History
Pioneered by Imperial Chemical Industries in Britain, its development was hailed as an anesthetic revolution. Originally thought to possess less hepatotoxicity than chloroform, and without the unpleasant pungency and flammability of ether, TCE use was nonetheless soon found to have several pitfalls. These included promotion of cardiac arrhythmias, low volatility and high solubility preventing quick anesthetic induction, reactions with soda lime used in carbon dioxide absorbing systems, prolonged neurologic dysfunction when used with soda lime, and evidence of hepatotoxicity as had been found with chloroform.
The introduction of halothane in 1956 greatly diminished the use of TCE as a general anesthetic. TCE was still used as an inhalation analgesic in childbirth given by self-administration. Fetal toxicity and concerns for carcinogenic potential of TCE led to its abandonment in developed countries by the 1980s.
Due to concerns about its toxicity, the use of trichloroethylene in the food and pharmaceutical industries has been banned in much of the world since the 1970s. Legislation has forced the substitution of trichloroethylene in many processes in Europe as the chemical was classified as a carcinogen carrying an R45 risk phrase. Many degreasing chemical alternatives are being promoted such as Ensolv and Leksol; however, each of these is based on n-propyl bromide which carries an R60 risk phrase and they would not be a legally acceptable substitute.
Groundwater contamination by TCE has become an important environmental concern for human exposure.
In 2005 it was announced by the USEPA (the United States Environmental Protection Agency) that the agency had completed its Final Health Assessment for Trichloroethylene and released a list of new TCE toxicity values. The results of the study have formally characterized the chemical as a human carcinogen and a non-carcinogenic health hazard. A 2011 toxicological review performed by the EPA continues to list trichloroethylene as a known carcinogen.
Read more about this topic: Trichloroethylene
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