Sodium metabisulfite is white or yellow crystalline powder or small crystals, with a strong odor of SO2, the proportion of 1.4, soluble in water, acidic aqueous solution, and the release of SO2 and acid exposure to the produce the corresponding salts, for a long time in air, the oxidation into Na2S2O6, so the product does not go far. Higher than 1500C, the decomposition of SO2.
Health hazards: the goods on the skin, mucous membrane significantly stimulated, can cause the conjunctiva, bronchitis symptoms. With allergies or asthma, are very sensitive. Direct skin contact can cause burns.