The U.S. Transportation Department (USDOT) told lawmakers late on Friday that a data breach is believed to have potentially impacted the personal information of 237,000 current and former federal employees who receive employee transit benefits.

The breach hit systems for processing TRANServe transit benefits that reimburse government employees for some commuting costs. 

USDOT said that the breach did not affect any transportation safety systems.

It was not clear if any of the personal information had been used for criminal purposes. 

USDOT notified Congress on Friday in an email stating how its initial investigation of the data breach has 'isolated the breach to certain systems at the department used for administrative functions, such as employee transit benefits processing.' 

The USDOT informed legislators it suspects a data breach may have exposed the personal information of approximately 237,000 present and former federal staff.

The DOT HQ in Washington D.C. is pictured, above

USDOT said in a statement that the breach did not affect any transportation safety systems. It did not say who might be responsible for the hack.

The department is investigating the breach and has frozen access to the transit benefit system until it has been secured and restored, it said.

USDOT 'has suspended access to relevant systems while we further investigate the issue, and secure and restore the systems.'

The maximum benefit allowance is $280 per month for federal employee mass transit commuting costs.

The breach impacted 114,000 current employees and 123,000 former employees. 

Pete Buttigieg is the United States Secretary of Transportation (file photo)

Federal employees and agencies have been target of hackers in the past.

Two breaches at the U.S.

Office of Personnel Management (OPM) in 2014 and 2015 compromised sensitive data belonging to more than 22 million people, including 4.2 million current and federal employees along with fingerprint data of 5.6 million of those individuals.

Suspected Russian hackers who used SolarWinds and Microsoft software to burrow into U.S.

federal agencies breached unclassified Justice Department networks and read emails at the Treasury, Commerce and Homeland Security departments.

Nine federal agencies were breached in 2021.