WASHINGTON (AP) — The chairman of the House Oversight Committee is seeking details from Interior Secretary Ryan Zinke about a $139,000 project to upgrade doors in Zinke’s office.

Oversight Chairman Trey Gowdy of South Carolina asked Zinke to explain the need for the replacement doors and provide details about the project’s cost estimates, bids and final contract.

The letter from the Republican chairman comes after The Associated Press reported earlier this month that Interior is spending nearly $139,000 to upgrade double doors in Zinke’s sixth-floor office overlooking the Washington Monument.

Zinke told the House Natural Resources Committee last week he has negotiated a significantly lower price for the project by “manipulating” contract terms. He did not elaborate.

An Interior spokeswoman said Friday that Zinke has directed changes in the project’s scope to save money. The new estimate is about 50 percent lower than the initial amount, spokeswoman Heather Swift said.

Swift said earlier this month that Zinke wasn’t aware of the contract until AP asked about it.

The Interior Department’s Office of Facilities and Administrative Services has called the $139,000 cost “reasonable,” noting that the project includes the installation of two sets of custom-built double doors and door frames, as well as demolition of existing doorways. The contract also covers repairs to another set of double doors that lead from a hallway to the secretary’s office.

Zinke said regulations regarding the 82-year-old, historic building near the National Mall significantly increase the cost of the renovations.

In his letter to Zinke, Gowdy said he is aware of “allegations of excess cost” and asked the department to provide a detailed briefing on the project, including information on the bid process and contract award, along with receipts for related expenses. The briefing should be scheduled by April 6, he said.

The Environmental Working Group, a Washington-based advocacy group, hailed Gowdy’s inquiry.

“Welcome to the resistance, Chairman Gowdy,” said Ken Cook, the group’s president.

“Taxpayer dollars flow out of the offices of Zinke and EPA chief Scott Pruitt like water from a fire hose,” Cook said, citing costs for first-class travel and other luxuries.