Harmful chemicals in sewage sludge spread on pasture as fertilizer pose a risk to people who regularly consume milk, beef and other products from those farms, in some cases raising cancer risk “several orders of magnitude” above what the Environmental Protection Agency considers acceptable, federal officials announced Tuesday.

When cities and towns treat sewage, they separate the liquids from the solids and treat the liquid. The solids need to be disposed of and can make a nutrient-rich sludge often spread on farm fields. The agency now says those solids often contain toxic, lasting PFAS that treatment plants cannot effectively remove. When people eat or drink foods containing these “forever” chemicals, the compounds accumulate in the body and can cause kidney, prostate and testicular cancer. They harm the immune system and childhood development.

Most at risk are people who drink one quart of milk per day from dairy cows raised on pasture with the biosolids, eat one or two servings of fish a week from a lake contaminated by runoff, or drink PFAS-laden water, the draft risk assessment said. The EPA looked only at farmers and those living nearby who regularly consumed these products over years — not the broader general public. Organic farms aren’t allowed to use the sludge, so the findings should not apply to consumers who purchase organic grass-fed beef.

The federal government has the power to regulate harmful substances in sewage sludge. It has set limits on some metals. But it does not regulate PFAS, or perfluoroalkyl and polyfluoroalkyl substances.

“This draft assessment provides important information to help inform future actions by federal and state agencies as well as steps that wastewater systems, farmers and other stakeholders can take to protect people from PFAS exposure, while ensuring American industry keeps feeding and fueling our nation,” EPA Acting Administrator Jane Nishida said in a statement.

Sewage sludge has been used as fertilizer for many years. Wastewater treatment plants produce millions of tons of sludge and tens of millions of acres of farmland have been permitted to use it, according to a group that’s compiled state data. The agency says this sludge is applied on less than 1% of fertilized acreage of productive agriculture each year.

The EPA said officials monitor the food supply to protect people from exposure to forever chemicals.

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