'Outrageous': Research Shows Pesticide Giants Withheld Brain Toxicity Studies From EU

New research published Thursday in the journal Environmental Health found that pesticide companies did not disclose to European Union regulators at least nine studies examining the brain toxicity of their chemical products—a finding that experts said is a scandal that must spur reforms.

"It is outrageous," Christina Rudén, a professor of regulatory ecotoxicology and toxicology at Stockholm University and a co-author of the new study, told The Guardian.

The researchers behind the new study found that pesticide companies submitted 35 developmental neurotoxicity (DNT) assessments to the U.S. Environmental Protection Agency between 1993 and 2015 as part of efforts to win regulatory approval for their products.

But the companies withheld nine of those 35 studies from E.U. regulators, the new analysis notes, raising concerns that the firms deliberately suppressed information that may have impacted risk assessments. The Guardian noted that "the pesticides identified in the new study include the insecticides abamectin, ethoprophos, and pyridaben and the fungicide fluazinam."

"These are, or have been, used on a range of crops including tomatoes, strawberries, potatoes, and aubergines," the newspaper added.

The researchers said their findings demonstrate that "non-disclosure of DNT studies to E.U. authorities, in spite of clear legal requirements, seems to be a recurring phenomenon." Last year, the same researchers discovered that an industry-sponsored DNT study on glyphosate found impacts on "neurobehavioural function, motor activity, in rat offspring"—findings that were not shared with E.U. officials.

Glyphosate is currently authorized for use in the E.U. through 2023, despite evidence of its negative effects on humans, animals, insects, and the environment.

"Without full access to all performed toxicity studies, there can be no reliable safety evaluation of pesticides by E.U. authorities," the researchers warned Thursday. "Rules should be amended so that future studies should be commissioned by authorities rather than companies. This ensures the authorities' knowledge of existing studies and prevents the economic interest of the company from influencing the design, performance, reporting, and dissemination of studies."

Bayer—which owns Monsanto, maker of the cancer-linked glyphosate product Roundup—and Nissan Chemical were among the sponsors of the studies withheld from E.U. authorities, who only learned about the assessments years after they were conducted.

As AFP reported, the brain toxicity studies "were conducted on pregnant rats, testing whether the offspring of those exposed to the compounds suffered developmental problems."

"Decreased weight gain, delayed sexual maturation, and deteriorating motor activity were among the side effects reported in adult offspring in the studies," the outlet continued. "Of the nine pesticide compounds, four have now been taken off the E.U. market, while another four are currently under review."

"It is outrageous and unbelievable that a good fraction of these studies do not make it to the authorities as required by law," Axel Mie, another study co-author, told AFP. "There must be legal consequences and serious ones for the companies if they do not follow the law."