# NIOSH Pocket Guide to Chemical Hazards
Magnesium oxide fume | CAS 1309-48-4
MgO | RTECS OM3850000
Synonyms & Trade Names Magnesia fume | DOT ID & Guide
Exposure Limits | NIOSH REL: See Appendix D
OSHA PEL†: TWA 15 mg/m3
IDLH 750 mg/m3 | Conversion
Physical Description Finely divided white particulate dispersed in air. [Note: Exposure may occur when magnesium is burned, thermally cut, or welded upon.]
MW: 40.3 | BP: 6512°F | MLT: 5072°F | Sol(86°F): 0.009%
VP: 0 mmHg (approx) | IP: NA |  | Sp.Gr: 3.58
Fl.P: NA | UEL: NA | LEL: NA |
Noncombustible Solid
Incompatibilities & Reactivities Chlorine trifluoride, phosphorus pentachloride
Measurement Methods NIOSH 7300; OSHA ID121
Personal Protection & Sanitation Skin: No recommendation Eyes: No recommendation Wash skin: No recommendation Remove: No recommendation Change: No recommendation | First Aid (See procedures) Breathing: Respiratory support
Respirator Recommendations OSHA Up to 150 mg/m3: (APF = 10) Any dust, mist, and fume respirator/(APF = 10) Any supplied-air respirator Up to 375 mg/m3: (APF = 25) Any supplied-air respirator operated in a continuous-flow mode/(APF = 25) Any powered, air-purifying respirator with a dust, mist, and fume filter Up to 750 mg/m3: (APF = 50) Any air-purifying, full-facepiece respirator with a high-efficiency particulate filter/(APF = 50) Any powered, air-purifying respirator with a tight-fitting facepiece and a high-efficiency particulate filter*/(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 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, skin and/or eye contact
Symptoms Irritation eyes, nose; metal fume fever: cough, chest pain, flu-like fever
Target Organs Eyes, respiratory system
See also: INTRODUCTION