New Hampshire has proposed cutting nearly in half the amount of a nonstick coating chemical it would allow in groundwater and drinking water.

The proposed standard for perfluorooctanoic acid (PFOA) would be 38 parts per trillion, the New Hampshire Department of Environmental Services announced Jan. 2. The state currently enforces a limit of 70 parts per trillion on PFOA and related per- and polyfluoroalkyl substances (PFAS).

New Hampshire is just the latest state to propose stricter limits on PFOA, which was widely used in manufacturing of nonstick coatings. New York now uses a limit of 10 parts...