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Ethyl benzene

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

CAS number: 100–41–4

NIOSH REL: 100 ppm (435 mg/m3) TWA, 125 ppm (545 mg/m3) STEL

Current OSHA PEL: 100 ppm (435 mg/m3) TWA

1989 OSHA PEL: 100 ppm (435 mg/m3) TWA, 125 ppm (545 mg/m3) STEL

1993-1994 ACGIH TLV: 100 ppm (434 mg/m3) TWA, 125 ppm (543 mg/m3) STEL

Description of Substance: Colorless liquid with an aromatic odor.

LEL:. . 0.8% (10% LEL, 800 ppm)

Original (SCP) IDLH: 2,000 ppm

Basis for original (SCP) IDLH: The chosen IDLH is based on the statement by Patty [1963] and ACGIH [1971] that in an experimental study 2,000 ppm caused dizziness in one man after a brief exposure of 5 minutes [Yant et al. 1930].

Short-term exposure guidelines: None developed


Lethal concentration data:






Adjusted 0.5-hr




Rat Smyth et al. 1962 ----- 4,000 4 hr 8,000 ppm (2.0) 800 ppm

Other animal data: RD50 (mouse): 1,430 ppm [DeCeaurriz et al. 1981;
RD50 (mouse): 4,060 ppm [Nielsen and Alarie 1982].

Human data: Dizziness was caused in one volunteer after a 5-minute exposure to 2,000 ppm [Yant et al. 1930].

Revised IDLH: 800 ppm [LEL]

Basis for revised IDLH: Based on health considerations and acute inhalation toxicity data in humans [Yant et al. 1930] and animals [DeCeaurriz et al. 1981; Smyth et al. 1962], a value between 800 and 2,000 ppm would have been appropriate. However, the revised IDLH for ethyl benzene is 800 ppm based strictly on safety considerations (i.e., being 10% of the lower explosive limit of 0.8%).


1. ACGIH [1971]. Ethylbenzene. In: Documentation of the threshold limit values for substances in workroom air. 3rd ed. Cincinnati, OH: American Conference of Governmental Industrial Hygienists, p. 104.

2. DeCeaurriz JC, Micillino JC, Bonnet P, Guenier JP [1981]. Sensory irritation caused by various industrial airborne chemicals. Toxicol Lett 9(4):137-143.

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

4. Patty FA, ed. [1963]. Industrial hygiene and toxicology. 2nd rev. ed. Vol. II. Toxicology. New York, NY: Interscience Publishers, Inc., p. 1232.

5. Smyth HF Jr, Carpenter CP, Weil CS, Pozzani UC, Striegel JA [1962]. Range-finding toxicity data: list VI. Am Ind Hyg Assoc J 23:95-107.

6. Yant WP, Schrenk HH, Waite CP, Patty FA [1930]. Acute response of guinea pigs to vapors of some new commercial organic compounds. II. Ethyl benzene. Public Health Rep 45:1241-1250.