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  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:
|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:
|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 ppm
Basis 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].
1. ATSDR . 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 . Sensory irritation caused by various industrial airborne chemicals. Toxicol Lett 9:137-147.
3. Marhold J . Prehled Prumyslove Toxikologie, Organicke Latky. Prague, Czechoslovakia: Avicenum, p. 290 (in Czechoslovakian).
4. Smyth HF Jr, Seaton J . 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 . An exploration of joint toxic action. II. Equitoxic versus equivolume mixtures. Toxicol Appl Pharmacol 17:498-503.
6. UCC . Toxicology studies: isophorone. New York, NY: Union Carbide Corporation.