MERRIMACK, N.H. (AP) — A French company that has been blamed for contaminating drinking water in some New Hampshire communities with a group of chemicals known as PFAS said Wednesday it plans to close its plant there and will 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 goals and what “is in line with the company’s mission and plan.”

The Paris-based company, which bought the Merrimack plant from ChemFAB in 2000, initially believed it wasn’t discharging anything harmful. 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 Services determined 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. They also don’t degrade in the environment and are linked to health issues that include low birthweight and kidney cancer.

The state didn’t move to do any groundwater testing until 2016 because there was no indication at the time that the emissions posed a threat to groundwater. That 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 most commonly known of PFAS. Wells in Bennington and North Bennington, Vermont, also were found to be contaminated with PFOA around the company’s now-closed plant in Bennington. 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 the contamination was caused by emissions from the Merrimack plant.

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

There are 164 workers at the Merrimack plant. Saint-Gobain said alternative roles and relocation assistance will be offered to eligible employees who wish to remain with the company, and support packages will be made available to those who will not continue.

State House Rep. Nancy Murphy, a Democrat from Merrimack, said residents will continue to pay a huge price after the plant closes.

“Beyond the costs borne by private well owners outside a far too small ‘consent decree area’, we have paid to filter the drinking water in our homes; we have paid to filter the public wells in our town; we have paid to filter the drinking water in our schools … and we are paying for the contamination of our air, water, and soil with our compromised health,” she said in a a statement.