President-elect Donald Trump is planning to nominate Oklahoma Attorney General Scott Pruitt – an outspoken critic of the EPA – to lead the environmental agency, a senior transition source confirmed to Fox News.

Word of Trump’s choice for the Environmental Protection Agency came as the president-elect also named Iowa Gov. Terry Branstad as his pick for ambassador to China and asked retired Gen. John Kelly to lead the Department of Homeland Security. Trump announced late Wednesday as well that he’ll nominate Linda McMahon, former chief executive of World Wrestling Entertainment, as administrator of the Small Business Administration.

Pruitt may be the most controversial pick of the four.

Pruitt, 48, has been a reliable booster of the fossil fuel industry and a critic of what he derides as the EPA’s “activist agenda.”

Representing his state as attorney general since 2011, Pruitt has repeatedly sued the EPA to roll back environmental regulations and other health protections. He joined with other Republican attorneys general in opposing the Clean Power Plan, which seeks to limit planet-warming carbon emissions from coal-fired power plants. Pruitt has argued that curbing carbon emissions would trample the sovereignty of state governments, drive up electricity rates, threaten the reliability of the nation’s power grid and “create economic havoc.”

His installment, if confirmed, would mark a significant break with the current EPA approach toward global warming.

In an opinion article published earlier this year by National Review, Pruitt suggested the debate over global warming “is far from settled” and claimed “scientists continue to disagree about the degree and extent of global warming and its connection to the actions of mankind.”

He also filed court briefs in support of the Keystone XL Pipeline project blocked by the Obama administration, which would have run through his state. And Pruitt sued the EPA over the agency’s recent expansion of water bodies regulated under the federal Clean Water Act.

“Respect for private property rights have allowed our nation to thrive, but with the recently finalized rule, farmers, ranchers, developers, industry and individual property owners will now be subject to the unpredictable, unsound and often byzantine regulatory regime of the EPA,” Pruitt said last year.

As word of Pruitt’s nomination spread Wednesday, environmental and liberal groups quickly responded with condemnation.

Public Citizen called him a “terrible choice,” saying in a statement: “Pruitt is cozy with the oil and gas industry and treats the EPA like an enemy.”

Business leaders in his home state, however, lauded Pruitt’s selection, especially those in the oil and gas industry.

“Scott Pruitt is a businessman and public servant and understands the impact regulation and legislation have in the business world,” said Jeffrey McDougall, chairman of the Oklahoma Independent Petroleum Association. “His appointment will put rational and reasonable regulation at the forefront.”

John Roberts and The Associated Press contributed to this report.