Hydrogen selenide (as Se)

May 1994
Immediately Dangerous to Life or Health Concentrations (IDLH)

CAS number: 7783–07–5

NIOSH REL: 0.05 ppm (0.2 mg/m3) TWA

Current OSHA PEL: 0.05 ppm (0.2 mg/m3) TWA

1989 OSHA PEL: Same as current PEL

1993-1994 ACGIH TLV: 0.05 ppm (0.16 mg/m3) TWA

Description of Substance: Colorless gas with an odor resembling decayed horse radish.

LEL:. . Unknown

Original (SCP) IDLH: 2 ppm

Basis for original (SCP) IDLH: The chosen IDLH is based on the report by Dudley and Miller [1941] that “12.5% of the guinea pigs which had been exposed for 2 hours at 1.8 ppm (0.006 mg/l) died within 30 days of the exposure. A 4-hour exposure to 1.8 ppm was lethal to 18.8% of the guinea pigs exposed, and a 4-hour exposure to 2.1 ppm was lethal to 25% of the animals exposed.”

Short-term exposure guidelines: None developed


Lethal concentration data:

Species Reference LC50




Time Adjusted 0.5-hr


Derived value
G. pig Dudley and Miller 1941 ----- 0.3 8 hr 0.75 ppm (2.5) 0.08 ppm
G. pig Dudley and Miller 1941 LC19: 1.8 ----- 4 hr 3.6 ppm (2.0) 0.36 ppm
G. pig Dudley and Miller 1941 LC25: 2.1 ----- 4 hr 4.2 ppm (2.0) 0.42 ppm
G. pig Dudley and Miller 1941 LC13: 1.8 ----- 2 hr 2.9 ppm (1.6) 0.29 ppm
Rat Wilber 1980 ----- 5.9 1 hr 7.4 ppm (1.25) 0.74 ppm

Human data: Although very toxic, no fatalities have been reported, possibly because hydrogen selenide is easily oxidized to red selenium on the surface of mucous membranes of the nose and throat [Friberg et al. 1979]. Concentrations of 1.5 ppm have been found to be intolerable due to eye and nasal irritation [Dudley and Miller 1941].

Revised IDLH: 1 ppm

Basis for revised IDLH: The revised IDLH for hydrogen selenide is 1 ppm based on acute inhalation data in humans [Dudley and Miller 1941; Friberg et al. 1979].


1. Dudley HC, Miller JW [1941]. Toxicology of selenium. VI. Effects of subacute exposure to hydrogen selenide. J Ind Hyg Toxicol 23(10):470-477.

2. Friberg L, Nordberg GR, Vouk VB [1979]. Handbook on the toxicology of metals. New York, NY: Elsevier North Holland, p. 568.

3. Wilber CG [1980]. Toxicology of selenium: a review. Clin Toxicol 17(2):171-230.

Page last reviewed: December 4, 2014