| Agent Name |
1,1,1-Trichloroethane |
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| Alternative Name |
Methyl chloroform |
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| CAS Number |
71-55-6 |
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| Formula |
C2-H3-Cl3 |
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| Major Category |
Solvents |
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| Synonyms |
TCA; Chloroethene; Methyl chloroform; Methyltrichloromethane; Trichloromethylmethane; alpha-Trichloroethane; alpha-T; [ATSDR CaseStudies # 24] UN2831 |
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| Category |
Chlorinated Solvents |
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| Description |
Colorless liquid with a mild, chloroform-like odor; [NIOSH] |
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| Sources/Uses |
Used for degreasing, cleaning, and thinning; [LaDou, p. 510] Used in photography (film cleaner); [www.ci.tucson.az.us/arthazards/medium.html] |
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| Comments |
For the general population, the most likely sources of exposure are home consumer products, building products, and contaminated food and water. TCA was used as a general anesthetic. Inhalation abuse of TCA can result in "sudden sniffing death," from cardiac dysrhythmias. [ATSDR Case Studies #24] Cardiac sensitization and low hepatotoxic potential have been documented in animal studies. [ACGIH] 1,1,1-Trichloroethane causes "trivial hepatotoxicity, unless exposure is very heavy or agent ingested." [Zimmerman, p. 333] Methyl chloroform is in the list of "Some volatile substances which may be abused by inhalation" published on the web site of the U.N. International Drug Control Programme, indicating its potential to cause narcosis in workers. [Flanagan et al. Volatile Substance Abuse] |
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| Restricted |
"Because 1,1,1-trichloroethane damages the ozone layer, production in the United States was phased out in 1996, but supplies as a raw material will be available until the year 2002." [ATSDR Medical Management] |
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| Reference Link |
ATSDR Medical Management - 1,1,1-Trichloroethane |
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| Exposure Assessment |
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| BEI |
Methyl chloroform in end-exhaled air = 40 ppm prior to last shift of workweek; for trichloroethanol in blood and urine and TCA in urine BEIs, see the ACGIH booklet; |
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| Skin Designation (ACGIH) |
No |
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| TLV (ACGIH) |
350 ppm |
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| STEL (ACGIH) |
450 ppm |
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| PEL (OSHA) |
350 ppm |
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| MAK |
200 ppm |
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| IDLH (NIOSH) |
700 ppm |
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| Excerpts from Documentation for IDLHs |
Other animal data: No significant signs of intoxication were seen in rats inhaling 500 ppm, 6 hours per day for 4 days [Savolainen et al. 1977]; in mice inhaling up to 1,300 ppm for 1 hour [Kjellstrand et al. 1985]; in rats inhaling up to 3,000 ppm for 0.5 to 4 hours [Mullin and Krivanek 1982]; or in baboons inhaling up to 1,400 ppm for 4 hours [Geller et al. 1982].
Human data: The onset of central anesthesia has occurred in individuals exposed for up to 7 hours to concentrations approaching 500 ppm [Stewart et al. 1969]. It has been stated that exposure to 900 to 1,000 ppm causes prompt, though minimal impairment of coordination; obvious disturbances in equilibrium have been noted above 1,700 ppm [MCA 1965]. Those exposed to 800 to 1,000 ppm have exhibited early anesthetic effects including incoordination [Stewart et al. 1961]. Volunteers exposed to 920 ppm for 5 to 45 minutes showed a slight loss of coordination and equilibrium [Stewart et al. 1961] |
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| Vapor Pressure |
124 mm Hg |
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| Odor Threshold Low |
16 ppm |
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| Odor Threshold High |
714 ppm |
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| Lethal Concentration |
LC50 (rats) = 18,000 ppm/4h |
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| Explanatory Notes |
Detection odor threshold from AIHA (mean = 390 ppm); |
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| Half Life |
Blood to expired air: 1-9 hours; trichloroethanol (blood): 10-27 hours; trichloroacetic acid (blood): 70-85 hours; [TDR, p. 1173] |
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| Reference Link |
ATSDR - ToxFAQs - 1,1,1-Trichloroethane |
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| Flammability (NFPA) |
1: must be preheated |
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| Adverse Effects |
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| Neurotoxin |
CNS Solvent Syndrome |
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| Hepatotoxin |
Hepatotoxin, Secondary |
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| IARC Carcinogen |
Not Classifiable |
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| Links to Other NLM Databases |
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| Health Studies |
Human Health Effects from Hazardous Substances Data Bank: 1,1,1-TRICHLOROETHANE
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