May 10, 2010
Image of Atrazine 3D Image of Atrazine

Atrazine, a widely used herbicide, was first described in 1960 in two Swiss patents. It is prepared from cyanuric chloride, a chemical that is also used to chlorinate swimming pools. It was first considered to be relatively nontoxic to humans and animals, but in the past decade new toxicity studies and atrazine's persistence in groundwater caused it to be banned in the European Union. It is still used in the United States and numerous other countries. Recently, biologists showed that atrazine causes sex changes in frogs.

MOTW update:
March 7, 2022

Herbicides atrazine1 and 2,4-dichlorophenoxyacetic acid2, the Molecule of the Week for August 12, 2012, both have been heavily used in commercial agriculture for decades and have increasingly come under environmental restrictions.

Now, after many years of neglect, the US Environmental Protection Agency is reassessing the use of these and many other pesticides in terms of their compliance under the Endangered Species Act of 1973. In response, manufacturers and farmers’ groups have complained that the new mitigation measures make it difficult to find alternative products so close to this year’s growing season.

1. CAS Reg. No. 1912-24-9.
2. CAS Reg. No. 94-57-5.

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