# NIOSH Pocket Guide to Chemical Hazards
Calcium sulfate | CAS 7778-18-9
CaSO4 | RTECS WS6920000
Synonyms & Trade Names Anhydrous calcium sulfate, Anhydrous gypsum, Anhydrous sulfate of lime, Calcium salt of sulfuric acid [Note: Gypsum is the dihydrate form & 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 Odorless, white powder or colorless, crystalline solid. [Note: May have blue, gray, or reddish tinge.]
MW: 136.1 | BP: Decomposes | MLT: 2840°F (Decomposes) | Sol: 0.3%
VP: 0 mmHg (approx) | IP: NA |  | Sp.Gr: 2.96
Fl.P: NA | UEL: NA | LEL: NA |
Noncombustible Solid
Incompatibilities & Reactivities Diazomethane, aluminum, phosphorus, water [Note: Hygroscopic (i.e., absorbs moisture from the air). Reacts with water to form Gypsum & Plaster of Paris.]
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 Skin: Soap wash Breathing: Fresh air
Respirator Recommendations To be added later
Exposure Routes inhalation, skin and/or eye contact
Symptoms Irritation eyes, skin, upper respiratory system; conjunctivitis; rhinitis, epistaxis (nosebleed)
Target Organs Eyes, skin, respiratory system
See also: INTRODUCTION