132 | doi=10.1093/occmed/kqr132 | title=Factors influencing respirator use at work in respiratory patients | date=2011 | last1=Fukakusa | first1=J. | last2=Rosenblat | first2=J. | last3=Jang | first3=B. | last4=Ribeiro | first4=M. | last5=Kudla | first5=I. | last6=Tarlo | first6=S. M. | journal=Occupational Medicine | volume=61 | issue=8 | pages=576–582 | pmid=21968940 | url-access=subscription }}{{cite web |url=https://doi.org/10.1093/annweh/wxae008 | doi=10.1093/annweh/wxae008 | title=Use, failure, and non-compliance of respiratory personal protective equipment and risk of upper respiratory tract infections—A longitudinal repeated measurement study during the COVID-19 pandemic among healthcare workers in Denmark | date=2024 | last1=Biering | first1=Karin | last2=Kinnerup | first2=Martin | last3=Cramer | first3=Christine | last4=Dalbøge | first4=Annett | last5=Toft Würtz | first5=Else | last6=Lund Würtz | first6=Anne Mette | last7=Kolstad | first7=Henrik Albert | last8=Schlünssen | first8=Vivi | last9=Meulengracht Flachs | first9=Esben | last10=Nielsen | first10=Kent J. | journal=Annals of Work Exposures and Health | volume=68 | issue=4 | pages=376–386 | pmid=38373246 }} with a survey noting non-compliance was due in large part due to discomfort from temperature increases along the face, and a large amount of respondents also noting the social unacceptability of provided N95 respirators during the survey.{{cite journal |url=https://doi.org/10.1016/j.ajic.2009.09.005 | doi=10.1016/j.ajic.2009.09.005 | title=Health care workers' views about respirator use and features that should be included in the next generation of respirators | date=2010 | last1=Baig | first1=Aliya S. | last2=Knapp | first2=Caprice | last3=Eagan | first3=Aaron E. | last4=Radonovich | first4=Lewis J. | journal=American Journal of Infection Control | volume=38 | issue=1 | pages=18–25 | pmid=20036443 | pmc=7132692 }} For reasons like mishandling, ill-fitting respirators and lack of training, the Hierarchy of Controls dictates respirators be evaluated last while other controls exist and are working. Alternative controls like hazard elimination, administrative controls, and engineering controls like ventilation are less likely to fail due to user discomfort or error.{{cite web|url=https://simplifiedsafety.com/blog/the-hierarchy-of-controls-part-four-personal-protective-equipment/|title=The Hierarchy of Controls, Part Four: Personal Protective Equipment|publisher=Simplified Safety|access-date=3 June 2024|archive-date=3 June 2024|archive-url=https://web.archive.org/web/20240603031949/https://simplifiedsafety.com/blog/the-hierarchy-of-controls-part-four-personal-protective-equipment/|url-status=live}}{{cite web|url=https://www.cdc.gov/niosh/learning/safetyculturehc/module-3/7.html|title=Personal Protective Equipment (PPE): Protect the Worker with PPE|date=5 May 2023|publisher=NIOSH|access-date=3 June 2024|archive-date=3 June 2024|archive-url=https://web.archive.org/web/20240603031949/https://www.cdc.gov/niosh/learning/safetyculturehc/module-3/7.html|url-status=live}}

A U.S. Department of Labor study{{cite book|last1=U.S. Department of Labor, Bureau of Labor Statistics|url=https://www.cdc.gov/niosh/docs/respsurv/pdfs/respsurv2001.pdf|title=Respirator Usage in Private Sector Firms, 2001|publisher=U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health|location=Morgantown, WV|pages=273|access-date=22 January 2019|archive-date=1 November 2017|archive-url=https://web.archive.org/web/20171101172745/https://www.cdc.gov/niosh/docs/respsurv/pdfs/respsurv2001.pdf|url-status=live}} showed that in almost 40 thousand American enterprises, the requirements for the correct use of respirators are not always met. Experts note that in practice it is difficult to achieve elimination of occupational morbidity with the help of respirators:

