May 1994
Immediately Dangerous to Life or Health Concentrations (IDLH)

CAS number: 79-01-6

NIOSH REL: 2 ppm 60-minute CEILING during usage as an anesthetic agent and 25 ppm TWA during all other exposures; NIOSH considers trichloroethylene to be a potential occupational carcinogen as defined by the OSHA carcinogen policy [29 CFR 1990].

Current OSHA PEL: 100 ppm TWA, 200 ppm CEILING,

300 ppm 5-minute MAXIMUM PEAK IN ANY 2 HOURS

1989 OSHA PEL: 50 ppm (270 mg/m3) TWA, 200 ppm (1,080 mg/m3) STEL

1993-1994 ACGIH TLV: 50 ppm (269 mg/m3) TWA, 100 ppm (537 mg/m3) STEL, A5

Description of substance: Colorless liquid (unless dyed blue) with a chloroform-like odor.

LEL (@77°F) : 8% (10% LEL(@77°F), 8,000 ppm)

Original (SCP) IDLH: 1,000 ppm

Basis for original (SCP) IDLH: The chosen IDLH is based on the results of experimental 2-hour exposures by Vernon and Ferguson [1969] of 8 young male volunteers (aged 21 to 30) to concentrations of 0, 100, 300, and 1,000 ppm. On the basis of a number of psychophysiological tests, decrements in performance were reported statistically at only 1,000 ppm. Because the exposure time was 2 hours at 1,000 ppm, a person should be able to escape within 30-minutes without injury or irreversible health effects.

Existing short-term exposure guidelines: National Research Council [NRC 1988] Emergency Exposure Guidance Levels (EEGLs):

1-hour EEGL: 200 ppm

24-hour EEGL: 10 ppm


Lethal concentration data:

Species Reference LC50




Time Adjusted 0.5-hr

LC (CF*)

Derived value
Human Bell 1951 ----- 2,900 ? ? ?
G. pig Davis et al. 1959 ----- 37,200 40 min 53,196 ppm (1.43) 5,320 ppm
Mouse Friberg et al. 1953 8,450 ----- 4 hr 114,075 ppm (13.5) 11,408 ppm
Cat Lehmann et al. 1936 ----- 5,952 2 hr 33,688 ppm (5.66) 3,369 ppm
Rat NRC 1988 ----- 8,000 4 hr 108,000 ppm (13.5) 10,800 ppm
Rat Vernot et al. 1977 26,300 ----- 1 hr 62,594 ppm (2.38) 6,259 ppm
Rabbit WHO 1970 ----- 11,000 ? ? ?

*Note: Conversion factor (CF) was determined with "n" = 0.8 [ten Berge et al. 1986].

Other human data: Exposure of eight volunteers for 2 hours to 1,000 ppm resulted in decrements in visual perception and motor skills, but 2-hour exposures to 100 and 300 ppm did not [Vernon and Ferguson 1969]. Tachypnea and ventricular arrhythmias have been equated with inhaled concentrations greater than 15,000 ppm during usage as an anesthetic [Vernon and Ferguson 1969].

Revised IDLH: 1,000 ppm [Unchanged]

Basis for revised IDLH: Based on acute inhalation toxicity data in volunteers [Vernon and Ferguson 1969], the original IDLH for trichloroethylene (1,000 ppm) is not being revised at this time. [Note: NIOSH recommends as part of its carcinogen policy that the "most protective" respirators be worn for trichloroethylene at concentrations above 25 ppm.]


1. Artusio JF, ed. [1963]. Clinical anesthesia halogenated anesthetics. Philadelphia, PA: F.A. Davis Co., pp. 43-65.

2. Bell A [1951]. Death from trichlorethylene in a dry-cleaning establishment. N Z Med J 50:119-126.

3. Davis EF, Tuma BL, Lee LC [1959]. Handbook of toxicology. Vol. V. Fungicides. Philadelphia, PA: W.B. Saunders Co., p. 76.

4. Friberg L, Kylin B, Nystrom A [1953]. Toxicities of trichlorethylene and tetrachlorethylene and Fujiwara’s pyridine-alkali reaction. Acta Pharmacol Toxicol 9:303-312.

5. Lehmann KB, Schmidt-Kehl L, Ruf H, Crescitelli, Dahl, Eppinghausen, Eshe, Falker, Grotefendt, Junkenita, Maier, Mergner, Pantehtsch, Schlitzer, Shoenes, Spettmann, Wirges, Bamsreiter, Benninger, Lazarus, Manasse, Kummeth, Reuss, Schwarzweller [1936]. The 13 most important chlorinated hydrocarbons of the aliphatic series from the standpoint of occupational hygiene. Arch Hyg Bakteriol 116:132-200 (translated).

6. NRC [1988]. Emergency and continuous exposure guidance levels for selected airborne contaminants. Vol. 8. Lithium chromate and trichloroethylene. Washington, DC: National Academy Press, Panel on Emergency Exposure Guidance Levels, Subcommittee on Submarine Air Quality, Committee on Toxicology, Board on Environmental Studies and Toxicology, Commission on Life Sciences, National Research Council, pp. 31-65.

7. Smyth HF Jr, Carpenter CP, Weil CS, Pozzani UC, Striegel JA, Nycum JS [1969]. Range-finding toxicity data: list VII. Am Ind Hyg Assoc J 30(5):470-476.

8. ten Berge WF, Zwart A, Appelman LM [1986]. Concentration-time mortality response relationship of irritant and systematically acting vapours and gases. J Haz Mat 13:301-309.

9. Vernon RJ, Ferguson RK [1969]. Effects of trichloroethylene on visual-motor performance. Arch Environ Health 18(6):894-900.

10. Vernot EH, MacEwen JD, Haun CC, Kinkead EK [1977]. Acute toxicity and skin corrosion data for some organic and inorganic compounds and aqueous solutions. Toxicol Appl Pharmacol 42:417-423.

11. WHO [1970]. Toxicological evaluation of some extraction solvents and certain other substances. Geneva, Switzerland: World Health Organization, Food and Agriculture Organization, Nutrition Meetings Report Series 48a:121-128.

Page last reviewed: December 4, 2014