Michael Chertoff (search) won unanimous Senate confirmation Tuesday as the second Homeland Security secretary despite some delays in the vote.

Chertoff was sworn in hours after the 98-0 vote.

Michigan Democratic Sen. Carl Levin (search) had put off confirmation while unsuccessfully demanding the Justice Department turn over a prisoner interrogation document that may have involved Chertoff, a former prosecutor and assistant attorney general. Levin said the Bush administration was interfering in the nomination process by keeping the document under wraps.

Chertoff, 51, was in charge of the Justice Department's criminal division when hundreds of foreigners in the United States were swept up following the Sept. 11, 2001, terror attacks and held on charges for an average of 80 days. Some detainees were denied their right to see an attorney, were not told of the charges against them or were physically abused, they reported.

At the Feb. 2 hearing before the Senate Homeland Security and Governmental Affairs Committee, Chertoff defended the strategy but conceded it "had not always been executed perfectly."

He also denied knowing anything about terror suspect abuse at Guantanamo Bay (search). Levin sought a May 2004 FBI memo labeled "Secret" that discussed interrogation techniques and which he suggested may have mentioned or involved Chertoff. The department refused to hand over the document but said Chertoff had nothing to do with it. Levin conceded that he had no reason to think the memo implicated Chertoff in any way. Others said it was critical not to delay his confirmation any longer.

"Judge Chertoff had nothing to do with this e-mail. I just think it's wrong to delay an important nomination over an unrelated issue," Sen. Susan Collins (search), R-Maine, chairwoman of the Senate Governmental Affairs Committee, told FOX News on Monday. Collins added that the Department of Homeland Security urgently needs a head since former Secretary Tom Ridge left on Feb. 1.

Earlier in the day, Levin and administration critic Sen. Ted Kennedy (search), D-Mass., said that even though they had not received the documents, they would vote to confirm Chertoff, a former Justice Department official and federal judge.

"I met with Judge Chertoff and raised my concerns about these detainees and his role in formulating the policy. He recognized and understood that significant problems had occurred at the Justice Department in the treatment of the detainees and indicated a willingness to re-evaluate current policies and put in place protocols to prevent these abuses from recurring," Kennedy said in a speech on the Senate floor.

Chertoff, who served last as a 3rd U.S. Circuit Court of Appeals judge, takes over the 180,000-employee Homeland Security Department in the wake of new regulations replacing salaries based on workers' seniority with a merit pay system. The regulations are being challenged in federal court by four labor unions that represent the agency's employees.

Sens. Max Baucus, D-Mont., and Arlen Specter, R-Pa., did not vote on the confirmation.

The Associated Press contributed to this report.