WASHINGTON, May 16, 2016 - “Glyphosate is unlikely to pose a carcinogenic risk to humans from exposure through the diet,” a World Health Organization/Food and Agriculture Organization panel has concluded.
The Joint WHO/FAO Meeting on Pesticide Residues (JMPR) came to the same conclusion about malathion and diazinon, two other pesticides evaluated along with glyphosate by the International Agency for Research on Cancer (IARC) in March 2015.
IARC concluded that all three chemicals were probable human carcinogens. The glyphosate finding has since become a rallying cry for glyphosate foes and an object of derision for Monsanto and other pro-glyphosate forces.
Monsanto, which sells glyphosate under the Roundup brand, touted the latest findings. “We welcome this rigorous assessment of glyphosate by another program of the WHO, which is further evidence that this important herbicide does not cause cancer,” said Phil Miller, Monsanto’s vice president for global regulatory and government affairs. “IARC’s classification was inappropriate and inconsistent with the science on glyphosate. Based on the overwhelming weight of evidence, the JMPR has reaffirmed the findings of regulatory agencies around the world that glyphosate is unlikely to pose a cancer risk.”
But the WHO said the two findings are complementary, not contradictory: IARC evaluated hazard, while the JMPR evaluated risk.
“IARC reviews published studies to identify potential cancer hazards. It does not estimate the level of ‘risk’ to the population associated with exposure,” the WHO said in a Q&A accompanying the report. “In contrast, JMPR reviews both published and unpublished studies to assess the level of health risk to consumers associated with dietary exposure to pesticide residues in food.”
FAO senior policy officer Harry van der Wulp told the Guardian that while the WHO/FAO analysis was comprehensive, “these conclusions relate to exposure through the diet – that is very important. It is not a general conclusion because anything beyond the diet was not in our mandate. It remains less clear what the situation is with occupational exposure.”
JMPR’s full report has not been completed. In a summary of its findings, JMPR said its risk assessment used a “weight-of-evidence approach” to conclude that the three compounds are unlikely to cause cancer in people via dietary exposure. “This means it is possible to establish safe exposure levels – acceptable daily intakes (ADI) – for consumers,” the WHO/FAO Q&A said.
The JMPR also concluded that the three substances are unlikely to be genotoxic through dietary exposure.
Jennifer Sass, a senior scientist at the Natural Resources Defense Council, said the JMPR report “ignores the evidence of cancer risk in rats, which IARC found convincing evidence, and in mice at higher doses. Ignoring high-dose cancer evidence ignores 50 years of established cancer toxicology and regulatory agency practice of presuming that what causes cancer in rodents in a well-conducted laboratory study will cause cancer in a person.”
Sass also took issue with the genotoxicity conclusion. “We know (glyphosate) is genotoxic when farmworkers and people in nearby communities were exposed from field spraying,” adding that “highly exposed populations are most at risk. If regulatory agencies are waiting for more evidence of cancer before they take action, those cancers are going to come from farmers, their families, and communities that alive near farms that spray glyphosate.”
The report comes at a critical moment for Monsanto. Later this week, a European Commission committee is scheduled to decide whether to reauthorize use of glyphosate.
A sticking point in that debate is the scientific foundation of the European Food Safety Authority’s finding that glyphosate is unlikely to cause cancer in humans. Critics, from environmental groups to scientists who served on the IARC glyphosate panel, say EFSA relied on unpublished industry data. EFSA has defended its work as scientifically credible.
In another study released recently, EPA’s Cancer Assessment Review Committee found glyphosate is unlikely to cause cancer in humans. But the agency, which said it mistakenly posted the report in its regulatory docket, said the report had not been finalized. Two congressional committees are now looking into the matter.