The Environmental Protection Agency (EPA) has issued an Emergency Order to suspend all registrations for pesticide products containing dimethyl tetrachloroterephthalate (DCPA), also known as Dacthal. This action comes in response to findings indicating significant health risks associated with DCPA exposure, particularly concerning thyroid hormone perturbations in foetuses.
Immediate Suspension of DCPA
The EPA has determined that the continued sale, distribution, or use of DCPA poses an imminent hazard that requires immediate suspension to prevent serious health risks. This decision is based on evidence showing that DCPA exposure can disrupt thyroid hormone levels in foetuses, potentially leading to low birth weight, impaired brain development, and long-term motor skill issues in children exposed in-utero.
Details of the Suspension
Effective immediately, the EPA's order halts the registration of all DCPA-containing products, which include:
- Dacthal Flowable Herbicide
- Dacthal W-75 Herbicide
- Technical Chlorthal Dimethyl
This suspension prohibits any sale, distribution, or use of these products. The EPA has also disallowed the use of existing stocks to mitigate risks during the suspension hearing period.
Health Risks and Evidence
The catalyst for this suspension stems from a series of studies, particularly a Comparative Thyroid Assay (CTA) conducted in 2021. The study revealed that even low levels of DCPA could significantly alter thyroid hormone levels in foetal rats. Human exposure estimates suggest that current levels of DCPA use might exceed safe thresholds, especially for pregnant individuals.
Economic and Agricultural Impact
While DCPA is widely used for preemergent weed control in Brassica vegetables and Allium crops, the EPA's analysis indicates that the health risks outweigh the economic benefits of continued use. Alternatives to DCPA, such as bensulide and trifluralin for Brassicas and pendimethalin for Alliums, are available, although they may increase costs and require more labour for weed control.
Regulatory and Legal Framework
The suspension is issued under the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA), granting the EPA authority to take such emergency actions. Registrants, like AMVAC Chemical Corporation, can request a hearing to challenge the suspension, but the EPA's order remains effective during any proceedings.
Next Steps for Stakeholders
The EPA has notified the sole registrant, AMVAC Chemical Corporation, and any affected parties of the suspension. The agency is also preparing a notice of intent to cancel DCPA registrations within the next 90 days. Stakeholders can access more information and submit comments via the docket on the EPA’s official website.
