© 2026 Sinochem Nanjing Corporation,
All Right Reserved
Chemical Name: Potassium Metabisulfite
Common Names: Potassium pyrosulfite, E224 in food contexts
Chemical Formula: K2S2O5
Appearance: White or colorless crystals or powder. This substance doesn’t stand out, but it carries strong sulfur dioxide smells, making it easy to spot in the lab or wine cellar.
Uses: Preserving food and beverages, sterilization, antioxidant, reducing agent for wine and beer, commercial cleaning and sanitizing, water purification.
Main Dangers: Harmful if swallowed or inhaled, skin and respiratory irritant, strong eye irritant, risk of allergic reactions (especially for asthmatics).
Physical Hazards: Non-combustible, but it releases toxic gases like sulfur dioxide when reacting with acids, moisture, or heat.
Health Risks: Repeated exposure or large doses can trigger headaches, nausea, asthmatic symptoms, or even more severe respiratory distress.
Environmental Hazards: Harmful to aquatic environments with long-lasting effects. This powder doesn’t just vanish—it can linger and harm local waterways and wildlife.
Primary Ingredient: Potassium Metabisulfite (K2S2O5), usually above 97% purity.
Impurities: Trace amounts of potassium sulfite, potassium sulfate, and other minor sulfite-based compounds. These can tweak the exact reaction you see in a brew tank or cleaning system, but they don’t swap out the main risks.
Inhalation: Move to fresh air; persistent symptoms call for immediate medical help. This stuff can play havoc with your lungs if you already deal with asthma or lung issues.
Skin Contact: Remove soiled clothing, rinse exposed skin with water and soap. It's no laughing matter for sensitive skin.
Eye Contact: Flush with clean water for several minutes, gently lifting eyelids, and get medical help if irritation sticks around.
Ingestion: Rinse mouth but don’t try to make yourself vomit without professional advice. Swift medical attention lowers the risk of complications, since even low exposure eats away at comfort for hours.
Flammability: Not flammable itself, but burns in contact with strong oxidizers and can feed a fire indirectly.
Combustion Products: Gives off sulfur dioxide, which sharply irritates lungs and eyes. First responders need decent breathing protection—standard stuff for sulfur-based chemicals.
Suitable Extinguishing Media: Water spray, dry chemical powder, or CO2. Foams aren’t ideal since water does the best job of diluting the release of sulfur dioxide.
Precautions: Contain runoff to protect water supplies, ventilate well, full protective equipment is must-have, including breathing masks.
Personal Protection: Gloves, goggles, and dust masks or respirators to cover inhalation risk.
Spill Cleanup: Sweep solid spills into secure containers, avoid stirring up dust. Wetting the area knocks dust out of the air; ventilate to clear any nasty vapors.
Environmental Measures: Prevent the powder from hitting storm drains, soil, or streams. Even small releases can raise local sulfur dioxide above safe levels for pets, animals, or people with respiratory sensitivities.
Handling: Keep containers sealed, use only in well-ventilated rooms or outdoors, limit time handling the powder, and avoid contact with acids or anything damp. Wash hands after use, don’t eat or drink while working with it.
Storage: Dry, cool, and away from sunlight—heat will trigger slow releases of sulfur dioxide or encourage lumps. Separate from acids and oxidizers. Tightly sealed jars or drums keep the powder dry and lower the risk of clumping or leaks.
Workplace Controls: Local exhaust ventilation, dust collection at main mixing areas, and always shut off ventilation when cleaning up powder spills.
Personal Protective Equipment: Nitrile or butyl gloves, chemical safety goggles, face shields, long sleeves, and shoes that don’t let the powder sneak in at the ankles. Dust masks or certified respirators in powdery environments.
Exposure Limits: National standards for sulfur dioxide: OSHA and ACGIH suggest limiting exposure to 2 ppm as an average over eight hours, with peaks always managed quickly. Stay under these levels by rotating jobs or using negative pressure filters if exposures start climbing.
Form: Fine crystals or powder
Color: White to faintly yellow
Odor: Sharp, pungent (sulfur)—an unmistakable chemical smell
Solubility in Water: Moderate; the heat of mixing raises as it begins to decompose, releasing pungent vapors
Melting / Decomposition Point: Doesn’t melt easily—breaks down with heat, releasing sulfur dioxide at about 150°C
pH: Solutions are strongly acidic, swinging the pH meter low enough to sting skin or eyes
Density: Slightly heavier than water; it can pack the bottom of storage drums if you’re not stirring or agitating during use.
Chemical Stability: Stable in sealed containers at room temperature, breaks down with heat, acid, or moisture exposure.
Reactive With: Acids (producing clouds of sulfur dioxide), water (speeds up decomposition), strong oxidizers (danger of combustion or violent reaction), basic substances.
Hazardous Byproducts: Sulfur dioxide and potassium sulfate will form as the main breakdown products.
Incompatibilities: Acids, oxidizers, and damp environments—avoid these to keep the powder from clumping or leaking gas.
Inhalation Effects: Cough, throat pain, shortness of breath. Sensitive people (like those with asthma) can face life-threatening attacks.
Ingestion Effects: Nausea, stomach pain, vomiting, diarrhea. High doses depress the central nervous system or lead to serious dehydration.
Skin and Eye Contact: Redness, itching, painful stinging; long or repeated exposure could lead to burns or lasting irritation.
Chronic Exposure: Low-level exposure ramps up asthma risk, irritates lungs, and can make allergies worse. This is not just theoretical; cases in the food industry show increased asthma rates among frequent handlers.
Aquatic Toxicity: Poisonous to fish and invertebrates; sulfite ions disturb water chemistry and disrupt breathing in aquatic animals.
Persistence and Degradation: Sulfite compounds break down, but sulfur dioxide sticks around and can acidify water or soil, stressing local plants.
Bioaccumulation: Does not build up in food chains, yet one spill can hammer a small pond.
Solid Waste: Treat as hazardous chemical; never flush; use approved chemical waste services.
Solution Disposal: Dilute in lots of water only if permitted by local drain codes, since most water treatment centers frown on untreated chemicals containing sulfur.
Container Disposal: Clean thoroughly before recycling, as powder residues persist. The real danger comes from carelessness—finding leftover crystals six months later can trigger new hazards.
Shipping Class: Regulated as a hazardous material. This brings extra paperwork and skilled handling—the stakes with spilled powder on the highway are much higher than they look.
Proper Shipping Name: Potassium Metabisulfite, solid
Hazard Label: Corrosive or irritant. Keep loads dry, sealed, and off the floor in case of leaks.
Food Use: Permitted as an additive at low concentrations, but banned in food meant for people sensitive to sulfites.
Workplace Safety: Covered under national chemical hazard communication standards, including requirements for worker training and exposure controls.
Environmental Law: Discharge into water systems or sewers without treatment typically restricted or penalized under local and national laws.
