Three major chemical manufacturers announced on Friday they will pay nearly US$1.2 billion to settle claims that they contaminated water sources across the United States with harmful "forever chemicals" known as PFAS.

Chemours, DuPont and Corteva said in a joint press release that they had "reached an agreement in principle to resolve all PFAS-related drinking water claims" for areas serving "the vast majority of the United States population."

A total of US$1.185 billion will be given to a settlement fund, with Chemours contributing US$592 million, DuPont paying US$400 million and another US$193 million added by Corteva.

The group of chemicals known as PFAS, per- and polyfluoroalkyl substances, have been found to cause cancer and other health problems, and take very long periods of time to break down.

They have been used since the 1940s in a wide variety of industrial and consumer products such as nonstick pans, carpeting, waterproof clothing, food packaging, cosmetics and cleaning items.

In addition to the agreement reached by the trio of companies, Bloomberg has reported that industrial giant 3M has signed an agreement in principle worth at least US$10 billion to settle other PFAS-related lawsuits brought by several US towns and cities.

When asked for comment on Friday evening, 3M did not immediately reply.

The agreement must be approved by a judge.

The US Environmental Protection Agency (EPA) earlier this year proposed new standards to limit PFAS in public drinking water, requiring utilities to monitor for six of the chemicals and reduce their levels.

EPA administrator Michael Regan at the time said the new water standards have the potential to prevent thousands of deaths and tens of thousands of PFAS-related illnesses.

"These toxic chemicals are so pervasive and so long-lasting in the environment that they've been found in food, soil and water even in the most remote corners of our planet," he said.

The EPA proposal, which will be finalised by the end of the year, would set national standards for PFAS in drinking water.

3M has also been the target of PFAS lawsuits in Europe.

In 2022, the company agreed to a settlement of 571 million euros (US$612 million) with the Belgian region of Flanders over the PFAS chemical discharges around its Zwijndrecht plant, near the Belgian city of Antwerp.

The Dutch government also said last week it would seek compensation from 3M for damages caused by its chemicals in the Western Scheldt river, which flows into the North Sea.

Last year, Dutch authorities warned against eating fish, shrimp, mussels and other products from the Western Scheldt because of high PFAS levels.

3M said in December that it would stop manufacturing PFAS substances by the end of 2025 in light of stricter regulation over the harmful health effects from their use. (AFP)