BILLINGS, Mont. >> As former U.S. Interior Secretary Ryan Zinke exits Washington chased by ethics investigations and criticism of his actions favoring industry, he told The Associated Press he’s lived up to the conservation ideals of Teddy Roosevelt and insisted the myriad allegations against him will be proven untrue.

The former Montana congressman also said he quit President Donald Trump’s cabinet on his own terms, despite indications he was pressured by the White House to resign effective Wednesday.

During almost two years overseeing an agency responsible for managing 500 million acres of public lands, Zinke’s broad rollbacks of restrictions on oil and gas drilling were cheered by industry. But they brought a scathing backlash from environmental groups and Democratic lawmakers who accused him of putting corporate profits ahead of preservation.

In his first interview since stepping down, Zinke said the changes he instituted meshed with Roosevelt’s belief in balance between nature and industry. He added that they were needed in part to unfetter energy companies bound by unreasonable drilling curbs, largely imposed under former President Barack Obama.

“Teddy Roosevelt said conservation is as much development as it is preservation,” Zinke said, reference a 1910 speech by the Republican president. “Our work returned the American conservation ethic to best science, best practices … rather than an elitist view of non-management that lets nature take its course.”

House Democrats plan to put Zinke’s almost two-year tenure under the spotlight with oversight hearings beginning next month, said Adam Sarvana, a spokesman for Rep. Raul Grijalva of Arizona, the Democrat in line to lead the House Natural Resources Committee.

The hearings initially will focus on policy changes such as “giveaways” to the oil and gas industry under the leadership of Zinke, Sarvana said. He added they later could be expanded to include the various ethics investigations pending against Zinke, a former Navy SEAL and avowed Trump loyalist.

The investigations have ranged from a probe into a land deal involving Zinke and the chairman of energy services giant Halliburton, to questions about his decision to reject a casino in Connecticut sought by two tribes.

During his interview with the AP, Zinke denied a Washington Post report that Interior Department investigators believe he may have lied to them, which has reportedly prompted an examination of potential criminal violations by the U.S. Justice Department’s public integrity section.

Several other investigations into Zinke concluded with no findings of wrongdoing. In one case he was faulted by investigators for violating a department policy by allowing his wife to ride in government vehicles with him. That report also said the Interior Department spent more than $25,000 to provide security for the couple during a vacation to Turkey and Greece.

For the energy industry, Zinke brought relief from rules imposed under Obama that were meant to limit drilling in sensitive wildlife habitat, curb emissions of the greenhouse gas carbon monoxide and protect water supplies.

Despite the Democrats’ newfound power in Washington after taking control of the House of Representatives, industry representatives said Zinke’s impact will be lasting. That’s because they involved agency regulations rather than congressional action and came at the order of Trump, said Dan Naatz, vice president of government relations for the Independent Petroleum Association of America.

“Although Secretary Zinke was effective at what he was doing, the policy really came from the president,” Naatz said. “We don’t expect any major changes.”

Until Trump nominates and the Senate confirms a permanent replacement, Zinke’s shoes will be filled on an acting basis by his deputy, David Bernhardt, a former lobbyist for the oil and gas industry. Left-leaning groups that campaigned against Zinke already have turned their attention to Bernhardt with claims that his prior work leaves him compromised.

“David Bernhardt is too conflicted to serve him in any position, whether it’s deputy, acting or full Interior secretary,” said Aaron Weiss with the Center for Western Priorities. Weiss also suggested the pending investigations against Zinke are likely to continue and said the former secretary “can’t make his trouble go away by simply walking away.”

In his resignation letter, Zinke said he was compelled to stop down because the political attacks against him had created a distraction from Trump’s drive to boost U.S. energy production.

He told the AP that the allegations fit into a “playbook” used by the administration’s critics to stifle Trump’s energy agenda, smear Zinke’s name and undercut any future bid he might make for public office. He said he won’t run for Montana governor in 2020, but did not rule out a future run.

In the weeks leading up to his resignation, the White House concluded Zinke was likely the Cabinet member most vulnerable to investigations led by newly empowered Democrats in Congress, according to an administration official not authorized to publicly discuss personnel matters who spoke on condition of anonymity.

In Zinke’s telling of events, Trump remained fully supportive to the end and it was the secretary himself who made the decision to go.

His departure comes amid a partial government shutdown in which Zinke ordered many national parks to stay open, saying visitors shouldn’t’ be penalized for the political feud centered on Trump’s proposed border wall with Mexico.

With reports of overflowing trash bins spurring calls for the parks to be closed until the shutdown ends, Zinke offered some parting advice as he prepared to head back to his hometown of Whitefish, Montana, just outside Glacier National Park: “I would encourage everyone that visits their parks to help pitch in, grab a trash bag and take some trash out with you,” he said. “Pack it in, pack it out.”