Then-Deputy Interior Secretary David Bernhardt in October. (Katherine Frey/The Washington Post)

The Interior Department’s Office of Inspector General is reviewing allegations that acting secretary David Bernhardt may have violated his ethics pledge by weighing in on issues affecting a former client, the office confirmed Tuesday.

The move comes as the Senate Energy and Natural Resources Committee is preparing to vote Thursday on whether to confirm Bernhardt as the next interior secretary, after which his nomination is expected to advance to the Senate floor.

At least two outside groups and two Democratic senators asked the agency watchdog to look into Bernhardt’s effort to weaken protections for imperiled fish species and to expand California farmers’ access to water, even though he once lobbied on behalf of a massive agricultural water district that stood to benefit from the changes. The New York Times, The Washington Post and other outlets reported on aspects of Bernhardt’s work.

Bernhardt, who represented the Westlands Water District at the firm Brownstein Hyatt Farber Schreck before joining the administration in August 2017, has consistently said that he has complied with all federal ethics rules and has not weighed in on particular matters affecting former clients. Under the administration’s ethics pledge, he should be recused from specific issues involving a former client for up to two years, though he can weigh in on policies affecting a broader group of parties.

In an interview, Office of Inspector General spokeswoman Nancy DiPaolo said the office has not launched a formal probe. “We’re reviewing the facts and requests to determine appropriate next steps,” she said.

An Interior Department spokeswoman said Tuesday that the agency cannot comment on matters pending before the inspector general’s office.

Several groups, including the Campaign Legal Center and the Campaign for Accountability, as well as Sens. Elizabeth Warren (D-Mass.) and Richard Blumenthal (D-Conn.), have questioned Bernhardt’s role in the Interior Department’s push to conduct an environmental analysis of proposed changes to federal and state water projects in California. That effort could free up more water for the Westlands Water District, which serves farmers in California’s Central Valley.

“It’s important that the inspector general look into this matter and see what happened here,” said Daniel Stevens, executive director of the Campaign for Accountability, who received a letter from the office Monday.

In response to an earlier inquiry by The Post, the Interior Department released a Feb. 19 memo signed by two ethics officials at the agency. It concluded that Bernhardt’s work on a draft environmental analysis of these water projects did not constitute a “particular matter” that would be covered by his ethics pledge.

And in a March 25 letter to Warren and Blumenthal, the Interior Department’s designated ethics official, Scott A. de la Vega, outlined several reasons he and his colleagues concluded that Bernhardt did not violate the recusal policy. He noted that because Westlands is a governmental entity, the recusal requirement lasted only for one year, as well as the fact that the bill Bernhardt lobbied on in connection with Westlands “addressed a broad range of issues and topics.”

“Please know that my office takes all credible allegations of potential ethics violations by any DOI employee very seriously and allegations against senior officials are an extremely high priority,” de la Vega wrote.

Some ethics experts questioned the validity of the February memo, which came after the New York Times had reported on details of Bernhardt’s involvement in California water policy. In a letter Thursday to the Interior Department’s acting inspector general, Mary Kendall, officials from the Campaign Legal Center said the memo inaccurately concluded that this work did not constitute a “particular matter” as defined under the federal ethics pledge and that the timing of its release “also raises concerns.”