– The Environmental Protection Agency’s inspector general will investigate allegations that William 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 Wehrum’s efforts at the EPA to weaken climate change and air pollution standards improperly benefited those former clients, a congressional aide said. Wehrum resigned in June 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 key rollbacks, including weakening Obama-era regulations on greenhouse gas emissions from automobile tailpipes and methane from oil and gas wells.

At issue in the new inquiry are 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 Donald Trump appointed Wehrum.

The House Energy and Commerce Committee has already opened an inquiry into a separate ethics case involving Wehrum. He could not be reached for comment.