A peer-reviewed paper identified at least 485 chemicals used in US pesticide products that are linked to breast cancer. Only about 145 are registered with the EPA as active ingredients; the list also includes hundreds classified as “inert.”
Federal health data detected 84 of the identified chemicals in the general population, but researchers say that figure is an undercount because the National Health and Nutrition Examination Survey does not track most compounds on the institute’s list. The chemicals also appear in products beyond crop pesticides, including lice treatments, lawn fertilizers and flea-and-tick treatments.
The paper says the EPA assesses each ingredient’s health risks separately, without evaluating the full pesticide formula or exposure to multiple pesticides; inactive ingredients typically do not receive thorough safety reviews. In 2023, the EPA rejected a legal petition seeking stricter review of inert ingredients.
