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