WASHINGTON – This week, the U.S. Environmental Protection Agency announced the emergency suspension of all registrations of the pesticide dimethyltetrachloroterephthalate (DCPA or Dacthal) under the Federal Insecticide, Fungicide and Rodenticide Act (FIFRA). This is the first time in nearly 40 years that the 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 to assess and address the risk posed by this pesticide.

The EPA took this action because unborn babies whose pregnant mothers are exposed to DCPA – sometimes without even knowing that such exposure has occurred – can experience changes in fetal thyroid hormone levels. These changes are generally associated with low birth weight, impaired brain development, reduced IQ, and impaired motor skills later in life, some of which may be irreversible.

“DCPA is so dangerous that it must be taken off the market immediately,” said Michal Freedhoff, Deputy Head of the Office for Chemical Safety and Pollution Prevention“EPA’s job is to protect people from exposure to dangerous chemicals. In this case, pregnant women who may not even know they were exposed to these chemicals could give birth to babies who suffer lifelong, irreversible health problems. That’s why, for the first time in nearly 40 years, EPA is using its emergency suspension authority to stop the use of a pesticide.”

Background information on the DCPA

DCPA is a pesticide that is approved for weed control in 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 approved pesticides to be re-evaluated every 15 years to ensure that they do not cause unreasonable negative 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 farmers 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, asking it to submit more than 20 studies to support its existing DCPA registrations. The required data included a comprehensive study of the effects of DCPA on thyroid development and function in adults and in developing children before and after birth, which had to be submitted by January 2016. Several of the studies submitted by AMVAC between 2013 and 2021 were deemed insufficient to answer 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 engineered product DCPA (used to manufacture end-use products) because AMVAC had not submitted the full set of required data, including the thyroid study, for nearly 10 years. While AMVAC submitted the required thyroid study in August 2022, EPA suspended registration solely because AMVAC continued to fail to submit other pending data following an administrative hearing on August 22, 2023. In November 2023, the suspension of data submission was lifted after AMVAC submitted sufficient data. Most DCPA applications on turf were voluntarily discontinued by AMVAC in December 2023, but unacceptable risks from other uses remained.

In May 2023, the EPA released its assessment of the risks of workplace and home exposure to products containing DCPA after analyzing the thyroid study submitted by AMVAC. The assessment found that the use and application of DCPA poses health risks, even when personal protective equipment and engineering control measures are used. The greatest risks are to the unborn babies of pregnant individuals. The EPA estimates that some pregnant individuals handling DCPA products could be exposed to levels four to twenty times higher than what the EPA considers safe for unborn babies.

Irreversible health risks

Also of concern are the risks to unborn babies of pregnant women who enter or work in areas where DCPA has already been applied (particularly workers who perform post-application tasks such as transplanting, weeding and harvesting). Current product labels state that entry into treated fields must be prohibited for 12 hours after application. However, evidence shows that for many crops and operations, DCPA concentrations in a treated field remain at unsafe levels for 25 days or more. Spray drift (the movement of pesticides through the air at the time of application or shortly thereafter to a location other than intended) from pesticide applications could also endanger the unborn babies of pregnant women living near areas where DCPA is used.

Since the release of the 2023 EPA assessment, AMVAC has proposed several changes to DCPA registrations, including deregistering DCPA products for use on lawns. These deregistrations virtually eliminate DCPA exposure during recreational activities on and around lawns. However, according to EPA’s analysis, AMVAC’s proposed changes to agricultural uses of DCPA do not adequately address the serious health risks to people who work with and around DCPA.

In April 2024, EPA issued a public alert regarding the significant health risks to unborn babies of pregnant individuals exposed to DCPA and its intent to take action as soon as possible to address the serious, and in some cases permanent and irreversible, health risks associated with the pesticide. In a letter to AMVAC dated March 27, 2024, EPA reiterated the risks identified by the agency and noted that the agency would pursue regulatory options as soon as possible, which could include elimination of the pesticide or an emergency suspension.

Immediately effective

If serious risks are identified, EPA may take action under FIFRA to suspend or delist a pesticide. Such actions are resource and time intensive, in part due to FIFRA’s procedural requirements. A delisting process can take at least several months (if not contested by the registrant) or potentially several years (if contested by the registrant, triggering an administrative hearing and subsequent appeal of a delisting order). FIFRA also allows EPA to request a suspension of a pesticide product while a delisting process is underway if the Administrator determines it is necessary to address an imminent hazard. EPA Administrator Regan has determined that an emergency exists due to the serious and imminent harm caused by DCPA, making this delisting order necessary to take effect immediately. EPA intends to issue a notice of intent to delist the DCPA products within the next 90 days.

The emergency order takes effect immediately. EPA has determined that the continued sale and use of DCPA products during the time it would take to complete the normal withdrawal process poses an imminent danger to unborn babies. Although AMVAC has attempted to address these concerns, EPA has determined that there are no practical remedies that would allow the continued use of DCPA.

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