International Chemical Safety Cards MESITYL OXIDE ICSC: 0814 4-Methyl-3-penten-2-one Methyl isobutenyl ketone C6H10O / (CH3)2C=CHCOCH3 Molecular mass: 98.1 ICSC #    0814 CAS #     141-79-7 RTECS # SB4200000 UN #        1229 EC #         606-009-00-1 March 26, 1998 Peer reviewed TYPES OF HAZARD/ EXPOSURE ACUTE HAZARDS/ SYMPTOMS PREVENTION FIRST AID/ FIRE FIGHTING FIRE Flammable. NO open flames, NO sparks, and NO smoking. AFFF, alcohol-resistant foam, powder, carbon dioxide. EXPLOSION Above 25°C explosive vapour/air mixtures may be formed. Above 25°C use a closed system, ventilation, and explosion-proof electrical equipment. In case of fire: keep drums, etc., cool by spraying with water. EXPOSURE STRICT HYGIENE!  •INHALATION Cough. Dizziness. Dullness. Headache. Shortness of breath. Sore throat. Ventilation, local exhaust, or breathing protection. Fresh air, rest. Artificial respiration if indicated. Refer for medical attention.  •SKIN MAY BE ABSORBED! Dry skin. Redness. Pain (further see Inhalation). Protective gloves. Protective clothing. Remove contaminated clothes. Rinse and then wash skin with water and soap. Refer for medical attention.  •EYES Redness. Pain. Face shield, or eye protection in combination with breathing protection. First rinse with plenty of water for several minutes (remove contact lenses if easily possible), then take to a doctor.  •INGESTION Abdominal cramps (further see Inhalation). Do not eat, drink, or smoke during work. Rinse mouth. Give a slurry of activated charcoal in water to drink. Refer for medical attention. SPILLAGE DISPOSAL STORAGE PACKAGING & LABELLING Ventilation. Collect leaking liquid in sealable containers. Absorb remaining liquid in sand or inert absorbent and remove to safe place. Do NOT wash away into sewer. (Extra personal protection: self-contained breathing apparatus). Fireproof. Separated from strong oxidants. Cool. Keep in the dark. Xn symbol R: 10-20/21/22 S: 2-25 UN Hazard Class: 3 UN Packing Group: III SEE IMPORTANT INFORMATION ON BACK ICSC: 0814 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 MESITYL OXIDE ICSC: 0814 I M P O R T A N T D A T A PHYSICAL STATE; APPEARANCE: COLOURLESS VISCOUS LIQUID , WITH CHARACTERISTIC ODOUR. DARKENS ON STANDING. PHYSICAL DANGERS: CHEMICAL DANGERS: The substance can presumably form explosive peroxides. Reacts violently with strong oxidants. Attacks many plastics. OCCUPATIONAL EXPOSURE LIMITS: TLV: 15 ppm; 60 mg/m3 (as TWA); 25 ppm; 100 mg/m3 (as STEL) (ACGIH 1997). OSHA PEL: TWA 25 ppm (100 mg/m3) NIOSH REL: TWA 10 ppm (40 mg/m3) NIOSH IDLH: 1400 ppm LEL ROUTES OF EXPOSURE: The substance can be absorbed into the body by inhalation of its vapour, through the skin and by ingestion. INHALATION RISK: A harmful contamination of the air can be reached rather quickly on evaporation of this substance at 20°C. EFFECTS OF SHORT-TERM EXPOSURE: The substance irritates the eyes, the skin and the respiratory tract. Exposure far above OEL may result in unconsciousness. EFFECTS OF LONG-TERM OR REPEATED EXPOSURE: The liquid defats the skin. The substance may have effects on the liver, kidneys and lungs. PHYSICAL PROPERTIES Boiling point: 130°C Melting point: -41.5°C Relative density (water = 1): 0.865 Solubility in water, g/100 ml at 20°C: 3.3 (moderate) Vapour pressure, kPa at 20°C: 1.2 Relative vapour density (air = 1): 3.4 Relative density of the vapour/air-mixture at 20°C (air = 1): 1.03 Flash point: 25°C c.c. Auto-ignition temperature: 340°C Explosive limits, vol% in air: 1.4-7.2 Octanol/water partition coefficient as log Pow: 1.7 ENVIRONMENTAL DATA The substance is harmful to aquatic organisms. N O T E S Other melting points: -59°C. Use of alcoholic beverages enhances the harmful effect. Depending on the degree of exposure, periodic medical examination is indicated. Check for peroxides prior to distillation; eliminate if found. Transport Emergency Card: TEC (R)-130 NFPA Code: H3; F3; R0 ADDITIONAL INFORMATION ICSC: 0814 MESITYL OXIDE (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.