The EPA should conduct “an urgent re-evaluation” of glyphosate, one of the most widely used pesticides in the world, in response to a determination by a World Health Organization agency that the weedkiller is probably carcinogenic for humans, said eight environmental groups. Glyphosate is best known in the United States under the brand name Roundup. In a letter to EPA administrator Gina McCarthy, the groups said the agency also should bar use of a new weedkiller, Enlist Duo, that combines glyphosate with 2,4-D. The EPA approved Enlist Duo for use in six states last October, and is considering whether to approve it for 10 additional states. Developers say Enlist Duo would be effective against “super weeds” that have developed resistance to glyphosate alone.
Last week, WHO’s International Agency for Cancer Research listed glyphosate as “probably carcinogenic” following a review of recent scientific studies. The EPA rated it as non-carcinogenic in 1991. Use of glyphosate soared with the development by Monsanto Co. of genetically engineered strains of corn and soybeans that tolerate the weedkiller. Monsanto disputes the IACR listing.