Lawsuits warn newly banned pesticide might linger for years in homes

The four lawsuits, filed on behalf of parents who say their children were hurt by the chemical known as chlorpyrifos, assert that traces of the chemical were found in their homes even after reductions in use of the substance, suggesting it might linger for years.

 “While it is laudable that there is a move to curtail the use of chlorpyrifos, that doesn’t diminish the legacy exposure risk,” said Stuart Calwell, a lawyer behind the suits, in an interview.

Last week, the EPA announced that it would ban the use of chlorpyrifos on food, citing public health. The agency said that six months after the final rule is published in the Federal Register, the pesticide will no longer be permitted in food. Publication is expected in the coming months.

“Ending the use of chlorpyrifos on food will help to ensure children, farmworkers, and all people are protected from the potentially dangerous consequences of this pesticide,” EPA Administrator Michael Regan said in a statement.

Exposure to the substance has been linked to mental delay and psychomotor delays, a loss of IQ points and reduced working memory.

Chlorpyrifos was banned for most residential use by the EPA in 2000. The agency said last week that it would continue to review any other non-food uses.

The general public can be exposed to chlorpyrifos through food, but agricultural workers and communities close to farms where pesticides are sprayed are at additional risk of coming into contact with the substance.

Calwell represents plaintiffs from across California's Central Valley who seek damages for harms allegedly caused by the chemicals.

The suits, filed in July and August, also allege that sampling from the plaintiffs’ California residences in September 2019 “revealed the presence of chlorpyrifos oxon in the home, establishing contamination long after the reduction of use in the Central Valley.”

Data from May 2019 through October 2019 from California's Department of Pesticide Regulation show that the use of chlorpyrifos in the state declined by more than 99 percent in 2019.

According to the state, the decline probably stemmed from restrictions that started at the beginning of 2019. A ban was announced in May of that year but enacted later.

Calwell said one challenge is that the chemical breaks down more slowly indoors.

“These compounds, if they’re exposed to the outdoor environment ... they do break down. But when they find their way into controlled environments like the inside of a building or a house, the degradation slows down dramatically,” the lawyer said.

“These things find themselves sequestered in carpet and upholstery ... and in dust in a house and they are basically in controlled environments such that the risk of exposure persists well beyond the active spraying that might take place in an agricultural field in the neighborhood,” he added.

The lawsuits claim that it’s likely that “hundreds, if not thousands” of other families living near the plaintiffs reside in homes that are “similarly contaminated.”

In addition to damages for the alleged harms, the plaintiffs also seek money for decontamination, essentially asking companies to pay to clean up traces of the chemical that may remain in houses.

A 2009 federal study called the American Healthy Homes Survey found traces of chlorpyrifos in more than two-thirds of homes analyzed years after the EPA’s initial ban on the chemical in 2000.

"The findings suggest that some insecticides might remain in homes, particularly if used in large quantities. It is thought that pesticide residues once introduced to the interior of residential dwellings are not in direct contact with the primary degrading factors found outdoors," the EPA said in a statement to The Hill when asked about the 2009 study, which lists an EPA scientist as its lead author.

"More research is required to determine if these temporal trends continue once a compound is removed from the market and if measured residues decline," the agency added.

Among the defendants of the suits, which allege that the children were injured due to exposure to the substance, are major chemical companies Dow and its spinoff Corteva.

A spokesperson for Dow declined to comment on the lawsuits, referring The Hill instead to Corteva because “Dow’s former agriculture business and all related expertise has been part of Corteva since 2019.”

Corteva did not respond to The Hill’s request for comment.

An EPA spokesperson did not immediately respond to separate questions from The Hill on whether it’s possible for the agency to take further action besides its most recent ban to clean up homes that are contaminated with chlorpyrifos — or whether it would want to.

But a former EPA regional Superfund division director told The Hill that any agency-led cleanup for chemicals that aren’t designated as hazardous substances could take a long time.

“It would be covered under that provision that deals with other pollutants and you have to go through that [Agency for Toxic Substances and Disease Registry] health evaluation to see if it is causing any risks,” the former official said. “This is kind of a lengthy, lengthy process to say the least.”