NIOSH Pocket Guide to Chemical Hazards

Acetylsalicyclic acid

CAS 50-78-2


RTECS VO0700000
Synonyms & Trade Names
o-Acetoxybenzoic acid, 2-Acetoxybenzoic acid, Aspirin
DOT ID & Guide


NIOSH REL: TWA 5 mg/m3
OSHA PEL†: none
IDLH N.D. See: IDLH INDEX Conversion
Physical Description
Odorless, colorless to white, crystal-line powder. [aspirin] [Note: Develops the vinegar-like odor of acetic acid on contact with moisture.]
MW: 180.2
BP: 284°F (Decomposes)
MLT: 275°F
Sol(77°F): 0.3%
VP: 0 mmHg (approx)

Sp.Gr: 1.35
Fl.P: NA
MEC: 40 g/m3
Combustible Powder; explosion hazard if dispersed in air.
Incompatibilities & Reactivities
Solutions of alkali hydroxides or carbonates, strong oxidizers, moisture [Note: Slowly hydrolyzes in moist air to salicyclic & acetic acids.]
Measurement Methods
NIOSH 0500
See: NMAM or OSHA Methods
Personal Protection & Sanitation (See protection)
Skin: Prevent skin contact
Eyes: Prevent eye contact
Wash skin: When contaminated
Remove: No recommendation
Change: Daily
Provide: Eyewash, Quick drench
First Aid (See procedures)
Eye: Irrigate immediately
Skin: Soap wash
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; increased blood clotting time; nausea, vomiting; liver, kidney injury
Target Organs

Cancer Site Eyes, skin, respiratory system, blood, liver, kidneys
See also: INTRODUCTION   See ICSC CARD: 0822