International Chemical Safety Cards MAGNESIUM CARBONATE ICSC: 0969 Magnesite Carbonic acid, magnesium salt MgCO3 Molecular mass: 84.3 ICSC #    0969 CAS #     546-93-0 RTECS # OM2470000 October 25, 1995 Peer reviewed TYPES OF HAZARD/ EXPOSURE ACUTE HAZARDS/ SYMPTOMS PREVENTION FIRST AID/ FIRE FIGHTING FIRE Not combustible. Gives off irritating or toxic fumes (or gases) in a fire. In case of fire in the surroundings: all extinguishing agents allowed. EXPLOSION EXPOSURE PREVENT DISPERSION OF DUST!  •INHALATION Cough. Avoid inhalation of fine dust and mist. Local exhaust or breathing protection. Fresh air, rest.  •SKIN Protective gloves. Rinse skin with plenty of water or shower.  •EYES Safety spectacles.  •INGESTION SPILLAGE DISPOSAL STORAGE PACKAGING & LABELLING Sweep spilled substance into covered containers; if appropriate, moisten first to prevent dusting. (Extra personal protection: P1 filter respirator for inert particles). Separated from acids. R: S: SEE IMPORTANT INFORMATION ON BACK ICSC: 0969 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 MAGNESIUM CARBONATE ICSC: 0969 I M P O R T A N T D A T A PHYSICAL STATE; APPEARANCE: WHITE POWDER. PHYSICAL DANGERS: CHEMICAL DANGERS: The substance decomposes on heating producing acrid smoke and irritating fumes. Reacts with acids liberating carbon dioxide gas. OCCUPATIONAL EXPOSURE LIMITS: TLV: 10 mg/m3 (as TWA) (ACGIH 1995-1996). OSHA PEL: TWA 15 mg/m3 (total) TWA 5 mg/m3 (resp) NIOSH REL: TWA 10 mg/m3 (total) TWA 5 mg/m3 (resp) NIOSH IDLH: No data 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 nuisance-causing concentration of airborne particles can, however, be reached quickly on spraying or when dispersed, especially if powdered. EFFECTS OF SHORT-TERM EXPOSURE: EFFECTS OF LONG-TERM OR REPEATED EXPOSURE: The substance may have effects on the lungs if the magnesite contains more than 1% crystalline silica. PHYSICAL PROPERTIES Melting point (decomposes): 350°C Relative density (water = 1): 2.95 Solubility in water, g/100 ml: none ENVIRONMENTAL DATA N O T E S If magnesite contains >1% crystalline silica, also consult ICSC # 0808. ADDITIONAL INFORMATION ICSC: 0969 MAGNESIUM CARBONATE (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.