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

CAS number: 542–92–7

NIOSH REL: 75 ppm (200 mg/m3) TWA

Current OSHA PEL: 75 ppm (200 mg/m3) TWA

1989 OSHA PEL: Same as current PEL

1993-1994 ACGIH TLV: 75 ppm (203 mg/m3) TWA

Description of Substance: Colorless liquid with an irritating, terpene-like odor.

LEL: . . Unknown

Original (SCP) IDLH: 2,000 ppm

Basis for original (SCP) IDLH: The chosen IDLH is based on the statement by Deichmann and Gerarde [1969] that 4 of 6 rats died from a 4-hour exposure to 2,000 ppm [Smyth et al. 1954].

Short-term exposure guidelines: None developed


Lethal concentration data:

Species Reference LC50(ppm) LCLo(ppm) Time Adjusted 0.5-hrLC (CF) Derivedvalue


Shashkina 1965Shashkina 1965

Smyth et al. 1954


LC67: 2,000



2 hr2 hr

4 hr

22,691 ppm (1.6)8,146 ppm (1.6)

4,000 ppm (2.0)

2,269 ppm815 ppm

400 ppm


Human data: None relevant for use in determining the revised IDLH.



1. Deichmann WB, Gerarde HW [1969]. Table 48. Acute toxicity of hydrocarbons. In: Toxicology of drugs and chemicals. New York, NY: Academic Press, Inc., p. 734.

2. Shashkina LF [1965]. Materials for substantiation of maximum permissible concentration of cyclopentadiene and of its dimer — dicyclopentadiene — in the atmosphere of industrial premises. Gig Tr Prof Zabol 9(12):13-19 (in Russian).

3. Smyth HF Jr, Carpenter CP, Weil CS, Pozzani UC [1954]. Range-finding toxicity data: list V. AMA Arch Ind Hyg Occup Med 10:61-68.

Page last reviewed: December 4, 2014