The Senate has confirmed Scott Pruitt to run the Environmental Protection Agency despite criticisms from Democrats and environmental groups.
The former Oklahoma attorney general spent years suing the agency which he will now lead over its efforts to regulate pollution.
Democrats and environmental groups fear for the future of the agency with Mr Pruitt at the helm, as he is well positioned to materialise President Donald Trump's campaign promises to "get rid" of the EPA "in almost every form".
Mr Pruitt – described by Bernie Sanders as “the worst of the worst” of Mr Trump’s cabinet picks – has sued the EPA on 13 occasions. He has also accused the agency of having an “activist agenda” and his opponents fear he will seek to dismantle the body.
Nonetheless, the Senate approved him by a vote of 52-46, a narrow victory.
The climate change denier won over the votes of two Democrats – West Virginia Sen Joe Manchin and Sen Heidi Heitkamp of North Dakota. One Republican, Sen Susan Collins of Maine, broke with her party and voted against the nominee. She said his views were "fundamentally different" from hers about how the EPA was meant to function.
Environmental activists were quick to condemn the confirmation of Mr Pruitt.
"Scott Pruitt is the worst pick ever confirmed to lead the EPA. He’s being sent there to hobble the agency we depend on to protect our health and environment. All the worse, Senate Republicans forced the confirmation vote before the public can know the truth about Pruitt’s ties to industrial polluters," said National Resources Defence Council president Rhea Suh.
"We’ll use every tool in the kit to stop him from harming our air and water, endangering our communities and surrendering our kids to climate catastrophe."
The New York Times revealed in 2014 that energy lobbyists drafted letters sent by Mr Pruitt to the EPA in behalf of the state of Oklahoma, airing his grievances about the hardships environmental regulations had on the coal, oil, and gas companies.
According to Democrats, a trove of emails are set to be released as early as Tuesday that could further elaborate on the new EPA director's relationship with those companies. Opposing Senators attempted to delay the confirmation vote so that all information could be reviewed.
"I reminded my colleagues that the release of these documents could be imminent and that we would be wise to wait to vote on Mr Pruitt's nomination until we had the opportunity to review them – and shame on us if we didn't," Delaware senator, and ranking member of the Senate Environment and Public Works Committee, Tom Carper said.
"Mr Pruitt has been nominated by a man who, as a nominee, as a president-elect, and now as president, has made clear his goals to degrade the EPA.
"Like many things President Trump says, we ask ourselves, 'Did he mean it?' With the nomination of Mr Pruitt, it's clear he did."