The world's most widely used weed killer can "probably" cause cancer, the World Health Organization said on Friday. The WHO's cancer arm, the International Agency for Research on Cancer, said glyphosate, the active ingredient in Roundup and other herbicides, was "classified as probably carcinogenic to humans." It also said there was "limited evidence" that glyphosate was carcinogenic in humans for non-Hodgkin lymphoma.
Monsanto, the world's largest seed company and Roundup's manufacturer, said in a statement that scientific data do not support the agency's conclusions and called on WHO to hold an urgent meeting to explain the findings.
Concerns about glyphosate on food have been a hot topic of debate in the United States recently, and contributed to the passage in Vermont last year of the country's first mandatory labeling law for foods that are genetically modified. The U.S. government says the herbicide is considered safe.
Glyphosate is mainly used on crops such as corn and soybeans that are genetically modified to survive it. The weed killer has been detected in food, water and in the air after it has been sprayed, according to the WHO agency's report. However, glyphosate use is generally low in and near homes where the public would face the greatest risk of exposure, the report said.