When a Plastics Factory Poisons the Water
Merrimack, New Hampshire — a town of roughly 26,000 people in southern Hillsborough County — found itself at the center of New Hampshire’s PFAS crisis in 2016. Testing revealed that PFOA and PFOS had contaminated both private wells and parts of the public water supply. The contamination was traced to Saint-Gobain Performance Plastics, which operates a manufacturing facility on Daniel Webster Highway.
The discovery came during the same period that PFAS contamination was being uncovered at Saint-Gobain facilities in Hoosick Falls, New York, and Bennington, Vermont. A pattern was emerging: facilities that used PFAS chemicals in manufacturing had been quietly contaminating surrounding communities for decades.
The Source of Contamination
Saint-Gobain’s Merrimack facility has manufactured Teflon-coated fabrics and other fluoropolymer products since the 1980s. The manufacturing process releases PFAS compounds — including PFOA and PFOS — into the air and potentially into the ground through waste handling.
Stack emissions from the facility deposited PFAS onto surrounding land, where the chemicals percolated into the soil and eventually reached groundwater. Private wells downgradient from the facility were hit hardest.
What the Testing Found
The contamination picture in Merrimack is complex:
- Private wells near the Saint-Gobain facility tested positive for PFOA and PFOS, some at levels well above New Hampshire’s maximum contaminant level of 12 ppt for PFOA and 15 ppt for PFOS
- The Merrimack Village District (MVD) public water supply, which serves about 11,000 residents, detected PFAS in some of its wells
- Neighboring communities including Litchfield and Bedford also found PFAS in some water sources, likely from the same contamination plume
- New Hampshire set some of the lowest PFAS standards in the nation: 12 ppt for PFOA, 15 ppt for PFOS, 18 ppt for PFHxS, and 11 ppt for PFNA
New Hampshire’s standards are significantly stricter than the EPA’s 2024 federal MCLs of 4 ppt for PFOA and PFOS individually, making the state one of the most protective in the country on PFAS.
The Community Response
The PFAS discovery triggered a major response:
- The Merrimack Village District installed granular activated carbon (GAC) treatment systems on affected public wells, at a cost of millions of dollars
- Saint-Gobain agreed to pay for treatment system installation and bottled water for affected private well owners
- The state ordered Saint-Gobain to conduct a comprehensive site investigation to determine the full extent of contamination
- A class-action lawsuit was filed by Merrimack residents against Saint-Gobain, seeking damages for property value losses, health monitoring, and remediation costs
- Blood testing offered to residents showed elevated PFAS levels in many participants, confirming long-term exposure
The state legislature responded by passing some of the strictest PFAS drinking water standards in the country and creating an NHDES PFAS Investigation program to address contamination statewide.
Current Status
As of 2025-2026, the situation in Merrimack continues to evolve:
- GAC treatment on public wells is operational and bringing PFAS levels below state MCLs
- Saint-Gobain has installed treatment systems on dozens of private wells
- The site investigation is ongoing, with groundwater monitoring wells tracking the contamination plume
- Legal proceedings continue, with Merrimack among several New Hampshire communities pursuing claims
- The facility continues to operate, though with emissions controls that Saint-Gobain says have significantly reduced PFAS releases
The long-term solution likely involves a combination of continued treatment, possible connection of private well users to the public supply, and source remediation at the facility.
Health Concerns
Residents who drank contaminated water for years have legitimate health concerns. PFAS exposure has been associated with:
- Increased risk of kidney and testicular cancers
- Thyroid disease
- Elevated cholesterol
- Reduced vaccine effectiveness
- Pregnancy-induced hypertension and preeclampsia
- Liver damage
The New Hampshire PFAS Health Study, conducted by the state Department of Health and Human Services, has been tracking health outcomes in affected communities. Residents are encouraged to discuss PFAS exposure with their healthcare providers and request PFAS blood testing if they haven’t already done so.
What Merrimack Residents Should Do
- Private well users: If you haven’t had your well tested for PFAS, contact NHDES or your local health department. Testing should include PFOA, PFOS, PFHxS, and PFNA at minimum.
- Check your treatment system: If you have a GAC filter installed, ensure it’s being maintained on schedule. Carbon media needs periodic replacement to remain effective.
- Know your rights: If you’ve been affected by the contamination, consult with legal counsel about your options. Multiple legal actions are underway.
- Stay informed: The NHDES PFAS response page provides regular updates on testing results, remediation progress, and health guidance.
If you’re concerned about your water quality in Merrimack or the broader southern New Hampshire area, a certified water treatment professional can test your water and recommend the right treatment solution for your specific contaminants and concentrations.
Sources: New Hampshire Department of Environmental Services (NHDES), EPA, New Hampshire Department of Health and Human Services, Merrimack Village District public notices