(Reuters) - One of the largest U.S. labor unions asked a federal judge on Wednesday to block Elon Musk's government cost-cutting effort from accessing the Department of Labor's systems, which the union warned could give the billionaire sensitive information about investigations into his companies.

President Donald Trump has deputized Musk, the world's richest person and owner of electric vehicle company Tesla and space technology company SpaceX, with leading the so-called Department of Government Efficiency, or DOGE, to identify fraud and waste in the government.

In a lawsuit filed in Washington, D.C. federal court, the American Federation of Labor and Congress of Industrial Organizations (AFL-CIO) asked U.S. District Judge John Bates to block what they called DOGE's imminent plan to access the Labor Department's information systems.

The union said that would potentially give Musk access to non-public information from the Occupational Safety and Health Administration's (OSHA) probes into his SpaceX, Tesla, and his tunneling company, The Boring Company, as well as investigations into his competitors.

Neither Musk, 53, nor spokespersons for DOGE responded to requests for comment. White House spokeswoman Karoline Leavitt said on Wednesday Musk will excuse himself from matters in which he has a conflict of interest.

Musk's rapid takeover of U.S. government agencies has enabled the South African-born businessman to exert unprecedented control over America's 2.2-million-member federal workforce and begin a dramatic reshaping of government.

In its complaint, the AFL-CIO said DOGE had already taken control of sensitive Treasury Department data, accessed sensitive information on federal workers housed at the Office of Personnel Management, and effectively dismantled USAID, the main U.S. agency responsible for foreign aid.

If DOGE representatives gain access to OSHA's databases, they could potentially give Musk information about people who filed complaints against Tesla and its competitors that would not normally be available to the public, the AFL-CIO's lawsuit said.

The complaint cited a Reuters report from 2023 that OSHA has investigated SpaceX over multiple safety incidents and fined the company in connection with one worker's death and other safety incidents. SpaceX defended its safety practices in written responses to OSHA and a state-level agency in California.

The AFL-CIO also said DOGE employees should not be able to see confidential records of workers' compensation and wage theft claims, and warned that DOGE taking control of the Bureau of Labor Statistics could threaten the agency's reputation as an independent source of economic data.

It was not clear when Bates, an appointee of Republican former President George W. Bush, would rule on the union's request for a temporary restraining order against DOGE.