It's all linked to a computer error dating back eight years ago, according to the Orange County Register.
In 2003, new software was installed which miscalculated some rates for payments to the pension fund.
The Orange County Register reported that pensions themselves shouldn't be affected by the mistake, but it will result in some hefty catch-up bills for agencies countywide. The Orange County Fire Authority, for example, will have to pay $76 million to make up for eight years in which funds went uncollected for special pay stipends for paramedics and others with specialized jobs, the newspaper reported.
The retirement agency is allowing the firefighters to pay the bill over a 25-year period beginning in July.
Orange County Employees Retirement System Assistant CEO Steve Cadena and Finance Officer Michelle Williamson have been placed on paid leave since Feb. 18, as the agency conducts an audit.
The Associated Press contributed to this report.