METHYL chloride in a rogue counterfeit refrigerant may be responsible for the explosions and three fatalities which have grounded hundreds of reefer units around the world.
Information supplied to the UK shipping insurers group UK P&I from Cambridge Refrigeration Technology suggests that the R134a refrigeration units had been contaminated with methyl chloride. Ironically, methyl chloride was formerly a common but highly toxic refrigerant responsible for a number of deaths prior to the introduction of CFCs in the 1930s.

According to the report to UK P&I, the methyl chloride contained in the counterfeit refrigerant blend which had been added to the systems reacted with the aluminium in the compressor forming trimethyl aluminium, a liquid at room temperature which ignites spontaneously on contact with air.

While standard tests will identify the counterfeit refrigerant, making the units safe may be more of a problem. According to Cambridge Refrigeration Technology (CRT) the liquid trimethyl aluminium will be sitting in the crankcase of the compressor. They suggest a possible solution being to find a reagent that could be injected into the compressor, which would slowly react with the trimethyl aluminium and passivate it. Another solution could be to find a way of puncturing the base of the crankcase and blowing out the oil and trimethyl aluminium into a barrel of water using dry nitrogen.

The source of the contaminated refrigerant in this instance is not yet known but last year ACR News reported on faulty refrigerant from China containing methyl chloride being sold in car centres in Korea.