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May 1994
Immediately Dangerous to Life or Health Concentrations (IDLH)

CAS number: 591–78–6

NIOSH REL: 1 ppm (4 mg/m3) TWA

Current OSHA PEL: 100 ppm (410 mg/m3) TWA

1989 OSHA PEL: 5 ppm (20 mg/m3) TWA

1993-1994 ACGIH TLV: 5 ppm (20 mg/m3) TWA

Description of Substance: Colorless liquid with an acetone-like odor.

LEL:. . Unknown

Original (SCP) IDLH: 5,000 ppm

Basis for original (SCP) IDLH: The chosen IDLH is based on the statements by AIHA [1968] that guinea pigs exposed to 6,000 ppm showed signs of beginning narcosis at 30 minutes and deep anesthesia at the end of 1 hour; death did not occur for 6.5 hours at this concentration [Specht et al. 1940]. Also, AIHA [1968] reported that 8,000 ppm killed all rats during a 4-hour exposure [Smyth et al. 1954]. [Note: For “convenience”, an IDLH of 5,000 ppm (50 × the OSHA PEL) was originally chosen rather than 6,000 ppm.]

Short-term exposure guidelines: None developed


Lethal concentration data:

Species Reference LC50(ppm) LCLo(ppm) Time Adjusted 0.5-hrLC (CF) Derivedvalue
RatG. pig


NPIRI 1974Schrenk et al. 1936

Smyth et al. 1954


LC100: 8,000



4 hr70 min

4 hr

16,000 ppm (2.0)26,600 ppm (1.33)

16,000 ppm (2.0)

1,600 ppm2,600 ppm

1,600 ppm


Lethal dose data:

Species Reference Route LD50(mg/kg) LDLo(mg/kg) Adjusted LD Derived value
G. pigRat


Schrenk et al. 1936Smyth et al. 1954

Tanii et al. 1936







4,358 ppm1,538 ppm

4,089 ppm

436 ppm154 ppm

409 ppm


Other animal data: Narcosis occurs in guinea pigs after 30 minutes of exposure to 20,000 ppm [Schrenk et al. 1936].

Human data: Volunteers exposed to 1,000 ppm reported a strong odor and transient, moderate eye and nasal irritation [DiVencenzo et al. 1978].

Revised IDLH: 1,600 ppmBasis for revised IDLH: The revised IDLH for 2-hexanone is 1,600 ppm based on acute inhalation toxicity data in humans [DiVencenzo et al. 1978] and animals [NPIRI 1974; Smyth et al. 1954]. This may be a conservative value due to the lack of relevant acute toxicity data for workers exposed to concentrations above 1,000 ppm.



1. AIHA [1968]. 2-Hexanone. In: Hygienic guide series. Am Ind Hyg Assoc J 29:618-620.

2. DiVencenzo GD, Hamilton ML, Kaplan CJ, et al. [1978]. Studies on the respiratory uptake and excretion and the skin absorption of methyl n-butyl ketone in humans and dogs. Toxicol Appl Pharmacol 44:593-604.

3. NPIRI [1974]. Raw materials data handbook, physical and chemical properties, fire hazard and health hazard data. Vol. 1. Organic solvents. Bethlehem, PA: National Printing Ink Research Institute, p. 78.

4. Schrenk HH, Yant WP, Patty FA [1936]. Acute response of guinea pigs to vapors of some noncommercial organic compounds. X. Hexanone (methyl butyl ketone). Public Health Rep 51:624-631.

5. 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.

6. Specht H, Miller JW, Valaer PJ, Sayers RR [1940]. Acute response of guinea pigs to the inhalation of ketone vapors. Washington, DC: U.S. Government Printing Office, Federal Security Agency, U.S. Public Health Service, National Institute of Health Bulletin No, 176, pp. 1-66.

7. Tanii H, Tsuji H, Hashimoto K [1936]. Structure-toxicity relationship of monoketones. Toxicol Lett 30:13-17.