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

CAS number: 25639–42–3

NIOSH REL: 50 ppm (235 mg/m3) TWA

Current OSHA PEL: 100 ppm (470 mg/m3) TWA

1989 OSHA PEL: 50 ppm (235 mg/m3) TWA

1993-1994 ACGIH TLV: 50 ppm (234 mg/m3) TWA

Description of substance: Straw-colored liquid with a weak odor like coconut oil.

LEL:. . Unknown

Original (SCP) IDLH: 10,000 ppm

Basis for original (SCP) IDLH: No data on acute inhalation toxicity are available on which to base the IDLH for methylcyclohexanol. The chosen IDLH, therefore, has been estimated from the rabbit oral lethal dose of 1.75 to 2.0 g/kg [Treon et al. 1943 cited by Browning 1965]. Because this compound has such a low vapor pressure, a concentration this great can only be achieved if the substance is heated.

Short-term exposure guidelines: None developed


Lethal dose data:

Species Reference Route LD50




Adjusted LD Derived value
Rat Deichmann & LeBlanc 1943 oral 1,660 ----- 2,446 ppm 245 ppm
Rabbit Treon et al. 1943a oral ----- 1,750-2,000 2,579-2,947 ppm 258-295 ppm

Other animal data: Rabbits exposed for 6 hours/day, 5 days/week for 10 weeks at 503 ppm had increased salivation, conjunctival irritation, and slight lethargy, while 232 ppm caused no such signs of intoxication [Treon et al. 1943b].

Human data: None relevant for use in determining the revised IDLH.

Revised IDLH: 500 ppm

Basis for revised IDLH: The revised IDLH for methylcyclohexanol is 500 ppm based on subchronic inhalation data in animals [Treon et al. 1943b]. This may be a conservative value due to the lack of relevant acute inhalation toxicity data for workers.


1. Browning E [1965]. Toxicity and metabolism of industrial solvents. New York, NY: Elsevier Publishing Company, p. 372.

2. Deichmann WB, LeBlanc TJ [1943]. Determination of the approximate lethal dose with about six animals. J Ind Hyg Toxicol 25(9):415-417.

3. Treon JF, Crutchfield WE Jr, Kitzmiller KV [1943a]. 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.

4. Treon JF, Crutchfield WE, Kitzmiller KV [1943b]. The physiological response of animals to cyclohexane, methyl cyclohexane, and certain derivatives of these compounds. II. Inhalation. J Ind Hyg Toxicol 25(8):323-347.