The Internal Revenue Service is trying to collect billions of dollars in late taxes from nearly half a million federal employees.
Documents obtained by WTOP radio through the Freedom of Information Act show the federal employees and retirees did not pay more than $3.5 billion in taxes owed last year.
The agency with the most delinquent employees was the U.S. Postal Service. Nearly 4.2 percent of its 747,000 workers are delinquent.
The IRS would not provide comparable data for the general population.
The Executive Office of the President, which includes the White House, has 58 employees who did not pay more than $319,000. More than 1,000 Capitol Hill workers are on the list.
About 152,000 of the delinquent federal workers have entered into payment plans.