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Isophorone
May 1994
Immediately Dangerous to Life or Health Concentrations (IDLH)
CAS number: 78–59–1
NIOSH REL: 4 ppm (23 mg/m3) TWA
Current OSHA PEL: 25 ppm (140 mg/m3) TWA
1989 OSHA PEL: 4 ppm (23 mg/m3) TWA
1993-1994 ACGIH TLV: 5 ppm (28 mg/m3) CEILING
Description of substance: Colorless to white liquid with a peppermint-like odor.
LEL:. . 0.8% (10% LEL, 800 ppm)
Original (SCP) IDLH: 800 ppm
Basis for original (SCP) IDLH: The chosen IDLH is based on the UCC [1971] report that exposure of animals for 1 hour to 880 ppm caused serious organ damage; only 1 of 6 animals died from an 8-hour exposure to air saturated with isophorone (approximately 525 ppm at 77°F).
Short-term exposure guidelines: None developed
ACUTE TOXICITY DATA:
Lethal concentration data:
| Species | Reference | LC50(ppm) | LCLo(ppm) | Time | Adjusted 0.5-hrLC (CF) | Derived value |
|---|---|---|---|---|---|---|
| Rat | ATSDR 1989 | —– | 885 | 6 hr | 2,036 ppm (2.3) | 204 ppm |
| G. pig | Marhold 1986 | 4,600 | —– | 8 hr | 11,500 ppm (2.5) | 1,150 ppm |
| Rat | Smyth & Seaton 1940 | —– | 1,840 | 4 hr | 3,680 ppm (2.0) | 368 ppm |
| Mammal | UCC 1971 | LC17: 525 | —– | 8 hr | 1,316 ppm (2.5) | 132 ppm |
Lethal dose data:
| Species | Reference | Route | LD50(mg/kg) | LDLo(mg/kg) | Adjusted LD | Derived value |
|---|---|---|---|---|---|---|
| Rat | Smyth et al. 1970 | oral | 2,330 | —– | 2,841 ppm | 284 ppm |
| Mouse | Smyth et al. 1970 | oral | 2,690 | —– | 3,280 ppm | 328 ppm |
Other animal data: RD50 (mouse), 27.8 ppm [DeCeaurriz et al. 1981]. It has been reported that exposure of animals for 1 hour to 880 ppm caused serious organ damage [UCC 1971].
Human data: A few of the 11 or 12 volunteers exposed for a few minutes to 200 or 400 ppm complained of nausea, headache, dizziness, faintness, inebriation, and a feeling of suffocation [Smyth and Seaton 1940].
| Revised IDLH: 200 ppmBasis for revised IDLH: The revised IDLH for isophorone is 200 ppm based on acute inhalation toxicity data in humans [Smyth and Seaton 1940] and animals [ATSDR 1989]. |
REFERENCES:
1. ATSDR [1989]. Toxicological profile for isophorone. Atlanta, GA: Agency for Toxic Substances and Disease Registry, ATSDR/TP-89/15.
2. DeCeaurriz JC, Micillino JC, Bonnet P, Guenier JP [1981]. Sensory irritation caused by various industrial airborne chemicals. Toxicol Lett 9:137-147.
3. Marhold J [1986]. Prehled Prumyslove Toxikologie, Organicke Latky. Prague, Czechoslovakia: Avicenum, p. 290 (in Czechoslovakian).
4. Smyth HF Jr, Seaton J [1940]. Acute response of guinea pigs and rats to inhalation of the vapors of isophorone. J Ind Hyg Toxicol 22(10):477-483.
5. Smyth HF Jr, Weil CS, West JS, Carpenter CP [1970]. An exploration of joint toxic action. II. Equitoxic versus equivolume mixtures. Toxicol Appl Pharmacol 17:498-503.
6. UCC [1971]. Toxicology studies: isophorone. New York, NY: Union Carbide Corporation.