Scott Pruitt, the administrator of the Environmental Protection Agency, is expected to field more tough questions from lawmakers about allegations of ethical abuses and excessive spending when he appears Wednesday before a Senate Appropriations Committee panel.

The hearing, to discuss the agency’s budget for the coming year, will be the first opportunity for senators to ask Mr. Pruitt about his first-class travel, foreign trips organized by lobbyists, renting a $50-a-night condo from a lobbyist with business before the agency and other issues that have become the subject of 12 different federal investigations. It follows appearances by Mr. Pruitt last month before two House panels.

While Mr. Pruitt’s last grilling from Congress was blistering, critics and supporters alike say the administrator walked away mostly unscathed. Republicans said they were largely satisfied by Mr. Pruitt’s answers, and President Trump has continued to express his support.

Mr. Pruitt’s champions said they expected him come through his Senate inquiry intact as well.

“I just think that President Trump has affirmed time and time again that he’s still very supportive of Scott Pruitt,” said Thomas J. Pyle, president of the Institute for Energy Research, which promotes fossil fuels. “Barring any shocking revelation, I think this drip, drip, drip of information is not likely to cause his ouster.”