{{blockquote|It is well known how ineffective ... trying to compensate the harmful workplace conditions with ... the use of respirators by employees.{{cite journal|author=Letavet A.A.|author-link=:ru:Летавет, Август Андреевич|date=1973|script-title=ru:Институт гигиены труда и профессиональных заболеваний в составе АМН СССР|trans-title=Research Institute of industrial hygiene and occupational diseases of AMS USSR|url=https://www.journal-irioh.ru/jour|journal=Occupational medicine and industrial ecology [Гигиена труда и профессиональные заболевания]|language=ru|pages=1–7|issn=1026-9428|number=9|access-date=22 January 2019|archive-date=23 January 2019|archive-url=https://web.archive.org/web/20190123011650/https://www.journal-irioh.ru/jour|url-status=live}}

Unfortunately, the only certain way of reducing the exceedance fraction to zero is to ensure that Co (note: Co - concentration of pollutants in the breathing zone) never exceeds the PEL value.{{cite journal|author=M. Nicas & R. Spear|date=1992|title=A Probability Model for Assessing Exposure among Respirator Wearers: Part II - Overexposure to Chronic versus Acute Toxicants|url=https://www.tandfonline.com/toc/aiha20/53/7?nav=tocList|journal=American Industrial Hygiene Association Journal|volume=53|pages=419–426|doi=10.1080/15298669291359889|pmid=1496932|access-date=22 January 2018|number=7|archive-date=7 April 2023|archive-url=https://web.archive.org/web/20230407193829/https://www.tandfonline.com/toc/aiha20/53/7?nav=tocList|url-status=live|url-access=subscription}}}}

File:Facial hairstyles and filtering facepiece respirators.pdf

Certain types of facial hair can reduce fit to a significant degree. For this reason, there are facial hair guidelines for respirator users.{{cite web|url=https://blogs.cdc.gov/niosh-science-blog/2017/11/02/noshave/|title=To Beard or not to Beard? That's a good Question!|date=2 November 2017|publisher=NIOSH|access-date=27 February 2020|archive-date=18 March 2020|archive-url=https://web.archive.org/web/20200318034249/https://blogs.cdc.gov/niosh-science-blog/2017/11/02/noshave/|url-status=live}}

Another disadvantage of respirators is that the onus is on the respirator user to determine if their respirator is counterfeit or has had its certification revoked. Customers and employers can inadvertently purchase non-OEM parts for a NIOSH-approved respirator which void the NIOSH approval and violate OSHA laws, in addition to potentially compromising the fit of the respirator.{{cite web|url=https://www.osha.gov/video/respiratory-protection/niosh/transcript|title=Transcript for the OSHA Training Video Entitled Counterfeit & Altered Respirators: The Importance of Checking for NIOSH Certification|date=January 2012|publisher=US Department of Labor, OSHA|access-date=3 June 2024|archive-date=3 June 2024|archive-url=https://web.archive.org/web/20240603060828/https://www.osha.gov/video/respiratory-protection/niosh/transcript|url-status=live}}

{{Wikisource-multi|Respirator Users' Notice Use of Unapproved Subassemblies|t1=Use of Unapproved Subassemblies (1984)|Letter to All Users of Supplied-Air Respirators Use of Unapproved Supplied-Air Respirators in the Paint Spray and Automotive Refinishing Industries|t2=Use of Unapproved Supplied-Air Respirators in the Paint Spray and Automotive Refinishing Industries (1996)}}

