Dacthal

Deep Dive on Dacthal

Dacthal (DCPA) is an herbicide used to prevent weeds and grasses from growing in fields where vegetables, turf, and other crops are cultivated. Dacthal appears as colorless, odorless crystals with slight solubility in water. 

Dacthal has been in use since 1958, but there have been concerns about its impact on groundwater and health.

In 2013, the EPA raised concerns about Dacthal, a product produced solely by AMVAC Chemical Corp. They asked the company to provide evidence that it was safe for human use. However, much of the research provided was found lacking, especially studies on thyroid effects. 

While product labels recommend staying out of treated fields for 12 hours after application, recent findings suggest that DCPA levels might remain unsafe for up to 25 days.

Emergency Order, Off the Market

The Environmental Protection Agency (EPA) issued an emergency order suspending all uses of Dacthal weedkiller. This is the first time in 40 years that such an action has been taken. The EPA plans to permanently ban products containing DCPA (the active ingredient in Dacthal), but this could take a few months or even years if the manufacturer challenges the decision.

In the meantime, the emergency suspension is in place to prevent any further harm. Some advocacy groups feel the EPA should have acted sooner. A 2019 study by the University of California at Berkeley found that over half of teenage girls from farmworker communities in California’s Salinas Valley had been exposed to DCPA. The chemical has been banned for use on crops in the European Union since 2009.