State regulators seeking clear criteria for cleaning up an emerging class of toxic contaminants found in firefighting foams and nonstick coatings will press the EPA at a national summit May 22 and 23.

The gathering will allow states to share information and strategies for cleaning up per- and polyfluoroalkyl substances, or PFAS, from drinking water systems. The chemicals, used to create heat- and water-resistant products, can contaminate groundwater and soil. Exposure can cause a range of health effects from low birth weights to elevated cholesterol levels.

Some of the states attending the summit will call for the government...