Don’t let EPA and Monsanto hide the truth on Roundup

Attorneys general in other states have joined with Monsanto to stop California from requiring warning labels that Roundup includes a carcinogen.
Attorneys general in other states have joined with Monsanto to stop California from requiring warning labels that Roundup includes a carcinogen. AP file

In the waning days of 2017, the U.S. Environmental Protection Agency quietly announced it had concluded that Roundup does not cause cancer.

And this month, 11 state attorneys general announced they’re backing Monsanto’s push to kill a California regulation that will require cancer warnings on glyphosate, Roundup’s active ingredient. Monsanto contends research conducted for the World Health Organization wrongly determined glyphosate to be a probable carcinogen.


The conflicting reports could cause people to ask: Should I be concerned about the safety of the Roundup in my garden shed?

The answer, according to the most rigorous analysis of independent, peer-reviewed research: Yes, you should.

Since the 1980s when Monsanto first sought EPA re-approval of glyphosate, the company has worked to discredit research indicating the pesticide is a carcinogen. After research indicating glyphosate caused rare kidney tumors in mice led the EPA to determine it was possible carcinogen, a scientist hired by Monsanto said he found a kidney tumor in one “control” mouse not dosed with glyphosate, which would discount the EPA’s conclusion.

After reviewing his findings, EPA scientists again confirmed that glyphosate triggers tumor development. Yet, after additional Monsanto-hired scientists weighed in, the EPA ignored its own scientists and announced that glyphosate was safe.

In the ensuing three decades, glyphosate has become the world’s most used pesticide, with 300 million pounds dumped on American fields, lawns and gardens every year.

Then in 2015 a research arm of the WHO – the gold standard for cancer research – analyzed all published studies and determined glyphosate is indeed a probable carcinogen, prompting California to add it to its list of cancer-causing chemicals.

While Monsanto insists the WHO experts “cherry-picked” research, they analyzed only public research reviewable by independent scientists, correctly excluding many of Monsanto’s confidential studies.

In response, the company initiated an “independent” review. But emails obtained in lawsuits against Monsanto by cancer victims revealed that the company paid two of the authors and an employee substantially edited the article.

The EPA’s most recent conclusion that glyphosate is unlikely to cause cancer required the agency to sidestep its own research guidelines. Instead of comparing treated animals to non-treated animals in the same experiment, the EPA compared them to non-treated animals from experiments done many years ago. And the EPA decided that if only one of two commonly used statistical tests showed a significant increase in cancer, the agency would use the more favorable test.

By contrast, the WHO analyzed many of the same studies but followed a more rigorous process accepted by independent scientists. That analysis spurred California to declare glyphosate products should include cancer warnings, prompting Monsanto to sue.

What’s clear is that Monsanto and the Scott Pruitt-led EPA want no part of a truly independent scientific process. And they’re confident the issue is complicated enough that the American public will just trust them.

But all the most compelling scientific evidence suggests that trust would be grossly misplaced.

Nathan Donley, a former cancer researcher, is a senior scientist at the Center for Biological Diversity’s environmental health program in Olympia, Wash. He can be contacted at