MERRIMACK, N.H. (AP) — A French company accused of contaminating drinking water in some New Hampshire communities with a group of chemicals called PFAS said Wednesday that it plans to close its plant there and with to work with the state on an ongoing environmental investigation.

Saint-Gobain Performance Plastics said in a statement that it will “restructure its composite solutions business in the United States” after evaluating the company's business objectives and “consistent with the company's mission and plan.”

The Paris-based company, which purchased ChemFAB's Merrimack plant in 2000, initially assumed it would not emit harmful substances. But the state said that changed in 2004 after the company installed more sophisticated technology. After the company alerted the state, the state Department of Environmental Conservation found that Saint-Gobain was exceeding state air limits for PFAS, and the company agreed to significantly reduce emissions.

PFAS is an abbreviation for perfluoroalkyl and polyfluoroalkyl substances. Known as “forever chemicals,” they are widespread, dangerous and expensive to remove from water. Additionally, they do not break down in the environment and are linked to health problems such as low birth weight and kidney cancer.

The state only began conducting groundwater testing in 2016 because at that time there was no evidence that the emissions posed a threat to groundwater. This came to light after wells near Saint Gobain facilities in Hoosick Falls, New York, were found to be contaminated with PFOA – or perfluorooctanoic acid, the best-known PFAS. Wells in Bennington and North Bennington, Vermont, around the company's now-closed Bennington plant were also found to be contaminated with PFOA. The contamination led to at least two class-action lawsuits against Saint-Gobain.

In 2019, the state lowered the standard for PFOA from 70 parts per trillion to 12 parts per trillion and launched an extensive well sampling program. It identified 1,000 properties with contaminated water and determined that the contamination was caused by emissions from the Merrimack plant.

Last year, Saint-Gobain agreed to provide properties in Bedford, Hudson, Litchfield, Londonderry and Merrimack with bottled drinking water and “permanent backup water as appropriate.” It also provided a framework should additional properties be affected.

The Merrimack plant employs 164 workers. Saint-Gobain said alternative roles and relocation support will be offered to eligible employees who wish to remain with the company, and support packages will be provided for those who do not wish to continue.

House Speaker Nancy Murphy, a Democrat from Merrimack, said residents will continue to pay a heavy price even after the plant closes.

“In addition to the costs borne by private well owners outside of a far too small 'permit decree area,' we have paid to filter the drinking water in our homes; we paid to filter the public fountains in our city; We paid to filter the drinking water in our schools… and we are paying for the pollution of our air, water and soil with our compromised health,” she said in a statement.