President-elect Donald Trump is nominating fast-food executive Andrew Puzder as secretary of labor. Here's what you need to know about him. (Sarah Parnass,Osman Malik,Danielle Kunitz,Adriana Usero/The Washington Post)

At least four Republican senators are still on the fence about whether to support Andrew Puzder, President Trump’s choice for labor secretary, putting more pressure on the restaurant executive and political novice to win over members of the president’s own party to win confirmation.

The four Republicans are all members of the Senate’s Health, Education, Labor and Pensions Committee, where Puzder is set to appear Thursday to answer questions. The high level of public concern is notable, given that Republicans have for the most part supported Trump’s Cabinet picks even before their confirmation hearings.

Among the skeptics is Sen. Susan Collins (R-Maine), who said Monday that she hasn’t made up her mind on Puzder and will wait to see how he fares at his confirmation hearing scheduled for Thursday.

“I’m going to wait until the issues that have arisen are fully explored at his hearing,” she told reporters. Collins said she has reviewed footage of an “Oprah Winfrey Show” interview with Puzder’s ex-wife, who once appeared in disguise on the program to discuss the multiple times she says that Puzder physically assaulted her in the 1980s.

Puzder’s ex-wife, Lisa Fierstein, recently retracted the allegations, and he has always denied that he abused her.

Collins added that “I am reviewing the other information that has come to light and I’m sure all of this will be explored thoroughly” — but she didn’t specify what other information is of concern.

Sen. Lamar Alexander (R-Tenn.), who chairs the health committee, told reporters Monday that he worked with Sen. Patty Murray (D-Wash.), the committee’s top Democrat, to arrange for senators to view a tape of the episode. Alexander said he has not seen the segment himself but he does plan to vote to approve Puzder’s nomination.

“His former wife has said it was all not true,” Alexander said. “She has reiterated that in a heartfelt letter to members of the committee and has been willing to talk to members of the committee so I don’t think that’s an issue.”

Puzder revealed last week that he once employed an undocumented immigrant to work as a housekeeper — the kind of revelation that has forced Cabinet nominees of administrations past to withdraw. He faces strong resistance from labor groups and Democrats who voice concern that he will not defend workers, citing reports of wage violations at his restaurants, his opposition to substantially raising the minimum wage and the use of sexually suggestive ads that opponents say are demeaning to women.

Puzder’s personal wealth has also earned scrutiny that has delayed his nomination for several weeks. Federal disclosure forms delivered to the Senate last week show that most of his wealth is tied to CKE Restaurants, which includes the burger chains Hardee’s and Carl’s Jr., and that he plans to divest those holdings over the next six months if he is confirmed to lead the Labor Department.

The White House is standing by Puzder, declaring last week that he would be confirmed. Senate Majority Leader Mitch McConnell (R-Ky.) told reporters that he is “enthusiastically” supporting the nominee.

In addition to Collins, Sens. Johnny Isakson (R-Ga.), Lisa Murkowski (R-Alaska) and Tim Scott (R-S.C.) are withholding judgment.

“Consistent with his policy on other nominees, Senator Isakson will make a final decision after Mr. Puzder’s confirmation hearing on Thursday,” Isakson spokeswoman Amanda Maddox said via email.

Murkowski “will be working to learn more about Mr. Puzder leading up to and during the upcoming hearing, as well as through additional one-one-one conversations with him,” spokeswoman Karina Petersen said.

“No real story here,” said Scott spokeswoman Michele Exner, noting that the senator hasn’t been commenting on nominees “until their confirmation hearing” with the exception of fellow South Carolina Republicans Nikki Haley, nominated to serve as U.N. ambassador, and Rep. Mick Mulvaney, Trump’s pick to lead the Office of Management and Budget.

But Scott also defended then-Senate colleague Jeff Sessions and his nomination for attorney general in a Washington Post article that was published before the Alabamian’s confirmation hearing.

Puzder faces another challenge in a Missouri court Tuesday, when a judge will hear a case brought by the Campaign for Accountability, a Washington-based watchdog group, to unseal Puzder’s divorce records.

Despite her concerns, Collins said the case shouldn’t be a reason to further delay Puzder’s nomination.

“His hearing’s been delayed several times,” she said.