1,3-Butadiene

CAS number: 106-99-0

NIOSH REL: None established; NIOSH considers 1,3-butadiene to be a potential occupational carcinogen as defined by the OSHA carcinogen policy [29 CFR 1990].

Current OSHA PEL: 1 ppm (2.2 mg/m³) TWA; 5 ppm (11.0 mg/m³) ST

1989 OSHA PEL: Same as current PEL

1993-1994 ACGIH TLV: 10 ppm (22 mg/m³) TWA, A2

Description of Substance: Colorless gas with a mild aromatic or gasoline-like odor.

LEL: 2.0% (10% LEL, 2,000 ppm)

Original (SCP) IDLH: 20,000 ppm [LEL]

Basis for original (SCP) IDLH: AIHA [1963] reported that narcosis did not occur in 2 humans inhaling 8,000 ppm during an 8-hour period [Carpenter et al. 1944]. AIHA [1963] also reported that inhalation of 6,700 ppm for 7.5 hours/day, 6 days/week for 8 months resulted in no significant chronic effects in rats, guinea pigs, rabbits, and dogs; some growth retardation and light cloudy swelling of livers did occur [Carpenter et al. 1944]. From the data given above, acutely toxic concentrations are obviously well above the lower explosive limit (LEL) of 20,000 ppm. For this draft technical standard, therefore, the LEL is used as the IDLH (i.e., the concentration above which only the "most protective" respirators are permitted).

Existing short-term exposure: 1991 American Industrial Hygiene Association guidelines (AIHA) Emergency Response Planning Guidelines

(ERPGs):
ERPG-1: 10 ppm (60-minute)
ERPG-2: 50 ppm (60-minute)
ERPG-3: 5,000 ppm (60-minute)

ACUTE TOXICITY DATA

Lethal concentration data:

					Adjusted
		LC50	LCLo		0.5-hr	Derived
Species	Reference	(ppm)	(ppm)	Time	LC (CF)	Value
Rabbit	Carpenter et al. 1944	-----	250,000	30 min	250,000 ppm(1.0)	25,000 ppm
Mouse	Dow 1941	115,111	-----	?	?	?
Rat	Dow 1941	LC40: 200,000	-----	30 min	200,000 ppm (1.0)	20,000 ppm
Mouse	Dow 1941	122,000	-----	2 hr	195,200 ppm (1.6)	19,500 ppm
Rat	Shugaev 1968	126,667	-----	4 hr	253,334 ppm (2.0)	25,334 ppm
Rat	Von Oettingen 1940	130,000	-----	4 hr	260,000 ppm (2.0)	26,000 ppm

Other animal data: Exposures to 6,700 ppm for 7.5 hours/day, 6 days/week for 8 months caused no progressive injury in rats, guinea pigs, rabbits, or 1 dog [Carpenter et al. 1944].

Human data: Narcosis did not occur in volunteers exposed to 8,000 ppm for 8 hours [Carpenter et al. 1944]. Exposure to 10,000 ppm for 5 minutes has resulted in slight irritation and dryness of the nose and mouth with some increase in pulse rate but no effect on blood pressure or respiration [Shugaev 1968].

Revised IDLH: 2,000 ppm [LEL] Basis for revised IDLH: Based on health considerations and acute inhalation toxicity data in humans [Carpenter et al. 1944; von Oettingen 1940] and animals [Carpenter et al. 1944; Dow 1941; Shugaev 1968; von Oettingen 1940], a value between 10,000 and 20,000 ppm would have been appropriate. However, the revised IDLH for 1,3-butadiene is 2,000 ppm based strictly on safety considerations (i.e., being 10% of the lower explosive limit of 2%). [Note: NIOSH recommends as part of its carcinogen policy that the "most protective" respirators be worn for 1,3-butadiene at any detectable concentration.]

References:

1. AIHA [1963]. 1,3-Butadiene. In: Hygienic guide series. Am Ind Hyg Assoc J 24:91-92.
2. Carpenter CP, Shaffer CB, Weil CS, Smyth HF Jr [1944]. Studies on the inhalation of 1,3-butadiene; with a comparison of its narcotic effect with benzol, toluol, and styrene, and a note on the elimination of styrene by the human. J Ind Hyg Toxicol 26(3):69-78.
3. Dow [1941]. Research report of inhalation toxicity of 1,3-butadiene. [Unpublished research]. Midland, MI: Dow Chemical Company. [From American Industrial Hygiene Association (AIHA) 1991 Emergency Response Planning Guidelines for 1,3-Butadiene.]
4. Shugaev BB [1968]. Distribution in the organism and toxicity of aliphatic hydrocarbons. Farmakol Toxsikol
5. 31:162-165 (translated).
6. von Oettingen WR [1940]. Toxicity and potential dangers of aliphatic and aromatic hydrocarbons. A critical review of the literature. Public Health Bulletin 255:25.