International Chemical Safety Cards HYDROGEN SELENIDE ICSC: 0284 Selenium hydride H2Se Molecular mass: 81.0 (cylinder) ICSC #    0284 CAS #     7783-07-5 RTECS # MX1050000 UN #        2202 EC #         034-002-00-8 September 20, 1993 Peer reviewed TYPES OF HAZARD/ EXPOSURE ACUTE HAZARDS/ SYMPTOMS PREVENTION FIRST AID/ FIRE FIGHTING FIRE Extremely flammable. NO open flames, NO sparks, and NO smoking. Shut off supply; if not possible and no risk to surroundings, let the fire burn itself out; in other cases extinguish with powder, carbon dioxide. EXPLOSION Gas/air mixtures are explosive. Closed system, ventilation, explosion-proof electrical equipment and lighting. In case of fire: keep cylinder cool by spraying with water. Combat fire from a sheltered position. EXPOSURE STRICT HYGIENE!  •INHALATION Burning sensation. Cough. Laboured breathing. Nausea. Sore throat. Weakness. Closed system and ventilation. Fresh air, rest. Half-upright position. Artificial respiration if indicated. Refer for medical attention.  •SKIN ON CONTACT WITH LIQUID: FROSTBITE. Cold-insulating gloves. ON FROSTBITE: rinse with plenty of water, do NOT remove clothes.  •EYES Redness. Pain. Safety goggles or face shield. First rinse with plenty of water for several minutes (remove contact lenses if easily possible), then take to a doctor.  •INGESTION SPILLAGE DISPOSAL STORAGE PACKAGING & LABELLING Evacuate danger area! Consult an expert! Ventilation. NEVER direct water jet on liquid (extra personal protection: complete protective clothing including self-contained breathing apparatus). Fireproof. Separated from strong oxidants. Cool. Note: A T symbol R: 23/25-33 S: 20/21-28-44 UN Hazard Class: 2.3 UN Subsidiary Risks: 2.1 SEE IMPORTANT INFORMATION ON BACK ICSC: 0284 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 HYDROGEN SELENIDE ICSC: 0284 I M P O R T A N T D A T A PHYSICAL STATE; APPEARANCE: COLOURLESS COMPRESSED LIQUEFIED GAS , WITH CHARACTERISTIC ODOUR. PHYSICAL DANGERS: The gas is heavier than air and may travel along the ground; distant ignition possible. CHEMICAL DANGERS: The substance decomposes on heating above 100°C producing toxic and flammable products including selenium (ICSC 0072) and Hydrogen (ICSC 0001). The substance is a strong reducing agent and reacts violently with oxidants causing fire and explosion hazard. On contact with air it emits toxic and corrosive fumes of selenium dioxide (ICSC 0946). OCCUPATIONAL EXPOSURE LIMITS: TLV (as Se): 0.05 ppm; 0.16 mg/m3 (as TWA) (ACGIH 1992-1993). OSHA PEL: TWA 0.05 ppm (0.2 mg/m3) NIOSH REL: TWA 0.05 ppm (0.2 mg/m3) NIOSH IDLH: 1 ppm ROUTES OF EXPOSURE: The substance can be absorbed into the body by inhalation. INHALATION RISK: A harmful contamination of the air can be reached very quickly on evaporation of this substance at 20°C. EFFECTS OF SHORT-TERM EXPOSURE: The substance irritates the eyes and the respiratory tract. Inhalation of the gas may cause pneumonitis. Exposure at high levels may result in death. EFFECTS OF LONG-TERM OR REPEATED EXPOSURE: The substance may have effects on the liver. PHYSICAL PROPERTIES Boiling point: -41°C Melting point: -66°C Relative density (water = 1): 2.1 (as liquid) Solubility in water, ml/100 ml at 22.5°C: 270 Vapour pressure, kPa at 21°C: 878 Relative vapour density (air = 1): 2.8 Flash point: Flammable Gas ENVIRONMENTAL DATA N O T E S The odour warning when the exposure limit value is exceeded is insufficient. Turn leaking cylinder with the leak up to prevent escape of gas in liquid state. Transport Emergency Card: TEC (R)-20G12 ADDITIONAL INFORMATION ICSC: 0284 HYDROGEN SELENIDE (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.