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Cancer Data Being Suppressed by International Organization

Right now, there is a controversy that has called into question a finding by an international organization that a common chemical is a cancer-causing agent.

Last month, Reuters reported on new data that might mean the final nail in the coffin for allegations that glyphosate, the active ingredient in the world’s most widely used weed killer, is a known carcinogen. As a direct result of Reuters’s reporting, Rep. Tom Cole (R-Okla.) asked Environmental Protection Agency Administrator Scott Pruitt to make sure the agency reviews the previously undisclosed data from a previously withheld Agricultural Health Study, which shows that glyphosate does not cause cancer.

In a controversial assessment of glyphosate, the International Agency for Research on Cancer, an arm of the World Health Organization, disregarded AHS data presented during deliberations that contradicted a finding that glyphosate is “probably carcinogenic.” That pronouncement caused confusion among consumers and controversy among policymakers on the safety of the common weed killer that is still playing out on the international stage.

For instance, the original IARC finding that glyphosate is a carcinogen led the European Commission to delay its decision on whether to re-license European Union-wide sale of herbicides containing the chemical, and caused some countries and municipalities to ban the use of the weed killer in parks, and even privately owned gardens. A petition in Europe calling for the herbicide to be banned gathered 1 million signatures, while a loophole in California’s Prop 65 used IARC’s study to force all glyphosate-based atomizers sold in the state to carry a disclaimer about its potential effects on human health.

Moreover, IARC’s decision frayed public trust in science-based regulations. So it’s not only in the interest of farmers and consumers that the EPA perform a full review and release the full data sets. It’s also in the interest of transparency and openness — critical features of science itself.

Since it was introduced in the mid-1970s, glyphosate has been seen as one of the most benign herbicides on the market. And that’s not just a matter of image. All international and national regulatory bodies have backed up this view. The EPA, the European Food Safety Authority, and others have all concluded that glyphosate does not cause cancer. The one outlier has been IARC.

What’s key here is that IARC’s methodology for establishing carcinogenicity — it’s evaluated more than 989 substances and activities — is vastly different from actual regulatory bodies. For one thing, IARC examines hazard, or the evidence of whether a given substance can theoretically cause cancer in any way — not the risk, or actual chance, that it will do so, based on how people actually use it. Second, it doesn’t perform its own studies, but only evaluates research that’s already been published in peer-reviewed scientific journals.

Both of these practices go a long way towards explaining why, in four decades’ worth of evaluations, IARC has only determined that one substance — an ingredient in nylon that’s used in yoga pants! — doesn’t cause cancer.

But more than anything, it’s IARC’s willingness to ignore valuable unpublished research that explains why its assessments have often been out in left field. And the Reuters story shows why.

Unpublished data from AHS, one of the most highly regarded investigations into the effects of pesticides on humans involving scientists from the EPA and other agencies, showed that there was no evidence of an association between glyphosate exposure and cancer. Aaron Blair — who was a senior researcher on that study and chaired IARC’s glyphosate review panel — had not only seen the data, but was a participant in the research in his role at the National Cancer Institute. So of course Blair was aware of its implications, which, he admitted under deposition, would’ve changed IARC’s mind.  

Blair never published the AHS’s data on glyphosate, which was available a full two years before IARC published its assessment — saying there was too much to fit into one paper. The National Cancer Institute also blamed “space constraints” as the reason why the new data wasn’t published. Meanwhile, two independent statisticians interviewed by Reuters both noted the significance of the research and couldn’t see why the data wasn’t published.

At this point, it’s too late to go back in time and there’s hardly anything the U.S. government can do (other than pressure IARC and threaten to withdraw taxpayer funding) to make it rethink its absurd ban on considering unpublished data. But the least we can do is to have the EPA not only review the AHS data, but also finally bring it out of the dark.

Dan Perrin is a former Senate staffer and a Republican strategist. He is the president of the HSA Coalition.

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