NIOSH Pocket Guide to Chemical Hazards

1,3,5-Trimethylbenzene CAS 108-67-8
C6H3(CH3)3 RTECS OX6825000
Synonyms & Trade Names
Mesitylene, Symmetrical trimethylbenzene, sym-Trimethylbenzene
DOT ID & Guide
2325 129
NIOSH REL: TWA 25 ppm (125 mg/m3)
OSHA PEL†: none
IDLH N.D. Conversion 1 ppm = 4.92 mg/m3
Physical Description
Clear, colorless liquid with a distinctive, aromatic odor.
MW: 120.2
BP: 329°F
FRZ: -49°F
Sol: 0.002%
VP: 2 mmHg
IP: 8.39 eV

Sp.Gr: 0.86
Fl.P: 122°F
UEL: ?
LEL: ?

Class II Flammable Liquid
Incompatibilities & Reactivities
Oxidizers, nitric acid
Measurement Methods
None available
Personal Protection & Sanitation
Skin: Prevent skin contact
Eyes: Prevent eye contact
Wash skin: When contaminated
Remove: When wet or contaminated
Change: No recommendation

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, throat, respiratory system; bronchitis; hypochromic anemia; headache, drowsiness, lassitude (weakness, exhaustion), dizziness, nausea, incoordination; vomiting, confusion; chemical pneumonitis (aspiration liquid)
Target Organs Eyes, skin, respiratory system, central nervous system, blood