The Environmental Protection Agency isn't convinced that Coakley Landfill's cap may be putting harmful chemicals into a nearby brook.
The agency asked for more data in a letter about the North Hampton Superfund site Friday.
The Coakley Landfill Group, which is responsible for cleanup at the site, suggested in an analysis earlier this week that the landfill's cap itself could be tainting stormwater runoff with PFAS chemicals.
If confirmed, it would upend the assumption that the chemicals are seeping up from contaminated groundwater under the site. And it would have major implications for other EPA-managed capped landfills nationwide that are similar to the Coakley site.
But the EPA disagrees with the landfill group on whether groundwater could be seeping up into runoff or surface water. The agency says more data is needed to prove that's not happening.
They also say it's premature to draw any conclusions about the cap or the PFAS in landfill runoff.
The EPA has given the Landfill Group 15 days to submit a work plan for further sampling and analysis.
Read the EPA's full letter to the Landfill Group below: