Acetonitrile

CAS number: 75-05-8

NIOSH REL: 20 ppm (34 mg/m3) TWA

Current OSHA PEL: 40 ppm (70 mg/m3) TWA

1989 OSHA PEL: 40 ppm (70 mg/m3 TWA), 60 ppm (105 mg/m3) STEL

1993-1994 ACGIH TLV: 40 ppm (67 mg/m3) TWA, 60 ppm (101 mg/m3) STEL

Description of substance: Colorless liquid with an aromatic odor.

LEL: 3.0% (10% LEL, 3,000 ppm)

Original (SCP) IDLH: 4,000 ppm

Basis for original (SCP) IDLH: The chosen IDLH is based on the UCC [1965] report that a 4-hour exposure to 4,000 ppm killed 3 of 30 rats, 8,000 ppm killed 10 of 30 rats, and 16,000 ppm killed 17 of 30 rats. It is also based on the statement by AIHA [1960] that some deaths occurred in rats, dogs, and guinea pigs at 4,000 ppm, but no deaths occurred at 1,000 ppm. Pozzani et al. [1959] reported that a 53,000 ppm exposure was lethal to 3 of 6 rats in 30 minutes.

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
G. pig	Pozzani et al. 1959	5,655	-----	4 hr	11,310 ppm (2.0)	1,131 ppm
Dog	Pozzani et al. 1959	-----	16,000	4 hr	32,000 ppm (2.0)	3,200 ppm
Rabbit	Pozzani et al. 1959	2,828	-----	4 hr	5,656 ppm (2.0)	566 ppm
Rat	Pozzani et al. 1959	53,000	-----	30 min	53,000 ppm (1.0)	5,300 ppm
Rat	Pozzani et al. 1959	7,500	-----	8 hr	18,750 ppm (2.5)	1,875 ppm
Mouse	Willhite 1981	2,693	-----	1 hr	3,366 ppm (1.25)	337 ppm

Human data: Exposures to 160 ppm for 4 hours has caused flushing of the face and a feeling of constriction in the chest; exposures to 500 ppm for brief (undefined) time periods has resulted in only irritation to the nose and throat [Deichmann and Gerarde 1969].

Revised IDLH: 500 ppm Basis for revised IDLH: The revised IDLH for acetonitrile is 500 ppm based on acute inhalation toxicity data in humans [Deichmann and Gerarde 1969]. This may be a conservative value due to the lack of relevant acute toxicity data for workers exposed to concentrations above 500 ppm.

REFERENCES:

1. AIHA [1960]. Acetonitrile. In: Hygienic guide series. Am Ind Hyg Assoc J 21:265-266.
2. Deichmann WB, Gerarde HW [1969]. Acetonitrile (methyl cyanide; ethanenitrile). In: Toxicology of drugs and chemicals. New York, NY: Academic Press, Inc., p. 65.
3. Pozzani UC, Carpenter CP, Palm PE, Weil CS, Nair JH III [1959]. An investigation of the mammalian toxicity of acetonitrile. J Occup Med 1:634-642.
4. UCC [1965]. Toxicology studies: acetonitrile. New York, NY: Union Carbide Corporation.
5. Willhite CC [1981]. Inhalation toxicology of acute exposure to aliphatic nitriles. Clin Toxicol 18(8):991-1003.