It’s hard to ignore the giant industrial plant sitting right off the Daniel Webster Highway. For years, the Saint-Gobain Merrimack NH facility was just a backdrop to daily commutes, a steady employer that specialized in high-tech coatings. Then the water tests came back.
Everything changed in 2016. That was the year New Hampshire officials discovered that per- and polyfluoroalkyl substances—better known as PFAS or "forever chemicals"—had leached into the local water supply. It wasn't just a few wells. We are talking about a massive plume affecting Merrimack, Litchfield, Bedford, and Londonderry.
If you live in southern New Hampshire, this isn't just a corporate news story. It's about what’s coming out of your kitchen faucet. It’s about the value of your home. It’s about the long-term health of your kids.
How the Contamination Actually Happened
Saint-Gobain Performance Plastics bought the site in 1999, taking over from Chemical Fabrics Corp. They weren't making plastic spoons. They were coating fabrics with Teflon and other high-performance materials. Think about the roof of the Denver International Airport or specialized industrial belts. To get those materials to be heat-resistant and non-stick, you need PFAS.
The problem? The chemicals didn't just stay on the fabric.
They went up the stacks. For decades, PFOA (perfluorooctanoic acid) was released into the air through the plant’s ventilation systems. Once those particles hit the air, they didn't just disappear. They settled onto the soil. They washed into the ground. Eventually, they hit the Merrimack Village District wells and private residential wells across the region.
It’s a slow-motion environmental disaster. Unlike a sudden oil spill, this was a constant, microscopic dusting of the landscape that lasted for years.
The Legal and Health Fallout
People are rightfully scared. PFAS are linked to a nasty list of health issues, including kidney cancer, testicular cancer, thyroid disease, and high cholesterol. In Merrimack, groups like Merrimack Citizens for Clean Water have spent years fighting for transparency. They aren't just activists; they’re parents who realized their families had been drinking contaminated water for most of their lives.
The state didn't sit still, though. New Hampshire eventually set some of the strictest PFAS limits in the country. We’re talking parts per trillion. To put that in perspective, one part per trillion is like a single drop of water in 20 Olympic-sized swimming pools.
Saint-Gobain has spent millions. They’ve funded water line extensions to hundreds of homes that previously relied on poisoned wells. They installed massive carbon filtration systems. But for many residents, a new pipe doesn't erase the anxiety of what’s already in their bloodstreams. A 2020 blood testing study in the area confirmed that residents had significantly higher levels of PFOA than the general U.S. population.
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The Decision to Close
In late 2023, Saint-Gobain dropped a bombshell: they were closing the Merrimack plant for good.
By mid-2024, the machines stopped. Most people expected a sense of relief, but the reality is more complicated. Closing the doors doesn't clean the aquifer. The "forever" in forever chemicals is literal. These carbon-fluorine bonds are some of the strongest in chemistry. They don't break down naturally.
The company claimed the closure was part of a "restructuring" and a move toward more sustainable business models. Critics, including State Representative Wendy Thomas, have been vocal about the timing. Is it a coincidence they closed just as environmental regulations and potential legal liabilities reached a fever pitch? Probably not.
What Most People Get Wrong About the Cleanup
There is a common misconception that once the plant is gone, the water gets clean.
Sadly, no.
The soil around the plant is still saturated. Every time it rains, more PFOA can be pushed deeper into the groundwater. Even with the plant closed, Saint-Gobain is still legally tethered to the site. Under a 2022 consent decree with the New Hampshire Department of Environmental Services (NHDES), the company is responsible for providing clean water to properties where PFAS levels exceed state standards.
This is a massive operation. It involves:
- Continuous monitoring of hundreds of private wells.
- Maintenance of Point-of-Entry (POE) filtration systems in people's basements.
- Massive expansion of public water mains into rural parts of Litchfield and Bedford.
If you’re moving to the area, you have to check the NHDES PFAS Map. You just have to. You cannot assume a house is "safe" because it’s a mile away from the plant. The plume is weirdly shaped, dictated by underground geology and airflow patterns from the old smokestacks.
The Economic Reality of the Exit
Merrimack is losing a major taxpayer. That’s a hit to the local budget. But honestly? Most residents seem fine with the trade-off. The "Business Friendly" reputation of New Hampshire has been tested here. How do you balance industrial jobs with the literal poisoning of the town's primary resource?
The site itself—located at 701 Daniel Webster Highway—is now a massive question mark. It’s a "brownfield" in the making. Who wants to buy a piece of land with that kind of environmental baggage? Any future developer is going to face a mountain of red tape and remediation costs.
Navigating the Future in Merrimack
If you live in the affected zone, you have to stay proactive. Do not wait for a letter in the mail.
First, if you are on a private well and haven't had it tested by the state or a certified lab in the last 12 months, do it now. The levels can fluctuate. New Hampshire’s current limit for PFOA is 12 parts per trillion. If you’re above that, Saint-Gobain is generally on the hook to provide you with bottled water or a filtration system, depending on the specific location and legal agreements in place.
Second, understand your filtration. Standard Brita filters or refrigerator filters are basically useless against PFAS. You need high-grade Activated Carbon or Reverse Osmosis systems.
Actionable Steps for Residents and Homebuyers:
- Check the Map: Visit the NHDES PFAS Sampling Map online. It’s a grainy, technical tool, but it shows every test result in the area. Find your specific street.
- Request Testing: If your property is within the "Consent Decree" area and hasn't been sampled, contact the NHDES Waste Management Division. They are the gatekeepers for getting Saint-Gobain to pay for the test.
- Blood Testing: Talk to your doctor about PFAS blood sampling. While it won't tell you "you will get sick," it establishes a baseline for your medical records.
- Filter Maintenance: If you have a state-provided carbon filter, make sure the service schedule is being followed. Those carbon beds eventually get "spent" and can actually dump chemicals back into your water if not changed.
- Stay Informed on the Property: Watch the Town of Merrimack planning board meetings. The future use of the Saint-Gobain site will determine a lot about the local property values and the intensity of the ongoing soil remediation.
The Saint-Gobain era in Merrimack is technically over, but the environmental legacy is just entering a new, quieter chapter of long-term management. It’s a reminder that "performance" in the industrial world often comes with a hidden, multi-generational price tag.