(CNN) Andrew Wheeler, the former coal lobbyist who is now acting administrator of the Environmental Protection Agency, was a "driving force" behind the agenda of Sen. James Inhofe, who called climate change a "hoax," according to people familiar with Wheeler's work for the senator.

President Donald Trump has said he intends to nominate Wheeler as the head of the EPA, and in the past five months as acting administrator, Wheeler has moved aggressively to roll back key environmental regulations, prompting critics and environmentalists to say he is fast confirming their worst fears for the agency's future.

Inhofe, an Oklahoma Republican, is an outspoken climate change skeptic who was at different times chairman and ranking member of the Senate Committee on Environment and Public Works. Inhofe told CNN last year the EPA was "brainwashing our kids," and famously once brought a snowball onto the Senate floor to demonstrate his belief that global warming isn't real.

Inhofe said in a 2003 Senate speech, "I have offered compelling evidence that catastrophic global warming is a hoax," adding, "the claim that global warming is caused by man-made emissions is simply untrue and not based on sound science."

Wheeler worked for Inhofe for 14 years, and was his chief counsel and staff director. In that role, Wheeler would have overseen hearings Inhofe held and approved reports Inhofe issued claiming humans have no direct impact on climate change, according to the sources, who asked not to be identified for fear of retribution. In videos of committee hearings at the time, Wheeler is often seen whispering in Inhofe's ear and handing him paperwork. In the 2008 "Almanac of the Unelected," Wheeler's job is described as "to work on (Inhofe's) agenda for the committee."

At a Washington Post forum last week, Wheeler said, "I believe ... that man does ... have an impact on the climate. That CO2 has an impact on the climate and we do take that seriously." At the same forum, he admitted he had not read the climate change report released by his agency, which outlined dire warnings of the impact of global warming.

Elizabeth Gore, who was chief of staff for Sen. Byron Dorgan, a North Dakota Democrat, and is now a senior vice president at the Environmental Defense Fund, told CNN that Wheeler "was very high profile, he was a driving force behind Inhofe's very dangerous agenda to attack climate change and undermine the policies that would protect us from carbon pollution."

Wheeler declined CNN's request for an interview, but in a statement the EPA said in part that the activing administrator, "has made it abundantly clear on multiple occasions ... that humans have an impact on the climate." An EPA official also said, "Mr. Wheeler was deeply honored to work for Senator Inhofe in several capacities, however Mr. Wheeler did not write and was not the architect of the Senator's climate science speeches."

Wheeler is one of six top EPA officials who either worked directly for Inhofe or on the Senate's Energy and Public Works Committee. Others are Wheeler's chief of staff, his principal deputy assistant administrator, his assistant administrator for enforcement and compliance, a senior adviser for policy and an associate administrator for policy. An EPA official said the staffers started working at EPA before Wheeler arrived.

Wheeler moved to the EPA'S top slot in July after then-Administrator Scott Pruitt was forced to resign amid numerous investigations, including questions surrounding his altering of federal documents, over-spending, use of security and other numerous scandals.

Like his former boss, Wheeler is seen to be focused on reversing regulations that protect the nation's air and water and instead promoting the wishes of the industries impacted by those regulations. Critics fear that Wheeler, who works quietly behind the scenes and knows how to get things done in Washington, is more dangerous to the nation's health than the scandal-plagued Pruitt ever was.

Michael Gerrard, faculty director of Columbia Law School's Climate Deregulation Tracker, which follows government deregulation, believes Wheeler will be more successful at reversing environmental protections, "because he understands the administrative and legal process better and he does not have all the craziness of Pruitt's personal proclivities that got in the way of his effectiveness."

From 2009 until he joined the EPA last year, Wheeler was a lobbyist for energy, mining and coal companies. Bob Murray, the powerful CEO of Murray Energy, paid Wheeler's lobbying firm nearly $3 million to, among other things, help the coal baron get access to major decision makers, such as a meeting in March 2017 with Energy Secretary Rick Perry.

When Trump was elected, Murray Energy drafted an "action plan" for the Trump administration, essentially a wish list to get the Environmental Protection Agency off the coal industry's back.

"Not a whole lot has changed from Pruitt to Wheeler," said Sen. Sheldon Whitehouse, a Rhode Island Democrat who has demanded the inspector general investigate Murray's wish list and Wheeler's ties to industry. "Now more than ever, Trump's EPA takes its marching orders from fossil fuel and other polluting industries. While Wheeler may not try to finagle a fast food franchise for his wife, he's no different from Pruitt when it comes to shilling for industry and pushing whatever policies they want."

The EPA said in a statement, "Mr. Wheeler did not lobby the Trump EPA while working for Murray Energy nor did he did work on the action plan or receive a copy of the memo."

But in the five months since Wheeler has taken over, the EPA has pulled back on regulating the two largest sources of greenhouse gas emissions in the United States, coal plants and motor vehicles.

Gerrard told CNN, "Wheeler is carrying out a wish-list of the industry lobbyists who wanted to shut down the environmental regulations, as he himself was a lobbyist with exactly the same objective. But now he is in the driver's seat."

In August, the EPA published the "Affordable Clean Energy" plan, designed to replace the Clean Power Plan, which was the Obama administration's key measure to address climate change. The new rule sets far less stringent emission guidelines.

That same month, the EPA and the National Highway Traffic Safety Administration published a proposed rule to weaken car emissions and fuel economy standards. And in September, the EPA published a proposed rule weakening methane emission standards for some oil and gas production and changing requirements on leak repairs.

At the Washington Post forum, Wheeler said the Trump administration deserves credit for a decline in carbon emissions. "In the first year of the Trump administration, we've seen a 2.7% reduction in CO2 from 2016 to 2017," he said.