Vermont has the strictest rules in the nation limiting fluorinated chemicals in drinking water, but those rules would get even tougher under a bill the Legislature cleared April 16.

Since July 2018, Vermont has enforced a limit of 20 parts per trillion combined for any of five common compounds known as per- and polyfluoroalkyl substances (PFAS), in public and private drinking water systems and wells.

The chemicals are widely used in firefighting foam, and as nonstick and stain-resistant compounds in a number of consumer and industrial products.

They have been detected in drinking water nationwide and have been linked to...