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1,3,5-TRIMETHYLBENZENE ICSC: 1155
Date of Peer Review: March 2002

Mesitylene
CAS # 108-67-8 C9H12
RTECS # OX6825000 Molecular mass: 120.2
UN # 2325
EC # 601-025-00-5
TYPES OF HAZARD / EXPOSURE ACUTE HAZARDS / SYMPTOMS PREVENTION FIRST AID / FIRE FIGHTING
FIRE Flammable.
NO open flames, NO sparks, and NO smoking.
Alcohol-resistant foam, dry powder, carbon dioxide.
EXPLOSION Above 50C explosive vapour/air mixtures may be formed.
Above 50C use a closed system, ventilation, and explosion-proof electrical equipment. Prevent build-up of electrostatic charges (e.g., by grounding).
In case of fire: keep drums, etc., cool by spraying with water.
EXPOSURE
PREVENT GENERATION OF MISTS!

Inhalation Confusion. Cough. Dizziness. Drowsiness. Headache. Sore throat. Vomiting.
Ventilation, local exhaust, or breathing protection.
Fresh air, rest. Refer for medical attention.
Skin Redness. Dry skin.
Protective gloves.
Remove contaminated clothes. Rinse skin with plenty of water or shower.
Eyes Redness. Pain.
Safety spectacles.
First rinse with plenty of water for several minutes (remove contact lenses if easily possible), then take to a doctor.
Ingestion (See Inhalation).
Do not eat, drink, or smoke during work.
Rinse mouth. Do NOT induce vomiting. Refer for medical attention.
SPILLAGE DISPOSAL PACKAGING & LABELLING
Collect leaking and spilled liquid in sealable containers as far as possible. Absorb remaining liquid in sand or inert absorbent and remove to safe place. Do NOT wash away into sewer. Do NOT let this chemical enter the environment. Personal protection: filter respirator for organic gases and vapours.
Marine pollutant.
EU Classification
Symbol: Xi, N
R: 10-37-51/53
S: (2-)-61
UN Classification
UN Hazard Class: 3
UN Pack Group: III
EMERGENCY RESPONSE SAFE STORAGE
Transport Emergency Card: TEC (R)-30S2325
NFPA Code: H0; F2; R0
Fireproof. Separated from strong oxidants. Well closed. Keep in a well-ventilated room.
IPCS
International
Programme on
Chemical Safety
Prepared in the context of cooperation between the International Programme on Chemical Safety and the Commission of the European Communities IPCS, CEC 2004

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1,3,5-TRIMETHYLBENZENE ICSC: 1155
IMPORTANT DATA
PHYSICAL STATE; APPEARANCE:
COLOURLESS LIQUID, WITH CHARACTERISTIC ODOUR.

CHEMICAL DANGERS:
The substance decomposes on burning producing toxic and irritating fumes. Reacts violently with strong oxidants causing fire and explosion hazard.

OCCUPATIONAL EXPOSURE LIMITS:
TLV: 25 ppm as TWA; (ACGIH 2004).
MAK: (all isomers) 20 ppm, 100 mg/m; Peak limitation category: II(2); Pregnancy risk group: C; (DFG 2004).
ROUTES OF EXPOSURE:
The substance can be absorbed into the body by inhalation.

INHALATION RISK:
A harmful contamination of the air will be reached rather slowly on evaporation of this substance at 20C; on spraying or dispersing, however, much faster.

EFFECTS OF SHORT-TERM EXPOSURE:
The substance is irritating to the eyes, the skin and the respiratory tract. If this liquid is swallowed, aspiration into the lungs may result in chemical pneumonitis. The substance may cause effects on the central nervous system.

EFFECTS OF LONG-TERM OR REPEATED EXPOSURE:
The liquid defats the skin. Lungs may be affected by repeated or prolonged exposure, resulting in chronic bronchitis. The substance may have effects on the central nervous system and blood. See Notes.
PHYSICAL PROPERTIES
Boiling point: 165C
Melting point: -45C
Relative density (water = 1): 0.86
Solubility in water: very poor
Vapour pressure, kPa at 20C: 0.25
Relative vapour density (air = 1): 4.1
Relative density of the vapour/air-mixture at 20C (air = 1): 1.01
Flash point: 50C (c.c.)
Auto-ignition temperature: 550C
Octanol/water partition coefficient as log Pow: 3.42
ENVIRONMENTAL DATA
The substance is harmful to aquatic organisms. Bioaccumulation of this chemical may occur in fish.
NOTES
Use of alcoholic beverages enhances the harmful effect. Depending on the degree of exposure, periodic medical examination is suggested. See ICSC 1433 1,2,4-Trimethylbenzene (Pseudocumene), ICSC 1362 1,2,3-Trimethylbenzene (Hemimellitene), ICSC 1389 Trimethyl benzene (mixed isomers).
Card has been partly updated in April 2005. See section Occupational Exposure Limits.
ADDITIONAL INFORMATION


LEGAL NOTICE Neither the CEC nor the IPCS nor any person acting on behalf of the CEC or the IPCS is responsible for the use which might be made of this information
IPCS, CEC 2004