(CNN) The Senate on Thursday confirmed David Bernhardt , a former fossil fuel lobbyist, to be the next Interior secretary. The vote was 56-41.

Bernhardt was first confirmed by the Senate to be the department's deputy secretary in July 2017. After former Interior Secretary Ryan Zinke resigned amid a host of ethics scandals at the end of 2018, Bernhardt became the Department's acting secretary.

The Interior Department is one of the largest federal agencies in the government, with an annual budget of more than $22 billion and over 700,000 employees. The department manages 20% of the country's land, including all national parks. It also sets critical policies that manage waterways, wildlife and energy resources throughout the country.

The confirmation vote comes at a time when the Trump Administration is struggling to get nominees confirmed. There are a number of acting secretaries serving in critical departments and positions, including the Department of Homeland Security, Defense Department, White House Office of Management and Budget, among others.

Controversial nominee

Bernhardt's confirmation comes after intense scrutiny from Democratic members of Congress and advocacy groups about how he has been spending his time at the agency since joining in 2017.

After months of advocacy groups and prominent Democratic lawmakers like House Natural Resources Committee Chairman Raul Grijalva calling for the release of Bernhardt's full calendars since joining the department, one week before the confirmation vote, the Interior Department released hundreds of pages of Bernhardt's "daily cards," which showed more information about his schedule than had previously been released.

The "daily cards" revealed, in many cases, whom Bernhardt met with in meetings that were previously marked "external meeting," including people who worked at places that Bernhardt formerly represented. The cards also, in many cases, revealed more information about internal meetings than was previously disclosed by including meeting topics.

Interior said these daily cards are a "synopsis of the Acting Secretary's calendar given to him as a reminder of his upcoming events" and are often "outdated by midday," Interior spokeswoman Faith Vander Voort told CNN.

CNN investigation also found that, since joining the department, Bernhardt has made policy changes that benefit his former clients 15 times.

Bernhardt entered into an ethics agreement when he joined the department in 2017, agreeing to recuse himself from any "particular matter" that involved his former clients. During his confirmation hearing, Bernhardt told the Senate Energy and Natural Resources Committee that he had been cleared by the Office of Government Ethics for nomination, and that Interior's designated ethics official had ensured that he was in compliance with his ethics agreement.

Ahead of the confirmation vote, Senate Minority Leader Chuck Schumer said on the Senate floor that he had asked Bernhardt the day before the vote whether he believed climate change was real and caused by humans. He also asked Bernhardt if he would commit to "not opening up the waters of our coasts to harmful drilling, even off the coasts of states opposed to such drilling." Schumer said that Bernhardt did not give him answers on either question.

"This is the same administration who promised to clean the swamp and rid Washington of corruption, and, yet, it's a twisted parody to think that President Trump wants an oil and gas lobbyist to lead the Department of Interior," Schumer said on the floor. "What a contradiction. What a betrayal."

Senate Majority Leader Mitch McConnell praised Bernhardt's impending confirmation on the Senate floor Thursday morning.

"David Bernhardt is no stranger to the Department. He's served twice before. In fact, this body has confirmed him twice before. Each time, his professionalism and dedication proved us right," McConnell said. "As solicitor and as deputy secretary, Mr. Bernhardt has offered capable leadership and a firm grasp on the complex policy environment surrounding our nation's public lands."

Bernhardt's confirmation has been so controversial that it has prompted unique methods of protest. The day before the confirmation vote, two people dressed in swamp monster masks delivered petitions against Bernhardt's nomination to McConnell's office. The group also sent a representative who put on a swamp monster mask to Bernhardt's confirmation hearing. The representative was removed during the hearing.