New research has found 485 chemicals used in US pesticide products that are linked to breast cancer. The findings raise fresh questions about how pesticides are regulated.

The peer-reviewed paper was published in Environmental Health Perspectives, a journal from the American Chemical Society. It was written by researchers at the Silent Spring Institute.

The review covers active pesticide ingredients. It also includes hundreds of so-called “inert” ingredients that do not get a full safety review. About one-third of the 485 chemicals, or 145, are registered with the EPA as active ingredients.

The chemicals are not only on crops. The report says they also show up in lice treatments for children, lawn fertilizers and flea and tick products.

The researchers say the EPA only looks at each ingredient alone. It does not consider the full formula or exposure to many pesticides at once. An earlier Silent Spring study found the EPA dismissed evidence linking 19 pesticides to mammary tumors.

The study does not prove these chemicals cause breast cancer in people. But the authors urge action to cut exposure.