Sodium metabisulfite

  • Disodium pyrosulfite
  • Sodium pyrosulfite
  • Disodium disulfite
Formula Na2O5S2
Structure
Description White to yellowish crystals or powder with an odor of sulfur dioxide.
Uses Pharmaceutic aid (antioxidant).

Registry Numbers and Inventories.
CAS 7681-57-4
EC (EINECS/ELINCS) 231-673-0
EC Index Number 016-063-00-2
EC Class Harmful; Irritant; Contact with acids liberates toxic gas
EC Risk Phrase R 22 31 41
EC Safety Phrase S 26 39 46
RTECS UX8225000
RTECS class Agricultural Chemical and Pesticide; Tumorigen; Mutagen; Reproductive Effector; Primary Irritant
UN (DOT) 1759
Merck 12,8784
Beilstein/Gmelin 88460 (G)
EPA OPP 111409
Swiss Giftliste 1 G-2598
Canada DSL/NDSL DSL
US TSCA Listed
Austrailia AICS Listed
New Zealand Listed
Japan ENCS (MITI) Listed
Korea ECL Listed

Properties.
Formula Na2O5S2
Formula mass 190.10
Melting point, °C 150
Density 1.48 g/cm3
Solubility in water 540 g/L

Hazards and Protection.
Storage Store in a tightly closed container. Store in a cool, dry, well-ventilated area away from incompatible substances. Keep away from strong acids.
Handling Wash thoroughly after handling. Minimize dust generation and accumulation. Avoid contact with eyes, skin, and clothing. Keep container tightly closed. Avoid ingestion and inhalation.
Protection Eyes: Wear appropriate protective eyeglasses or chemical safety goggles as described by OSHA's eye and face protection regulations in 29 CFR 1910.133 or European Standard EN166. Skin: Wear appropriate protective gloves to prevent skin exposure. Clothing: Wear appropriate protective clothing to prevent skin exposure.
Respirators Follow the OSHA respirator regulations found in 29CFR 1910.134 or European Standard EN 149. Always use a NIOSH or European Standard EN 149 approved respirator when necessary.
Small spills/leaks Clean up spills immediately, using the appropriate protective equipment. Sweep up, then place into a suitable container for disposal. Avoid generating dusty conditions. Provide ventilation. Do not get water inside containers.
Stability Stable under normal shipping and handling conditions. However, may decompose if heated.
Incompatibilities Strong oxidizers. Substance may produce sulfur dioxide gas when in contact with acids and/or water (ice).
Decomposition Oxides of sulfur, toxic fumes of sodium oxide.

Fire.
Fire fighting Wear a self-contained breathing apparatus in pressure-demand, MSHA/NIOSH (approved or equivalent), and full protective gear. During a fire, irritating and highly toxic gases may be generated by thermal decomposition or combustion. To extinguish fire, use water fog, dry chemical, carbon dioxide, or regular foam.
Fire potential Non-combustible, substance itself does not burn but may decompose upon heating to produce corrosive and/or toxic fumes.
Hazards Contact with metals may evolve flammable hydrogen gas.
Combustion products Fire may produce irritating, corrosive and/or toxic gases.
NFPA Health 2
  Flammability 0  
  Reactivity 0  

Health.
Exposure limit(s) NIOSH REL: TWA 5 mg/m3
Poison_Class 3
Exposure effects Prolonged or repeated skin contact may cause dermatitis. Reproductive effects have been reported in animals. Repeated or prolonged exposure may cause allergic reactions in sensitive individuals.
   Ingestion May cause gastrointestinal irritation with nausea, vomiting and diarrhea. May be harmful if swallowed. Exposure may cause central nervous system depression, gastrointestinal and cardiac abnormalities, and violent colic. Sulfite compounds may cause a severe allergic reaction in sensitive individuals and some asthmatics.
   Inhalation May cause allergic respiratory reaction. May cause effects similar to those described for ingestion. Inhalation of dust may cause respiratory tract irritation.
   Skin May cause skin irritation. May cause skin sensitization, an allergic reaction, which becomes evident upon re-exposure to this material.
   Eyes May cause eye irritation.

First aid
 
   Ingestion Do NOT induce vomiting. If victim is conscious and alert, give 2-4 cupfuls of milk or water. Get medical aid immediately.
   Inhalation Remove from exposure to fresh air immediately. If not breathing, give artificial respiration. If breathing is difficult, give oxygen. Get medical aid. DO NOT use mouth-to-mouth respiration. If breathing has ceased apply artificial respiration using oxygen and a suitable mechanical device such as a bag and a mask.
   Skin Get medical aid. Immediately flush skin with plenty of soap and water for at least 15 minutes while removing contaminated clothing and shoes. Wash clothing before reuse.
   Eyes Immediately flush eyes with plenty of water for at least 15 minutes, occasionally lifting the upper and lower eyelids. Get medical aid immediately.

Transport.
UN number 1759
Response guide 154
Hazard class 8
Packing Group I; II; III  
HS Code 2832 10 00  
Std. Transport # 4936350