International Chemical Safety Cards 4-THIAPENTANAL ICSC: 0515 beta-(Methylmercapto) propionaldehyde beta-(Methylthio) propionaldehyde Methional C4H8OS / CH3SCH2CH2CHO Molecular mass: 104.3 ICSC #    0515 CAS #     3268-49-3 RTECS # UE2285000 UN #        2785 October 09, 1997 Peer reviewed TYPES OF HAZARD/ EXPOSURE ACUTE HAZARDS/ SYMPTOMS PREVENTION FIRST AID/ FIRE FIGHTING FIRE Combustible. NO open flames. NO contact with hot surfaces. Powder, alcohol-resistant foam, water spray, carbon dioxide. EXPLOSION Above 58°C explosive vapour/air mixtures may be formed. Above 58°C use a closed system, ventilation. In case of fire: keep drums, etc., cool by spraying with water. Combat fire from a sheltered position. EXPOSURE PREVENT GENERATION OF MISTS! STRICT HYGIENE!  •INHALATION Cough. Sore throat. Ventilation, local exhaust, or breathing protection. Fresh air, rest. Refer for medical attention.  •SKIN Redness. Protective gloves. Protective clothing. Remove contaminated clothes. Rinse skin with plenty of water or shower. Refer for medical attention.  •EYES Redness. Pain. 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 Do not eat, drink, or smoke during work. Rinse mouth. Do NOT induce vomiting. Refer for medical attention. SPILLAGE DISPOSAL STORAGE PACKAGING & LABELLING Ventilation. Collect leaking liquid in sealable containers. (Extra personal protection: chemical protection suit including self-contained breathing apparatus). Separated from strong oxidants, strong bases, strong acids, food and feedstuffs. Do not transport with food and feedstuffs. R: S: UN Hazard Class: 6.1 UN Packing Group: III SEE IMPORTANT INFORMATION ON BACK ICSC: 0515 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 4-THIAPENTANAL ICSC: 0515 I M P O R T A N T D A T A PHYSICAL STATE; APPEARANCE: COLOURLESS LIQUID , WITH PUNGENT ODOUR. PHYSICAL DANGERS: The vapour is heavier than air and may travel along the ground; distant ignition possible. CHEMICAL DANGERS: The substance decomposes on burning on contact with hot surfaces, producing toxic fumes. Reacts with strong oxidants, strong acids and strong bases. OCCUPATIONAL EXPOSURE LIMITS: TLV not established. ROUTES OF EXPOSURE: The substance can be absorbed into the body by inhalation. 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: The substance irritates severely the eyes, the skin and the respiratory tract. EFFECTS OF LONG-TERM OR REPEATED EXPOSURE: Repeated or prolonged contact may cause skin sensitization. PHYSICAL PROPERTIES Boiling point: 165°C Melting point: -75°C Relative density (water = 1): 1.03 Solubility in water, g/100 ml at 37.8°C: 17.5 Vapour pressure, Pa at 20°C: 100 Relative vapour density (air = 1): 3.60 Flash point: 58-63°C Auto-ignition temperature: 255°C Explosive limits, vol% in air: 1.3-26.1 Octanol/water partition coefficient as log Pow: -0.16 ENVIRONMENTAL DATA N O T E S Transport Emergency Card: TEC (R)-61G65c NFPA Code: H; F1; R0; ADDITIONAL INFORMATION ICSC: 0515 4-THIAPENTANAL (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.