The Bush administration has asked for public comment on a long list of options for controlling greenhouse gas emissions under existing federal law, but emphasized that it has no intention of pursuing any of them. The announcement confirms that the Bush administration will not move to regulate greenhouse gas emissions and will pass this concern on to the next president and to Congress. The advanced notice of proposed rulemaking released by the US Environmental Protection Agency is the agency's response to the landmark Supreme Court decision in April 2007 that gave the EPA authority under the Clean Air Act to regulate carbon dioxide - the predominant greenhouse gas - as a pollutant. The high court ruling required EPA to reconsider its refusal to determine whether greenhouse gas emissions from motor vehicles endanger public health.

An 'endangerment' finding would require the EPA to take action to regulate and limit emissions under the Clean Air Act.

But the Bush administration has effectively sidestepped the question and rejected the idea of using the Clean Air Act to regulate emissions.

The massive document contains some 1,000 pages of internal agency deliberations as well as comments from other agencies largely focused on whether the Clean Air Act is suitable to regulate greenhouse gases from a range of sources, including power plants and motor vehicles.

EPA Administrator Stephen Johnson said the complex document underscores his determination that the Clean Air Act is simply 'ill-suited' for the task.

'It is the wrong tool,' Johnson told reporters on a press call.

The potential regulation of greenhouse gases 'under any portion of the Clean Air Act could result in an unprecedented expansion of EPA's authority that could have a profound effect on virtually every sector of the economy and every household,' Johnson said.

If EPA were to use the law to require cuts in emissions, the agency would be forced to take a piecemeal approach, he said.

The result would be scores of individual regulations that would take decades to craft, all of which would be subject to litigation and delay, Johnson explained.

'If our nation is truly serious about regulating greenhouse gases, the Clean Air Act is the wrong tool for the job,' said Johnson. 'It really is at the feet of Congress.'

But Congress has thus far shown little appetite for the job.The Senate's attempt to consider legislation dissolved last month in a wave of partisan bickering and the House is unlikely to take up a bill this year.

Johnson's announcement is a reversal of earlier conclusions by EPA staff who had determined that the Clean Air Act indeed provided an adequate and workable framework for regulating greenhouse gas emissions. A December 2007 draft by the agency went so far as to conclude that greenhouse gases from motor vehicles do endanger public welfare.

Subsequent drafts leaked in May and released by the agency last month did not include an endangerment finding, but did include the final document's focus on the view that the Clean Air Act is unworkable and too costly.

The final version contains assumptions that gasoline prices will be some $2 per gallon and that oil will cost $58 a barrel - far lower than the current national U.S. average of more than $4 a gallon and than current oil prices of some $140 a barrel.

These assumptions result in an estimate that cutting greenhouse gases from motor vehicles would result in net benefits of some $830 billion. Previous EPA estimates found net benefits could total some $2 trillion.