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Plaster of Paris

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Synonyms & Trade Names
Calcium sulfate hemihydrate, Dried calcium sulfate, Gypsum hemihydrate, Hemihydrate gypsum [Note: Plaster of Paris is the hemihydrate form of Calcium Sulfate & Gypsum is the dihydrate form.]
CAS No.
26499-65-0
RTECS No.
TP0700000
DOT ID & Guide
Formula
CaSO4 • 0.5H2O
Conversion
IDLH
N.D.
See: IDLH INDEX
Exposure Limits
NIOSH REL
TWA 10 mg/m3 (total) TWA 5 mg/m3 (resp)
OSHA PEL
TWA 15 mg/m3 (total) TWA 5 mg/m3 (resp)
Measurement Methods
NIOSH 0500 , 0600
See: NMAM or OSHA Methods
Physical Description
White or yellowish, finely divided, odorless powder.
Molecular Weight
145.2
Boiling Point
?
Melting Point
325°F (Loses H2O)
Solubility
(77°F): 0.3%
Vapor Pressure
0 mmHg (approx)
Ionization Potential
NA
Specific Gravity
2.5
Flash Point
NA
Upper Explosive Limit
NA
Lower Explosive Limit
NA
Noncombustible Solid
Incompatibilities & Reactivities
Moisture, water [Note: Hygroscopic (i.e., absorbs moisture from the air). Reacts with water to form Gypsum.]
Exposure Routes
inhalation, ingestion, skin and/or eye contact
Symptoms
irritation eyes, skin, mucous membrane, respiratory system; cough
Target Organs
Eyes, skin, respiratory system
Personal Protection/Sanitation
(See protection codes)
Skin:No recommendation
Eyes:No recommendation
Wash skin:No recommendation
Remove:No recommendation
Change:No recommendation
First Aid
(See procedures)
Eye:Irrigate immediately

Breathing:Respiratory support
Swallow:Medical attention immediately
Respirator Recommendations

Not available.

Important additional information about respirator selection

See also
INTRODUCTION   ICSC CARD: 1217
Page last reviewed: October 30, 2019
Content source: National Institute for Occupational Safety and Health