DES scientist outlines how Saint-Gobain emissions drove local PFAS deposition and groundwater contamination

Jeff Martz, administrator of the Hazardous Waste Remediation Bureau at the New Hampshire Department of Environmental Services, told the House study commission that airborne emissions from the Saint‑Gobain manufacturing facility in Merrimack drove widespread deposition of PFOA and other PFAS and are a key pathway for the contamination now found in groundwater across a large area.

Martz summarized the site history and transport pathways and said the “main pathway that we’re concerned about… is the air emissions pathway,” adding that PFOA and other PFAS “were essentially driven off the fabric and emitted through a series of smokestacks” and later deposited to soil where they could leach to groundwater.

Why it matters: the 2018 consent decree around Saint‑Gobain defines a roughly 64‑square‑mile investigation area that includes thousands of public and private supply wells; the commission and DES are relying on combined air‑deposition models, soil data and groundwater sampling to prioritize further testing and remediation.

Martz described several release mechanisms at the plant: particulate and vapor stack emissions, discrete spills of chemical…