International Chemical Safety Cards URANIUM DIOXIDE ICSC: 1251 Uranous oxide Black uranium oxide UO2 Molecular mass: 270.0 ICSC #    1251 CAS #     1344-57-6 RTECS # YR4705000 EC #         092-002-00-3 March 15, 1995 Peer reviewed TYPES OF HAZARD/ EXPOSURE ACUTE HAZARDS/ SYMPTOMS PREVENTION FIRST AID/ FIRE FIGHTING FIRE Combustible. NO open flames. Water spray, powder. EXPLOSION EXPOSURE PREVENT DISPERSION OF DUST! STRICT HYGIENE! IN ALL CASES CONSULT A DOCTOR!  •INHALATION Avoid inhalation of fine dust and mist. Ventilation (not if powder), local exhaust, or breathing protection. Fresh air, rest. Refer for medical attention.  •SKIN Protective gloves. Remove contaminated clothes. Rinse and then wash skin with water and soap. Refer for medical attention.  •EYES Redness. Pain. Safety goggles or eye protection in combination with breathing protection if powder. 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. Wash hands before eating. Rinse mouth. Refer for medical attention. SPILLAGE DISPOSAL STORAGE PACKAGING & LABELLING Sweep spilled substance into sealable containers; if appropriate, moisten first to prevent dusting. Then remove to safe place. Personal protection: P3 filter respirator for toxic particles. Well closed. Note: A T+ symbol N symbol R: 26/28-33-51/53 S: 1/2-20/21-45-61 SEE IMPORTANT INFORMATION ON BACK ICSC: 1251 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 URANIUM DIOXIDE ICSC: 1251 I M P O R T A N T D A T A PHYSICAL STATE; APPEARANCE: BLACK TO BROWN CRYSTALS OR BLACK TO BROWN POWDER . PHYSICAL DANGERS: CHEMICAL DANGERS: The substance may spontaneously ignite on contact with air when heated above 700°C. OCCUPATIONAL EXPOSURE LIMITS: TLV: (as U) 0.2 mg/m³ as TWA; 0.6 mg/m³ as STEL; A1 (confirmed human carcinogen); (ACGIH 2004). ROUTES OF EXPOSURE: The substance can be absorbed into the body by inhalation of its aerosol.> INHALATION RISK: Evaporation at 20°C is negligible; a harmful concentration of airborne particles can, however, be reached quickly on spraying or when dispersed, especially if powdered. EFFECTS OF SHORT-TERM EXPOSURE: The substance is irritating to the eyes . EFFECTS OF LONG-TERM OR REPEATED EXPOSURE: Lungs may be affected by repeated or prolonged exposure to dust particles. PHYSICAL PROPERTIES Melting point: 2865°C Relative density (water = 1): 11.0 Solubility in water: none ENVIRONMENTAL DATA N O T E S Insufficient data are available on the effect of this substance on human health, therefore utmost care must be taken. Do NOT take working clothes home. Card has been partly updated in April 2005. See section Occupational Exposure Limits. ADDITIONAL INFORMATION ICSC: 1251 URANIUM DIOXIDE (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.