EPA Will Work With Developer To Cap Toxic Waste At Nashua’s Mohawk Tannery Site

Oct 7, 2019

The site of the former Mohawk tannery complex in Nashua.
Credit Dan Tuohy / NHPR

The Environmental Protection Agency will move forward on a plan to cap toxic waste at a former industrial site in Nashua.

In a recently released cleanup plan, the agency says it plans to split the cost of remediating the former Mohawk Tannery with the city and a private developer.

The tannery is in a residential area on the Nashua River. It’s been proposed as a federal Superfund site for nearly 20 years, with cleanup on hold as the city looked for a developer to take it on.

Last year, the project landed on a new, national EPA list of hazardous waste sites targeted for “intense, immediate action.” It was one of only a few sites on the list that weren’t officially Superfunds or where redevelopment was an active possibility.

Now, the EPA says it will work with the state, Nashua and developer Bernie Plante of Blaylock, LLC to design and carry out the agency’s chosen cleanup plan for the Tannery.

That plan involves consolidating more than 82,000 cubic yards of toxic sludge and soil onto a northern section part of the property, then walling the waste off, and covering it with an impermeable cap. Some asbestos would also be contained on the property.

The project will cost between $7 million and $15 million and take at least a year and a half.

An example of some of the sludge material from the old plant - during a site walk in 2018.
Credit Dan Tuohy / NHPR

When it’s done, some of the property will be safe for recreational use, with other parts safe for all uses, says Bryan Olson, who directs the EPA’s Superfund program in New England.

“We will allow people to be able to walk on this, recreate on this, ultimately, after it’s done,” Olson says. “So it’s not going to be something that’s going to be fenced in – it’s going to be perfectly safe for people to be there.”

In their cleanup memo, the EPA responds to some of residents’ long-standing concerns. The agency says it does not believe contaminants will leach from beneath the site into groundwater, and that the wall around the waste will prevent it from washing into the river in case of floods.

Residents have also called on the EPA to remove the toxic waste from the Tannery site altogether. Years ago, the agency had recommended this, but Olson says it would now be too expensive.

That’s partly because more contamination has since been discovered and disposal costs have gone up. In addition, he says, it would be harder to get the developer on board with those high costs – meaning the government would have to pay for it, likely delaying cleanup.

So he says on-site containment now makes the most sense.  

"This property, once cleaned up, is worth a fair amount of money – it's a really good development opportunity,” Olson says. “So this is the kind of thing that we look for."

He says Plante, the developer, is also interested in consolidating some waste from neighboring properties, about which residents have raised concerns.

Plante would bear the cost of doing so, Olson says, under supervision from the state and in line with the EPA’s plans.

The EPA notified residents of its cleanup decision by email this month. A spokeswoman says they also plan to go door-to-door to update neighbors on the project.

The EPA will show those neighbors its final cleanup design and cost-sharing agreement with the city and developer later this year. Construction is set to start next spring.