Chemicals known as PFOA and PFOS that can be found in sewage sludge used as fertilizer may pose a risk to human health, the U.S. Environmental Protection Agency says.

The E.P.A.’s report follows a growing body of research that has found that sludge can be contaminated with human-made “forever chemicals” known as per- and polyfluoroalkyl substances, or PFAS, which are used in a wide range of household items such as nonstick cookware, waterproof clothing and stain-resistant carpets.