Hunton Andrews Kurth made no immediate comment on Wednesday following an announcement that a former partner, William Wehrum, is leaving his post as assistant administrator for air and radiation with the Environmental Protection Agency.

Wehrum was a partner with predecessor firm Hunton & Williams and head of the firm's administrative law group before his confirmation to serve as an EPA official in 2017. He has been the subject of sustained scrutiny by Democrats on the U.S. House Committee on Energy and Commerce into actions he has taken at the agency that allegedly favored his and his law firm's clients.

William L. Wehrum, assistant administrator of the Environmental Protection Agency for Air and Radiation. (Photo: Eric Vance/EPA via Wikimedia Commons)

Leaders of the committee launched an investigation in April into whether Wehrum and another former Hunton lawyer “violated federal ethics rules” by allegedly using their positions at EPA to promote the agenda of the Utility Air Regulatory Group, a now-dissolved Hunton client that committee members called ”a secretive front group funded by utility companies and devoted to rolling back Clean Air Act regulations.”

In a statement on Wednesday, Energy and Commerce Chairman Frank Pallone Jr., D-New Jersey, said Wehrum's departure from the EPA was “welcome.”

“Much like UARG suddenly dissolving in the face of scrutiny, Wehrum is now suddenly leaving amidst investigations into his potential ethical misconduct—investigations that should, and will, continue,” Pallone said in a statement.

Neither a Hunton Andrews Kurth spokesperson nor the EPA responded Wednesday to requests for comment on Wehrum's departure, including on any connection between his leaving and the House investigation. Eric Murdock, the current chair of the firm's administrative law team, also had no immediate comment. Hunton Andrews Kurth also did not respond to a request for comment on whether Wehrum would rejoin the firm.

In a statement, EPA administrator Andrew Wheeler thanked Wehrum for his service and indicated his departure was not sudden.

“While I have known of Bill's desire to leave at the end of this month for quite some time, the date has still come too soon,” Wheeler said in the statement. “I applaud Bill and his team for finalizing the Affordable Clean Energy regulation last week and for the tremendous progress he has made in so many other regulatory initiatives.”

Wheeler announced that Anne Idsal, principal deputy assistant administrator, would take Wehrum's place as acting assistant administrator upon his departure.

After former EPA administrator Scott Pruitt resigned last year, The New York Times labeled Wehrum “the single biggest threat inside the EPA” to environmental activists seeing more robust regulation of industries that contribute to global climate change.

Other EPA lawyers facing scrutiny over their industry ties have prepared to leave the agency in recent months, including Erik Baptist, who said earlier this month he was joining Wiley Rein.

In financial disclosure forms Wehrum filed before taking up his EPA post, he reported partner income of close to $2.2 million from Hunton & Williams, which is now Hunton Andrews Kurth. He listed the Utility Air Regulatory Group among his top sources of income, along with other clients including the American Forest & Paper Association, the American Fuel & Petrochemical Manufacturers and the American Petroleum Institute.