Recently, the U.S. Environmental Protection Agency (EPA) issued a Draft Interim Registration Review Decision (PID) for the organophosphate pesticide malathion, proposing new mitigation measures to reduce its ecological risks, which will be open to the public for a 60-day comment period.

Malathion is a pesticide widely used in agriculture and public health, and plays a particularly important role in controlling pests and preventing mosquito-borne diseases. However, its ecological impacts have also raised concerns at the EPA. Under the Endangered Species Act, EPA is required to ensure that its actions do not adversely affect endangered species and their habitats.A 2017 Biological Assessment indicated that malathion could have negative impacts on these species, prompting EPA to consult with the relevant services and, in August 2023, implement the necessary mitigation measures.

In March 2024, EPA released a draft ecological risk and human health risk assessment that found potential risks from malathion to non-endangered species, particularly in fish, birds, and mammals. The human health risk assessment, on the other hand, indicated that malathion does not pose a health risk of concern when used in accordance with label directions.

To further reduce ecological risks, EPA proposed mandatory drift controls in the PID, as well as measures to ensure that water used to irrigate rice paddies would allow pesticide residues to dissipate, among other things, with the aim of minimizing the impact of pesticide drift on non-targeted areas and allowing pesticide residues sufficient time to dissipate before release.