NIOSH Publication No. 2005-151:

NIOSH Pocket Guide to Chemical Hazards

September 2005

1,2,4-Trimethylbenzene

CAS
95-63-6

C6H3(CH3)3

RTECS
DC3325000
Synonyms & Trade Names

Asymmetrical trimethylbenzene, psi-Cumene, Pseudocumene [Note: hemimellitene is a mixture of the 1,2,3-isomer with up to 10% of related aromatics such as the 1,2,4-isomer.]
DOT ID & Guide

Exposure
Limits

NIOSH REL: TWA 25 ppm (125 mg/m3)
OSHA PEL: none
IDLH
N.D. See: IDLH INDEX
Conversion
1 ppm = 4.92 mg/m3
Physical Description
Clear, colorless liquid with a distinctive, aromatic odor.
MW: 120.2
BP: 337°F
FRZ: -77°F
Sol: 0.006%
VP(56°F): 1 mmHg
IP: 8.27 eV

Sp.Gr: 0.88
Fl.P: 112°F
UEL: 6.4%
LEL: 0.9%

Class II Flammable Liquid
Incompatibilities & Reactivities

Oxidizers, nitric acid
Measurement Methods
OSHA PV2091
See: NMAM or OSHA Methods
Personal Protection & Sanitation
(See protection)
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
Not available.
Important additional information about respirator selection
Exposure Routes
inhalation, ingestion, skin and/or eye contact
Symptoms
Irritation eyes, skin, nose, throat, respiratory system; bronchitis; hypochromic anemia; headache, drowsiness, fatigue, dizziness, nausea, incoordination; vomiting, confusion; chemical pneumonitis (aspiration liquid)
Target Organs
Eyes, skin, respiratory system, central nervous system, blood
See also: INTRODUCTION   See ICSC CARD: 1433