WASHINGTON — The Environmental Protection Agency’s inspector general will investigate allegations that William L. Wehrum, the agency’s former air quality chief, violated ethics rules when he met with former clients from his days as a lawyer and lobbyist for the oil, gas and coal industries.
The inquiry will look into whether Mr. Wehrum’s efforts at the E.P.A. to weaken climate change and air pollution standards improperly benefited those former clients, a congressional aide said.
At issue are Mr. Wehrum’s ties to the Utility Air Regulatory Group, a coalition of utilities and trade groups that lobbies on behalf of coal-fired power plants, which he represented as a lawyer at his former firm, Hunton & Williams.
That relationship first drew scrutiny last year after Politico reported that the 25 power companies and six trade groups that make up the coalition paid the firm more than $8 million in 2017 just before President Trump appointed Mr. Wehrum. (The law firm is now known as Hunton Andrews Kurth. The Utility Air Regulatory Group announced in May that it would disband after winding down operations.)
Mr. Wehrum resigned last month after helping to finalize a regulation that would relax restrictions the Obama administration had sought to impose on greenhouse gas emissions from coal-fired power plants. As the agency’s assistant administrator for air and radiation, he was the legal expert behind other rollbacks of key climate change and air pollution regulations, including weakening Obama-era regulations on greenhouse gas emissions from automobile tailpipes and methane from oil and gas wells.
The House Energy and Commerce Committee has already opened an inquiry into whether Mr. Wehrum and David Harlow — a senior counsel at the E.P.A. who worked with Mr. Wehrum at the law firm — improperly worked to reverse an enforcement action that would have aided a former client, DTE Energy.
Senator Tom Carper of Delaware, the top Democrat on the Senate Environment and Public Works Committee, and Senator Sheldon Whitehouse, a Rhode Island Democrat, on Sunday sent an investigative report to the E.P.A. inspector general that outlined new allegations about both Mr. Wehrum and Mr. Harlow. Those included accusations that Mr. Wehrum’s recusal statements did not disclose some meetings with former clients.
In a letter to Charles J. Sheehan, the inspector general, the senators accused the Trump administration of ethical failings and an absence of accountability, and said those shortcomings “should not be aided by an implicit message that one can avoid investigation if one simply resigns before the investigation is complete.”
Mr. Wehrum could not immediately be reached for comment. Michael Abboud, an E.P.A. spokesman, issued a statement disputing the facts of the Senate Democrats’ report and described it as “a replay of old allegations that have repeatedly been answered by the agency and Mr. Wehrum.”
The new investigation was first reported by The Washington Post.
Under ethics rules developed under both the Obama and Trump administrations, public officials are not permitted to take part in “particular matters” involving specific parties that they represented in the private sector. They are, however, allowed to offer general expertise.
Jeffrey R. Holmstead, a lawyer for the electric utility industry, accused opponents of the Trump administration’s policies of using ethics rules to attack Mr. Wehrum personally.
“We’re talking about regulations and policies of general applicability,” he said.
The E.P.A. has been the focus of numerous ethics investigations under the Trump administration. The former administrator, Scott Pruitt, faced more than a dozen internal and congressional inquiries before resigning in July 2018.