Fire services could be hit with multimillion-pound bills due to an accounting error.
The miscalculation dates back to 2006 when changes to financial arrangements for injury payments to retired firefighters were made.
Essex Fire Authority has announced it will raid its reserves to repay a £15 million debt to the Government which it has amassed as the underpayment was missed despite annual independent auditing.
It is understood several other fire services are investigating similar underpayments and the county's fire chief warned that other fire authorities may not be in a position to meet the unexpected bill easily .
A spokesman for the Department for Communities and Local Government (DCLG) said it was too early to say what the full impact of the mistake would be.
He said: "This is a very technical issue about an auditing procedure and the rules on pension administration.
"Essex have jumped the gun, given absolutely no decision has been made on this issue, and it is something that the department will be discussing with the fire authority in more detail in due course."
Essex reported a shortfall of £1.8 million a year since 2006.
The payments relate to firefighters who have left the service since 1992 and were given early access to their pensions because of a injury suffered in the line of duty.
Accounts have been submitted to the Audit Commission and DCLG each year but both failed to pick up on the liability, the fire authority said.
Acting chief fire officer Adam Eckley said: "Because of our prudent financial management over the last few years we have built up significant reserves and we are in a healthy financial position and able to wipe out this debt immediately.
"This is a significant burden but unlike other fire and rescue services that will likely face a similar financial challenge, the fire authority has the cash to pay while remaining financially sound.
"Essex is still far better off than many fire authorities nationwide who have already had to look to job cuts and station closures to balance their books."
The treasurer and financial director of neighbouring Kent Fire and Rescue Service has been appointed to carry out an independent inquiry into how the mistake came about.
Mr Eckley said: " We have reviewed our governance arrangements and believe that no individual is to blame.
"While the treasurer and finance director is clearly accountable, we are not looking for any scapegoats."
"This was a genuine oversight by a number of parties and was brought to the fire authority's attention as soon as it was discovered."