Glyphosate classified as ‘probably carcinogenic’

Monsanto questions results of report, which also includes diazinon, malathion and parathion

crop sprayer operating in the field

The decision by an international group of cancer experts to classify the active ingredient in Roundup herbicide as “probably carcinogenic” has drawn fire from the product’s main maker.

The International Agency for Research on Cancer (IARC), a France-based arm of the World Health Organization, last Friday released its working group’s evaluations on the cancer-causing potential for glyphosate herbicide and four other organophosphate pesticides — diazinon, malathion, parathion and tetrachlorvinphos.

For glyphosate, malathion and diazinon, IARC’s 17-member group found “limited” evidence of cancer sites in humans, but “sufficient” evidence in animals for glyphosate and malathion. The group has classified all three chemicals in the agency’s Group 2A — “probably carcinogenic to humans.”

Parathion and tetrachlorvinphos, meanwhile, were placed in Group 2B — “possibly” carcinogenic.

Monsanto — the company that first brought broad-spectrum glyphosate to market under the Roundup name in 1974, followed by Roundup Ready crops starting in 1996 — said Friday the agency’s report offers no new research or data, but instead relies on certain studies while disregarding others.

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