# NIOSH Pocket Guide to Chemical Hazards
Calcium hydroxide | CAS 1305-62-0
Ca(OH)2 | RTECS EW2800000
Synonyms & Trade Names Calcium hydrate, Caustic lime, Hydrated lime, Slaked lime | DOT ID & Guide
Exposure Limits | NIOSH REL: TWA 5 mg/m3
OSHA PEL: TWA 15 mg/m3 (total) 5 mg/m3 (resp)
IDLH N.D. | Conversion
Physical Description White, odorless powder. [Note: Readily absorbs CO2 from the air to form calcium carbonate.]
MW: 74.1 | BP: Decomposes | MLT: 1076°F (Decomposes) (Loses H2O) | Sol(32°F): 0.2%
VP: 0 mmHg (approx) | IP: NA |  | Sp.Gr: 2.24
Fl.P: NA | UEL: NA | LEL: NA |
Noncombustible Solid
Incompatibilities & Reactivities Maleic anhydride, phosphorus, nitroethane, nitromethane, nitroparaffins, nitropropane [Note: Attacks some metals.]
Measurement Methods NIOSH 7020; ID121
Personal Protection & Sanitation Skin: Prevent skin contact Eyes: Prevent eye contact Wash skin: When contaminated/Daily Remove: When wet or contaminated Change: Daily Provide: Eyewash, Quick drench | First Aid (See procedures) Eye: Irrigate immediately Skin: Soap flush immediately Breathing: Respiratory support Swallow: Medical attention immediately
Respirator Recommendations To be added later
Exposure Routes inhalation, ingestion, skin and/or eye contact
Symptoms Irritation eyes, skin, upper respiratory system; eye, skin burns; skin vesiculation; cough, bronchitis, pneumonitis
Target Organs Eyes, skin, respiratory system
See also: INTRODUCTION