The EPA and White House said the greenhouse gas document did not require more independent scrutiny because the scientific evidence it was based on already had been thoroughly reviewed. – AP Photo

WASHINGTON: The Obama administration cut corners before concluding that climate-change pollution can endanger human health, a key finding underpinning costly new regulations, an internal government watchdog said Wednesday.

Regulators and the White House disagreed with the finding, and the report itself did not question the science behind the administration’s conclusions. Still, the decision by the Environmental Protection Agency’s inspector general is sure to encourage industry lawyers, global warming doubters in Congress and elsewhere, and Republicans taking aim at the agency for what they view as an onslaught of job-killing environmental regulations.

The report said EPA should have followed a more extensive review process for a technical paper supporting its determination that greenhouse gases pose dangers to human health and welfare, a finding that ultimately compelled it to issue controversial and expensive regulations to control greenhouse gases for the first time.

‘‘While it may be debatable what impact, if any, this had on EPA’s finding, it is clear that EPA did not follow all the required steps,’’ Inspector General Arthur A. Elkins, Jr. said in a statement Wednesday.

The EPA and White House said the greenhouse gas document did not require more independent scrutiny because the scientific evidence it was based on already had been thoroughly reviewed. The agency did have the document vetted by 12 experts, although one of those worked for EPA.

‘‘The report importantly does not question or even address the science used or the conclusions reached,’’ the EPA said in a statement. The environmental agency said its work ‘‘followed all appropriate guidance,’’ a conclusion supported by the White House budget official who wrote the peer review guidelines in 2005.

EPA Administrator Lisa Jackson has said repeatedly that her conclusions were based on the underlying science, not the agency’s summary of it.

The greenhouse gas decision – which marked a reversal from the Bush administration – was announced in December 2009, a week before President Barack Obama headed to international negotiations in Denmark on a new treaty to curb global warming. At the time, progress was stalled in Congress on a new law to reduce emissions in the United States.

In 2010, a survey of more than 1,000 of the world’s most cited and published climate scientists found that 97 per cent believe climate change is very likely caused by the burning of fossil fuels.

But by highlighting what it calls ‘‘procedural deviations,’’ the report provides ammunition to Republicans and industry lawyers fighting the Obama administration over its decision to use the 40-year-old Clean Air Act to fight global warming. While the Supreme Court said in 2007 that the act could be used to control greenhouse gases, the Republican-controlled House has passed legislation that would change that. The bill has so far been stymied by the Democratic-controlled Senate.

Sen. James Inhofe, the Republican who requested the investigation and one of Congress’ most vocal climate skeptics, said Wednesday the report confirmed that ‘‘the very foundation of President Obama’s job-destroying agenda was rushed, biased and flawed.’’ Sen. John Barrasso, another critic of EPA regulations, said the agency sacrificed scientific protocol for ‘‘political expediency.’’

Environmentalists, meanwhile, said the inspector general was nitpicking at the public’s expense. The investigation cost nearly $300,000.

‘‘The process matters, but the science matters more,’’ said Francesca Grifo, a senior scientist with the Union of Concerned Scientists. ‘‘Nothing in this report questions the agency’s ability to move forward with global warming emissions rules.’’

A prominent environmental attorney and Columbia University law professor questioned what effect, if any, the report would have on global warming policy or the more than a dozen lawsuits filed by manufacturers, refiners, the state of Texas and others challenging the EPA’s finding.

Michael Gerrard said that while lawyers and politicians would try to use the report to fight EPA regulations, the scientific case for global warming has only gotten stronger. The worst-case scenario for the agency is that a federal judge sends the document back for reworking, putting its global warming regulations on cars, trucks, power plants and refineries in limbo.