Update Feb. 28, 2019, 2PM ET: Andrew Wheeler has been confirmed to permanently lead the EPA. Wheeler had been acting director of the agency since Scott Pruitt resigned in July. Lobbyists have called him “a very solid follow” to Pruitt.

Scott Pruitt, the head of the Environmental Protection Agency, is no friend of the agency he leads. Since he entered office, Pruitt has tried to roll back multiple regulations that curb greenhouse gas emissions and limit pollution from cars and trucks, all the while cozying up with the polluters he’s supposed to keep in check. Pruitt also is neck-deep in all sorts of scandals, and his departure is a real possibility. But the first in line to replace him — the newly named deputy Andrew Wheeler — may be an even greater threat to the EPA and the environment.

Pruitt has had a short but eventful tenure as head of the EPA. He’s come under fire for flying first class and spending way too much taxpayer money while traveling abroad, using two secret EPA email addresses, and having a chief of security who had heated confrontations with EPA officials who challenged Pruitt’s lavish spending. Earlier this month, The New York Times revealed that last year, Pruitt got an unusually cheap, $50-a-night deal on a Washington, DC apartment tied to an energy lobbyist. (For a complete list of Pruitt’s screwups, you can check out Earther.)

As an administrator, it’s unclear if Pruitt has had a lasting impact on deregulation. Pruitt’s effectiveness at repealing environmental policies is a “myth,” says David Doniger, the director of the Climate & Clean Air Program at the Natural Resources Defense Council. “By and large, his rollbacks have not yet passed the proposal stage, and some of them are not even at the proposal stage yet,” Doniger says. Pruitt is also losing lawsuits because he’s not following the rules. Last year, for example, he tried to suspend methane emissions regulations without going through the formal process of allowing the public to comment, among other things. As a result, the US Court of Appeals for the District of Columbia Circuit declared the action illegal.

“Pruitt has been sloppy in following the required administrative procedures,” says Michael Gerrard, director of the Sabin Center for Climate Change Law at Columbia Law School. “Wheeler may be better at fixing that.”

Pruitt’s new second in command “keeps a lower profile, he’s not as flashy,” says Zach Drennen, the communications manager at Climate Advisers, a consulting firm that focuses on climate change policy. But he also has a clear track record of changing policies. Wheeler is a Washington insider who’s been working for years to weaken environmental protections out of the public eye. His career includes a stint as the chief counsel for Sen. James Inhofe (R-OK), a known climate denier who famously brought a snowball in the Senate as proof that global warming isn’t real. Wheeler has also worked as a lobbyist for clients including Murray Energy, a coal giant that sued the EPA multiple times. “As a former coal lobbyist, he’s got more of an appreciation of the intricacies of the system,” Drennen says.

This isn’t the first time Republicans have attempted to kill the EPA from within. In 1981, Ronald Reagan appointed Anne Gorsuch to head the EPA, an attorney who had served in the Colorado House of Representatives. Gorsuch tried to gut the agency by slashing its budget and workforce, staffing its ranks with people from the industry, and failing to punish polluters who didn’t follow the law. Gorsuch’s career at the EPA came to a scandalous conclusion in 1983: she resigned after she was accused of mismanaging the agency’s $1.6 billion Superfund budget and was charged with contempt of Congress when she hid documents Reagan had requested. Reagan replaced her with William Ruckelshaus, who worked hard to restore credibility and follow the mission of the EPA, Doniger says.

Wheeler began his career at the EPA under President George H. W. Bush, and in 1997, he began working at the Senate Environment and Public Works Committee, which deals with many environmental bills. Wheeler ran Inhofe’s anti-environmental portfolio when he served as the senator’s staff director. (Staff directors help their bosses draft bills and then negotiate with lawmakers in both the Senate and the House to win support and get the legislation passed.) During Wheeler’s tenure with Inhofe, the senator introduced the 2003 Clear Skies bill, which did little to cap smog and soot and did not attempt to reduce greenhouse gas emissions to limit global warming. (The bill never became law.) In the Energy Policy Act of 2005, Inhofe fought to include specific language encouraging greater reliance on alternative oil sources such as oil shale. The law, which is still on the books, included “a piñata of perks for energy industries,” according to a Washington Post article at the time, including tax breaks and laxer pollution rules for oil and gas companies. It also exempts most fracking from regulation on drinking water safety, which has allowed the fracking industry to boom with “little federal oversight,” Gerrard writes in an email to The Verge.

