The state Department of Environmental Protection has set itself a June deadline to negotiate a payment agreement with two companies, a university, and the US Department of Defense, all of which have been deemed partially responsible for polluting the former National Fireworks Co. site in Hanover.
If an accord isn’t reached by then, agency officials say they will ask the federal government to declare the site a Superfund area and oversee the remediation effort, a decision that could potentially help with funding the estimated $25 million price tag.
In a letter to Hanover selectmen, who want the state to continue negotiating toward a solution, DEP Commissioner Kenneth L. Kimmel said his agency has made significant progress in talks between the “responsible parties’’ and is “fully engaged’’ in reviewing potential cleanup options.
Still, Kimmel said, “we reserve the right to recommend commencement of the Superfund listing process if the issues are not resolved by that time.’’
The sprawling property located off King and Winter streets also borders Hanson and Pembroke. One of its early inhabitants was an 18th-century forge that made cannonballs for Old Ironsides.
Over the years, the property also hosted the National Fireworks Co., which made pyrotechnics from firecrackers to cherry bombs, and the Defense Department, which used the site to manufacture munitions and explosives for the military from World War I to the 1970s.
As a result of those uses, pockets of mercury, lead, and other heavy metals and solvents from the manufacturing processes are buried in the sediment of the adjoining Factory Pond and tributaries of the North River.
The state has already completed three phases of cleanups at the site, including removal of human health risks like drums of chemicals left there decades ago by the Massachusetts Institute of Technology.
The state is currently in negotiations with Kerr-McGee Chemical Co., National Coating Inc., MIT, and the Department of Defense, said Donald Nagle, an environmental lawyer hired by the five-member Hanover board to help shepherd the mitigation process.
Tronox, another former owner, settled with the federal government two years ago and then went bankrupt, he said.
Under Phase Four of the cleanup plan, ecological hazards would be excavated from the sediment or capped, officials have said.
It’s the second six-month extension the town has requested and received in a year.
Hanover selectmen have been insistent that they want the state to retain control while also laying the groundwork to get a long-overdue cleanup on its way, Nagle said.
DEP officials, though, have said that moving the site onto a federal priority list could potentially force the Department of Defense to get involved in what some state officials have characterized as one of the most contaminated sites in the state.
Hanover officials have said the town, which is the current owner of about 180 of the acres, also wants to protect new owners of portions of the remaining acreage and hold them harmless from any financial responsibility.
If the federal Environmental Protection Agency got involved, the bureaucracy could tangle up the process for decades before any movement was seen, Nagle said.
While there is no imminent safety risk to those who use the area for passive recreation, people are warned not to eat the fish, said Nagle.
The towns of Hanson and Pembroke, which are close enough to share concerns about the site, have agreed to work with Hanover to find a solution.
“We are on the sidelines, knowing that if things get stirred up in Factory Pond, it could get into Indian Head River and the North River and then that could be a concern,’’ said Pembroke Town Administrator Edwin J. Thorne.
The site saw a number of accidents and explosions over the years, including a massive fire in 1902 that ignited 2,000 cases of pyrotechnics, which detonated for three hours, according to a story in The New York Times.
Another report, by Town Moderator Doug Thomson on the town’s website, said the military briefly used the facility during World War II to house prisoners of war.
Michele Morgan Bolton can be reached at email@example.com.