Federal and state authorities are investigating the series of explosions that ripped through the Blue Rhino propane plant in Tavares, Florida this past week. Seven people suffered injuries and were transported to nearby hospitals, four of which were listed in critical condition with severe burns to their arms, torsos and faces. An eighth individual was struck by a vehicle while fleeing the explosion. The explosion shook houses several miles from the plant according to witnesses.
Flames from the blast reached as high as 200 feet in the air and propane canisters began raining down from the sky reminding those of us in St. Louis of a similar industrial accident at Praxair in South St. Louis in 2005. Like the Praxair explosion, residents were evacuated within a significant radius around the plant. Blue Rhino is a subsidiary of Ferrellgas, a Kansas based national propane gas provider.
Although the cause of the Florida industrial accident is unknown at this point, the Taveras Fire Chief speculated that the explosion was likely caused by some combination of human error and bad practices. The explosions appear to have begun near the loading area where the plant’s 53,000 twenty-pound propane canisters are stored on plastic pallets. The explosions could have been significantly worse had they spread to the 30,000 pound storage containers that refill the canisters. According to reports, the plant’s concrete lot was covered with thousands of charred 20-pound canisters the next day.
Propane explosions are referred to as a boiling liquid expanding vapor explosions (BLEVE), and occur when the pressure inside the tank exceeds that at which the safety relief valve can safely vent the excess pressure into the outside atmosphere. A propane tank BLEVE will occur when the canister is subject to extreme heat under the right conditions. According to a propane industry website, while single canister explosions are extremely remote, one of the more potentially dangerous situations occurs when a group of canisters are stored together and an ignited propane leak on one canister impinges on an adjacent cylinder, resulting in the opening of its relief valve and igniting a chain reaction of propane cylinder fires which ultimately result in explosion.