WASHINGTON (Dow Jones/AP) — The US government is asking a bankruptcy court to hold Arizona copper-mining company Asarco LLC fully responsible for polluted sites around the country, saying the same environmental laws that apply outside of Chapter 11 protection should also apply to companies in bankruptcy.In court papers filed last Friday, the Environmental Protection Agency asked the court to hold Asarco "joint and severally liable" for the pollution claims, which would allow state and federal officials to seek full damages from the company, even if it shares liability with other polluters.

Asarco, facing as much as $6.5 billion in environmental liabilities, has assumed responsibility at more than 100 sites across the United States for environmental claims ranging from $3.8 billion to $4 billion. The United States and 16 states have filed claims against the company under environmental laws, including the Comprehensive Environmental Response, Compensation and Liability Act, known as Superfund.

The US Bankruptcy Court in Corpus Christi, Texas, which is overseeing Asarco's Chapter 11, is slated to begin hearings in July to estimate the value of the mining company's environmental liabilities. Asarco said it should be held responsible only for its share of cleanup costs, but the government says environmental laws allow it to seek full damages from Asarco. The application of joint and several liability, which allows a plaintiff to recover all the damages from any defendants regardless of their individual share of the liability, provides an incentive for polluters to reach settlements, the EPA said.

The federal government said it also fears the impact of a decision in Asarco's favor could have on other polluters facing environmental liabilities.

"It would provide a significant reason for polluters to flee to bankruptcy court," the EPA said.

Asarco, a subsidiary of Mexican conglomerate Grupo Mexico SA, filed for bankruptcy in August 2005.