Propylene oxide

CAS number: 75–56–9

NIOSH REL: None established; NIOSH considers propylene oxide to be a potential occupational carcinogen as defined by the OSHA carcinogen policy [29 CFR 1990].

Current OSHA PEL: 100 ppm (240 mg/m³) TWA

1989 OSHA PEL: 20 ppm (50 mg/m³) TWA

1993-1994 ACGIH TLV: 20 ppm (48 mg/m³) TWA

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

LEL: . 2.3% (10% LEL, 2,300 ppm)

Original (SCP) IDLH: 2,000 ppm

Basis for original (SCP) IDLH: The chosen IDLH is based on the dog 4-hour LC_LO of 2,005 ppm and the mouse 4-hour LC₅₀ of 1,740 ppm [Jacobson et al. 1956 cited by NIOSH 1976].

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
Mouse Dog Rat G. pig Rat	Jacobson et al. 1956 Jacobson et al. 1956 Jacobson et al. 1956 Rowe et al. 1956 Smyth et al. 1969	1,740 ----- 4,000 ----- LC67: 4,000	----- 2,005 ----- 4,000 -----	4 hr 4 hr 4 hr 4 hr 4 hr	3,480 ppm (2.0) 4,010 ppm (2.0) 8,000 ppm (2.0) 8,000 ppm (2.0) 8,000 ppm (2.0)	348 ppm 401 ppm 800 ppm 800 ppm 800 ppm

Lethal dose data:

Species	Reference	Route	LD50 (mg/kg)	LDLo (mg/kg)	Adjusted LD	Derived value
G. pig Rat Mouse Rat G. pig	Gig Tr Prof Zabol 1981 Pugaeva et al. 1970 Pugaeva et al. 1970 Smyth et al. 1941 Smyth et al. 1941	oral oral oral oral oral	660 380 440 1,140 690	----- ----- ----- ----- -----	1,909 ppm 1,099 ppm 1,273 ppm 3,298 ppm 4,830 ppm	191 ppm 110 ppm 127 ppm 330 ppm 483 ppm

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

Revised IDLH: 400 ppm Basis for revised IDLH: The revised IDLH for propylene oxide is 400 ppm based on acute inhalation toxicity data in animals [Jacobson et al. 1956]. [Note: NIOSH recommends as part of its carcinogen policy that the "most protective" respirators be worn for propylene oxide at any detectable concentration.]

REFERENCES:

1. Gig Tr Prof Zabol [1981]; 46(7):76 (in Russian).

2. Jacobson KH, Hackley EB, Feinsilver L [1956]. The toxicity of inhaled ethylene oxide and propylene oxide vapors. Acute and chronic toxicity of ethylene oxide and acute toxicity of propylene oxide. AMA Arch Ind Health 13(3):237-244.

3. NIOSH [1976]. TZ29750. Propane, 1,2-epoxy-. In: Registry of toxic effects of chemical substances, 1976 ed. Cincinnati, OH: U.S. Department of Health, Education, and Welfare, Public Health Service, Center for Disease Control, National Institute for Occupational Safety and Health, DHEW (NIOSH) Publication No. 76-191, p. 968.

4. Pugaeva VP, Klochkova SE, et al. [1970]. Experimental materials on hygienic reglamentation of propylene oxide. Gig Tr Prof Zabol 14(11):55-57 (in Russian).

5. Rowe VK, Hollingsworth RL, Oyen F, McCollister DD, Spencer HC [1956]. Toxicity of propylene oxide determined on experimental animals. AMA Arch Ind Health 13:228-236.

6. Smyth HF Jr, Carpenter CP, Weil CS, Pozzani UC, Striegel JA, Nycum JS [1969]. Range-finding toxicity data: list VII. Am Ind Hyg Assoc J 30(5):470-476.

7. Smyth HF, Seaton J, Fisher L [1941]. The single dose toxicity of some glycols and derivatives. J Ind Hyg Toxicol 23:259-268.