International Chemical Safety Cards DIKETENE ICSC: 1280 But-3-en-3-olide 3-Buteno-beta-lactone 4-Methylene-2-oxetanone Acetyl ketene C4H4O2 Molecular mass: 84.1 ICSC #    1280 CAS #     674-82-8 RTECS # RQ8225000 UN #        2521 EC #         606-017-00-5 March 25, 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. Carbon dioxide. Dry sand. NO hydrous agents. NO water. NO powder (Purple K). EXPLOSION Above 33°C explosive vapour/air mixtures may be formed. Risk of fire and explosion on contact with acid(s), base(s) and water. Above 33°C use a closed system, ventilation, and explosion-proof electrical equipment. In case of fire: cool drums, etc., by spraying with water but avoid contact of the substance with water. EXPOSURE PREVENT GENERATION OF MISTS!  •INHALATION Cough. Sore throat. Shortness of breath. Ventilation, local exhaust, or breathing protection. Fresh air, rest. Half-upright position. Refer for medical attention.  •SKIN Redness. Pain. Protective gloves. Protective clothing. Remove contaminated clothes. Rinse skin with plenty of water or shower. Refer for medical attention.  •EYES Redness. Pain. Blurred vision. Safety goggles 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 pain. 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. NEVER direct water jet on liquid. Personal protection: filter respirator for organic gases and vapours. Fireproof. Separated from acids, bases food and feedstuffs . Cooled. Dry. Store only if stabilized. Do not transport with food and feedstuffs. Transport only if stabilized. Note: D Xn symbol R: 10-20 S: 2-3 UN Hazard Class: 6.1 UN Subsidiary Risks: 3 UN Packing Group: I SEE IMPORTANT INFORMATION ON BACK ICSC: 1280 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 DIKETENE ICSC: 1280 I M P O R T A N T D A T A PHYSICAL STATE; APPEARANCE: COLOURLESS LIQUID , WITH PUNGENT ODOUR. PHYSICAL DANGERS: CHEMICAL DANGERS: The substance will polymerize slowly on standing, and violently due to warming or under the influence of acid(s) and base(s) with fire or explosion hazard. Reacts violently with water . OCCUPATIONAL EXPOSURE LIMITS: TLV not established. MAK: IIb (not established but data is available); (DFG 2004). ROUTES OF EXPOSURE: The substance can be absorbed into the body by inhalation of its aerosol 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 is severely irritating to the eyes , the skin and the respiratory tract . Inhalation of vapour of this substance may cause lung oedema (see Notes). EFFECTS OF LONG-TERM OR REPEATED EXPOSURE: PHYSICAL PROPERTIES Boiling point: 127°C Melting point: -7°C Relative density (water = 1): 1.09 Solubility in water: reaction Vapour pressure, kPa at 20°C: 1 Relative vapour density (air = 1): 2.9 Relative density of the vapour/air-mixture at 20°C (air = 1): 1.02 Flash point: 33°C Auto-ignition temperature: 275°C Explosive limits, vol% in air: 2-11.7 ENVIRONMENTAL DATA This substance may be hazardous to the environment; special attention should be given to fish. N O T E S Reacts violently with fire extinguishing agents such as water. The symptoms of lung oedema often do not become manifest until a few hours have passed and they are aggravated by physical effort. Rest and medical observation are therefore essential. Immediate administration of an appropriate inhalation therapy by a doctor or a person authorized by him/her, should be considered. An added stabilizer or inhibitor can influence the toxicological properties of this substance, consult an expert. Vinylaceto-beta-lactone is also used as a synonym. Card has been partly updated in April 2005. See sections Occupational Exposure Limits, Emergency Response. Transport Emergency Card: TEC (R)-61S2521 or 61GTF1-I NFPA Code: H3; F2; R2 ADDITIONAL INFORMATION ICSC: 1280 DIKETENE (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.