o-Methylcyclohexanone
May 1994
Immediately Dangerous to Life or Health Concentrations (IDLH)
CAS number: 583–60–8
NIOSH REL: 50 ppm (230 mg/m3) TWA, 75 ppm 345 mg/m3) STEL [skin]
Current OSHA PEL: 100 ppm (460 mg/m3) TWA [skin]
1989 OSHA PEL: 50 ppm (230 mg/m3) TWA, 75 ppm (345 mg/m3) STEL [skin]
1993-1994 ACGIH TLV: 50 ppm (229 mg/m3) TWA, 75 ppm (344 mg/m3) STEL [skin]
Description of substance: Colorless liquid with a weak, peppermint-like odor.
LEL:. . . Unknown
Original (SCP) IDLH: 2,500 ppm
Basis for original (SCP) IDLH: The chosen IDLH is based on the statement by Patty [1963] that rabbits and cats exhibited sleepiness, respiratory irregularities, and poor coordination after a 1-hour exposure to 2,500 ppm; a 30-minute exposure to 3,500 ppm caused prostration in mice, guinea pigs, and rats [Gross as cited by Lehmann and Flury 1943].
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 |
| Rat | Smyth et al. 1969 | 2,800 | ----- | 4 hr | 5,600 ppm (2.0) | 560 ppm |
Lethal dose data:
| Species | Reference | Route | LD50 (mg/kg) |
LDLo (mg/kg) |
Adjusted LD | Derived value |
| Rat | Smyth et al. 1969 | oral | 2,140 | ----- | 3,215 ppm | 322 ppm |
| Rabbit | Treon et al. 1943 | oral | ----- | 1,000-1,250 | 1,502-1,878 ppm | 150-188 ppm |
Other animal data: Mice, guinea pigs, and rats exposed at 3,500 ppm for 30 minutes suffered irritation of the mucous membranes and exhibited signs of central nervous system depression [Clayton and Clayton 1981]. Rabbits and cats exhibited sleepiness, respiratory irregularities, and poor coordination after a 1-hour exposure to 2,500 ppm [Clayton and Clayton 1981].
Human data: None relevant for use in determining the revised IDLH.
| Revised IDLH: 600 ppm Basis for revised IDLH: The revised IDLH for o-methylcyclohexanone is 600 ppm based on acute inhalation toxicity data in animals [Smyth et al. 1969]. This may be a conservative value due to the lack of relevant acute inhalation toxicity data for workers. |
REFERENCES:
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. 4722-4723, 4782-4784.
2. Gross E [?]. Unpublished. [From Lehmann KB, Flury F, eds. [1943]. Toxicology and hygiene of industrial solvents. Translated by E. King and H.F. Smyth, Jr. Baltimore, MD: Williams & Wilkins Company, p. 247.]
3. Lehmann KB, Flury F, eds. [1943]. Toxicology and hygiene of industrial solvents. Translated by E. King and H.F. Smyth, Jr. Baltimore, MD: Williams & Wilkins Company, p. 247.
4. Patty FA, ed. [1963]. Industrial hygiene and toxicology. 2nd rev. ed. Vol. II. Toxicology. New York, NY: Interscience Publishers, Inc., p. 1770.
5. Smyth HF Jr, Carpenter CP, Weil CS, Pozzani UC, Striegel JA, Nycum JS [1969]. Range-finding toxicity data: list VII. Am Ind Hyg Assoc J 30(5):470-476.
6. Treon JF, Crutchfield WE Jr, Kitzmiller KV [1943]. The physiological response of rabbits to cyclohexane, methylcyclohexane, and certain derivatives of these compounds. I. Oral administration and cutaneous application. J Ind Hyg Toxicol 25(6):199-214.