# NIOSH Pocket Guide to Chemical Hazards
Selenium | CAS 7782-49-2
Se | RTECS VS7700000
Synonyms & Trade Names Elemental selenium, Selenium alloy | DOT ID & Guide 2658 152 (powder)
Exposure Limits | NIOSH REL*: TWA 0.2 mg/m3 [*Note: The REL also applies to other selenium compounds (as Se) except Selenium hexafluoride.]
OSHA PEL*: TWA 0.2 mg/m3 [*Note: The PEL also applies to other selenium compounds (as Se) except Selenium hexafluoride.]
IDLH 1 mg/m3 (as Se) | Conversion
Physical Description Amorphous or crystalline, red to gray solid. [Note: Occurs as an impurity in most sulfide ores.]
MW: 79.0 | BP: 1265°F | MLT: 392°F | Sol: Insoluble
VP: 0 mmHg (approx) | IP: NA |  | Sp.Gr: 4.28
Fl.P: NA | UEL: NA | LEL: NA |
Combustible Solid
Incompatibilities & Reactivities Acids, strong oxidizers, chromium trioxide, potassium bromate, cadmium
Measurement Methods NIOSH 7300, S190 (II-7); OSHA ID121
Personal Protection & Sanitation Skin: Prevent skin contact Eyes: No recommendation Wash skin: When contaminated Remove: When wet or contaminated Change: No recommendation Provide: Quick drench | First Aid (See procedures) Eye: Irrigate immediately Skin: Soap wash immediately Breathing: Respiratory support Swallow: Medical attention immediately
Respirator Recommendations NIOSH/OSHA Up to 1 mg/m3: (APF = 5) Any dust and mist respirator^*/(APF = 10) Any dust, mist, and fume respirator*/(APF = 50) Any air-purifying, full-facepiece respirator with a high-efficiency particulate filter/(APF = 25) Any powered, air-purifying respirator with a dust and mist filter^*/(APF = 25) Any powered, air-purifying respirator with a dust, mist, and fume filter*/(APF = 10) Any supplied-air respirator*/(APF = 50) Any self-contained breathing apparatus 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 Escape: (APF = 50) Any air-purifying, full-facepiece respirator with a high-efficiency particulate filter/Any appropriate escape-type, self-contained breathing apparatus
Exposure Routes inhalation, ingestion, skin and/or eye contact
Symptoms Irritation eyes, skin, nose, throat; visual disturbance; headache; chills, fever; dyspnea (breathing difficulty), bronchitis; metallic taste, garlic breath, gastrointestinal disturbance; dermatitis; eye, skin burns; in animals: anemia; liver necrosis, cirrhosis; kidney, spleen damage
Target Organs Eyes, skin, respiratory system, liver, kidneys, blood, spleen
See also: INTRODUCTION