# NIOSH Pocket Guide to Chemical Hazards
Sodium hydroxide | CAS 1310-73-2
NaOH | RTECS WB4900000
Synonyms & Trade Names Caustic soda, Lye, Soda lye, Sodium hydrate | DOT ID & Guide 1823 154 (dry, solid) 1824 154 (solution)
Exposure Limits | NIOSH REL: C 2 mg/m3
OSHA PEL†: TWA 2 mg/m3
IDLH 10 mg/m3 | Conversion
Physical Description Colorless to white, odorless solid (flakes, beads, granular form).
MW: 40.0 | BP: 2534°F | MLT: 605°F | Sol: 111%
VP: 0 mmHg (approx) | IP: NA |  | Sp.Gr: 2.13
Fl.P: NA | UEL: NA | LEL: NA |
Noncombustible Solid, but when in contact with water may generate sufficient heat to ignite combustible materials.
Incompatibilities & Reactivities Water; acids; flammable liquids; organic halogens; metals such as aluminum, tin & zinc; nitromethane [Note: Corrosive to metals.]
Measurement Methods NIOSH 7401
Personal Protection & Sanitation Skin: Prevent skin contact Eyes: Prevent eye contact Wash skin: When contaminated Remove: When wet or contaminated Change: Daily Provide: Eyewash, Quick drench | First Aid (See procedures) Eye: Irrigate immediately Skin: Water flush immediately Breathing: Respiratory support Swallow: Medical attention immediately
Respirator Recommendations NIOSH/OSHA Up to 10 mg/m3: (APF = 25) Any supplied-air respirator operated in a continuous-flow mode£/(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 = 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, ingestion, skin and/or eye contact
Symptoms Irritation eyes, skin, mucous membrane; pneumonitis; eye, skin burns; temporary loss of hair
Target Organs Eyes, skin, respiratory system
See also: INTRODUCTION