{{Gallery

|title=Counterfeit respirator identification

|align=center

|File:Counterfeit 3M Surgical mask N95.jpg

|A counterfeit N95 respirator with no TC#

|alt1=Counterfeit 3M respiurator

|File:3M 1860 N952020.jpg

|Compared to the official 3M

|alt2=3M respirator with TC#

|File:Counterfeit and Altered Respirators - The Importance of NIOSH Certification.webm

|OSHA video on modified and counterfeit respirators

|alt3=Video by OSHA

}}

If respirators must be used, under 29 CFR 1910.134, OSHA requires respirator users to conduct a respirator fit test, with a safety factor of 10 to offset lower fit during real world use.{{cite web|title=MAJOR REQUIREMENTS OF OSHA'S RESPIRATORY PROTECTION STANDARD 29 CFR 1910.134|url=https://www.osha.gov/sites/default/files/training-library_major_requirements.pdf|publisher=United States Department of Labor, OSHA|access-date=3 June 2024|archive-date=27 January 2024|archive-url=https://web.archive.org/web/20240127222116/https://www.osha.gov/sites/default/files/training-library_major_requirements.pdf|url-status=live}} However, NIOSH notes the large amount of time required for fit testing has been a point of contention for employers.{{cite web|url=https://blogs.cdc.gov/niosh-science-blog/2016/01/05/fit-testing/|title=New NIOSH Study Supports the OSHA Annual Fit Testing Requirements for Filtering Facepiece Respirators|publisher=NIOSH|date=5 January 2016|first1=Ziqing|last1=Zhuang|first2=Michael|last2=Bergman|first3=Jaclyn|last3=Krah}}

Other opinions concern the change in performance of respirators in use compared to when fit testing, and compared to engineering control alternatives:

{{blockquote|The very limited field tests of air-purifying respirator performance in the workplace show that respirators may perform far less well under actual use conditions than is indicated by laboratory fit factors. We are not yet able to predict the level of protection accurately; it will vary from person to person, and it may also vary from one use to the next for the same individual. In contrast, we can predict the effectiveness of engineering controls, and we can monitor their performance with commercially available state-of-the-art devices.{{cite journal|author=Edwin C. Hyatt|date=1984|title=Respirators: How well do they really protect?|url=http://www.isrp.com/|journal=Journal of the International Society for Respiratory Protection|volume=2|pages=6–19|issn=0892-6298|access-date=22 January 2018|number=1|archive-date=22 October 2016|archive-url=https://web.archive.org/web/20161022021929/http://www.isrp.com/|url-status=live}}}}

