Isobutyl acetate
May 1994
Immediately Dangerous to Life or Health Concentrations (IDLH)
CAS number: 110–19–0
NIOSH REL: 150 ppm (700 mg/m3) TWA
Current OSHA PEL: 150 ppm (700 mg/m3) TWA
1989 OSHA PEL: Same as current PEL
1993-1994 ACGIH TLV: 150 ppm (713 mg/m3) TWA
Description of substance: Colorless liquid with a fruity, floral odor.
LEL: . . 1.3% (10% LEL, 1,300 ppm)
Original (SCP) IDLH: 7,500 ppm
Basis for original (SCP) IDLH: The chosen IDLH is based on the following statements: a 4-hour exposure to 8,000 ppm killed 4 of 6 rats [UCC 1971; Smyth et al. 1962 as cited by ACGIH 1971] and no deaths resulted from a 4-hour exposure of 6 rats to 4,000 ppm [UCC 1971; Smyth 1964 as cited by ACGIH 1971]. [Note: For “convenience” an IDLH of 7,500 ppm (50 ´ the OSHA PEL of 150 ppm) was chosen rather than 8,000 ppm.]
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 |
| Mammal | Clayton & Clayton 1981 | LC100: 21,000 | ----- | 2.5 hr | 35,700 ppm (1.7) | 3,570 ppm |
| Rat | Smyth et al. 1962 | LC67: 8,000 | ----- | 4 hr | 16,000 ppm (2.0) | 1,600 ppm |
Lethal dose data:
| Species | Reference | Route | LD50 (mg/kg) |
LDLo (mg/kg) |
Adjusted LD | Derived value |
| Rabbit | Munch 1972 | oral | 4,673 | ----- | 6,772 ppm | 677 ppm |
| Rat | NPIRI 1974 | oral | 13,400 | ----- | 19,420 ppm | 1,942 ppm |
Other animal data: It was reported that no rats dies following a 4-hour exposure to 4,000 ppm [UCC 1971].
Human data: None relevant for use in determining the revised IDLH.
| Revised IDLH: 1,300 ppm [LEL] Basis for revised IDLH: Based on health considerations and acute inhalation toxicity data in animals [Smyth et al. 1962], a value of about 1,600 ppm would have been appropriate for isobutyl acetate. However, the revised IDLH for isobutyl acetate is 1,300 ppm based strictly on safety considerations (i.e., being 10% of the lower explosive limit of 1.3%). |
REFERENCES:
1. ACGIH [1971]. Isobutyl acetate. In: Documentation of the threshold limit values for substances in workroom air. 3rd ed. Cincinnati, OH: American Conference of Governmental Industrial Hygienists, p. 139.
2. Clayton GD, Clayton FE, eds. [1981]. Patty’s industrial hygiene and toxicology. 3rd rev. ed. Vol. 2A. Toxicology. New York, NY: John Wiley & Sons, Inc., p. 2273.
3. Munch JC [1972]. Aliphatic alcohols and alkyl esters: narcotic and lethal potencies to tadpoles and to rabbits. Ind Med 41:31-33.
4. NPIRI [1974]. Raw materials data handbook, physical and chemical properties, fire hazard and health hazard data. Vol. 1. Organic solvents. Bethlehem, PA: National Printing Ink Research Institute, p. 8.
5. Smyth HF Jr [1964]. Private communication. [From ACGIH [1971]. Isobutyl acetate. In: Documentation of the threshold limit values for substances in workroom air. 3rd ed. Cincinnati, OH: American Conference of Governmental Industrial Hygienists, p. 139.]
6. Smyth HF Jr, Carpenter CP, Weil CS, Pozzani UC, Striegel JA [1962]. Range-finding toxicity data: list VI. Am Ind Hyg Assoc J 23:95-107.6
7. UCC [1971]. Toxicology studies: isobutyl acetate. New York, NY: Union Carbide Corporation.