This paper is based on findings resulting from ASHRAE Research Project RP-1665.

Instances of counterfeit refrigerants causing violent andunexpected explosions, resulting in multiple fatalities, havebeen reported in mobile refrigeration units around the world.In addition, counterfeit refrigerants have caused system reliabilityissues in numerous air-conditioning applications. Itwas initially believed the inclusion of methyl chloride (R-40)in the refrigerant composition caused these explosions andreliability issues. ASHRAE Research Project RP-1665 wascommissioned to examine reactivity of R-40 with R-134a(methylene chloride) refrigeration system materials. R-40reactivity, in concentration ranges of 0.01% to 10%, was studiedin the presence of R-134a, polyolester (POE) lubricant,aluminum 1100 metal, aluminum 380 metal, iron metal,copper metal, sodium potassiumaluminumsilicate zeolite,andalumina catalysts. R-40 was shown to have varying levels ofreactivity--generally mild, but showing the potential for catastrophicreactivity. This paper contains a summary of the workfrom ASHRAE RP-1665 and provides insights into the impactof R-40 contamination by providing the chemistry of the reactions,preventative safeguards, threshold levels, and assessmentprocedures.