The city firefighters union is accusing the Bloomberg administration of fudging the numbers when it comes to the department's response times.
The Uniformed Firefighters Association is going public with its claims in a radio ad set to run during next week's subway series.
In it, UFA President Stephen Cassidy says, "Last week, FDNY commissioner Cassano deliberately misled the City Council when he testified about response times. He said the fire department doesn't know the amount of time a 911 caller spends with the 911 operator. That's the lie."
The union says the city lowballs data on response times in order to justify closing more fire companies.
In the ad, the union says city officials have the real numbers but won't release them because it would increase response times by a full minute.
In a statement, Fire Commissioner Sal Cassano says the department has always been transparent about how it calculates response times.
He also says its response has never been faster.