Potassium metabisulfite

  • Potassium pyrosulfite
  • Dipotassium disulfite
  • Dipotassium metabisulfite
Formula
K2S2O5
Structure
Description
White crystals or powder, sulfur dioxide odor, pungent, sharp odor.
Uses
Antiseptic reagent, source of sulfurous acid, brewing (cleaning casks and vats), winemaking (to kill undesirable yeast and bacteria), food preservative, developing agent, process engraving, dyeing, antioxidant and bleaching agent.

Registry Numbers and Inventories.
CAS
16731-55-8
EC (EINECS/ELINCS)
240-795-3
EC Class
irritant
R 31 36/37/38
RTECS
TT4920000
RTECS class
Tumorigen; Mutagen; Reproductive Effector
UN (DOT)
1759
Merck
12,7811
Beilstein/Gmelin
56106 (G)
Swiss Giftliste 1
G-5662
Canada DSL/NDSL
DSL
US TSCA
Listed
Austrailia AICS
Listed
New Zealand
Listed
Japan ENCS (MITI)
Listed
Korea ECL
Listed

Properties.
Formula
K2O5S2
Formula mass
222.33
Melting point, °C
190
Density
1.2 g/cm3 (20 C)
Solubility in water
450 g/L

Hazards and Protection.
Storage
Keep away from heat and flame. Store in a cool, dry place. Store in a tightly closed container. Store in a cool, dry, well-ventilated area away from incompatible substances.
Handling
Wash thoroughly after handling. Remove contaminated clothing and wash before reuse. Use with adequate ventilation. Avoid contact with eyes, skin, and clothing. Keep container tightly closed. Avoid ingestion and inhalation. Do not allow contact with water. Wash clothing before reuse.
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
A respiratory protection program that meets OSHA's 29 CFR 1910.134 and ANSI Z88.2 requirements or European Standard EN 149 must be followed whenever workplace conditions warrant a respirator's use.
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.
Stability
Stable at room temperature in closed containers under normal storage and handling conditions.
Incompatibilities
Strong oxidizing agents, acids.
Decomposition
Oxides of potassium, sulfur oxides (SOx), including sulfur oxide and sulfur dioxide, potassium sulfite.

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. Substance is noncombustible. Extinguishing media: Substance is noncombustible; use agent most appropriate to extinguish surrounding fire. In case of fire use water spray, dry chemical, carbon dioxide, or appropriate 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.
Health
1
 
Flammability
0
 
 
Reactivity
0
 

Health.
Poison_Class
3
Exposure effects
Effects may be delayed.
   Ingestion
May cause gastrointestinal irritation with nausea, vomiting and diarrhea. May cause worsening of asthma in asthmatics. Individuals sensitive to sulfides may experience stomach upset, tightness in the chest, or
   Inhalation
Causes respiratory tract irritation. May cause asthmatic attacks due to allergic sensitization of the respiratory tract. Can produce delayed pulmonary edema.
   Skin
Causes skin irritation.
   Eyes
Causes eye irritation. May cause chemical conjunctivitis.

First aid
 
   Ingestion
Never give anything by mouth to an unconscious person. Get medical aid. Do NOT induce vomiting. If conscious and alert, rinse mouth and drink 2-4 cupfuls of milk or water.
   Inhalation
Remove from exposure to fresh air immediately. If not breathing, give artificial respiration. If breathing is difficult, give oxygen. Get medical aid.
   Skin
Get medical aid. 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.

Transport.
UN number
1759
Response guide
Hazard class
8
Packing Group
I; II; III
 
HS Code
2832 20 00