WASHINGTON — Scott Pruitt, the Environmental Protection Agency chief, had an easier time than expected on Capitol Hill on Thursday as he deflected Democrats’ pointed questions about accusations of ethical infractions and lavish personal spending at the taxpayers’ expense.

He insisted that the charges were false and that decisions involving illegal actions had been made by his staff members without his knowledge.

“I have nothing to hide,” Mr. Pruitt said. Republicans were largely sympathetic.

His performance, supporters said, may have saved his job and his standing with President Trump.

“It’s an audience of one, and Pruitt acquitted himself well,” said Frank V. Maisano, a principal at the law firm Bracewell, which represents energy companies that lobby the E.P.A.