"The department was fully aware that this situation was going to arise. But they continue to cut fire marshal positions, making it easier to commit the crime of arson," said Ed Burke, the fire marshal representative for the Uniformed Firefighters Association.
Of the 4,121 fires probed last year by the city's 80 fire marshals, 1,907, or 46 percent, turned out to be arson, Burke said.
Burke said the 46 percent rate can be extrapolated to the 1,861 uninvestigated blazes - showing that around 850 of them were probably set.
Marshals investigate all fires that are three alarms or above, involve death or serious injury and are deemed suspicious by a fire officer at the scene, said FDNY spokesman Frank Gribbon.
The department believes the union's claim of uninvestigated arson blazes is severely inflated, Gribbon said.
The number of uninvestigated fires increased last year because of a change in city regulations on which fires must be probed, said Gribbon.
The city expects the number of uninvestigated blazes will drop this year when the rules are changed in September to require probes of suspicious car fires, Gribbon said.
