The Office of Inspector General (IG) said in a report issued this week that the Environmental Protection Agency (EPA) should have conducted a more detailed scientific review before determining that greenhouse-gas emissions pose a threat to public health and welfare. The IG probe was requested by Senator James M. Inhofe (R-OK), the top Republican on the Senate Environment and Public Works Committee.

“The review did not meet all Office of Management and Budget requirements for peer review of a highly influential scientific assessment primarily because the review results and EPA’s response were not publicly reported and because 1 of the 12 reviewers was an EPA employee,” the study said.

The IG investigation did not examine the scientific evidence underpinning the EPA finding of a connection between human activity and global warming over the past half-century.  However, Senator Inhofe said the report raises the question of whether the Obama administration should have concluded that greenhouse gases qualify as pollutants under the Clean Air Act, saying that EPA’s endangerment finding was “rushed, biased, and flawed.”  The report “calls the scientific integrity of EPA’s decision-making process into question and undermines the credibility of the endangerment finding,” Inhofe said in a statement.

EPA defended its approach, and the IG report concluded that the agency met the legal requirements for issuing its “endangerment finding,” which provides the basis for federal limits on carbon dioxide from power plants and other big sources.  However, the IG report said EPA’s technical support document did not meet the threshold for a “highly influential scientific assessment, because it did not cover new science.”

It is not clear whether the report will affect a legal challenge to the endangerment finding that several industries affected by the regulations have mounted in federal court.  Some think that EPA’s failure to follow peer review procedures could be a factor in the federal court case.  On the other hand, others have said that the IG report will not affect the case because it concluded that EPA followed all the rulemaking procedures and its decision on greenhouse gases is supported by the underlying science.

House oversight committee Chairman Darrell Issa (R-CA) said he is considering hold hearings on the matter.  “This report raises serious questions that our committee and staff will further review,” Rep. Issa said in a statement.