Agent Name

Trimethyl benzene isomers

CAS Number

25551-13-7; 526-73-8; 95-63-6; 108-67-8

Formula

C9-H12

Major Category

Solvents

Synonyms

Mesitylene; Symmetrical trimethylbenzene; sym-Trimethylbenzene; Assymetrical trimethylbenzene; psi-Cumene; Pseudocumene; Hemimellitene; Hemelitol; [NIOSH] Methylxylene; Trimethyl benzene; Benzene, trimethyl-; Benzene, trimethyl- (mixed isomers); Trimethylbenzenes; [ChemIDplus] 1,2,3-Trimethylbenzene; 1,2,4-Trimethylbenzene; 1,3,5-Trimethylbenzene; [Hawley] UN1993; UN2325 (1,3,5-Trimethylbenzene)

Category

Aromatic Solvents

Description

Clear, colorless liquid with a distinctive, aromatic odor; [NIOSH]

Sources/Uses

Used in the synthesis of organic chemicals; also used in plastics as an ultraviolet stabilizer and in solvents; [ACGIH]

Comments

Hemimellitene is a mixture of the 1,2,3-isomer with up to 10% of related aromatics such as the 1,2,4-isomer. Hemelitol is the 1,2,3-isomer. [NIOSH] A skin, eye, and respiratory tract irritant; Inhalation of high concentrations may cause CNS effects; [ICSC] "Some of the reported blood dyscrasias may have been due to contamination of the trimethyl benzene with benzene." Systemic intoxication after skin absorption is unlikely; [ACGIH]

Exposure Assessment
Skin Designation (ACGIH)

Insufficient data

TLV (ACGIH)

25 ppm, mixed isomers

MAK

20 ppm

Vapor Pressure

2.1 mm Hg

Odor Threshold Low

0.006 ppm

Odor Threshold High

2.4 ppm

Explanatory Notes

Detection odor threshold from AIHA (mean = 2.4 ppm and 2.2 ppm respectively for 1,2,4-trimethyl benzene and 1,3,5-trimethyl benzene); The Guide from the Emergency Response Guidebook is for "1,3,5-Trimethylbenzene."

Adverse Effects
Neurotoxin

CNS Solvent Syndrome

Links to Other NLM Databases
Health Studies

Human Health Effects from Hazardous Substances Data Bank:

Toxicity Information

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Chemical Information

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Related Information in HazMap
Diseases

Occupational diseases associated with exposure to this agent: