Future of Top Pesticide Uncertain After Grueling Cancer Review

The future of glyphosate, the most widely used pesticide in the world, is uncertain after a grueling, four-day review of the Environmental Protection Agency’s scientific evaluation of the chemical’s cancer-causing potential.

The 15 scientists assembled by the EPA to analyze glyphosate, the active ingredient in Monsanto’s Roundup and dozens of other weed killers, struggled to reach a consensus amid an ocean of conflicting and, in some cases, flawed data on the health and environmental effects of the chemical.

The scientists now have three months to make a formal recommendation to the agency that could strongly influence its upcoming decision on whether it should impose new safety restrictions on how glyphosate is used.

With the chemical’s ubiquity on farms, especially alongside genetically engineered crops, any measure the EPA takes to rein in glyphosate could have seismic economic effects for the agriculture industry. The amount of the chemical used has grown exponentially over the past 30 years and is now approaching 300 million pounds annually, according to data the EPA presented to the scientists.


In advance of the panel’s session this week, the EPA prepared hundreds of pages of scientific evidence supporting its conclusion that glyphosate is likely not carcinogenic. This conclusion diverged from a 2015 World Health Organization review that found glyphosate is probably carcinogenic, a finding that triggered numerous lawsuits against Monsanto from cancer sufferers. The European Union also is conducting a risk review of the chemical.

Charla Lord, a Monsanto spokeswoman, told Bloomberg BNA that “the overwhelming conclusion of experts worldwide, including the EPA, has been that glyphosate can be used safely. No regulatory agency in the world considers glyphosate to be a carcinogen.”

However, the scientists assembled by the EPA weren’t so certain. They spent four days, including one and a half days devoted solely to hearing comments from the public, poring over scientific studies on links between glyphosate and cancer, particularly a type of immune system cancer called non-Hodgkin’s lymphoma that farmers suffer at higher rates than other occupational groups.

Many of the panel’s scientists were reluctant to declare that glyphosate definitively does not cause cancer, as the EPA had done. But they also said the data indicating the chemical is a cancer danger is far from clear.

“There’s been 30 years of study on this chemical, and I’m surprised we’re still at this level of uncertainty on this,” panelist Kenneth Portier, a statistician with the American Cancer Society, said.

‘Clear as Mud’

One of the key disputes among the panel was whether the increased lymphoma rate among farmers is caused by glyphosate exposure or by some other aspect of agricultural work.

Dr. Eric Johnson, a panelist who teaches epidemiology at the University of Arkansas, said this could be settled by comparing data on cancer rates among farmers who spray glyphosate with the same data on factory workers who manufacture the chemical. This would also reveal whether the raw chemical itself is causing cancer or whether it’s the mixture of glyphosate with other commonly used inert ingredients.

However, EPA officials informed Johnson that they don’t have access to the factory worker data because these workers fall under the jurisdiction of occupational health and safety authorities. Industry representatives, meanwhile, told Johnson they couldn’t supply him with the data.

“We’re asking EPA to be transparent, but we’re not seeing that from industry,” Johnson said. “These are the types of things that make people suspicious of industry.”

At the end of a lengthy discussion on this topic, filled with cross-talk and raised voices, the chairman of the scientific panel asked EPA official Anna Lowit if the agency understood the panel’s position.

“It’s clear as mud,” Lowit replied.

Panel Makeup

To make matters more complicated, the very makeup of the panel itself was a point of contention.

The scientists were supposed to have met in October but, just days before it was to begin, the EPA postponed the meeting until Dec. 13. The delay was “due to the voluntary departure of a panel member,” EPA spokesman Nick Conger told Bloomberg BNA at the time.

As it turned out, that member was likely Peter Infante, a scientist who had in the past strongly condemned Monsanto and its research into the risks posed by its own products. The pesticide industry trade group CropLife America had asked the EPA to remove Infante from the panel, citing his alleged biases against its members. Infante responded to these claims with a subsequent letter of his own to the EPA.

But while Infante was not sitting on this week’s panel, he did attend its deliberations and made comments to the panel as a member of the public. He also told Bloomberg BNA that his removal was not voluntary, but he declined to elaborate further on what happened.

The EPA also declined to comment on Infante’s status. The environmental advocacy group the Center for Food Safety sent the EPA a letter earlier this week arguing that Infante’s removal violated federal laws on advisory committees.

Next Steps

Now that the panelists have concluded their public deliberations, they will have 90 days to synthesize their thoughts into an official but nonbinding report to the EPA.

The EPA will use that report to inform its decision on how glyphosate can be used, not only on farms but also for weed control in residential and commercial buildings.

The EPA has been revisiting the terms of its approval of glyphosate as a part of its periodic registration review process, in which it’s legally required to review the risks and efficacy of all pesticides at least once every 15 years.

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