Following a decade of orders, studies and warnings, the Environmental Protection Agency has issued an emergency order to cease all usage of the weed killer Dacthal, also known as DCPA.

The emergency order took immediate effect on Tuesday and all of the pesticide’s registrations have been suspended. This marks the first time in nearly 40 years that the EPA has issued an emergency suspension of this nature.

The order stems from the EPA’s determination that unborn babies of pregnant women who are exposed to the pesticide could be at risk of several serious health conditions.

“Farmworkers face burdensome conditions in the fields and often face exposure to harmful pesticides while working to feed our nation,” Arizona congressman Raúl Grijalva said in an EPA statement. “I applaud the emergency action by the EPA which prioritizes farmworker health and safety, especially for pregnant women, by suspending this harmful chemical from our agricultural systems.”

Emerging health concerns involving several types of weed killers, such as Roundup and paraquat, have led to lawsuits in recent years.

Roundup lawsuits allege a potential link between the pesticide’s active ingredient glyphosate and non-Hodkin lymphoma, while paraquat lawsuits center on Parkinson’s disease claims.

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EPA Assessment Highlights DCPA Effects on Fetal Thyroid Development

The emergency suspension is the latest step in a back-and-forth between the EPA and Dacthal manufacturer AMVAC Chemical Corporation that began in 2013 when the agency issued a data call-in requesting studies to support Dacthal’s registration.

At the time, a study on Dacthal’s effects on thyroid development was among the data that AMVAC was required to submit.

The EPA set a January 2016 due date for the data but announced in 2022 that AMVAC had still not submitted all of the required information.

A specific type of the pesticide was briefly suspended in 2023, the same year that the EPA released an assessment highlighting health risks associated with its use.

The EPA went on to issue a public warning regarding Dacthal’s health risks to unborn babies earlier this year before finally issuing this week’s emergency suspension.

Who Is at Risk from Dacthal Exposure?

Potential health impacts on unborn babies are the main concern that led to the EPA’s emergency order.

The agency determined that Dacthal exposure could cause changes to fetal thyroid levels that may result in serious issues after birth such as impaired brain development, decreased IQ and impaired motor skills later in life.

According to Delaware Health and Social Services, Dacthal has often been applied to home flower gardens and nursery stock. It’s also commonly used in agriculture, with the EPA highlighting broccoli, brussels sprouts, cabbage and onions as crops where it is primarily used.

The EPA’s 2023 assessment found that there are still health risks associated with Dacthal even when protective equipment is used.

Weed Killer Makers Face Thousands of Lawsuits

Dacthal is not the first weed killer to be tied to potential health concerns. More than 4,300 lawsuits pending in federal multidistrict litigation in California claim Roundup exposure caused non-Hodgkin lymphoma.

Multiple plaintiffs have been awarded major verdicts against the popular pesticide in recent years, including a Pennsylvania man who was awarded $2.25 billion in damages in January. That verdict was later reduced to $400 million.

Just this week, Judge Nancy Rosenberg selected 10 bellwether test trials in litigation involving paraquat and claims that its manufacturer failed to warn customers about its potential ties to the development of Parkinson’s disease.

New cases continue to be filed as part of these litigations, and DCPA lawsuits could be next.