1973 in the environment

• Several thousand pounds of polybrominated biphenyls were accidentally mixed with livestock feed that was distributed to farms in Michigan, because the plant also produced a feed precursor ingredient, magnesium oxide, which was sold to the feed manufacturer.{{cite journal | author=Carter, Luther J | title=Michigan's PBB incident: Chemical Mix-Up Leads to Disaster | journal=Science | volume=192 | pages=240–243 | date=1976-04-16 | doi=10.1126/science.192.4236.240 | pmid=17831151 | issue=4236}} Adverse reproductive-system effects continued 40 years later to be found in the grandchildren of those who consumed tainted farm products.{{cite web|url=http://michiganradio.org/post/40-years-after-toxic-mix-researchers-continue-study-michiganders-poisoned-pbb |author=Rebecca Williams |title=40 years after toxic mix-up, researchers continue to study Michiganders poisoned by PBB |publisher= Michigan Public Media, The Regents of the University of Michigan |year=2014 |accessdate=2014-11-13}}

• The snail darter controversy delayed the construction of the Tellico Dam on the Little Tennessee River in the United States when the snail darter fish was discovered in the river.

• The International Agreement on the Conservation of Polar Bears was signed in Oslo, Norway.

• The Endangered Species Act was signed into law in the United States by President Richard Nixon.United States. Endangered Species Act of 1973. {{USPL|93|205}} Approved 1973-12-27.

{{Portal|Environment}}

• Human impact on the environment
• List of environmental issues

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