Methylcyclohexane
May 1994
Immediately Dangerous to Life or Health Concentrations (IDLH)
CAS number: 108–87–2
NIOSH REL: 400 ppm (1,600 mg/m3) TWA
Current OSHA PEL: 500 ppm (2,000 mg/m3) TWA
1989 OSHA PEL: 400 ppm (1,600 mg/m3) TWA
1993-1994 ACGIH TLV: 400 ppm (1,610 mg/m3) TWA
Description of substance: Colorless liquid with a faint, benzene-like odor.
LEL:. . 1.2% (10% LEL, 1,200 ppm)
Original (SCP) IDLH: 10,000 ppm
Basis for original (SCP) IDLH: With no reported human toxicological data, the chosen IDLH is based on the statement by Browning [1965] that Treon et al. [1943] were able to produce light narcosis in mice at 10,054 ppm. Browning [1965] also reported that Lazarew [1929] found the narcotic dose for mice to be 7,500 to 10,000 ppm. ACGIH [1971] noted that this narcotic dose (7,500 to 10,000 ppm) was for a 2-hour exposure [Lazarew 1929; Treon et al. 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 |
| Mouse | Izmerov et al. 1982 | 10,172 | ----- | 2 hr | 16,275 ppm (1.6) | 1,268 ppm |
| Mouse | Lazarew 1929 | 10,000-12,500 | ----- | 2 hr | 16,000-20,000 ppm (1.6) | 1,600-2,000 ppm |
| Rabbit | Treon et al. 1943 | 15,227 | ----- | 1 hr | 19,034 ppm (1.25) | 1,903 ppm |
Lethal dose data:
| Species | Reference | Route | LD50 (mg/kg) | LDLo (mg/kg) | Adjusted LD | Derived value |
| Mouse | Izmerov et al. 1982 | oral | 2,250 | ----- | 3,860 ppm | 386 ppm |
Human data: None relevant for use in determining the revised IDLH.
| Revised IDLH: 1,200 ppm [LEL] Basis for revised IDLH: Based on health considerations and acute inhalation toxicity data in animals [Izmerov et al. 1982; Lazarew 1929; Treon et al. 1943], a value of about 1,600 ppm would have been appropriate for methylcyclohexane. However, the revised IDLH for methylcyclohexane is 1,200 ppm based strictly on safety considerations (i.e., being 10% of the lower explosive limit of 1.2%). |
REFERENCES:
1. ACGIH [1971]. Methylcyclohexane. In: Documentation of the threshold limit values for substances in workroom air. 3rd ed. Cincinnati, OH: American Conference of Governmental Industrial Hygienists, pp. 162-163.
2. Browning E [1965]. Toxicity and metabolism of industrial solvents. New York, NY: Elsevier Publishing Company, pp. 136-137.
3. Izmerov NF, Sanotsky IV, Sidorov KK [1982]. Toxicometric parameters of industrial toxic chemicals under single exposure. Moscow, Russia: Centre of International Projects, GKNT, p. 82.
4. Lazarew NW [1929]. Uber die giftigkeit verschiedener kohlenwasserstoffdampfe. Arch Exp Pathol Pharmakol 143:223-233 (in German).
5. Lazarew NW [1929]. Zur toxikologie des benzins (The toxicology of gasoline). Arch Hyg, pp. 228-239 (translated).
6. Treon JF, Crutchfield WE, Kitzmiller KV [1943]. 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.