We’ve known for a while that Monsanto buried the truth about Roundup weedkiller by ignoring concerns by its own scientists. Now it seems Dow Chemical Co. has been using the same playbook.

Dow (renamed DowDuPont after its 2017 merger with DuPont) likely knew for decades that its widely used chlorpyrifos insecticide is harmful to humans—especially children and developing fetuses. But the company hid that information from regulators, both in the U.S. and EU, according to a new study, published in the journal Environmental Health.

The revelation comes as the U.S. Environmental Protection Agency (EPA) is duking it out in the legal system over an August 2018 court ruling requiring the agency to finalize a the ban on chlorpyrifos that was originally proposed under the Obama administration, but overturned after Trump took office.

On September 24, the EPA—the agency charged with protecting us from environmental contaminants—asked the courts to rehear the case. The move means that chlorpyrifos is still being used while the request for a rehearing plays out in the courts. Organic Consumers Association is collecting signatures on a petition to the EPA, asking the agency to rescind its request for a rehearing, and ban chlorpyrifos now.

In California alone, 800,000 acres and dozens of crops continue to be doused with a pesticide that Beyond Pesticides describes this way:

A neurological toxicant, chlorpyrifos damages the brains of young children: impacts of exposure, even at very low levels, include decreased cognitive function, lowered IQ, attention deficit disorder,and developmental and learning delays.

Dow Chemical study produced ‘misleading’ results

The scientists who conducted the new study used public information requests to expose the raw data behind safety studies Dow submitted to European regulators in the late 1990s.

The data is of particular importance as it was used in the EU’s decision to approve chlorpyrifos in 2006. The same studies were also submitted to officials at the EPA.

The study’s authors attempted to replicate the findings in Dow’s original study. But they discovered serious flaws, even omissions, in the company’s analysis. The industry study found “no selective effects on neurodevelopment” in rats, even at high levels of exposure to chlorpyrifos. This contradicts mounting evidence linking chlorpyrifos to neurodevelopmental problems in developing fetuses and young children—even at very low levels.

The scientists found “treatment-related changes in a brain dimension measure for chlorpyrifos at all dose levels tested.” These findings went unreported in Dow’s original analysis. In other words, Dow’s own data showed that chlorpyrifos hurt rats, but company didn’t communicate that fact to regulators. According to the study authors:

We further found issues which inappropriately decrease the ability of the studies to reveal true effects, including a dosage regimen that resulted in too low exposure of the nursing pups for chlorpyrifos and possibly for chlorpyrifos-methyl, and a failure to detect any neurobehavioral effects of lead nitrate used as positive control in the chlorpyrifos study.

Our observations thus suggest that conclusions in test reports submitted by the producer may be misleading. This discrepancy affects the ability of regulatory authorities to perform a valid and safe evaluation of these pesticides. The difference between raw data and conclusions in the test reports indicates a potential existence of bias that would require regulatory attention and possible resolution.

Chlorpyrifos applied to 50 different crops

Chlorpyrifos, an organophosphate pesticide (OP) widely used in agriculture, is approved for use in 100 countries. The insecticide is used on an upwards of 50 crops including almonds, cotton, citrus fruits, grapes, corn, broccoli, sugar beets, peaches and nectarines.

Despite being allowed on all these foods, chlorpyrifos was banned for indoor home use in 2001.

Chlorpyrifos and other OPs are highly controversial due to the damaging effects they have on the human nervous system. The class of pesticides works by blocking an enzyme needed by the brain to regulate communication between nerve cells.

As a result, exposure to chlorpyrifos, including at low levels, has been shown to cause neurodevelopmental effects such as decreased cognitive function, lowered IQ, attention deficit disorder and developmental and learning delays in young children. Chlorpyrifos also has been linked to a loss of memory in farmworkers.

Given the evidence of harm caused by chlorpyrifos in humans, and especially children, any push to keep the chemical on the market is nothing short of unconscionable.

"What type of society poisons its children?” said Andre Leu, author of “The Myths of Safe Pesticides,” in an email to the Organic Consumers Association. “This shows the corruption of the Poison Cartels and how they are damaging the developing brains of children—they must be stopped!"

Several U.S. states have moved to restrict or ban chlorpyrifos, including California, Hawaii, Maryland and New Jersey. In June 2018, Hawaii became the first state to ban it.

California, which applies chlorpyrifos to more than 800,000 acres and on dozens of crops, has proposed several restrictions on the use of the insecticide. Through its Department of Pesticide Regulation (DPR), the state is pushing to ban all aerial application of chlorpyrifos, as well as discontinue its use on most crops.

DPR is also recommending a quarter-mile buffer zone during all allowed applications of the pesticide and for 24 hours afterward, and a 150-foot setback from houses, businesses and schools.

Julie Wilson is communications associate for the Organic Consumers Association (OCA). To keep up with OCA news and alerts, sign up for our newsletter.