Eight US states have joined forces to file law suits against five giant power firms challenging their gas emissions.
The case was being launched in the federal district court of Manhattan using the common law of “public nuisance” to demand cuts.
The five are American Electric Power, Southern Co, Xcel Energy, Cinergy and the Federal Tennessee Valley Authority.
The New York Attorney General’s office described the combined action as a “precedent-setting” move.
The states – California, Connecticut, Iowa, New Jersey, New York, Rhode Island, Vermont and Wisconsin – contend that the five are the US’s biggest emitters of carbon dioxide.
None of the power companies are in the states that are suing.
High profile case
But the Attorneys General – the state officials filing the suit – say the “public nuisance” law provides a right to curb pollution coming from sources in other states.
They claim the federal government and the Bush administration have failed to deal effectively with the threats from global warming.
The BBC’s Emma Simpson in New York says they are not asking for financial damages, but for the court to require the firms to cut their emissions.
The action would “for the first time put global warming on the litigation map,” a spokesman for New York Attorney General Eliot Spitzer said.
A representative from the National Association of Manufacturers, which represents some of the power companies involved, said regulating carbon dioxide emissions would severely depress the US economy.
Power companies also argue that regulation would limit their use of fossil fuels.
Xcel Energy and TVA say they are already taking steps to reduce carbon dioxide emissions.
Carbon dioxide greenhouse gases are believed to be linked to global warming.
Scientists worry that industrial exhaust gases enter the atmosphere, raising temperatures and potentially damaging crops as well as human health.
The combined action follows the refusal of President George Bush’s administration to take part in the Kyoto agreement on climate change.
Greenhouse gas emissions from industrialised nations are likely to increase over the next few years, despite international agreements such as the Kyoto Protocol, according to a United Nations report published last year.