=== Issues with respirator design ===

Extended or off-label use of certain negative-pressure respirators, like a filtering facepiece respirator paired with a surgical mask,"...as compared with FFRs without SM [surgical mask], higher average inhaled CO2 were observed in four of six workloads among FFRs with SM". {{cite journal |author1=E.J. Sinkule|author2=J.B. Powell|author3=F.L. Goss |title=Evaluation of N95 respirator use with a surgical mask cover: effects on breathing resistance and inhaled carbon dioxide |journal=Annals of Occupational Hygiene |date=2013 |volume=57 |issue=3 |pages=384–398 |doi=10.1093/annhyg/mes068 |pmid=23108786 |publisher=Oxford University Press |language=en |issn=2398-7308 |doi-access=free }} can result in higher levels of carbon dioxide from dead space and breathing resistance (pressure drop) which can impact functioning and sometimes can exceed the PEL.{{cite journal |author1=R.J. Roberge|author2=A. Coca|author3=W.J. Williams|author4=J.B. Powell|author5=A.J. Palmiero |title=Physiological Impact of the N95 Filtering Facepiece Respirator on Healthcare Workers |journal=Respiratory Care |date=2010 |volume=55 |issue=5 |pages=569–577 |pmid=20420727 |url=http://rc.rcjournal.com/content/55/5/569 |publisher=American Association for Respiratory Care (AARC) |issn=0020-1324 |access-date=28 February 2021 |archive-date=31 October 2020 |archive-url=https://web.archive.org/web/20201031043804/http://rc.rcjournal.com/content/55/5/569 |url-status=live }}{{cite journal |author1=Carmen L. Smith|author2=Jane L. Whitelaw|author3=Brian Davies |title=Carbon dioxide rebreathing in respiratory protective devices: influence of speech and work rate in full-face masks |journal=Ergonomics |date=2013 |volume=56 |issue=5 |pages=781–790 |doi=10.1080/00140139.2013.777128 |pmid=23514282 |url=https://ro.uow.edu.au/cgi/viewcontent.cgi?article=1836&context=smhpapers |publisher=Taylor & Francis |s2cid=40238982 |issn=0014-0139 |access-date=28 February 2021 |archive-date=1 November 2020 |archive-url=https://web.archive.org/web/20201101065517/https://ro.uow.edu.au/cgi/viewcontent.cgi?article=1836&context=smhpapers |url-status=live }} This effect was significantly reduced with powered air purifying respirators.{{cite journal | doi=10.1186/s12879-021-06056-0 | doi-access=free | title=Carbon dioxide increases with face masks but remains below short-term NIOSH limits | date=2021 | last1=Rhee | first1=Michelle S. M. | last2=Lindquist | first2=Carin D. | last3=Silvestrini | first3=Matthew T. | last4=Chan | first4=Amanda C. | last5=Ong | first5=Jonathan J. Y. | last6=Sharma | first6=Vijay K. | journal=BMC Infectious Diseases | volume=21 | issue=1 | page=354 | pmid=33858372 | pmc=8049746 }} In various surveys among healthcare workers, headaches,{{cite journal |url=https://doi.org/10.1007/s11916-021-00968-x | doi=10.1007/s11916-021-00968-x | title=Headache Related to PPE Use during the COVID-19 Pandemic | date=2021 | last1=Ong | first1=Jonathan J. Y. | last2=Chan | first2=Amanda C. Y. | last3=Bharatendu | first3=Chandra | last4=Teoh | first4=Hock Luen | last5=Chan | first5=Yee Cheun | last6=Sharma | first6=Vijay K. | journal=Current Pain and Headache Reports | volume=25 | issue=8 | page=53 | pmid=34129112 | pmc=8203491 }} dermatitis and acne have been reported.{{cite journal |author1=Chris C.I. Foo|author2=Anthony T.J. Goon|author3=Yung-Hian Leow|author4=Chee-Leok Goh |title=Adverse skin reactions to personal protective equipment against severe acute respiratory syndrome – a descriptive study in Singapore |journal=Contact Dermatitis |date=2006 |volume=55 |issue=5 |pages=291–294 |doi=10.1111/j.1600-0536.2006.00953.x |publisher=John Wiley & Sons |pmid=17026695 |pmc=7162267 |language=en |issn=0105-1873|doi-access=free }}

Complaints have been leveled at early LANL NIOSH fit test panels (which included primarily military personnel) as being unrepresentative of the broader American populace.{{cite web|url=https://www.cdc.gov/niosh/docket/archive/pdfs/NIOSH-137/0137-081809-DraftNIOSHReport.pdf|title=Determination of Sample Size and Passing Criteria for Fit Test Panels|access-date=3 June 2024|archive-date=8 August 2023|archive-url=https://web.archive.org/web/20230808002256/https://www.cdc.gov/niosh/docket/archive/pdfs/NIOSH-137/0137-081809-DraftNIOSHReport.pdf|url-status=live}} However, later fit test panels, based on a NIOSH facial survey conducted in 2003, were able to reach 95% representation of working US population surveyed.{{cite journal |url=http://dx.doi.org/10.1080/15459620701497538 | doi=10.1080/15459620701497538 | title=New Respirator Fit Test Panels Representing the Current U.S. Civilian Work Force | date=2007 | last1=Zhuang | first1=Ziqing | last2=Bradtmiller | first2=Bruce | last3=Shaffer | first3=Ronald E. | journal=Journal of Occupational and Environmental Hygiene | volume=4 | issue=9 | pages=647–659 | pmid=17613722 | url-access=subscription }} Despite these developments, 42 CFR 84, the US regulation NIOSH follows for respirator approval, allows for respirators that don't follow the NIOSH fit test panel provided that: more than one facepiece size is provided, and no chemical cartridges are made available.§135, §198, and §205. {{cite web|url=https://www.ecfr.gov/current/title-42/chapter-I/subchapter-G/part-84|title=PART 84—APPROVAL OF RESPIRATORY PROTECTIVE DEVICES|access-date=3 June 2024|archive-date=15 March 2024|archive-url=https://web.archive.org/web/20240315131316/https://www.ecfr.gov/current/title-42/chapter-I/subchapter-G/part-84|url-status=live}}

