Testifying at his nomination hearing to lead the U.S. EPA, Oklahoma Attorney General Scott Pruitt said the role of a regulator is to "make things regular." Pruitt defended his environmental record and participation in litigation against the agency, specifically in cases that challenged the interstate transfer of air pollution.

Chaired by Republican Sen. John Barrasso of Wyoming, the Senate Committee on Environment and Public Works is reviewing Pruitt's nomination for administrator of the EPA on Jan. 18.

Pruitt, who was nominated to lead the EPA by President-elect Donald Trump, has been called "unfit for duty" by environmental groups and is facing criticism from others opposing his nomination. Over 170 environmental groups in a Jan. 17 letter to senators questioned the nominee's commitment to the environment. Other critics said Pruitt's litigation history would prevent him from being an objective administrator of the EPA.

But during the opening round of questioning on Capitol Hill, Pruitt pledged to be a good steward of the environment and said he would lead the EPA with the rule of law in mind. He called public participation key and said protecting the environment while growing the economy is "not an either/or proposition."

In his capacity as attorney general, Pruitt brought an unsuccessful lawsuit against the EPA's regional haze rule, arguing that it amounted to regulatory overreach by the agency. When questioned, Pruitt said he believed that some air and water quality issues cross state lines. Noting in his opening statement that he handled "weighty issues" in his role as attorney general, Pruitt said a state's top legal officer should not succumb to personalizing matters.

Sen. Jeff Merkley, D-Ore., questioned Pruitt over a letter he sent to the EPA in his role as attorney general that was later found by a New York Times investigation to have been penned largely by attorneys from one of Oklahoma's largest oil and gas companies, Devon Energy Corp. Merkley asked if Pruitt was aware of the origin of the language he used when he sent the letter and whether it best served the interests of Oklahomans. Pruitt acknowledged that the letter was written by Devon Energy but assured Merkley that the message behind it represented other interests as well.

Also addressing the Devon Energy letter, Sen. Corey Booker, D-N.J., asked Pruitt about the asthma rate in Oklahoma, noting that 100,000 children in that state suffer from the condition. Booker wondered whether Pruitt had ever brought the subject of the public health crisis of asthma to the EPA.

"Did you ever let any of [those children] write letters on your letterhead?" Booker asked.

Sen. Dan Sullivan, R-Alaska, pushed back against Booker's line of questioning, asking Pruitt bluntly if he cares about Oklahoma's children. The nominee responded by noting that his own children that were in attendance at the hearing and affirming that he indeed is concerned about the issues raised by Booker.

"I care very much about the environment," Pruitt said. "There's an idea in Washington that the states … don't care about the water we drink and the air that we breathe."

Addressing the conflict-of-interest issues repeatedly mentioned by the Democratic members of the committee, Barrasso noted that the U.S. Office of Government Ethics has cleared Pruitt of any perceived conflicts. Barrasso asked Pruitt to affirm that he would follow the advice of the EPA's ethics office, and Pruitt said he would.

Another of Pruitt's opponents' concerns is his stance on climate change. Environmentalists have called Pruitt a climate change denier, but in response to a question from Sen. Ed Markey, D-Mass., Pruitt agreed with the senator that Trump's statement disputing the reality of climate change is incorrect.

"I do not believe that climate change is a hoax," Pruitt said.

Sen. Bernie Sanders, D-Vt., pressed Pruitt on his stance regarding earthquakes in Oklahoma that have been linked to hydraulic fracturing. Sanders asked Pruitt to note the times he has stood up to the companies responsible for the fracking on behalf of the people of Oklahoma. Pruitt said he is "very concerned about the issue" but insisted that the Oklahoma Corporation Commission has jurisdiction over the matter.

Dissatisfied with that response, Sanders continued to ask Pruitt for concrete examples of times he has worked on enforcement actions related to earthquakes and fracking. Pruitt did not provide any evidence of such actions, which Sanders said was worrisome.

"If that's the kind of EPA administrator you will be, you're not going to get my vote," Sanders said.

Sen. Mike Rounds, R-S.D., asked Pruitt about his stance on the EPA's authority and deference to Congress. Pruitt said he believes that Congress gives authority to the EPA but the agency has been out of step with Congress's intentions. He said that, if confirmed, he would provide members of Congress with confidence that the EPA would stick to the matters that are within its authority.

Pruitt has been a staunch opponent of federal overreach throughout his time as attorney general; in fact, he created Oklahoma's first federalism unit to tackle the issue. Sullivan questioned Pruitt on cooperative federalism, quipping that the concept was created by Congress and was "not a Scott Pruitt idea."

Sullivan asked whether Pruitt considered the EPA's Clean Water Rule, which is commonly referred to as Waters of the United States, or WOTUS, was an example of cooperative federalism, considering that 32 states sued the EPA to stop the rule. Pruitt responded that WOTUS was not and that the authority of states must be respected. He added that when states' rights are disregarded, litigation, such as the cases in which he has been involved, result.

With respect to the Clean Power Plan, Pruitt, who was among the attorneys general who sued the EPA over the rule, said the agency went beyond the authority granted to it by Congress to regulate greenhouse gases from power plants. He noted the Supreme Court's unprecedented stay of the rule, which he said was granted because of the likelihood that the opponents of the regulation would be successful.

"[In] respect to power generation, there has to be a significant finding that it poses a risk to public health and welfare," Pruitt said. "They did not do that."

Pruitt asserted that the EPA unlawfully allowed measures that are "outside the fenceline" of the power plant, such as offsetting generation with renewables located or energy efficiency efforts occurring elsewhere.

Several senators on either side of the aisle questioned Pruitt's stance on the Renewable Fuel Standard, which Pruitt has previously opposed. That is one area of Pruitt's background analysts say could give some Republicans representing Midwestern states reservations over his confirmation.