The principal regulations regarding propane delivery, use, storage and transportation are in Chapter 5F-11 of the Florida Administrative Code and Chapter 527 of Florida Statutes. Though the FDACS Bureau of LP Gas Inspection is the top Florida authority regulating propane, other agencies may have additional requirements. Under these regulations, propane is treated as a fire hazard. Under the relevant fire hazard statutes, numerous regulatory agencies may issue citations. These would include but might not be limited to the Division of the State Fire Marshal, local fire departments and fire safety inspectors, the health departments, building code inspectors and aw enforcement officers.
NFPA No. 58
In Chapter 527, Florida adopted the National Fire Protection Association standards for storing propane. These regulations are part of NFPA No. 58, LP-Gas Code. The relevant section of NFPA No. 58 as far as storing gas on a porch goes is Chapter 8, Storage of Cylinders Awaiting Use, Resale or Exchange.
Section 126.96.36.199 of NFPA 58: Liquefied Petroleum Gas Code, prohibits storing cylinders "in buildings near exits, near stairways or in areas normally used, for the safe egress of occupants." This means you cannot store a propane tank on a porch. It isn't because storing propane on porches is more dangerous than elsewhere; it is illegal because a porch is normally used to get in and out of the building.
Fines for safety code violations are rare. Typically an order is issued for the hazard to be dealt with. If a follow-up inspection verifies the matter has been handled, no further action is taken. In the event of a fire hazard being deemed an immediate threat to health, a building may be ordered evacuated. The owner would not be allowed to use the building until the threat had been dealt with. In the event of repeated failures to correct a fire safety violation, the officials of the Division of State Fire Marshall can seek fines of up to $10,000 per day until compliance is achieved. A criminal negligence charge with a possible two-year prison sentence can be made on intentional safety violations.