HC-12a, also called ES-12a, OZ-12a, DURACOOL 12a [1] and Hydrocarbon Blend B, is marketed as a "drop-in" replacement refrigerant for R-12 and other refrigerants. HC-12a is a mixture of hydrocarbons, specifically propane (R-290) and isobutane (R-600a), and is therefore considered nearly non-ozone-depleting. The hydrocarbon blend is compatible with hoses and oils used in R-12 systems.
As it is flammable, it is illegal for use as an R-12 replacement in the United States. [2] [3] Its use in public transport vehicles has also been illegal in the United States since 1990. [4] [5]
This hydrocarbon blend caused [6] the Tragedia de La Cresta in October 2006, [7] a bus fire which killed 18 people and injured 25, some severely, which in turn led to an overhaul of Panama City's public transport system. [5] [8] [9] [10] The refrigerant ignited due to an electrical spark [11] which followed a refrigerant leak, [12] which quickly set the bus ablaze as the fire spread from the refrigeration system towards the interior of the bus. [13] [5] [4] The bus lacked emergency exits and fire extinguishers, and the occupants' peril was aggravated by the location of the engine and the refrigeration system compressor—below a cover on the inner side of the only passenger exit door. [14] A lawsuit in a US court against Northcutt, which imported the HC-12 involved in the tragedy, and OZ Technology, Inc., which manufactured the HC-12 [11] [6] [15] [16] [17] began in 2008; in 2018, Northcutt reached a settlement with the victims of the tragedy and their relatives. [5] [18] [19]
Unacceptable This designation means that it is illegal to use a product as a substitute for an ODS in a specific end-use.