Methyl isobutyl carbinol

CAS number: 108–11–2

NIOSH REL: 25 ppm (100 mg/m³) TWA, 40 ppm (165 mg/m³) STEL [skin]

Current OSHA PEL: 25 ppm (100 mg/m³) TWA [skin]

1989 OSHA PEL: 25 ppm (100 mg/m³) TWA, 40 ppm (165 mg/m³) STEL [skin]

1993-1994 ACGIH TLV: 25 ppm (104 mg/m³) TWA, 40 ppm (167 mg/m³) STEL

Description of substance: Colorless liquid with a mild odor.

LEL: . . . 1.0% (10% LEL, 1,000 ppm)

Original (SCP) IDLH: 2,000 ppm

Basis for original (SCP) IDLH: The chosen IDLH is based on the statements by Browning [1965] and Patty [1963] that exposures for 8 hours to 2,000 ppm killed 5 of 6 rats, but no rats died from a 2-hour exposure to the saturated vapor [Smyth et al. 1951].

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	Browning 1965	LC83: 2,000	-----	8 hr	5,000 ppm (2.5)	500 ppm
Rat	Carpenter et al. 1949	2,000	-----	4 hr	4,000 ppm (2.0)	400 ppm
Mouse	McOmie & Anderson 1949	LC60: 4,600	-----	10 hr	12,420 ppm (2.7)	1,242 ppm

Lethal dose data:

Species	Reference	Route	LD50 (mg/kg)	LDLo (mg/kg)	Adjusted LD	Derived value
Mouse Rat	McOmie &Anderson 1949 Smyth et al. 1951	oral oral	----- 2,590	1,000 -----	1,647 ppm 4,266 ppm	165 ppm 427 ppm

Other animal data: It has been reported that rats survived a 2-hour exposure to the saturated vapor (about 4,000 ppm at 68°F) [Smyth et al. 1951].

Human data: Eye irritation has occurred after exposures to 50 ppm for 15 minutes [Silverman et al. 1946].

Revised IDLH: 400 ppm Basis for revised IDLH: The revised IDLH for methyl isobutyl carbinol is 400 ppm based on acute inhalation toxicity data in animals [Browning 1965; Carpenter et al. 1949]. This may be a conservative value due to the lack of relevant acute toxicity data for workers exposed to concentrations above 50 ppm.

REFERENCES:

1. Browning E [1965]. Toxicity and Metabolism of Industrial Solvents. New York, NY: Elsevier Publishing Company, p. 369.

2. Carpenter CP, Smyth HF Jr, Pozzani UC [1949]. The assay of acute vapor toxicity, and the grading and interpretation of results on 96 chemical compounds. J Ind Hyg Toxicol 31:343-346.

3. McOmie WA, Anderson HH [1949]. Comparative toxicologic effects of some isobutyl carbinols and ketones. University of California Publication, Pharmacology 2:217-230.

4. Patty FA, ed. [1963]. Industrial hygiene and toxicology. 2nd rev. ed. Vol. II. Toxicology. New York, NY: Interscience Publishers, Inc., p. 1460.

5. Silverman L, Schulte HF, First MW [1946]. Further studies on sensory response to certain industrial solvent vapors. J Ind Hyg Toxicol 28:262-266.

6. Smyth HF Jr, Carpenter CP, Weil CS [1951]. Range-finding toxicity data: list IV. AMA Arch Ind Hyg Occup Med 4:119-122.