The International Agency for Research on Cancer's (IARC) recently classified of glyphosate as a group 2A "probable carcinogen".
But since 2009, the US Environmental Protection Agency (EPA) has been reviewing the test orders (requests for data) of several widely used herbicides and pesticides, including glyphosate, as part of the Endocrine Disruptor Screening Program (EDSP).
Endocrine disruptors are chemicals that can interfere with hormone systems and cause adverse developmental, reproductive, neurological, and immune effects in mammals.
Manufacturers Monsanto said glyphosate was included in the programme purely because of its extensive use and therefore high exposure potential, not because it was deemed to be particularly hazardous.
On 29 June, the EPA released a memorandum concluding that "glyphosate demonstrates no convincing evidence of potential interaction with estrogen, androgen or thyroid pathways in mammals." It also said that the next level of testing "is not recommended for glyphosate since there was no convincing evidence of potential interaction with estrogen, androgen or thyroid pathways."
Glyphosate, the active ingredient in Roundup, the world's best selling weed killer, is currently up for its routine, 10-year renewal by the European Union. The review has made glyphosate a target of anti-pesticide activists worldwide.
Monsanto said: "At Monsanto, we are committed to providing farmers, regulators and consumers with regular updates on glyphosate safety and benefits research. We know our products present no unacceptable risks when used in accordance with instructions, while they do offer farmers and society significant value. The EPA's finding provides a factual, science-based response to all the unscientific nonsense about glyphosate that seems to dominate social media."