CONCORD, N.H. – The state said Monday it wants to seize miles of potentially polluted riverbed in the North Country to smooth the sale of a closed paper mill complex.

Gov. Jeanne Shaheen called a special Executive Council hearing for Tuesday on seizing a stretch of Androscoggin River riverbed by eminent domain.

Two top agency heads, George Bald and Dana Bisbee, could not say how much legal liability the state might incur for cleaning up the riverbed. But they and Shaheen said buyers won’t take the mills unless they are relieved of cleanup liability, so the state will face the problem regardless.

“We have this problem whether or not Fraser Paper comes to Berlin,” said Bisbee, acting head of the Department of Environmental Services.

Fraser recently agreed to pay $30 million for the complex, a pulp mill in Berlin and paper mill in neighboring Gorham.

Bisbee and Bald, the state commissioner of resources and economic development, said whoever buys the mills would be exempt from liability for most past pollution under a new federal “brownfields” law. The law is intended to encourage companies to redevelop old industrial sites.

The law does not exempt buyers of such sites from cleaning up polychlorinated biphenyls, or PCBs, cancer-causing chemicals used in electrical transformers until they were banned in 1977. Bisbee said the state proposes taking one known site contaminated by PCBs.

The U.S. Environmental Protection agency worked with a previous owner of the mills to clean up that site, and the land-seizure proposal includes about $1 million to finish cleaning it up, Bisbee said.

PCB dumping into the Hudson River in upstate New York decades ago has been the subject of lengthy court battles, and just planning that cleanup is expected to cost about $30 million.

Bisbee said the known PCB site in Berlin is minuscule by comparison. He said it is a small area on the grounds of the pulp mill.

“We don’t know anything about PCBs in the river at this point,” he said.

Shaheen and the agency heads said the state could try to track down and sue the original polluters for any cleanup costs that become its responsibility.

The mills closed in August, putting 860 employees out of work. Their owner, American Tissue Inc. of Hauppauge, N.Y., filed for bankruptcy soon afterward.

Fraser, based in Stamford, Conn., recently offered $30 million for the complex, but other companies could bid at an auction ordered by a bankruptcy judge for next month.

Bisbee said the state already has split off a landfill and two other undesirable parts of the complex to expedite the sale. He said there isn’t time before the auction to follow the same procedure with the riverbed.

He said the proposal is an excellent trade-off for the state.

“We have the opportunity for a respected, good company to come into Berlin and Gorham and run the mills,” he said.

Shaheen agreed.

“We need to act quickly to keep the sale of the mills on track,” she said in a statement. “This action will remove a significant obstacle to selling the Berlin and Gorham mills and getting people back to work.”