AUGUSTA, Maine (AP) — A pharmaceutical company must complete the cleanup of the former HoltraChem Manufacturing Co. plant in Orrington, Maine's highest court said Thursday.

Mallinckrodt LLC, which inherited responsibility for the site after HoltraChem went bankrupt, had sought to overturn an order requiring it to complete an environmental cleanup that could cost $130 million. The Supreme Judicial Court unanimously rejected Mallinckrodt's appeal.

The chemical plant used mercury in its manufacturing processes and dumped waste directly into the Penobscot River. The plant later deposited waste in five landfills on its 235-acre campus.

"It is our hope that Mallinckrodt will stop using delay tactics through the court system and clean up the site," said Maine Department of Environmental Protection Commissioner Patricia Aho. "The department stands ready and willing to work with Mallinckrodt on the long-overdue remediation so the site can be returned to productive use."

The original cleanup plan ordered by the DEP commissioner in 2008 called for Mallinckrodt to haul away material from all five landfills at a cost of $250 million. But the cleanup plan was later modified to require Mallinckrodt to excavate two landfills and to secure and monitor three other landfills. Mallinckrodt estimates the cost to be $130 million.

A spokesman said Mallinckrodt's U.S. division, based in St. Louis, said the company is currently reviewing the supreme court decision.

"We are hopeful that we can move forward cooperatively with the Maine DEP to discuss how best to implement the court's decision," said Ernie Corrigan, the company spokesman.