US EPA issues emergency order to stop use of pesticide dacthal to address serious health risk

Aug. 6, the U.S. Environmental Protection Agency is announcing the emergency suspension of all registrations of the pesticide dimethyl tetrachloroterephthalate (DCPA or Dacthal) under the Federal Insecticide, Fungicide and Rodenticide Act (FIFRA). This is the first time in almost 40 years EPA has taken this type of emergency action, following several years of unprecedented efforts by the Biden-Harris Administration to require the submission of long-overdue data and then assess and address the risk this pesticide poses.

EPA has taken this action because unborn babies whose pregnant mothers are exposed to DCPA, sometimes without even knowing the exposure has occurred, could experience changes to fetal thyroid hormone levels, and these changes are generally linked to low birth weight, impaired brain development, decreased IQ, and impaired motor skills later in life, some of which may be irreversible.

″DCPA is so dangerous that it needs to be removed from the market immediately,″ said Assistant Administrator for the Office of Chemical Safety and Pollution Prevention Michal Freedhoff. ″It’s EPA’s job to protect people from exposure to dangerous chemicals. In this case, pregnant women who may never even know they were exposed could give birth to babies that experience irreversible lifelong health problems. That’s why for the first time in almost 40 years, EPA is using its emergency suspension authority to stop the use of a pesticide.″

″Farmworkers face burdensome conditions in the fields and often face exposure to harmful pesticides while working to feed our nation. 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. We must continue to build on this progress and ensure all farmworkers are given the protection, worker’s rights, and overtime pay they deserve,″ said Congressman Raúl Grijalva (AZ-07).

″Alianza is pleased to see the EPA make this historic decision.  As an organization led by farmworker women, we know intimately the harm that pesticides, including dimethyl tetrachloroterephthalate (DCPA or Dacthal), can inflict on our bodies and communities.  This emergency decision is a great first step that we hope will be in a series of others that are based on listening to farmworkers, protecting our reproductive health, and safeguarding our families,″ said Mily Treviño Sauceda, Executive Director of Alianza Nacional de Campesinas.

Background on DCPA and Biden-Harris Administration Efforts to Assess and Address Risks

DCPA is a pesticide registered to control weeds in both agricultural and non-agricultural settings, but is primarily used on crops such as broccoli, Brussels sprouts, cabbage and onions. DCPA is currently undergoing registration review, a process that requires reevaluating registered pesticides every 15 years to ensure they cause no unreasonable adverse effects on human health or the environment.

In deciding whether to issue today’s Emergency Order, EPA consulted with the U.S. Department of Agriculture to understand how growers use DCPA and alternatives to this pesticide. In 2013, the agency issued a Data Call-In (DCI) to AMVAC Chemical Corporation, the sole manufacturer of DCPA, requiring it to submit more than 20 studies to support the existing registrations of DCPA. The required data included a comprehensive study of the effects of DCPA on thyroid development and function in adults and in developing young before and after birth, that was due by January 2016. Several of the studies that AMVAC submitted from 2013-2021 were considered insufficient to address the DCI, while the thyroid study and other studies were not submitted at all.

In April 2022, EPA issued a very rarely used Notice of Intent to Suspend the DCPA technical-grade product (used to manufacture end-use products) based on AMVAC’s failure to submit the complete set of required data for almost 10 years, including the thyroid study. While AMVAC submitted the required thyroid study in August 2022, EPA suspended the registration based solely on AMVAC’s continued failure to submit other outstanding data on Aug. 22, 2023, following an administrative hearing.  In November 2023, the data submission suspension was lifted after AMVAC submitted sufficient data. Most DCPA use on turf was voluntarily canceled by AMVAC in December 2023, but unacceptable risks from other uses remained.

In May 2023, EPA released its assessment on the risks of occupational and residential exposure to products containing DCPA, following its analysis of the thyroid study submitted by AMVAC. The assessment found health risks associated with DCPA use and application, even when personal protective equipment and engineering controls are used. The most serious risks are to the unborn babies of pregnant individuals. EPA estimates that some pregnant individuals handling DCPA products could be subjected to exposures four to 20 times greater than what EPA has estimated is safe for unborn babies.

Also of concern are risks to unborn babies of pregnant individuals entering or working in areas where DCPA has already been applied (especially post-application workers involved in tasks such as transplanting, weeding and harvesting). Current product labels specify that entry into treated fields must be restricted for 12 hours after application. However, the evidence indicates that for many crops and tasks, levels of DCPA in a treated field remain at unsafe levels for 25 days or more. Spray drift (the movement of pesticide through the air at the time of application or soon after, to any site other than the area intended) from pesticide application could also put at risk the unborn babies of pregnant individuals living near areas where DCPA is used.

Since the release of EPA’s 2023 assessment, AMVAC has proposed several changes to the DCPA registrations, including the cancellation of DCPA products registered for use on turf. Those cancellations practically eliminate exposures to DCPA from recreational activities on and around turf. But according to EPA’s analysis, 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. 

In April 2024, EPA issued a public warning regarding the significant health risks to unborn babies of pregnant individuals exposed to DCPA and its intent to pursue action to address the serious, and in some instances, permanent, and irreversible health risks associated with the pesticide as quickly as possible. In a letter to AMVAC dated March 27, 2024, EPA restated the risks the agency found and noted that the agency would be pursuing regulatory options as soon as possible which could include cancelling the pesticide or seeking an emergency suspension.

When serious risks are identified, EPA can take action under FIFRA to suspend or cancel a pesticide. Taking such action is resource and time intensive, partly due to the procedural requirements of FIFRA. A cancellation proceeding may take at least several months (if uncontested by the registrant) or potentially several years (if contested by the registrant, thus triggering an administrative hearing and any subsequent appeal of a cancellation order). FIFRA also allows EPA to seek a suspension of a pesticide product while cancellation proceedings are ongoing if the Administrator determines it is necessary to prevent an imminent hazard.  EPA Administrator Regan has determined that, due to the serious and imminent harm posed by DCPA, an emergency exists such that this order of suspension effective immediately is necessary. EPA intends to issue a notice of intent to cancel the DCPA products within the next 90 days.

The Emergency Order is effective immediately. EPA determined that the continued sale and use of DCPA products during the time it would take to follow the normal cancellation process poses an imminent hazard to unborn babies. While AMVAC has attempted to address these concerns, EPA has determined there are no practical mitigation measures that can be put in place to allow DCPA’s continued use.

Additional information is available in the DCPA registration review docket EPA-HQ-OPP-2011-0374.  

Read the DCPA Emergency Order.