The U.S. Environmental Protection Agency (EPA) has proposed to cancel all agricultural uses of the pesticide acephate based on risk assessments conducted by the agency showing significant dietary risks from drinking water for currently registered uses of the chemical.

Acephate is an organophosphate (OP) pesticide that is registered for both agricultural uses, such as cotton and soybean, and non-agricultural uses, such as tree injections for forestry and ant mound treatment around homes. Acephate interacts with the nervous system by inhibiting the acetylcholinesterase (AChE) enzyme. This process makes the pesticide effective against insects, but it can also occur in mammals, including humans, depending on the level of acephate exposure. At high levels of OP exposures, AChE inhibition can lead to neurological effects such as tremors, fatigue, and nausea. AChE inhibition has been found to be the most sensitive human health effect for evaluating exposures to acephate.

EPA is proposing to maintain the use of acephate only for tree injection because it does not contribute to drinking water exposure, there are no risks for workers, and, with label changes, it would not pose risks to the environment. Tree injections allow the pesticide to move throughout the tree to control pests. This use of acephate is allowed only for trees that do not produce food for human consumption.