Immediately Dangerous to Life or Health Concentrations (IDLH)
CAS number: 123–91–1
NIOSH REL: 1 ppm (3.6 mg/m3) 30-minute CEILING; NIOSH considers dioxane to be a potential occupational carcinogen as defined by the OSHA carcinogen policy [29 CFR 1990].
Current OSHA PEL: 100 ppm (360 mg/m3) TWA [skin]
1989 OSHA PEL: 25 ppm (90 mg/m3) TWA [skin]
1993-1994 ACGIH TLV: 25 ppm (90 mg/m3) TWA [skin]
Description of Substance: Colorless liquid or solid (below 53 F) with a mild, ether-like odor.
LEL:. . 2.0% (10% LEL, 2,000 ppm)
Original (SCP) IDLH: 2,000 ppm
Basis for original (SCP) IDLH: The chosen IDLH is based on the acute inhalation toxicity data cited by AIHA  in which a lethal concentration of 1,000 to 3,000 ppm for 3 hours is reported for guinea pigs, and on the lethal concentration of 2,085 ppm (8 hours) for mice [Klimmer 1937] reported by Spector . ACGIH  reported that guinea pigs could tolerate 2,000 ppm for several hours without serious symptoms [Yant et al. 1930]. Therefore, exposure of workers to 2,000 ppm for 30 minutes probably would not impede escape or cause any irreversible health effects.
Short-term exposure guidelines: None developed
ACUTE TOXICITY DATA
Lethal concentration data:
|Species||Reference||LC50(ppm)||LCLo(ppm)||Time||Adjusted 0.5-hrLC (CF)||Derivedvalue|
|AIHA 1960Izmerov et al. 1982
Kosm Biol Aviak Med 1977
|3 hr2 hr
|1,800-5,400 ppm (1.8)16,174 ppm (1.6)
28,853 ppm (2.4)
5,213 ppm (2.5)
20,109 ppm (1.6)
|180-540 ppm1,617 ppm
Other animal data: Guinea pigs can tolerate 2,000 ppm by inhalation for several hours without serious symptoms; higher concentrations produced eye, nose, and lung irritation [Yant et al. 1930].
Human data: None relevant for use in determining the revised IDLH.
|Revised IDLH: 500 ppmBasis for revised IDLH: The revised IDLH for dioxane is 500 ppm based on acute inhalation toxicity data in animals [AIHA 1960; Klimmer 1937]. [Note: NIOSH recommends as part of its carcinogen policy that the “most protective” respirators be worn for dioxane at concentrations above 1 ppm.]|
1. ACGIH . Dioxane. In: Documentation of the threshold limit values for substances in workroom air. 3rd ed. Cincinnati, OH: American Conference of Governmental Industrial Hygienists, p. 94.
2. AIHA . Dioxane. In: Hygienic guide series. Am Ind Hyg Assoc J 21:533-534.
3. Izmerov NF, Sanotsky IV, Sidorov KK . Toxicometric parameters of industrial toxic chemicals under single exposure. Moscow, Russia: Centre of International Projects, GKNT, p. 63.
4. Klimmer O . Dissertation: Beitrag zur toxikologischen wirkung technischer losungsmittel (in German). Germany: Pharmakologischen Institut der Universitat Wurzburg.
5. Kosm Biol Aviak Med ; 11(6):53-57 (in Russian).
6. Spector WS, ed. . Handbook of toxicology. Vol. I. Acute toxicities of solids, liquids and gases to laboratory animals. Philadelphia, PA: W.B. Saunders Co., pp. 334-335.
7. Yant WP, Schrenk HH, Patty FA, Waite CP . Acute response of guinea pigs to vapors of some new commercial organic compounds. VI. Dioxan. Public Health Rep 45(2):2023-2032.