NIOSH Publication No. 2005-151:

NIOSH Pocket Guide to Chemical Hazards

September 2005

Hydrogen selenide



Synonyms & Trade Names

Selenium dihydride, Selenium hydride
DOT ID & Guide
2202 / 117 (anhydrous)


NIOSH REL: TWA 0.05 ppm (0.2 mg/m3)
OSHA PEL: TWA 0.05 ppm (0.2 mg/m3)
1 ppm See: 7783075
1 ppm = 3.31 mg/m3
Physical Description
Colorless gas with an odor resembling decayed horseradish. [Note: Shipped as a liquefied compressed gas.]
MW: 81.0
BP: -42°F
FRZ: -87°F
Sol(73°F): 0.9%
VP(70°F): 9.5 atm
IP: 9.88 eV
RGasD: 2.80

Fl.P: NA (Gas)
UEL: ?
LEL: ?

Flammable Gas
Incompatibilities & Reactivities

Strong oxidizers, acids, water, halogenated hydrocarbons
Measurement Methods
None available
See: NMAM or OSHA Methods
Personal Protection & Sanitation
(See protection)
Skin: Frostbite
Eyes: Frostbite
Wash skin: No recommendation
Remove: When wet (flammable)
Change: No recommendation
Provide: Frostbite wash
First Aid
(See procedures)
Eye: Frostbite
Skin: Frostbite
Breathing: Respiratory support

Respirator Recommendations
Up to 0.5 ppm:
(APF = 10) Any supplied-air respirator
Up to 1 ppm:
(APF = 25) Any supplied-air respirator operated in a continuous-flow mode*
(APF = 50) Any self-contained breathing apparatus with a full facepiece
(APF = 50) Any supplied-air respirator with a full facepiece
Emergency or planned entry into unknown concentrations or IDLH conditions:
(APF = 10,000) Any self-contained breathing apparatus that has a full facepiece and is operated in a pressure-demand or other positive-pressure mode
(APF = 10,000) Any supplied-air respirator that has a full facepiece and is operated in a pressure-demand or other positive-pressure mode in combination with an auxiliary self-contained positive-pressure breathing apparatus
(APF = 50) Any air-purifying, full-facepiece respirator (gas mask) with a chin-style, front- or back-mounted canister providing protection against the compound of concern/Any appropriate escape-type, self-contained breathing apparatus
Important additional information about respirator selection
Exposure Routes
inhalation, skin and/or eye contact
Irritation eyes, nose, throat; nausea, vomiting, diarrhea; metallic taste, garlic breath; dizziness, lassitude (weakness, exhaustion); liquid: frostbite; in animals: pneumonitis; liver damage
Target Organs
Eyes, respiratory system, liver
See also: INTRODUCTION   See ICSC CARD: 0284