Fatal Fire with "nonflammable" Methyl Chloroform with Welding in a Vapor Degreaser

Methyl chloroform (1,1,1-Trichloroethane) is widely used as a solvent because of its low toxicity and good solvent properties. Its inability to burn as a liquid (no flash point) can lead users to believe that methyl chloroform will not burn under any circumstances. Attached is an article from the September/October 1986, Archives of Environmental Health entitled, "A Fatal Fire with "nonflammable" Methyl Chloroform." This article dispels the common belief that this material is nonflammable. This article also describes a fatal welding accident and discusses related technical issues.

There is little evidence or experience with these types of fatal accidents or incidents with similar chemicals; however, it is important that OSHA CSHO's are aware of the implications involved with the use of halogenated hydrocarbons in welding or other operations which may cause vaporization.