WASHINGTON—The Labor Department’s statistical arm—which prepares the jobs report and other market-sensitive information about the U.S. economy—was breached in the SolarWinds hack, but data wasn’t lost or corrupted, Labor Secretary Eugene Scalia said.

The breach was a “serious episode,” Mr. Scalia said in an interview. He added that the intrusion was isolated and that the hack didn’t affect the Bureau of Labor Statistics data, nor did it spread to other agencies within the department.

“The public can have total confidence in the data that BLS has,” he said. He added that the department determined that none of the bureau’s data was “exfiltrated,” or transferred from the bureau’s systems. “No data was lost or corrupted,” Mr. Scalia said.

U.S. officials and cybersecurity experts have characterized the attack as a cyber-espionage campaign, not one intended to damage computer systems.

Mr. Scalia became labor secretary in September 2019. He previously worked as a corporate-regulation and labor-law attorney. In the interview he discussed his concerns with the unemployment-insurance system, the transition to the Biden administration and the need to protect democracy in the wake of the Capitol riot. He declined to comment on impeachment proceedings or calls to remove President Trump from office. He is expected to step down as labor secretary when President-elect Joe Biden is inaugurated Jan. 20.