International Chemical Safety Cards 1,3,5-TRIMETHYLBENZENE ICSC: 1155 Mesitylene C9H12 Molecular mass: 120.2 ICSC #    1155 CAS #     108-67-8 RTECS # OX6825000 UN #        2325 EC #         601-025-00-5 March 06, 2002 Peer reviewed 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 50°C explosive vapour/air mixtures may be formed. Above 50°C 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 STORAGE 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. (Extra personal protection: filter respirator for organic gases and vapours.) Fireproof. Separated from strong oxidants. Well closed. Keep in a well-ventilated room. Marine pollutant. Xi symbol N symbol R: 10-37-51/53 S: 2-61 UN Hazard Class: 3 UN Packing Group: III SEE IMPORTANT INFORMATION ON BACK ICSC: 1155 Prepared in the context of cooperation between the International Programme on Chemical Safety & the Commission of the European Communities (C) IPCS CEC 1994. No modifications to the International version have been made except to add the OSHA PELs, NIOSH RELs and NIOSH IDLH values.

International Chemical Safety Cards 1,3,5-TRIMETHYLBENZENE ICSC: 1155 I M P O R T A N T D A T A PHYSICAL STATE; APPEARANCE: COLOURLESS LIQUID , WITH CHARACTERISTIC ODOUR. PHYSICAL DANGERS: 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 (as mixed isomers): 25 ppm; (ACGIH 2001). MAK (all isomers): 20 ppm; 100 mg/m3; class II 1 © (2001) OSHA PEL: none NIOSH REL: TWA 25 ppm (125 mg/m3) NIOSH IDLH: No data 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 20°C; 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: 165°C Melting point: -45°C Relative density (water = 1): 0.86 Solubility in water: very poor Vapour pressure, kPa at 20°C: 0.25 Relative vapour density (air = 1): 4.1 Relative density of the vapour/air-mixture at 20°C (air = 1): 1.01 Flash point: 50°C (c.c.) Auto-ignition temperature: 550°C 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. N O T E S Use of alcoholic beverages enhances the harmful effect. Depending on the degree of exposure, periodic medical examination is indicated. See ICSC 1433 1,2,4-Trimethylbenzene (Pseudocumene), ICSC 1362 1,2,3-Trimethylbenzene (Hemimellitene), ICSC 1389 Trimethyl benzene (mixed isomers). Transport Emergency Card: TEC (R)-30S2325 NFPA Code: H0; F2; R0 ADDITIONAL INFORMATION ICSC: 1155 1,3,5-TRIMETHYLBENZENE (C) IPCS, CEC, 1994

IMPORTANT LEGAL NOTICE: Neither NIOSH, the CEC or the IPCS nor any person acting on behalf of NIOSH, the CEC or the IPCS is responsible for the use which might be made of this information. This card contains the collective views of the IPCS Peer Review Committee and may not reflect in all cases all the detailed requirements included in national legislation on the subject. The user should verify compliance of the cards with the relevant legislation in the country of use. The only modifications made to produce the U.S. version is inclusion of the OSHA PELs, NIOSH RELs and NIOSH IDLH values.