# NIOSH Pocket Guide to Chemical Hazards
Gypsum | CAS 13397-24-5
CaSO4 • 2H2O | RTECS MG2360000
Synonyms & Trade Names Calcium(II) sulfate dihydrate, Gypsum stone, Hydrated calcium sulfate, Mineral white [Note: Gypsum is the dihydrate form of calcium sulfate; Plaster of Paris is the hemihydrate form.] | DOT ID & Guide
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)
IDLH N.D. | Conversion
Physical Description White or nearly white, odorless, crystalline solid.
MW: 172.2 | BP: ? | MLT: 262-325°F (Loses H2O) | Sol(77°F): 0.2%
VP: 0 mmHg (approx) | IP: NA |  | Sp.Gr: 2.32
Fl.P: NA | UEL: NA | LEL: NA |
Noncombustible Solid
Incompatibilities & Reactivities Aluminum (at high temperatures), diazomethane
Measurement Methods NIOSH 0500, 0600
Personal Protection & Sanitation Skin: No recommendation Eyes: No recommendation Wash skin: No recommendation Remove: No recommendation Change: No recommendation | First Aid (See procedures) Eye: Irrigate immediately Breathing: Fresh air
Respirator Recommendations To be added later
Exposure Routes inhalation, skin and/or eye contact
Symptoms Irritation eyes, skin, mucous membrane, upper respiratory system; cough, sneezing, rhinorrhea (discharge of thin mucus)
Target Organs Eyes, skin, respiratory system
See also: INTRODUCTION