WASHINGTON — Scott Pruitt, the head of the Environmental Protection Agency, testified on Capitol Hill on Thursday in what turned out to be a daylong grilling over allegations of ethical infractions and lavish spending.

The E.P.A. chief, whose job may be hanging by a thread, delivered a typically lawyerly performance.

As Democrats opened an aggressive, coordinated line of questioning — on Mr. Pruitt’s spending, housing arrangements, security team and raises for political appointees — he stayed quiet and calm, never raising his voice or his temper, but rarely giving direct answers to those questions.

Here are the highlights from the two sessions:

An opening barrage from Democrats

Representative Paul Tonko, Democrat of New York, got the morning questioning off to a start by asking Mr. Pruitt to answer “yes or no” to whether he had approved pay raises for two E.P.A. employees he brought with him from Oklahoma.

Mr. Pruitt said he had delegated the authority to grant such approvals, or as he put it, “There was delegation given in my authority.” He said, “I was not aware of the amount, and I was not aware of the bypassing that was going on.”