Material Safety Data Sheet: Sodium Metabisulphite

Identification

Product Name: Sodium Metabisulphite
Chemical Formula: Na₂S₂O₅
CAS Number: 7681-57-4
Synonyms: Disodium disulphite, Sodium pyrosulfite
Recommended Use: Preservative, antioxidant, water treatment, bleaching agent
Supplier Details: Manufacturer name, address, phone number, emergency contact
Product Code: Specific batch or lot number if available
Identification of Relevant Uses: Food industry, photography, textile processing, water dechlorination

Hazard Identification

GHS Classification: Acute toxicity (oral, inhalation), Eye irritation, Skin irritation, Respiratory sensitization
Signal Word: Warning
Hazard Pictograms: Exclamation mark
Hazard Statements: Harmful if swallowed, May cause respiratory irritation, Causes serious eye irritation, Causes skin irritation
Precautionary Statements: Avoid breathing dust, Use only outdoors or in a well-ventilated area, Wash hands thoroughly after handling, Wear protective gloves/protective clothing/eye protection/face protection
Potential Health Effects: Eye damage, skin redness, asthma-like symptoms, coughing, potential for allergic reaction in susceptible individuals
Environmental Hazards: Harmful to aquatic life with long-lasting effects

Composition / Information on Ingredients

Chemical Name: Sodium Metabisulphite
Concentration: 98-100% by weight
Impurities: Trace sodium sulphate, sodium chloride
Molecular Weight: 190.1 g/mol
Ingredient Classification: Inorganic salt

First Aid Measures

Inhalation: Move affected person to fresh air, seek medical attention if symptoms such as wheezing, coughing, or shortness of breath occur
Ingestion: Rinse mouth with water, do not induce vomiting, seek immediate medical care
Skin Contact: Remove contaminated clothing, flush skin with plenty of water for at least fifteen minutes, obtain medical attention for persistent irritation
Eye Contact: Rinse cautiously with water for several minutes, remove contact lenses if present and easy, continue rinsing, get urgent medical advice
Most Important Symptoms: Burns, pain, redness, respiratory distress for inhalation exposure
Notes for Doctors: Symptoms may be delayed due to slow onset of allergic reactions; treat accordingly to symptoms

Fire-Fighting Measures

Suitable Extinguishing Media: Use water spray, carbon dioxide, dry chemical, or alcohol-resistant foam
Unsuitable Extinguishing Media: Avoid high-pressure water jets
Specific Hazards: Decomposes when heated, releasing toxic gases like sulfur dioxide
Protective Equipment for Fire Fighters: Self-contained breathing apparatus, fully protective clothing
Special Procedures: Approach from upwind, keep containers cool with water spray, avoid breathing fumes
Explosion Hazard: Can decompose explosively at high temperatures if confined

Accidental Release Measures

Personal Precautions: Use personal protective equipment, avoid dust formation, evacuate non-essential personnel
Environmental Precautions: Prevent release to drains, surface waters or soil
Methods for Cleaning Up: Scoop up and remove spilled material, place into suitable containers for disposal, wash spill site with copious water after material pickup
Ventilation: Ensure adequate ventilation during cleanup
Disposal: Comply with local, regional, national regulations

Handling and Storage

Handling: Use in well-ventilated areas, avoid breathing dust or vapors, avoid contact with skin and eyes, handle away from acids and oxidizers
Storage: Store in tightly closed containers in a cool, dry, and well-ventilated place, protect from moisture and direct sunlight, segregate from acids and strong oxidizing agents
Storage Temperature: Room temperature
Hygiene Practices: Wash thoroughly after handling, keep work area clean, do not eat, drink or smoke while handling

Exposure Controls and Personal Protection

Occupational Exposure Limits: OSHA PEL: 5 mg/m³ (as SO₂), ACGIH TLV: 5 mg/m³ (as SO₂)
Engineering Controls: Use local exhaust ventilation to minimize exposure
Personal Protection: Wear chemical-resistant gloves (nitrile or rubber), safety goggles, protective clothing
Respiratory Protection: Use approved dust mask or respirator if exposure limits may be exceeded
Eye/Face Protection: Tight-fitting safety goggles or full-face shield
Hand Protection: Chemical-resistant gloves
Skin/Body Protection: Long-sleeved lab coat or work clothing
Hygiene Measures: Wash hands before breaks and after work, take off contaminated clothing immediately

