State officials say Saint-Gobain demolition nearly complete; testing planned for concrete pad and runoff

Saint-Gobain Performance Plastics has finished most demolition work at its Merrimack facility and will carry out tests of the former building pad and runoff, New Hampshire Department of Environmental Services (DES) staff told the legislative PFAS commission on July 11, 2025. DES project manager Andy Fuller said the company “completed all their manufacturing operations, removed all equipment from the facility in 2024,” and that as of July 2 the demolition was “nearly a 100% complete.” Fuller told commissioners the company has removed materials from the property and disposed of them, and that remaining work includes decommissioning a transformer and a short stretch of sanitary sewer in the railroad right-of-way. Why it matters: commissioners said the condition of the concrete pad and any leaching from it could affect soil and groundwater in the broader consent-decree area around the plant. DES said those tests will inform whether the pad is a continuing source of PFAS contamination. Fuller said Saint-Gobain plans to evaluate potential leaching from the concrete using EPA LEAF methods and a simulated rain/runoff test. “They’re gonna be completing this using the EPA’s, the LEAF, methods and guidance,” Fuller said. He added that Saint-Gobain told DES it used the LEAF protocol published in 2017 and did not adopt draft 2024 updates because they are not yet finalized. DES told the commission it has required Saint-Gobain to provide periodic updates and a final demolition and decommissioning report to the state; Fuller said DES expects to receive that final report later in 2025. Fuller also said the transformer does not contain PCB oil based on current information and that the transformer will be drained of oil before removal. Commissioners asked whether DES has authority to require removal of the concrete pad. Fuller said DES does not believe it has a legal mechanism to force the company to remove the pad. “It wasn't—we didn't really have the legal authority to tell them to decommission the building in the first place either. I don't think that we have a legal mechanism to force them to remove the concrete pad either,” Fuller said. He said DES will use the LEAF analyses and runoff testing to understand the pad’s ongoing contribution to PFAS in soil and groundwater. DES also said the final sanitary sewer work is delayed by coordination with the railroad (CSX) and that site security fencing and cameras will remain in place. Fuller said the demolition has left the former building pad as the only remaining structure on the property. Discussion vs. decision: the presentation was an informational update; there was no formal enforcement action, permit termination decision, or new rule adopted during the meeting. Fuller said Saint-Gobain had requested termination of its air permit, but the agency has taken no action on that request and the company remains responsible for reporting and emission fees until permit termination is finalized. Looking ahead: DES said it expects additional site investigation work plans and a remedial addendum from Saint-Gobain this month to address data gaps DES identified in prior submittals. Those materials will inform any future remedial decisions and whether the state can require further on-site work. Ending: commissioners asked DES for timelines and lab details; Fuller said sampling and lab analyses are ongoing, that Ramboll is Saint-Gobain’s contractor for simulated-runoff testing, and that DES has pushed for timely sharing of results but does not yet have final concrete results to release.