Environmental Protection Agency Administrator Scott Pruitt on Tuesday refused to rule out an effort to repeal an EPA finding that empowers the agency to create rules to fight climate change.

Scrapping the determination, known as the endangerment finding, would make it easier for President Donald Trump to wipe the slate clear of Obama-era environmental regulations.

Pruitt's comment came during a combative Senate hearing, his first appearance before the chamber's Environment and Public Works Committee since his confirmation hearing a year ago.

During that 2017 hearing, Pruitt said he had no intention of reviewing the endangerment finding, the EPA's 2009 determination that carbon dioxide and other greenhouse gases are a danger to the public health and welfare of Americans and future generations.

But on Tuesday Sen. Tom Carper of Delaware, the ranking Democrat on the committee, asked whether Pruitt would refuse to repeal or replace the endangerment finding. Pruitt said there is "no decision or determination on that."

A dedicated group of conservative climate change skeptics has pushed Pruitt to scrap the endangerment finding. They believe repeal is the key to permanently unraveling former President Barack Obama's efforts to control emissions from automobiles, power plants, oil and gas wells, and other sources.

The Trump administration has rolled back Obama-era environment regulations, but it must replace many of those rules so long as the endangerment finding stands. Pruitt has so far resisted calls to kill the finding, which would require him to refute a huge body of evidence the EPA cited in making its decision.

Pruitt also said Tuesday that an EPA-sponsored debate between mainstream climate scientists and climate change skeptics, known as the red team-blue team exercise, is still under consideration.