As Scott Pruitt prepares to unveil his latest proposal aimed at curtailing scientific research, the embattled Environmental Protection Agency (EPA) administrator looks to be ever closer to an ouster as congressional support falls and public outrage over his corruption allegations continues to grow.

"We trust that Scott Pruitt's days of chiseling the taxpayers and pandering to polluters are numbered," said Environmental Working Group (EWG) President Ken Cook in a statement Tuesday. "He should have been dismissed long ago."

Pruitt is the subject of mounting controversy, amid reports that he wasted tens of thousands of taxpayer dollars keeping up a lavish lifestyle, lied about raises he attempted to give staffers, and obtained a sweetheart condo rental deal from an energy lobbyist who he met with to discuss policy last year.

As the New York Times detailed last week, there are currently 10 federal inquiries into Pruitt's behavior at the helm of the EPA.

The White House has publicly defended Pruitt in recent weeks, but support among Republicans appears to be eroding, with four Party members now calling for his resignation and three GOP senators demanding hearings on Monday to get to the bottom of the corruption allegations. Pruitt will face House budget hearings this Thursday, where his personal spending and ties to lobbyists are expected to be discussed.

The potential abandonment of Pruitt by his own party comes as he is preparing to unveil new rules that would create new standards limiting the scientific research that can be used to write regulations—a supposed bid for transparency that critics say would block research on issues like the danger of pesticides and pollution.

"What is transparent is the unabashed takeover of EPA leadership by individuals who have demonstrated disinterest in helping communities combat pollution by using the best available science," Andrew Rosenberg of the Union of Concerned Scientists (UCS) told the Washington Post.

The new rules, expected to be announced on Tuesday, are the latest of Pruitt's policy proposals to draw the ire of environmental advocates. The administrator purged independent science advisers from the EPA's advisory boards last year, and has moved to roll back regulations on greenhouse gas emissions and water pollution.