The FDNY unit responsible for inspecting the storage of hazardous materials is doing a lousy job, city Comptroller John Liu charged yesterday.

Liu’s auditors found 27 of 30 locations storing those materials were operating with expired permits during at least one of the three years reviewed.

A science lab at the College of Staten Island had an expired permit for the entire three-year period.

Fire Commissioner Sal Cassano said he agreed with all the comptroller’s recommendations for improvements and, in fact, “had already started to address many of them, having previously recognized a number of the same issues.”