Acting interior secretary David Bernhardt. (Katherine Frey/The Washington Post)

Acting Interior Department Secretary David Bernhardt, a former lobbyist who was nominated by President Trump for a permanent appointment, faced pointed questions at his Senate confirmation hearing Thursday about his ability to avoid conflicts of interest while leading an agency that regulates the oil and gas interests he once represented.

Under his leadership with former secretary Ryan Zinke, Interior dramatically weakened enforcement of the 100-year-old Migratory Bird Treaty Act, allowing individuals and companies to kill scores of protected birds so long as investigators determine it was not intentional.

The pair also oversaw a rollback of National Park Service rules on federal land in Alaska that will allow hunters to kill mother bears and their cubs sleeping in dens as well as shooting animals from boats as they swim between shores.

More recently, Bernhardt presided over a rule change that opened millions of acres of protected sage grouse habitat in the West to oil and gas interests.

As secretary, Bernhardt promised to pursue a pro-energy agenda.

“If confirmed,” the nominee assured members of the Senate Energy and Natural Resources Committee, “I will tirelessly promote President Trump’s goals for the Department of the Interior.”

At the confirmation hearing, Sen. Lisa Murkowski (R-Alaska), the committee chair, lauded Bernhardt’s record as a solicitor under George W. Bush and as a deputy secretary and later acting secretary after Zinke’s resignation.

“You come to us with a level of experience and qualifications we rarely see. Really unprecedented,” Murkowski said.

But even she was concerned about the potential for conflicts at a department that was rocked by multiple scandals involving Zinke. “For whatever reason, you seem to have outside groups working against your nomination more than anyone else we’ve had in front of us,” Murkowski said.

Bernhardt assured the chairman that he would comply with laws and ethics rules. A top Democrat on the committee, Sen. Ron Wyden (Ore.), was not convinced. In strident remarks, Wyden said he had read documents showing that Bernhardt intervened over an analysis that said toxic pesticides used by landowners threatened endangered animals.

“You asked to come to my office to say you stood for strong ethics,” Wyden said. “A few hours after we met, I saw documents that show within the last two years you blocked the release of a Fish and Wildlife analysis of toxic chemicals.”

Bernhardt said he intervened because the analysis did not have a legal review and that he “kicked it to career lawyers” because “you can’t ignore the law.”

Wyden cut him off, saying he had read documents related to Bernhardt’s actions that “make you sound like just another corrupt official.” The senator said the nominee’s past as a lobbyist is likely to hurt his ability to lead Interior.

“I think you are so conflicted … if you get confirmed, you’re going to have to disqualify yourself from so many matters I don’t know how you’re going to spend your day.”

As Bernhardt answered questions from nearly every person on the panel, a woman seated two rows behind him slipped on the green rubber mask of a swamp monster, the Creature from the Black Lagoon, to protest his nomination. Outside the committee room, a man with the liberal group Clean Water Action wore a yeti-like get-up and a mask made from a picture of the nominee’s face.

Bernhardt’s confirmation is all but assured. Republicans widely praise Bernhardt, citing his intelligence and relentless work ethic.

“I think there’s an absolute double standard being applied here,” Sen. Cory Gardner (R-Colo.) said in response to Wyden’s remarks. He noted that while Bernhardt’s ties to industry have come under scrutiny, former interior secretary Sally Jewell’s experience as a petroleum engineer and outdoor industry executive was praised and considered a plus.

Bernhardt’s former lobbying work has drawn persistent scrutiny.

Since his arrival at the Interior Department in summer 2017, he has had to recuse himself from matters directly affecting at least 26 former clients to adhere to the Trump administration’s ethics requirements. His critics say he should have recused himself from far more.

Bernhardt has wielded influence over the department’s most important agencies. Within months of becoming Zinke’s deputy, Bernhardt played a role in decisions to increase national park fees, roll back endangered species protections enforced by the Fish and Wildlife Service, open massive amounts of public lands to more drilling, and weaken safety rules for ocean oil production platforms.

In fall 2017, the Bureau of Land Management held a closed meeting where officials and public lands stakeholders discussed ways to circumvent laws meant to protect wildlife and their habitats. That September, the department blocked a Fish and Wildlife Service analysis providing guidance that would limit the use of chemicals that harmed endangered animals, according to documents obtained under the Freedom of Information Act by the Center for Biological Diversity and the New York Times.

The following month, Interior proposed to significantly increase entry fees at national parks to deal with a multibillion-dollar maintenance backlog, but the plan ultimately failed in the face of public outrage.

In April 2018, Interior clipped the wings of the Migratory Bird Treaty Act. The department issued guidance to police, who enforce the law, that an individual or group cannot be held liable for killing birds, even endangered ones, if the actions were not intentional. As an example, it said, “all that is relevant is that the landowner undertook an action that did not have killing of barn owls as its purpose.”

The next month, Interior moved to end a federal ban on Alaska hunting practices that many consider cruel. Rules that protected bear cubs and their mothers from being shot while hibernating in dens of federal land were lifted, leaving the state to determine their fate. Similarly, federal rules prohibiting animals from being shot from helicopters and boats while swimming between shores were swept away.

Even Democrats not sitting on the Senate Energy and Natural Resources Committee used Thursday as an opportunity to question how Bernhardt’s work affected his former clients.

In a letter, Sen. Chris Van Hollen (D-Md.) pressed Bernhardt to explain his role in a Dec. 22, 2017, legal opinion easing legal liability for oil and gas firms whose operations end up killing birds protected under the Migratory Bird Treaty Act.

Noting that Bernhardt had represented an oil industry group seeking this change in policy and that newly released public records indicated Bernhardt weighed in on the decision, Van Hollen asked him to “explain why the American people should have confidence that you are not merely putting the interests of your former corporate clients first.”

As he helped relax key federal regulations, Bernhardt promoted Trump’s energy dominance agenda, which focuses on producing as much oil and gas as possible on land and sea. The department has offered nearly 25 million acres of federal land for industry leases. In September alone, a lease sale brought $973 million in New Mexico, a record for BLM. The administration boasted that it was a gift to the U.S. Treasury.

But it comes at a cost, according to BLM estimates. Boosting drilling in New Mexico over the next 20 years will equal the greenhouse gas emissions of 733 coal-fired power plants operating for a year.

Bernhardt also is moving to expand oil and gas industry leases at sea. In January 2018, Interior announced an unprecedented proposal to lease 90 percent of the U.S. outer continental shelf, including areas of the Arctic that had never been drilled, and the Atlantic seaboard, where drilling has not happened in more than a half-century.

Five permits to map the Atlantic Ocean floor are pending, along with the finalization of a five-year administration plan to offer the leases. Every governor on the Pacific and Atlantic coasts opposes the plan.

During the hearing, under questioning from Sen. Joe Manchin III (D-W.Va.), Bernhardt acknowledged human-caused climate change even as Interior attempts to roll back rules seeking to limit the emission of methane, a potent greenhouse gas, from oil and gas operations.

“I recognize that climate is changing and that man is contributing to that,” he said.

But he went on to note that the fourth National Climate Assessment, a major federal report published in November, pointed out the “uncertainty” of “projecting future climate conditions.”

“What our scientists say is: Recognize that there’s no one single model or one single scenario that’s right,” Bernhardt said.

Dino Grandoni contributed to this report.