NIOSH Pocket Guide to Chemical Hazards

Calcium hydroxide

CAS 1305-62-0


RTECS EW2800000
Synonyms & Trade Names
Calcium hydrate, Caustic lime, Hydrated lime, Slaked lime
DOT ID & Guide


NIOSH REL: TWA 5 mg/m3
OSHA PEL: TWA 15 mg/m3 (total) 5 mg/m3 (resp)
IDLH N.D. See: IDLH INDEX 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)

Sp.Gr: 2.24
Fl.P: NA

Noncombustible Solid
Incompatibilities & Reactivities
Maleic anhydride, phosphorus, nitroethane, nitromethane, nitroparaffins, nitropropane [Note: Attacks some metals.]
Measurement Methods
NIOSH 7020; OSHA ID121
See: NMAM or OSHA Methods
Personal Protection & Sanitation (See protection)
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
Important additional information about respirator selection
Respirator Recommendations Not available.
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   See ICSC CARD: 0408