The French company Saint-Gobain has begun the demolition of its Merrimack facility, where manufacturing processes released PFAS chemicals into surrounding communities for years, contaminating drinking water for nearby residents.
Steel from the site will be recycled as scrap. Debris from parts of the facility heavily contaminated with PFAS, or so-called “forever chemicals,” will be shipped out of state to a hazardous waste landfill. The company plans to leave behind the concrete foundation, with contaminants scraped off.
But groundwater and soil at Saint-Gobain’s site — a patch of land across from a bowling alley on the Daniel Webster Highway, on the banks of the Merrimack River — is still heavily contaminated, according to state regulators.
The company has brought treated water to more than 1,600 properties affected by contamination through agreements with state officials. And they’re required to continue those efforts.
But how much Saint-Gobain must remediate the PFAS pollution in soil and groundwater is an ongoing debate between company officials and New Hampshire’s Department of Environmental Services.
Read more: Saint-Gobain announces closure of Merrimack facility at the center of PFAS controversy
In May 2023, the company submitted a “remedial action plan,” laying out alternatives for treating contaminated soil and groundwater. They chose a mix of “institutional controls” and “natural attenuation” — options that include no actual cleanup, but instead limit the use of the site in the future and require the company to monitor pollution as the chemicals degrade naturally.
That plan would prohibit future residential use of the site and adjacent properties, and would require any activity that disturbed soil to have a management plan. It would also limit the ability of industrial or residential developments to use groundwater affected by the contamination.
The company doesn’t specify the timeline for restoration of the soil or groundwater under that plan, simply saying it would be “long.” PFAS chemicals are known for their resistance to degrading naturally in the environment.
In a supplement submitted early this year, Saint-Gobain stood firm in their decision, saying other methods like excavating and disposing of soil or extracting and treating groundwater would not be more effective at remediating the site and would have higher costs and risks.
In October, state regulators sent the company a letter saying their plan was inadequate and didn’t include any efforts to reduce or mitigate high concentrations of contamination that continue to impact groundwater and surface water.
In one part of the letter, regulators say that the company “makes no attempt” to eliminate ongoing pollution from “grossly impacted soils,” which can discharge contaminants into groundwater, a nearby brook, and the Merrimack River — a source of public drinking water.
Mike Wimsatt, the director of the waste management division for the Department of Environmental Services, said remedial action plans are created anytime regulated contaminants are released into soil or groundwater at concentrations above the state’s standards. The goal of those plans is to get the site back to accepted standards — but sometimes that can’t happen quickly.
“What we generally look for in those cases is a remedial action plan that uses the technology available to do the best job that you can, with an expectation that over a time — and it may be a long time or even decades — there will be some expectation that soil and groundwater can meet the standards,” he said. “It's a very tall order at this site because the contamination is significant and the concentrations at which we regulate these compounds are very low.”
Wimsatt said the company’s proposal doesn’t come close to reducing the mass of contamination at the site as much as possible.
In an email Friday, a Saint-Gobain North America representative said their plan “aligns with appropriate industry and environmental practices.”
“Natural attenuation and institutional controls are broadly accepted as an effective remedial measure at sites like this throughout the state and across the country. We remain committed to remediation efforts in the community and continue to work with NHDES to finalize the Remedial Action plan for the site,” the email said.
Saint-Gobain has until mid-January to respond with a revised plan for remediating soil and groundwater at their facility.
Meanwhile, demolition continues. In a Dec. 12 report, the company told state regulators they planned to complete their interior asbestos abatement and PCB remediation this month, take apart emissions control equipment, and start more demolition as they receive permits from the Town of Merrimack.
The company says they expect all phases of their demolition to be completed in late 2025.
