Scott Pruitt is known as a fierce critic of the Environmental Protection Agency and used his former post as Attorney General of Oklahoma to repeatedly sue the agency.
One of Donald Trump's most controversial appointments takes office as head of the Environmental Protection Agency.
Scott Pruitt was sworn in by Justice Samuel Alito on Friday after the US Senate confirmed him over the objections of Democrats and environmentalists who are worried he will gut the agency.
The Senate confirmed Pruitt as the Trump administration readies executive orders to ease regulation on drillers and miners.
The installation of Pruitt, who sued the agency he intends to lead more than a dozen times as Oklahoma Attorney General, reinforces expectations on both sides of the political divide that America will cede its position as a leader in the global fight on climate change.
Democratic lawmakers attempted to delay the confirmation, citing Pruitt's earlier calls to dismantle the EPA as well as his close ties to the fossil fuel industry.
Senators voted 52-46 to approve Pruitt, who was to be sworn in at the White House.
TRT World spoke to Dina Demetrius in Los Angeles.