Isophorone

IDLH Documentation
CAS number: 78­59­1

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

1993­1994 ACGIH TLV: 5 ppm (28 mg/m3) CEILING

Description of substance: Colorless to white liquid with a peppermint­like 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 8­hour exposure to air saturated with isophorone (approximately 525 ppm at 77°F).

Short­term 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
RatATSDR 1989
-----
885
6 hr
2,036 ppm (2.3)
204 ppm
G. pigMarhold 1986
4,600
-----
8 hr
11,500 ppm (2.5)
1,150 ppm
RatSmyth & Seaton 1940
-----
1,840
4 hr
3,680 ppm (2.0)
368 ppm
MammalUCC 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
RatSmyth et al. 1970
oral
2,330
-----
2,841 ppm
284 ppm
MouseSmyth 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].

REFERENCES:

1. ATSDR [1989]. Toxicological profile for isophorone. Atlanta, GA: Agency for Toxic Substances and Disease Registry, ATSDR/TP­89/15.

2. DeCeaurriz JC, Micillino JC, Bonnet P, Guenier JP [1981]. Sensory irritation caused by various industrial airborne chemicals. Toxicol Lett 9:137­147.

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):477­483.

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 17:498­503.

6. UCC [1971]. Toxicology studies: isophorone. New York, NY: Union Carbide Corporation.


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