Cyclopentadiene

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

ACUTE TOXICITY DATA

Lethal concentration data:

Species	Reference	LC50 (ppm)	LCLo (ppm)	Time	Adjusted 0.5-hr LC (CF)	Derived value
Rat Mouse Rat	Shashkina 1965 Shashkina 1965 Smyth et al. 1954	14,182 5,091 LC67: 2,000	----- ----- -----	2 hr 2 hr 4 hr	22,691 ppm (1.6) 8,146 ppm (1.6) 4,000 ppm (2.0)	2,269 ppm 815 ppm 400 ppm

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.]

REFERENCES:

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.