Is it legal to store gasoline in a public building?

Local codes and fire inspectors will apply the appropriate rules, but the NFPA National Fire Code does not prohibit it.

The maximum allowable quantity (MAQ) of any flammable liquid being stored depends upon the type of occupancy (the purpose of the building), how it is stored (in safety containers or cabinets), where it is stored, what type of construction it is, if there are sprinklers, among other things.

Gasoline is a Class IB flammable liquid (flash point below 73 F and boiling point above 100 F). Do not confuse this with the DOT HazMat class 3 flammable liquids.

Under NFPA 1 (2009):

Most occupancies are allowed to store a total of 10 gallons Class I and II flammable liquids in one control area (fire separation) with up to 4 areas on the ground floor. Mercantile, warehouse and industrial buildings may have different rules (e.g., up to 120 gallons in containers in an industrial facility).

If the storage area is not on the first floor, the numbers are reduced. For example, at the 3d floor, only 50 percent of the quantity allowed in the occupancy type is allowed at that level (i.e., no more than 5 gallons of gasoline) and stored in no more than two areas, separated by a one-hour fire barrier.