EPA Suspends All Registrations of Pesticide Dacthal, Citing Effects on Fetal Development
On Aug. 6, EPA announced the emergency suspension of all registrations of dimethyl tetrachloroterephthalate, a pesticide also known as DCPA or Dacthal. The sale, distribution, and use of all DCPA products is prohibited as of Aug. 7, when a notice signed by EPA Administrator Michael S. Regan appeared in the Federal Register. According to an agency press release, EPA took this action because the unborn babies of pregnant people who have been exposed to DCPA are at risk for changes in fetal thyroid hormone levels linked to low birth weight, impaired brain development, decreased IQ, and impaired motor skills. This is the first time EPA has ordered the emergency suspension of a pesticide under the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) in almost 40 years.
DCPA is registered for use on crops such as broccoli, Brussels sprouts, cabbages, and onions and on non-residential turf such as golf courses and athletic fields. EPA’s press release explains that AMVAC Chemical Corporation, the sole manufacturer of DCPA, failed to submit data required to support the pesticide’s continuing registrations for almost 10 years. This data included a major study on DCPA’s effects on thyroid development. In 2023, EPA suspended the registration for the DCPA technical-grade product, used to manufacture end-use products. EPA rescinded the suspension following AMVAC’s provision of the requested documents.
In a risk assessment following AMVAC’s submission of the thyroid study, EPA concluded that health risks associated with DCPA use and application exist “even when personal protective equipment and engineering controls are used.” People who handle DCPA while pregnant may have exposures four to 20 times greater than what EPA has estimated is safe for unborn babies. For many crops and tasks, EPA found that DCPA levels in treated fields remain unsafe for 25 days or more. Pregnant people who live near areas where DCPA is used may be exposed to the pesticide through spray drift, when it moves through the air to locations other than where it was applied.
AMVAC voluntarily cancelled the use of DCPA on turf in December 2023. According to EPA, this practically eliminated exposures to DCPA during recreational activities. However, “AMVAC’s proposed changes to agricultural uses of DCPA do not adequately address the serious health risks for people who work with and around DCPA,” EPA’s press release states.
FIFRA authorizes EPA to suspend or cancel a pesticide when significant risks are associated with its use, although EPA rarely does so due to the time and resources required. FIFRA also permits EPA to suspend a pesticide while cancellation proceedings are in progress if the EPA administrator determines that continued sale, distribution, or use of the product poses an imminent hazard. EPA intends to issue a notice cancelling the registration of all DCPA products within 90 days.
“EPA has determined that there is no combination of practicable mitigations under which DCPA use can continue without presenting an imminent hazard,” the emergency suspension notice states.
More information is available in EPA’s notice of emergency suspension and press release.