Pruitt, one of the highest profile members of President Donald Trump’s cabinet and a staunch opponent of federal global warming regulations, has embarked on an aggressive deregulatory campaign since taking office, reversing numerous environmental rules, most notably the Clean Power Plan, Obama’s signature climate change policy regulating power plants. (The Supreme Court placed a hold on the Clean Power Plan in February 2016 pending a U.S. Court of Appeals decision.)

Pruitt, who was confirmed by the Senate back in February with a mostly party line 52-46 vote, hails from Lexington, Kentucky. Growing up, he seemed like more of an enthusiast for baseball than science.

He attended the University of Kentucky on a baseball scholarship, and later earned a law degree from the University of Tulsa College of Law. (A former law professor of Pruitt’s recently said that he felt partly responsible for Pruitt’s assault on environmental rules: “I’m at least partially to blame for failing to nurture in him a deep regard for seeing law as an instrument for addressing real facts on the ground, not simply implementing a political ideology, regardless the facts.”)

Pruitt made a living as a private practice lawyer and also co-owned a AAA minor league baseball team, the Oklahoma City RedHawks.

He was elected to the Oklahoma Senate in 1998, serving for eight years, and later was elected attorney general of Oklahoma in 2010, where he famously filed 14 lawsuits against the EPA’s environmental regulations.

When asked why he filed so many lawsuits against the Obama administration, he said: “They deserved it and they deserved it because they exceeded their statutory authority, they exceeded their constitutional authority.”

Most of Pruitt’s lawsuits against the EPA failed, with the exception of his challenge of the Clean Power Plan.

During his time as attorney general, Pruitt often worked with oil and gas companies in Oklahoma to formulate challenges against Obama’s air, water and climate rules.

Now, as the chief bureaucrat in charge of the agency suited with protecting human health and the environment, Pruitt has set his sights on rolling back regulations that he deems government overreach.

Earlier this year, he said the Clean Power Plan “pushed the bounds of (the EPA’s) authority” and formally announced plans to scuttle the policy in October.

“We are committed to righting the wrongs of the Obama Administration by cleaning the regulatory slate,” Pruitt declared in a statement.

The EPA did not respond to weather.com’s requests for comment on this story.

Doug Deason, a Texas businessman and friend of Pruitt, told weather.com in a phone interview that he didn’t doubt the EPA administrator’s commitment to ecological stewardship.

“He certainly wants clean air,” Deason said. “He looks at the Clean Power Plan as overreach, that doesn’t mean that we doesn’t think that we should eliminate pollution and do what we can to make air quality safer for people, because we have to breathe it everyday. He’s a very common sense, pragmatic person.”

But the reaction from environmental groups and others has been stark.

“Not since Anne Gorsuch in the 1980s has the EPA been led by an administrator who is so overtly hostile to the agency’s core mission and to the enforcement of environmental laws,” Paul Sabin, an environmental historian at Yale University, told weather.com in an email.

Christine Todd Whitman, who had Pruitt’s job under President George W. Bush, called the deregulation spree a “dangerous political turn of an agency that is supposed to be guided by science.”