Isobutyl acetate

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.