The Environmental Protection Agency finalized a rule on Wednesday that will limit the amount of “forever chemicals” in public water utilities.

The rule will be the first to limit the amount of PFAS, or perfluoroalkyl and polyfluoroalkyl chemicals, in drinking water, according to the Associated Press. PFAS do not degrade and can negatively affect the public’s health, according to the report, and was announced as being part of President Joe Biden’s “cancer moonshot” initiative.

“Drinking water contaminated with PFAS has plagued communities across this country for too long,” EPA Administrator Michael Regan said. “That is why President Biden has made tackling PFAS a top priority, investing historic resources to address these harmful chemicals and protect communities nationwide. Our PFAS Strategic Roadmap marshals the full breadth of EPA’s authority and resources to protect people from these harmful forever chemicals. Today, I am proud to finalize this critical piece of our Roadmap, and in doing so, save thousands of lives and help ensure our children grow up healthier.”

The EPA estimates the rule will affect between 6% and 10% of the 66,000 public drinking water systems, which the agency said serve approximately 100 million people in the United States.

Water companies initially pushed back on the rule, arguing the restrictions would be costly to implement. The EPA estimates the cost will be $1.5 billion a year, though the agency said the regulation could prevent thousands of deaths a year.

Water companies will have about three years to test for the chemicals, and if the tests exceed the EPA’s limits, the companies will have two years to take action.