Respirators designed to non-US standards may not be subject to as much or any scrutiny:

• In China, under GB2626-2019, which includes standards like KN95, there is no procedure for fit testing.{{cite web |url=https://openstd.samr.gov.cn/bzgk/gb/newGbInfo?hcno=16D8935B45AD7AE40228801B7FADFC6C |title=国家标准|Gb 2626-2019 |access-date=3 June 2024 |archive-date=3 June 2024 |archive-url=https://web.archive.org/web/20240603192044/https://openstd.samr.gov.cn/bzgk/gb/newGbInfo?hcno=16D8935B45AD7AE40228801B7FADFC6C |url-status=live }}

Some jurisdictions allow for respirator filtration ratings lower than 95%, respirators which are not rated to prevent respiratory infection, asbestos, or other dangerous occupational hazards. These respirators are sometimes known as dust masks for their almost exclusive approval only against dust nuisances:

• In Europe, regulation allows for dust masks under FFP1, where 20% inward leakage is allowed, with a minimum filtration efficiency of 80%.{{cite web|url=https://www.moldex-europe.com/en/moldex-good-to-know/protection-levels-ffp1-masks-ffp2-masks-ffp3-masks/|title=Protection levels: FFP1 masks, FFP2 masks, FFP3 masks|publisher=Moldex Europe|access-date=3 June 2024|archive-date=2 June 2024|archive-url=https://web.archive.org/web/20240602194300/https://www.moldex-europe.com/en/moldex-good-to-know/protection-levels-ffp1-masks-ffp2-masks-ffp3-masks/|url-status=live}}
• South Korea allows 20% filter leakage under KF80.

In the US, NIOSH noted that under standards predating the N95, 'Dust/Mist' rated respirators could not prevent the spread of TB.{{cite web|url=https://archives.federalregister.gov/issue_slice/1994/10/28/54237-54364.pdf|title=DEPARTMENT OF HEALTH AND HUMAN SERVICES Centers for Disease Control and Prevention Guidelines for Preventing the Transmission of Mycobacterium Tuberculosis in Health-Care Facilities, 1994|publisher=US Federal Register|access-date=2024-05-08|archive-date=8 June 2024|archive-url=https://web.archive.org/web/20240608020741/https://archives.federalregister.gov/issue_slice/1994/10/28/54237-54364.pdf|url-status=live}}

The choice and use of respirators in developed countries is regulated by national legislation. To ensure that employers choose respirators correctly, and perform high-quality respiratory protection programs, various guides and textbooks have been developed:

For standard filter classes used in respirators, see Mechanical filter (respirator)#Filtration standards.

{{Wikisource-multi|29 CFR 1910.134 Appendix D|Non-occupational Uses of Respiratory Protection – What Public Health Organizations and Users Need to Know|t2=Non-occupational Uses of Respiratory Protection – What Public Health Organizations and Users Need to Know (2018)}}

{{excerpt|N95 respirator|Voluntary respirator use}}

{{clear}}

• {{annotated link|Dust mask}}
• {{annotated link|Face shield}}
• {{annotated link|Gas mask}}
• {{annotated link|Health belief model}}
• {{annotated link|Minimum efficiency reporting value}}
• {{annotated link|Respirator assigned protection factors}}
• {{annotated link|Permissible exposure limit}}
• {{annotated link|Personal protective equipment}} (PPE)
• {{annotated link|Surgical mask}}
• {{annotated link|Workplace respirator testing}}

