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 also 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 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 could reassure consumers who purchase organic grass-fed beef, although farms that transitioned to being organic may have had it applied earlier.

The federal government does have the power to regulate harmful substances in sewage sludge. Years ago, it 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.

President-elect Donald Trump has nominated Lee Zeldin to head the EPA. When Trump announced the pick, he said Zeldin, “will ensure fair and swift deregulatory decisions” while also keeping the water and air clean.

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

PFAS chemicals were used in nonstick pans, firefighting foam and other products in wide use. The two most common types of PFAS, the ones assessed by the agency, are not manufactured in the U.S. anymore, but are still in the environment and wastewater. Paper and textile manufacturers have released PFAS into the environment.

The risk may be higher for some farmers than the EPA assessment indicates. Many farms have far higher concentrations of PFAS than the study assumed. As the amount of PFAS increases, so does the health threat. And the EPA assumed people weren’t exposed to PFAS from other sources when estimating risk, even though many people are.

Scott Faber, senior vice president of government affairs at the nonprofit Environmental Working Group, said the assessment finally makes official what regulators, polluters and utility operators have known for decades -– that PFAS-contaminated fertilizer was getting into food and animal products. He called for tougher rules on its farm use and said EPA should limit how much PFAS manufacturers may release into waterways.

“There is no doubt that sending PFAS waste to wastewater treatment plants and then using that sludge as a fertilizer was a mistake. The only question is whether we’ll continue to make the same mistake,” Faber said.

The Biden administration has taken several actions to reduce PFAS levels in the environment including writing a rule to drastically reduce PFAS in drinking water.

A small number of states including Maine and Connecticut have limited or banned the use of PFAS-contaminated fertilizers made from sewage.

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