U.S. Sen. Tom Carper sent a letter Monday asking EPA Inspector General Sean O'Donnell to expand the agency's investigation into the new fuel efficiency rules adopted under the Trump administration.
In late February, Carper asked the inspector general to open an investigation into "potentially unlawful efforts and procedural problems" related to the vehicle emissions rules, citing reports received by his office that EPA political officers were dodging certain rule-making and procedural requirements and appeared to be trying to conceal documents critical of the draft rules.
President Donald Trump's rollback of Obama-era vehicle emissions standards was completed March 31. The new rules require 1.5 percent annual increases in efficiency through 2026. The final rules take effect June 29.
In the letter Monday, the Delaware congressman and top Democrat on the Senate Environment and Public Works Committee said his office has obtained new documents revealing "significant inaccuracies and technical errors in the final rule" that EPA officials had asked the Department of Transportation to correct.
"These materials describe a fundamentally and legally flawed rule created by what may be the most procedurally problematic process my office has ever reviewed," Carper wrote in the letter.
Carper is asking the inspector general to further investigate whether EPA officials "improperly circumvented the Clean Air Act, regulatory and other procedural requirements throughout the administration's preparation and review of the final Safer Affordable Fuel Efficient Vehicles rule," according to a news release from the committee.
"I request that you determine how so many significant changes were made to the rule after it was signed and before it was published, and whether the process followed to make such changes was appropriate, transparent and precedented," Carper said.
Jeffrey Lagda, a spokesman for the EPA inspector general, said in an email to Automotive News that O'Donnell has received the letter.
"He and his leadership team are currently reviewing the letter and the information provided," Lagda said.