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

CAS number: 107–87–9

NIOSH REL: 150 ppm (530 mg/m3) TWA

Current OSHA PEL: 200 ppm (700 mg/m3) TWA

1989 OSHA PEL: 200 ppm (700 mg/m3) TWA, 250 ppm (875 mg/m3) STEL

1993-1994 ACGIH TLV: 200 ppm (705 mg/m3) TWA, 250 ppm (881 mg/m3) STEL

Description of substance: Colorless to water-white liquid with a characteristic acetone-like odor.

LEL: . . 1.5% (10% LEL, 1,500 ppm)

Original (SCP) IDLH: 5,000 ppm

Basis for original (SCP) IDLH: The chosen IDLH is based on the statement by Patty [1963] that the maximum concentration that caused no serious disturbances in guinea pigs in 1 hour was 5,000 ppm [Yant et al. 1936].

Short-term exposure guidelines: None developed


Lethal concentration data:

Species Reference LC50 (ppm) LCLo (ppm) Time Adjusted 0.5-hr LC (CF) Derived value
Rat Smyth et al. 1962 LC17: 2,000 ----- 4 hr 4,000 ppm (2.0) 400 ppm
Rat Smyth et al. 1962 LC100: 4,000 ----- 4 hr 8,000 ppm (2.0) 800 ppm
G. pig Yant et al. 1936 ----- 50,000 50 min 60,000 ppm (1.2) 6,000 ppm
G. pig Yant et al. 1936 ----- 13,000 5 hr 27,950 ppm (2.15) 2,795 ppm

Lethal dose data:

Species Reference Route LD50 (mg/kg) LDLo (mg/kg) Adjusted LD Derived value
Rat Clayton and Clayton 1982 oral 1,600 ----- 3,128 ppm 313 ppm
Mouse Clayton and Clayton 1982 oral 1,600 ----- 3,128 ppm 313 ppm

Human data: Exposure to a concentration of 1,500 ppm was associated with complaints of ocular and upper respiratory irritation [Yant et al. 1936].

Revised IDLH: 1,500 ppm

Basis for revised IDLH: The revised IDLH for 2-pentanone is 1,500 ppm based on acute inhalation toxicity data in humans [Yant et al. 1936]. This may be a conservative value due to the lack of relevant acute toxicity data for workers exposed to concentrations above 1,500 ppm. Also, this value is 10% of the lower explosive limit of 1.5%.


1. Clayton GD, Clayton FE, eds. [1982]. Patty's industrial hygiene and toxicology. 3rd rev. ed. Vol. 2A. Toxicology. New York: John Wiley & Sons, Inc., p. 4735.

2. Patty FA, ed. [1963]. Industrial hygiene and toxicology. 2nd rev. ed. Vol. II. Toxicology. New York, NY: Interscience Publishers, Inc., p. 1734.

3. Smyth HF Jr, Carpenter CP, Weil CS, Pozzani UC, Striegel JA [1962]. Range-finding toxicity data: list VI. AMA Arch Ind Hyg Occup Med 23:95-107.

4. Yant WP, Patty FA, Schrenk HH [1936]. Acute response of guinea pigs to vapors of some new commercial organic compounds. IX. Pentanone (methyl propyl ketone). Public Health Rep 51:392-399.