Physical and Chemical Properties

Appearance: White or pale yellow crystalline powder
Odor: Sulfurous, slight rotten egg smell
Odor Threshold: Not available
pH (1% solution): 3.5—5.0
Melting Point/Freezing Point: Decomposes at 150°C
Boiling Point: Not applicable; decomposes
Solubility: Easily soluble in water, insoluble in alcohol
Flash Point: Not flammable
Vapor Pressure: Not applicable
Relative Density: 1.48 at 20°C
Partition Coefficient: Not determined
Auto-ignition Temperature: Not self-igniting
Decomposition Products: Sulfur dioxide, sodium sulfate

Stability and Reactivity

Chemical Stability: Stable under recommended storage conditions, absorbs moisture leading to slow decomposition
Reactivity: Reacts vigorously with acids, releasing sulfur dioxide gas
Hazardous Reactions: Vigorous exotherm with oxidizing agents or acids, may react with water producing heat and SO₂
Materials to Avoid: Acids, strong oxidizers, water (for bulk stored product), reducing agents
Decomposition Products: Sulfur dioxide, sodium sulfate, possible release of toxic fumes
Polymerization: Will not occur

Toxicological Information

Possible Routes of Exposure: Inhalation, ingestion, skin and eye contact
Acute Toxicity: Oral LD₅₀ (rat) ~1310 mg/kg; inhalation may cause bronchospasm, coughing, throat irritation
Chronic Effects: Prolonged exposure may cause allergic respiratory reaction especially in asthmatics or sensitive individuals
Skin Irritation: Causes redness, itching, burning
Eye Damage: May cause severe irritation, tearing, pain, lasting dryness or visual impairment
Sensitization: People with sulfite sensitivity or underlying respiratory disease face increased risk
Carcinogenicity: Not classified as carcinogenic by IARC, NTP, or OSHA
Mutagenicity/Reproductive Toxicity: No data suggesting mutagenic or reproductive effects from normal exposure

Ecological Information

Ecotoxicity: Harmful to aquatic organisms, risk of harmful effects in the environment if released in large quantities
Persistence and Degradability: Hydrolyzes to sodium bisulfite and then to sulfate, which is less toxic
Bioaccumulation Potential: Low, does not bioaccumulate in aquatic organisms
Mobility in Soil: Highly soluble in water, may leach into soil and groundwater
Other Adverse Effects: High local concentrations can impact pH and aquatic life due to oxygen depletion

Disposal Considerations

Waste Treatment Methods: Dispose of in accordance with local, regional, and national regulations
Product Disposal: Dilute with large volume of water and neutralize with alkaline materials before disposal
Contaminated Packaging: Rinse containers before recycling or disposal, manage rinsate as hazardous waste
Environmental Hazards: Do not release directly into environment, avoid runoff to stormwater
Disposal Regulations: Refer to local environmental protection agencies and hazardous waste management authorities for instructions

Transport Information

UN Number: 3077
UN Proper Shipping Name: Environmentally hazardous substance, solid, n.o.s. (Sodium metabisulphite)
Transport Hazard Class: 9 (Miscellaneous dangerous substances)
Packing Group: III
Marine Pollutant: Yes
Special Transport Precautions: Secure and label containers, protect against physical impact, avoid water exposure during transport
Label Requirements: Marked with required hazard symbols and handling instructions

Regulatory Information

Inventory Status: Listed on US TSCA, EINECS, AICS, DSL/NDSL, ENCS, and other national inventories
OSHA Hazards: Target organ effect, irritant
SARA Title III Sections 302/304: Not listed as an extremely hazardous substance
SARA Title III Section 313: Not subject to reporting
Canada WHMIS Classification: D2B (Toxic Material Causing Other Toxic Effects)
California Proposition 65: Not listed
Other Local Regulations: Check global, national, state, and municipal requirements for specific restrictions or guidelines