Inhofe has also been one of the staunchest deniers of climate change in Congress. In 2003, when Inhofe was the chairman of the Environment and Public Works Committee — and Wheeler was his staff director — Inhofe organized a hearing showcasing climate change skeptics to cast doubt on the fact that humans are causing global warming. One witness at the hearing was Willie Soon, an astrophysicist who that year published a highly criticized and flawed paper that “said the 20th-century warming trend was unremarkable compared with other climate shifts over the last 1,000 years,” according to a New York Times article at the time. (Soon has continued casting doubt on global warming, all while being paid by the fossil fuel industry.) Generally, staff directors help their bosses organize such hearings, recruit the witnesses on the panel, and write statements and memos to prepare the other senators, so Wheeler was likely involved.

Inhofe has also repeatedly called global warming “the greatest hoax ever perpetrated on the American people,” and he has accused the UN Intergovernmental Panel on Climate Change (IPCC), a leading institution on climate change science, of being “politically alarmist.” When it comes to climate change, Wheeler’s views echo Inhofe’s. In 2010, Wheeler wrote in a blog post saying that the IPCC “has functioned more as a political body than a scientific body,” according to The New York Times.

Wheeler was very effective at both helping Inhofe pass the legislation he wanted and blocking the Democrat-backed legislation Inhofe opposed, says Chris Hessler, the founder of the lobbying firm AJW, who worked with Wheeler at the Environmental Public and Works Committee under Sen. John Chafee (R-RI). “He’s really smart, and he knows the law very well and he knows the procedures very well,” Hessler tells The Verge. “When he shows up, he’s well prepared.”

Since 2009, Wheeler has worked to weaken environmental protections as a lobbyist for the fossil fuel industry as well as chemical and nuclear power companies. Last year, Wheeler persuaded the Trump administration to cut the size of Utah’s Bears Ears National Monument, so that his client, Energy Fuels Resources, could access uranium deposits. Wheeler has also been paid more than $3 million by the coal giant Murray Energy for his work as a lobbyist, according to The Daily Beast. Last year, Murray Energy and Pruitt met with the National Mining Association to build support for Trump’s decision to leave the Paris climate agreement, according to Politico. Wheeler attended that meeting, and urged other mining companies to come out against the deal, says John Coequyt, the Sierra Club’s global climate policy director. After the meeting, the National Mining Association decided to support the withdrawal. (The Verge emailed the National Mining Association to confirm that Wheeler was at the meeting and what role he played. We’ll update if we hear back.)

Also while on Murray Energy’s dime, Wheeler lobbied the Department of Energy to try to get government subsidies for coal plants. The Federal Energy Regulatory Commission struck down the proposal earlier this year, but if it had passed, it could have profoundly changed the energy landscape in the US, setting back renewables for years to come, says Drennen at Climate Advisers. “It can really change what the market looks like,” he says.

The Verge emailed the EPA to ask how Wheeler’s career as a lobbyist will interfere with his work as deputy administrator. In response, EPA spokesperson Molly Block emailed The Verge a number of accolades from several Republican members of Congress, as well the following quote from Pruitt:

“Andrew Wheeler has spent his entire career advancing sound environmental policies and I look forward to him bringing his expertise and leadership to the agency. … I look forward to working with Andrew to implement President Trump’s environmental agenda.”

President Trump has so far sided with Pruitt. Earlier this month, Trump tweeted that the EPA administrator “is doing a great job but is TOTALLY under siege.” If Pruitt does get the boot, Wheeler would have to be confirmed again by the Senate before he became more than the acting administrator. That’s not likely to happen before the 2018 midterm elections, according to Drennen. But even if Pruitt stays, Wheeler can play an important role within the EPA, helping the chief be more effective at repealing environmental regulations. He definitely has the expertise required for the job.

“Andy really does understand the details of the process very very well,” Hessler says. “He’s very careful and detail-oriented ... I think he’ll be a real asset to Scott Pruitt in that regard.”