An additional 1,700 workers got bonuses even though they had been disciplined for some kind of misconduct within the previous year.
Overall, the IRS's inspector general said the agency paid more than $2.8 million in bonuses from 2010 to 2012 to employees who had conduct issues.
In a report issued Tuesday, the inspector general said the bonus program complied with federal regulations. But, the report said, paying bonuses to workers who owe back taxes conflicts with the IRS mission to enforce tax laws.
The IRS said it has stopped issuing awards to executives with disciplinary problems. The agency said it is considering a similar policy for union workers, subject to negotiations.