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

CAS number: 108–88–3

NIOSH REL: 100 ppm (375 mg/m3) TWA, 150 ppm (560 mg/m3) STEL

Current OSHA PEL: 200 ppm TWA, 300 ppm CEILING,

500 ppm 10-minute MAXIMUM PEAK

1989 OSHA PEL: 100 ppm (375 mg/m3) TWA, 150 ppm (560 mg/m3) STEL

1993-1994 ACGIH TLV: 50 ppm (188 mg/m3) TWA [skin]

Description of substance: Colorless liquid with a sweet, pungent, benzene-like odor.

LEL: . . 1.1% (10% LEL, 1,100 ppm)

Original (SCP) IDLH: 2,000 ppm

Basis for original (SCP) IDLH: The chosen IDLH seems reasonable based on the statements by Patty [1963] and ANSI [1973]. Patty [1963] reported that with 600 ppm, extreme fatigue, mental confusion, exhilaration, nausea, headache, and dizziness resulted by the end of 3 hours [von Oettingen et al. 1942]. ANSI [1973] reported that exposures to concentrations greater or longer than 4,000 ppm for 5 minutes might limit self-rescue ability.

Existing short-term exposure guidelines: National Research Council [NRC 1987] Emergency Exposure Guidance Levels (EEGLs):

1-hour EEGL: 200 ppm

24-hour EEGL: 100 ppm


Lethal concentration data:

Species Reference LC50




Time Adjusted 0.5-hr


Derived value
Rat Benignus 1981 >26,700 ----- 1 hr >33,375 ppm (1.25) >3,338 ppm
Mouse Benignus 1981 400 ----- 24 hr 1,440 ppm (3.6) 144 ppm
Rabbit Smyth & Carpenter 1944 ----- 55,000 40 min 60,500 ppm (1.1) 6,050 ppm

Other animal data: RD50 (mouse), 5,300 ppm [Nielsen and Alarie 1982].

Human data: It has been reported that extreme fatigue, mental confusion, exhilaration, nausea, headache and dizziness resulted from exposures to 600 ppm by the end of 3 hours [von Oettingen et al. 1942]. In addition, the following observations have been made: some workers will tolerate concentrations ranging up to 200 ppm for 6 to 8 hours daily with no demonstrable ill effects; 200 to 500 ppm for 6 to 8 hours will cause tiredness and lassitude in most workers; and concentrations over 500 ppm for 1 to 3 hours are definitely dangerous and will cause symptoms attributable to depression of the central nervous system and the bone marrow [Wilson 1943]. It has also been reported that exposure to concentrations greater than 4,000 ppm for more than 5 minutes might limit self rescue ability [ANSI 1973]. After 20 minutes, exposures to concentrations at 300, 500, or 700 ppm resulted in significant increases in reaction times; a significant decrease in perceptual speed resulted after a 20-minute exposure to 700 ppm [Gamberale and Hultengren 1972].

Revised IDLH: 500 ppm

Basis for revised IDLH: The revised IDLH for toluene is 500 ppm based on acute inhalation toxicity data in humans [Gamberale and Hultengren 1972; von Oettingen et al. 1942; Wilson 1943].


1. ANSI [1973]. American National Standard, acceptable concentrations of toluene. New York, NY: American National Standards Institute, p. 6.

2. Benignus VA [1981]. Health effects of toluene: a review. Neurotoxicol 2:567-588.

3. Gamberale F, Hultengren M [1972]. Toluene exposure. II. Psychophysiological functions. Scand J Work Environ Health 9:131-139.

4. Nielsen GD, Alarie Y [1982]. Sensory irritation, pulmonary irritation, and respiratory stimulation by airborne benzene and alkylbenzenes: prediction of safe industrial exposure levels and correlation of their thermodynamic properties. Toxicol Appl Pharmacol 65:459-477.

5. NRC [1987]. Emergency and continuous exposure guidance levels for selected airborne contaminants. Vol. 7. Ammonia, hydrogen chloride, lithium bromide, and toluene. Washington, DC: National Academy Press, Committee on Toxicology, Board on Toxicology and Environmental Health Hazards, Commission on Life Sciences, National Research Council, pp. 47-61.

6. Patty FA, ed. [1963]. Industrial hygiene and toxicology. 2nd rev. ed. Vol. II. Toxicology. New York, NY: Interscience Publishers, Inc., p. 1227.

7. Smyth HF Jr, Carpenter CP [1944]. The place of the range finding test in the industrial toxicology laboratory. J Ind Hyg Toxicol 26:269-273.

8. von Oettingen WF, Neal PA, Donahue DD [1942]. The toxicity and potential dangers of toluene: preliminary report. JAMA 118:579-584.

9. Wilson RH [1943]. Toluene poisoning. JAMA 123:1106-1108.

Page last reviewed: December 4, 2014