- Collins is the first Republican to break ranks over Pruitt
- "Mr. Pruitt and I have fundamentally different views of the role and mission of the EPA," she said
Collins -- who voted against the confirmation of Education Secretary Betsy DeVos and, according to sources
, indicated she was likely to vote against Andrew Puzder for labor secretary before he withdrew Wednesday -- is the first Republican to break ranks over Pruitt.
"The fact is, Mr. Pruitt and I have fundamentally different views of the role and mission of the EPA," Collins said in a statement
Collins did say, however, she would vote to invoke cloture on Pruitt's nomination, which would help clear him from the threat of a filibuster.
Republicans currently hold a 52-48 majority in the Senate, with Vice President Mike Pence holding a tie-breaking vote. A source told CNN that West Virginia Democratic Sen. Joe Manchin will likely support Pruitt.
Pruitt is currently the Oklahoma attorney general, and in that office, he has led lawsuits against the agency he stands to lead.
Despite overwhelming scientific consensus on climate change, Pruitt has said
human impact on the climate needs more debate.
Environmentalists have staunchly opposed his nomination, while many Republicans have praised him for combating what they view as regulatory overreach.
A vote to break the filibuster is scheduled for Thursday, and a final confirmation vote is expected Friday afternoon, assuming Democrats do not yield back time. They have not signaled their intention to do so and worked to delay recent confirmation votes.