Sen. Joe Manchin, D-W.Va., on Wednesday flipped his vote on President Trump’s nominee to join a panel of independent energy regulators on the grounds that the candidate downplayed climate change and supports fossil fuels.

All Democrats opposed Bernard McNamee’s nomination to join the Federal Energy Regulatory Commission during a procedural vote Wednesday, which he survived on a count of 50-49, setting up a final vote Thursday.

Manchin, a vocal supporter of the coal industry, also voted against McNamee, despite earlier voting for him in committee. The change of heart is notable because Manchin is facing pressure from environmentalists as he seeks to become the top Democrat of the Senate Energy and Natural Resources Committee.

Manchin said he was disturbed after viewing a newly unearthed video from earlier this year, reported recently by Utility Dive, that shows McNamee criticizing renewable energy and favoring fossil fuels.

McNamee, who was working for the conservative Texas Public Policy Foundation, delivered a speech in February to Texas lawmakers in which he said fossil fuels are "key to our way of life" and renewable energy "screws up the whole physics of the grid."

“After viewing video footage, which I had not previously seen, where Bernard McNamee outright denies the impact that humans are having on our climate, I can no longer support his nomination to be a FERC commissioner,” Manchin said in a statement Wednesday. “I would hope that Mr. McNamee will be open to considering the impacts of climate change and incorporates these considerations into his decision-making at FERC.”

The Sunrise Movement, a young progressive activist group, rallied outside Senate Minority Leader Chuck Schumer’s New York office on Monday, urging him to block Manchin from leading Democrats on the committee.

Manchin could lead Democrats on the key committee because the current ranking member, Maria Cantwell, D-Wash., is reportedly considering becoming the top minority senator on the Commerce Committee.

Other liberals with seniority over Manchin on the Energy and Natural Resources Committee have said they are not interested in taking over, including Sen. Bernie Sanders, I-Vt., the former presidential candidate who held a town hall on Monday to rally for legislation to mitigate climate change.

Manchin’s potential elevation has environmentalists worried because he is a devout supporter of the coal industry, a cornerstone of the economy in his state. He also has a working relationship with Trump. He has encouraged Trump to take action to save retiring coal and nuclear plants. Manchin met with Trump on Monday, where the two discussed coal miners’ pension reform, among other issues.

Manchin on Wednesday dismissed critics of his green credentials, telling reporters, “I don’t think they’re senators.”

Al Weaver contributed reporting.