International Chemical Safety Cards METHANESULFONYL CHLORIDE ICSC: 1163 Mesyl chloride Methylsulfonyl chloride Methanesulfonic acid chloride CH3ClO2S Molecular mass: 114.6 ICSC #    1163 CAS #     124-63-0 RTECS # PB2790000 UN #        3246 October 23, 1995 Peer reviewed TYPES OF HAZARD/ EXPOSURE ACUTE HAZARDS/ SYMPTOMS PREVENTION FIRST AID/ FIRE FIGHTING FIRE Combustible. Gives off irritating or toxic fumes (or gases) in a fire. NO open flames. Powder, water spray, foam, carbon dioxide. EXPLOSION EXPOSURE  •INHALATION Corrosive. Burning sensation. Cough. Sore throat. Ventilation, local exhaust, or breathing protection. Fresh air, rest. Refer for medical attention.  •SKIN Redness. Pain. Blisters. Protective gloves. Protective clothing. Remove contaminated clothes. Rinse skin with plenty of water or shower. Refer for medical attention.  •EYES Redness. Pain. Severe deep burns. Safety goggles, 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. Burning sensation. Do not eat, drink, or smoke during work. Rinse mouth. Do NOT induce vomiting. Refer for medical attention. SPILLAGE DISPOSAL STORAGE PACKAGING & LABELLING Evacuate danger area! Consult an expert! Collect leaking liquid in sealable dry containers. Absorb remaining liquid in sand or inert absorbent and remove to safe place. Do NOT wash away into sewer (extra personal protection: complete protective clothing including self-contained breathing apparatus). Separated from food and feedstuffs. Dry. Well closed. Keep in a well-ventilated room. Airtight. Unbreakable packaging; put breakable packaging into closed unbreakable container. Do not transport with food and feedstuffs. R: S: UN Hazard Class: 6.1 UN Subsidiary Risks: 8 UN Packing Group: I SEE IMPORTANT INFORMATION ON BACK ICSC: 1163 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 METHANESULFONYL CHLORIDE ICSC: 1163 I M P O R T A N T D A T A PHYSICAL STATE; APPEARANCE: COLOURLESS TO PALE YELLOW FUMING LIQUID. PHYSICAL DANGERS: CHEMICAL DANGERS: The substance decomposes on heating or on burning producing toxic and corrosive fumes including hydrogen chloride and sulphur oxides. Reacts violently with bases including ammonia and many other substances causing fire and explosion hazard. Reacts with water and steam producing toxic and corrosive fumes including hydrogen chloride. OCCUPATIONAL EXPOSURE LIMITS: TLV not established. ROUTES OF EXPOSURE: The substance can be absorbed into the body by inhalation or by ingestion. INHALATION RISK: No indication can be given about the rate in which a harmful concentration in the air is reached on evaporation of this substance at 20°C. EFFECTS OF SHORT-TERM EXPOSURE: Tear drawing. The substance is corrosive to the eyes, the skin and the respiratory tract. Corrosive on ingestion. EFFECTS OF LONG-TERM OR REPEATED EXPOSURE: PHYSICAL PROPERTIES Boiling point at 97.3kPa: 161°C Melting point: -32°C Relative density (water = 1): 1.5 Solubility in water: reaction Vapour pressure, kPa at 20°C: 0.27 Relative vapour density (air = 1): 4.0 Relative density of the vapour/air-mixture at 20°C (air = 1): 1.01 Flash point: >110°C ENVIRONMENTAL DATA The substance is harmful to aquatic organisms. N O T E S Transport Emergency Card: TEC (R)-61G61a ADDITIONAL INFORMATION ICSC: 1163 METHANESULFONYL CHLORIDE (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.