{{Reflist|2}}

{{refbegin |colwidth=30em}}

{{rma |tag=ND2 |reference={{cite web|url=http://www.cdc.gov/niosh/pdfs/sap_0101.pdf|archive-url=https://web.archive.org/web/20030319064642/http://www.cdc.gov/niosh/pdfs/sap_0101.pdf|date=January 2001|archive-date=2003-03-19|title=STANDARD APPLICATION PROCEDURES FOR THE CERTIFICATION OF RESPIRATORS|publisher=CDC NIOSH}}}}

{{rma |tag=C1 |reference={{citation|url=https://www.govinfo.gov/content/pkg/FR-1994-05-24/pdf/FR-1994-05-24.pdf|title=Federal Register |volume=59 |issue=99 |date=1994-05-24 |pp=26850-26893}}}}

{{rma |tag=C4 |reference={{citation|url=https://www.govinfo.gov/content/pkg/FR-1995-06-08/pdf/95-13287.pdf| title=Federal Register |volume=60 |issue=110 |date=1995-06-08 |pp=30336-30397}}}}

{{rma |tag=C5 |reference={{cite wikisource|wslink=29 CFR 1910.134 Appendix D |title=29 CFR 1910.134 Appendix D}}}}

{{rma |tag=N1 |reference={{cite wikisource|wslink=Changes in Occupational Safety Regs Will Permit Better Respirators to Protect Against Dust and Disease| title=Changes in Occupational Safety Regs Will Permit Better Respirators to Protect Against Dust and Disease| date=June 1995 |publisher=NIOSH}}}}

{{rma |tag=N2 |reference={{cite wikisource|wslink=NIOSH Guide to the Selection and Use of Particulate Respirators Certified Under 42 CFR 84 | title=NIOSH Guide to the Selection and Use of Particulate Respirators Certified Under 42 CFR 84 | date=January 1996 |scan=Index:DHHS Pub 96-101 NIOSH Guide to the Selection & Use of Particulate Respirators Certified Under 42 CFR 84.pdf |publisher=NIOSH}}}}

• {{cite book |title=A Performance Evaluation of DM and DFM Filter Respirators Certified for Protection Against Toxic Dusts, Fumes, and Mists WORKING DRAFT |date=1992 |publisher=CDC NIOSH |ref={{harvid|NIOSH|1992}}}} (Commons link) {{source-attribution}}
• {{citation |last1=Wetherell |first1=Anthony |last2=Mathers |first2=George |year=2007 |contribution=Respiratory Protection |editor-last=Marrs |editor-first=Timothy |editor2-last=Maynard |editor2-first=Robert |editor3-last=Sidell |editor3-first=Frederick |title=Chemical Warfare Agents: Toxicology and Treatment|location=New York |publisher=Wiley |pages=157–174 |isbn=978-0470013595}}
• {{citation |last1=Mayer-Maguire |first1=Thomas |last2=Baker |first2=Brian |year=2015 |title=British Military Respirators and Anti-Gas Equipment of the Two World Wars |publisher=Crowood}}
• {{Cite book |title=Essentials of Fire Fighting and Fire Department Operations |publisher=IFSTA |year=2008 |isbn=978-0135151112 |edition=5th | ref={{harvid|IFSTA|2008}}}}
• {{cite book |url=https://books.google.com/books?id=1Y64oZHP9zYC | title=NIOSH Guide to Industrial Respiratory Protection | last1=Bollinger | first1=Nancy J. | date=1987 }}
• {{citation |url=https://webstore.ansi.org/preview-pages/ASSE/preview_ANSI+ASSE+Z88.2-2015.pdf?srsltid=AfmBOoqcRAVMMGlzi5vb9BRw7GGDyQE8rcp4zLI1iLD9BE8z4rJYSm3e|title=ANSI/ASSE Z88.2 - 2015 American National Standard Practices for Respiratory Protection |date=April 2015 |url-access=limited| ref={{harvid|ANSI Z88.2|2015}}}}

