State regulators have ordered the former owner of the HoltraChem facility in Orrington to remove hundreds of thousands of tons of contaminated soil from the site in what would be one of the largest environmental cleanup projects in Maine history.

The Maine Department of Environmental Protection has been working with representatives from Mallinckrodt Inc., for several years to dismantle and remove most of the contaminated structures at the former factory.

But the state and the company have clashed over how to address the soils laced with mercury and other toxins that are buried in five large landfills on the site, which is located on the banks of the Penobscot River.

After several months of intensive yet unsuccessful negotiations, DEP officials signed an order Monday requiring Mallinckrodt to begin the cleanup of the soils by May.

DEP Commissioner David Littell said the department decided it could no longer afford to wait to begin the cleanup of what he described as “the most heavily contaminated site in the state.”

“We moved forward with this remedy because it is necessary to protect the public health of residents in the area and to protect the long-term ecological health of the Penobscot River in the Orrington area,” Littell said.

HoltraChem Manufacturing Co. produced chlorine and other chemicals at the factory beginning in the mid-1960s. At the time the factory closed in 2000, HoltraChem was New England’s largest polluter of toxic mercury.

Mallinckrodt, which is the sole former owner still in business, has spent more than $35 million removing metallic mercury, mercury sludge and contaminated storage tanks and buildings from the 235-acre site.

But the company has resisted DEP plans to remove an estimated 370,000 tons of mercury-contaminated soil buried in landfills and elsewhere on the site. Orrington town officials, meanwhile, have said they want the soils removed so that the scenic riverfront site can be redeveloped.

Facing a price tag likely exceeding $100 million for the work, Mallinckrodt officials have argued in the past that it would be faster, easier and safer to encapsulate the contamination on site.

Mallinckrodt spokeswoman JoAnna Schooler said Monday that company officials had not yet seen the final cleanup order, and therefore, could not comment.

Littell said leaving the contaminated soils in the five landfills – which encompass more than 120,000 square feet – was not an option because of the contamination’s proximity to nearby residences and the river. The department also wanted to make sure local residents and the environment are protected well into the future, regardless of Mallinckrodt’s status as a company, he said.

The DEP order requires Mallinckrodt to remove the tainted soils to a licensed treatment or disposal facility.

“It’s really a stew of hazardous waste in these five landfills,” Littell said.

The DEP order, which Littell said likely will be appealed, would also require Mallinckrodt to remove an industrial sewer and the concrete slab of the former “cell building” as well as any contaminated soil under the slab.

Littell said he hopes the company will continue to work with the department on other agreed-upon cleanup projects at the site if the latest order is appealed to the Maine Board of Environmental Protection.

Soil contamination is not the only contentious issue left at the HoltraChem site.

A court-ordered study panel has been assessing the scope of mercury pollution in the Penobscot River downstream from the HoltraChem facility.

That scientific study panel, which Mallinckrodt is required to finance, is investigating whether it makes more sense to attempt to physically remove the mercury pollution from the muddy bottom or to allow the river to flush the toxins naturally.

Mercury is a bioaccumulative toxin, meaning concentrations of the toxin increase at each level of the food chain. Predators at the top of the food chain – such as humans and bald eagles – that eat fish contaminated with mercury are at higher risk from the neurotoxin.

Mercury is particularly dangerous to pregnant women and young children.

kmiller@bangordailynews.net

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