WASHINGTON, Nov. 12 (UPI) -- Glyphosate, a chemical used in many herbicides, is unlikely to cause cancer in humans, researchers at the European Food Safety Authority found after a review of research. Despite the finding, the agency set new limits on the amount of the chemical considered safe for human exposure.
The review was spurred by a report from the International Agency for Research on Cancer, which said the chemical was "probably" carcinogenic.
The use of glyphosate, the main ingredient in herbicides such as Roundup, has increased dramatically in recent years as crops genetically-modified to resist the chemical have been developed.
Concerns about chemicals used in the growth of food crops causing cancer have grown significantly as studies have shown glyphosate can cause cancer, although research, some of it by Monsanto, the company that makes Roundup, has shown otherwise.
"This has been an exhaustive process -- a full assessment that has taken into account a wealth of new studies and data," said Jose Tarazona, head of the EFSA's pesticides unit, in a press release. "By introducing an acute reference dose we are further tightening the way potential risks from glyphosate will be assessed in the future. Regarding carcinogenicity, it is unlikely that this substance is carcinogenic."
Researchers at the EFSA reviewed more than 100 studies on glyphosate, finding the link between it and cancer was weak, at best. In several studies, there was no evidence it caused or increased the risk of cancer.
In a complementary explanation of the review, the researchers note glyphosate's effect on cancer rates is often analyzed together with other pesticides and herbicides, and exposure is difficult to measure based on interviews that have intrinsic recall bias. On top of this, the researchers said reporting of types of cancer and adverse outcomes are inconsistent and the toxicity of exposure to other chemicals cannot be accurately assessed.
Even with the decision that glyphosate is "unlikely" to cause cancer, the scientists set acceptable exposure levels for people who work with the chemical at 0.1 mg per kilogram of body weight per day and consumer intake of the chemical at 0.5 mg per kilogram of body weight per day.
Tarazona said the EFSA will use the limits during a review for regulation of glyphosate in food set for next year, and the agency will forward its review to the European Commission for final rulings on use of the chemical in the European Union.
The full review is published in the EFSA Journal.