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  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
ACUTE TOXICITY DATA
Lethal concentration data:
Smyth et al. 1954
|22,691 ppm (1.6)
8,146 ppm (1.6)
4,000 ppm (2.0)
Human data: None relevant for use in determining the revised IDLH.
|Revised IDLH: 750 ppm
Basis for revised IDLH: The revised IDLH for cyclopentadiene is 750 ppm based on acute inhalation toxicity data in animals [Shashkina 1965]. [Note: It was decided to use the 2-hour lethal concentration data in mice rather than the 4-hour lethal concentration data in rats so as not to magnify the conservatism already present in the correction factors.]
1. Deichmann WB, Gerarde HW . Table 48. Acute toxicity of hydrocarbons. In: Toxicology of drugs and chemicals. New York, NY: Academic Press, Inc., p. 734.
2. Shashkina LF . 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 . Range-finding toxicity data: list V. AMA Arch Ind Hyg Occup Med 10:61-68.