Center for Biological Diversity

For Immediate Release, November 16, 2018

Contact: Nathan Donley, (971) 717-6406,

Study: Dow-funded Chlorpyrifos Research Omitted Results, Leading to Inaccurate Conclusion of Pesticide's Safety

 'Misleading' Findings Impaired EPA's Ability to Assess Pesticide's Harms

PORTLAND, Ore.— Unpublished research funded by Dow Agrosciences, the maker of the pesticide chlorpyrifos, omitted key results on the brain-harming effects of the pesticide, undermining the Environmental Protection Agency’s ability to accurately assess its safety, according to a peer-reviewed study published this week in the journal Environmental Health.

The two unpublished studies, looking at how chlorpyrifos and the closely related chlorpyrifos-methyl harmed the offspring of pregnant rats, were used by the EPA to evaluate the pesticides. It was found that the summaries of the research provided to the agency left out important information on harm to brain morphology and contained egregious errors in scientific methodology that masked harmful effects.

In sharp contrast to these industry-funded studies, numerous independent studies have found significant adverse health effects of chlorpyrifos exposure on developing nervous systems, such as lowered IQ, at current exposure levels.

“It’s shameful that Trump’s EPA embraced Dow’s misleading studies to push for ongoing use of this brain-damaging poison,” said Nathan Donley, a senior scientist at the Center for Biological Diversity. “Instead of relying on independent, peer-reviewed research to accurately assess this pesticide’s harms and protect our children, team Trump is using incomplete industry studies. This is what pesticide regulation looks like when industry calls all the shots at the EPA.” 

The researchers assessing the Dow study found that “[t]he difference between raw data and conclusions in the test reports indicates a potential existence of bias that would require regulatory attention and possible resolution.”

Those discrepancies directly affect “the ability of regulatory authorities to perform a valid and safe evaluation of these pesticides,” the new report stated.

Shortly after President Trump’s election, then EPA administrator Scott Pruitt reversed a plan to ban the use of chlorpyrifos on all food crops. But in August of this year, a federal appeals court ruled that the EPA must prohibit the pesticide’s use on food because of its well-documented brain-damaging effects on children. The Trump Department of Justice immediately vowed to fight the ruling and in September filed an appeal.

“The Trump EPA not only reversed this important effort to protect our children but is ignoring the best science available to help out Dow, which gave the administration a $1 million inaugural gift,” said Donley.

Five million pounds of chlorpyrifos are used in the United States every year on crops such as corn, peanuts, plums and wheat. A recent study at the University of California at Berkeley found that 87 percent of umbilical-cord blood samples tested had detectable levels of chlorpyrifos.

Early childhood exposure to organophosphates like chlorpyrifos has been linked to cognitive delay and attention deficit hyperactivity disorder, or ADHD.

Organophosphates were used as nerve agents in chemical warfare and have been linked to Gulf War syndrome, which causes fatigue, headaches, skin problems and breathing disorders. 

The Center for Biological Diversity is a national, nonprofit conservation organization with more than 1 million members and online activists dedicated to the protection of endangered species and wild places.

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