# NIOSH Pocket Guide to Chemical Hazards
Trimellitic anhydride | CAS 552-30-7
C9H4O5 | RTECS DC2050000
Synonyms & Trade Names 1,2,4-Benzenetricarboxylic anhydride; 4-Carboxyphthalic anhydride; TMA; TMAN; Trimellic acid anhydride [Note: TMA is also a synonym for Trimethylamine.] | DOT ID & Guide
Exposure Limits | NIOSH REL: TWA 0.005 ppm (0.04 mg/m3) Should be handled in the workplace as an extremely toxic substance.
OSHA PEL†: none
IDLH N.D. | Conversion 1 ppm = 7.86 mg/m3
Physical Description Colorless solid.
MW: 192.1 | BP: ? | MLT: 322°F | Sol: ?
VP: 0.000004 mmHg | IP: ? |  | Sp.Gr: ?
Fl.P: NA | UEL: NA | LEL: NA |
Combustible Solid
Incompatibilities & Reactivities None reported
Measurement Methods NIOSH 5036; OSHA 98
Personal Protection & Sanitation Skin: Prevent skin contact Eyes: Prevent eye contact Wash skin: When contaminated Remove: When wet or contaminated Change: Daily | First Aid (See procedures) Eye: Irrigate immediately Skin: Soap wash Breathing: Respiratory support Swallow: Medical attention immediately
Respirator Recommendations To be added later
Exposure Routes inhalation, ingestion, skin and/or eye contact
Symptoms Irritation eyes, skin, nose, respiratory system; pulmonary edema, respiratory sensitization; rhinitis, asthma, cough, wheezing, dyspnea (breathing difficulty), malaise (vague feeling of discomfort), fever, muscle aches, sneezing
Target Organs Eyes, skin, respiratory system
See also: INTRODUCTION