Key facts
- At least 485 chemicals in US pesticide products are linked to breast cancer.
- The study highlights deficiencies in US pesticide regulation, including the review of "inert" ingredients.
- The EPA does not consider the entire pesticide formula or exposure to multiple pesticides.
- Breast cancer incidence rates have increased by 1% per year in the US.
- About 84 of the identified breast cancer-linked chemicals are present in the general population.
- Only about 145 of the identified pesticide chemicals were registered with the EPA as active ingredients.
New research has identified at least 485 chemicals used in US pesticide products that are linked to breast cancer, prompting concerns about regulatory oversight and public health. The peer-reviewed study, published in Environmental Health Perspectives, criticizes the US regulatory framework, particularly the EPA's approach to evaluating pesticide safety.
The review encompasses both active and hundreds of "inert" ingredients, which typically receive less rigorous safety scrutiny. The EPA currently assesses each ingredient individually and does not account for the combined health risks of entire pesticide formulas or exposure to multiple chemicals. These chemicals are found not only in agricultural pesticides but also in products like lice treatments, home fertilizers, and flea and tick treatments.
Jenny Kay, a co-author from the Silent Spring Institute, stated that "Adding these exposures up gets pretty consequential and concerning." Breast cancer is the second most commonly diagnosed cancer in the US, with incidence rates increasing by 1% annually, and faster among younger women. Federal health data indicates that 84 of the identified breast cancer-linked chemicals are present in the general population, though scientists believe this is an undercount.
The Silent Spring Institute's broader effort has identified approximately 500 breast cancer-linked chemicals in common consumer goods and 462 in drinking water. Only about 145 of the identified pesticide chemicals were registered as active ingredients, suggesting that the "inert" status may be used to circumvent health reviews. These "inert" ingredients, often added as surfactants or penetrating agents, are not biologically inactive and can pose significant health risks.
Kay highlighted a "regulatory blind spot" regarding chemicals that disrupt hormones and cause disease at low exposure levels, a phenomenon known as "non-monotonic dose response." The EPA rejected a petition in 2023 to more stringently review inert ingredients. Furthermore, the study noted that top officials in the EPA's pesticide and chemical safety offices have backgrounds as former industry lobbyists, raising concerns about industry influence.
The Silent Spring Institute recommended expanding California's Proposition 65, which requires warnings for chemicals known to cause cancer or reproductive harm, to include 16 pesticides not currently listed. Consumers can reduce exposure by opting for organic produce and pesticide-free products. For those unable to avoid treated produce, Consumer Reports offers a guide to fruits and vegetables with typically high pesticide residue levels, including blueberries, watermelon, kale, and green beans. Additionally, water filtration systems using activated carbon or reverse osmosis can help remove pesticides like atrazine, a known hormone disruptor linked to breast cancer, from drinking water.