International Chemical Safety Cards SILICON ICSC: 1508 Si Atomic mass: 28.09 ICSC #    1508 CAS #     7440-21-3 RTECS # VW0400000 UN #        1346 November 28, 2003 Peer reviewed TYPES OF HAZARD/ EXPOSURE ACUTE HAZARDS/ SYMPTOMS PREVENTION FIRST AID/ FIRE FIGHTING FIRE Combustible under specific conditions. NO open flames. Special powder, dry sand, NO hydrous agents. EXPLOSION Finely dispersed particles form explosive mixtures in air. Risk of fire and explosion on contact with halogens oxidants. Prevent deposition of dust; closed system, dust explosion-proof electrical equipment and lighting. Prevent build-up of electrostatic charges (e.g., by grounding). EXPOSURE  •INHALATION Cough. Local exhaust or breathing protection. Fresh air, rest.  •SKIN Redness. Roughness. Protective gloves. Rinse skin with plenty of water or shower.  •EYES Redness. Safety goggles. 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. SPILLAGE DISPOSAL STORAGE PACKAGING & LABELLING Sweep spilled substance into containers; if appropriate, moisten first to prevent dusting. Separated from incompatible materials . See Chemical Dangers. R: S: UN Hazard Class: 4.1 UN Packing Group: III SEE IMPORTANT INFORMATION ON BACK ICSC: 1508 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 SILICON ICSC: 1508 I M P O R T A N T D A T A PHYSICAL STATE; APPEARANCE: STEEL-GREY CRYSTALS OR BLACK TO BROWN AMORPHOUS POWDER PHYSICAL DANGERS: Dust explosion possible if in powder or granular form, mixed with air. If dry, it can be charged electrostatically by swirling, pneumatic transport, pouring, etc. CHEMICAL DANGERS: Reacts violently with oxidants , halogens , metal carbonates and metal acetylides causing fire hazard. Reacts violently with metal hexafluorides causing fire and explosion hazard. Reacts on heating with water forming flammable/explosive gas (hydrogen - see ICSC0001) . OCCUPATIONAL EXPOSURE LIMITS: TLV: 10 mg/m³ as TWA; (ACGIH 2003). MAK not established. ROUTES OF EXPOSURE: The substance can be absorbed into the body by inhalation. INHALATION RISK: A nuisance-causing concentration of airborne particles can be reached quickly when dispersed. EFFECTS OF SHORT-TERM EXPOSURE: May cause mechanical irritation tothe eyesandthe respiratory tract. EFFECTS OF LONG-TERM OR REPEATED EXPOSURE: PHYSICAL PROPERTIES Boiling point: 2355°C Melting point: 1410°C Density: 2.33 g/cm3 Solubility in water: none ENVIRONMENTAL DATA N O T E S Reacts violently with fire extinguishing agents such as water. Transport Emergency Card: TEC (R)-41GF3-II+III ADDITIONAL INFORMATION ICSC: 1508 SILICON (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.