{{refend}}

{{wikisource-multi|TB Respiratory Protection - Administrators Review|What You Should Know in Deciding Whether to Buy Escape Hoods, Gas Masks, or Other Respirators for Preparedness at Home and Work|Voluntary Program for Acceptance of Applications for the Testing and Evaluation of Full-Facepiece Air Purifying Respirators (APR) for Use Against Chemical, Biological, Radiological and Nuclear (CBRN) Agents|t1=TB Respiratory Protection - Administrator's Review (2002)|t2=What You Should Know in Deciding Whether to Buy Escape Hoods, Gas Masks, or Other Respirators for Preparedness at Home and Work (2003)|t3=NIOSH CBRN letter to respirator makers (2003)}}

{{refbegin}}

• [https://gerryowood.com/uploads/3/4/7/2/34729297/atom72.pdf A Sideline Mushroomed] - Summary of LANL involvement in respirators
• {{cite journal | first1=Victor E. | last1=Schwartz | first2=Cary | last2=Silverman | first3=Christopher E. | last3=Appel. | title=Respirators to the Rescue: Why Tort Law Should Encourage, Not Deter, the Manufacture of Products that Make Us Safer. | journal=Am. J. Trial Advoc. | volume=33 | issue=13 | date=2009 | url=https://www.shb.com/-/media/files/professionals/s/silvermancary/respiratorstotherescue.pdf}}
• {{cite court |litigants=3M COMPANY f/k/a MINNESOTA MINING AND MANUFACTURING COMPANY v. SIMEON JOHNSON, JAMES CURRY, BOBBY JOE LAWRENCE AND PHILLIP PATE |court=Supreme Court of Mississippi |date=2002-01-30 |url=https://courts.ms.gov/images/OPINIONS/CO23457.PDF |quote=dismissed with prejudice |reporter=2002-CA-01651-SCT }}
• {{cite book | first=Nicholas | last = Cheremisinoff | year=1999 | title=Handbook of Industrial Toxicology and Hazardous Materials | publisher=Marcel Dekker | isbn=978-0-8247-1935-7}}
• [https://www.cdc.gov/niosh/npptl/topics/respirators/disp_part/ NIOSH-Approved Disposable Particulate Respirators (Filtering Facepieces)]
• [http://www.tsi.com/uploadedFiles/Product_Information/Literature/Application_Notes/ITI-041.pdf TSI Application note ITI-041: Mechanisms of Filtration for High Efficiency Fibrous Filters] {{Webarchive|url=https://web.archive.org/web/20170829125133/http://www.tsi.com/uploadedFiles/Product_Information/Literature/Application_Notes/ITI-041.pdf |date=29 August 2017 }}
• British Standard BS EN 143:2000: Respiratory protective devices – Particle filters – Requirements, testing, marking
• British Standard BS EN 149:2001: Respiratory protective devices – Filtering half masks to protect against particles – Requirements, testing, marking

{{refend}}

{{Commons-inline|list=

• What's Special About Chemical, Biological, Radiological, and Nuclear (CBRN) Air-Purifying Respirators (APR)? (2013)

}}

{{Commons category|Respirators}}

• [http://webapps.msanet.com/ResponseGuide Mine Safety Appliance Company (MSA) Respirator Classification Guide] MSA.com
• [http://www.osha.gov/video/respiratory_protection/index.html OSHA videos on respiratory protection] {{Webarchive|url=https://web.archive.org/web/20120204230017/http://www.osha.gov/video/respiratory_protection/index.html |date=4 February 2012 }} osha.gov

{{Breathing apparatus|industrial|state=expanded}}

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Category:National Institute for Occupational Safety and Health