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
|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:
|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%).
1. ACGIH . 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. . Patty’s industrial hygiene and toxicology. 3rd rev. ed. Vol. 2A. Toxicology. New York, NY: John Wiley & Sons, Inc., p. 2273.
3. Munch JC . Aliphatic alcohols and alkyl esters: narcotic and lethal potencies to tadpoles and to rabbits. Ind Med 41:31-33.
4. NPIRI . 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 . Private communication. [From ACGIH . 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 . Range-finding toxicity data: list VI. Am Ind Hyg Assoc J 23:95-107.6
7. UCC . Toxicology studies: isobutyl acetate. New York, NY: Union Carbide Corporation.