The largest union of federal workers indicated Wednesday that it's mulling an appeal of a federal judge's decision to dismiss a lawsuit against the Office of Personnel Management for that agency's failure to stop a data breach that resulted in the theft of data on 22.1 million current and former federal workers.

"OPM failed to keep our most private and sensitive information from getting into the hands of Chinese hackers," AFGE president J. David Cox Sr. said Wednesday. "We are deeply disappointed by the judge's ruling in favor of OPM."

"AFGE is seriously evaluating all options to challenge this decision and will continue to fight on behalf of the millions of current, future, and retired federal employees and their family members whose lives were forever disrupted by this unprecedented data breach," he said.

A federal judge this week dismissed a lawsuit brought by two federal worker unions against the Office of Personnel Management for that agency's failure to stop a data breach that resulted in the theft of data on 22.1 million current and former federal workers.

AFGE and the National Treasury Employees Union sued OPM after the 2015 data theft. OPM responded to the data breach by offering affected people free credit monitoring services.

But the U.S. District Court for the District of Columbia said the unions don't have standing to sue, as they didn't demonstrate actual injury from the event.

"Plaintiffs allege that some of them have incurred actual out-of-pocket expenses, that others have expended time and effort, and that others have experienced emotional distress or may be subject to identity theft or some other harm in the future," Judge Amy Berman Jackson wrote.

"Plaintiffs also contend that all of them have suffered the injury of the breach itself," she added. "The Court is not persuaded that the factual allegations in the complaints are sufficient to establish constitutional standing."