Skip directly to search Skip directly to A to Z list Skip directly to navigation Skip directly to page options Skip directly to site content


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

CAS number: 541–85–5

NIOSH REL: 25 ppm (130 mg/m3) TWA

Current OSHA PEL: 25 ppm (130 mg/m3) TWA

1989 OSHA PEL: Same as current PEL

1993-1994 ACGIH TLV: 25 ppm (131 mg/m3) TWA

Description of substance: Colorless liquid with a pungent odor.

LEL: . . Unknown

Original (SCP) IDLH: 3,000 ppm

Basis for original (SCP) IDLH: The chosen IDLH is based on the statement by Patty [1963] that 0 of 6 rats died, but 3 of 6 mice died when exposed for 4 hours to about 3,000 ppm [Shell 1958].

Short-term exposure guidelines: None developed


Lethal concentration data:

Species Reference LC50




Time Adjusted 0.5-hr


Derived value
Mouse Shell 1958 3,000 ----- 4 hr 6,000 ppm (2.0) 600 ppm
Rat Shell 1958 LC67: 6,000 ----- 8 hr 15,000 ppm (2.5) 1,500 ppm
Rat Shell 1961 ----- 3,484 8 hr 8,710 ppm (2.5) 871 ppm
Mouse Shell 1961 ----- 3,484 4 hr 6,968 ppm (2.0) 697 ppm

Other animal data: It has been reported that rats survived a 4-hour exposure to 3,000 ppm [Shell 1958].

Human data: Humans exposed to 25 ppm experienced irritation of the eyes and respiratory tract and detected a strong odor, while 100 ppm caused irritation of the mucous membranes, headache, and nausea which was too severe to tolerate for more than a few minutes [Clayton and Clayton 1981].

Revised IDLH: 100 ppm

Basis for revised IDLH: The revised IDLH for 5-methyl-3-heptanone is 100 ppm based on acute inhalation toxicity data in humans [Clayton and Clayton 1981].


1. Clayton GD, Clayton FE, eds. [1981]. Patty's industrial hygiene and toxicology. 3rd rev. ed. Vol. 2C. Toxicology. New York, NY: John Wiley & Sons, Inc., pp. 4767-4768.

2. Patty FA, ed. [1963]. Industrial hygiene and toxicology. 2nd rev. ed. Vol. II. Toxicology. New York, NY: Interscience Publishers, Inc., p. 1744.

3. Shell [1958]. Toxicity data sheet: SC 57-99. Houston, TX: Shell Chemical Corporation, Industrial Hygiene Bulletin Toxicity Data Sheet.

4. Shell [1961]. Unpublished report. Houston, TX: Shell Chemical Corporation, p. 6.