Material Safety Data Sheet: Food Grade Sodium Metabisulfite

Identification

Product Name: Sodium Metabisulfite, Food Grade
Chemical Formula: Na2S2O5
Synonyms: Disodium disulfite, Sodium pyrosulfite
CAS Number: 7681-57-4
Recommended Use: Food preservative, antioxidant, disinfectant, and bleaching agent in the food industry
Supplier Contact Information: Name, address, emergency phone number, and email for supplier or manufacturer
Emergency Phone: 24-hour chemical emergency contact for guidance in urgent situations

Hazard Identification

Classification: Acute toxicity (oral, inhalation), Eye irritation, Skin irritation
Hazard Statements: Causes serious eye irritation, may cause respiratory irritation or allergic reactions, harmful if swallowed
Pictograms: Exclamation mark, health hazard
Signal Word: Warning
Precautionary Statements: Avoid breathing dust or fumes, wear eye and face protection, wash hands thoroughly after handling, use only outdoors or in well-ventilated areas

Composition / Information on Ingredients

Chemical Name: Sodium Metabisulfite
Concentration: 97%–100% by weight
Impurities: Typically contains trace levels of sodium sulfate and sodium sulfite, often considered food-safe within regulatory thresholds

First Aid Measures

Inhalation: Move person to fresh air, monitor for difficulty breathing, seek medical attention if symptoms persist or worsen
Skin Contact: Remove contaminated clothing, rinse skin with plenty of water, wash thoroughly with soap, obtain medical advice if irritation develops
Eye Contact: Rinse cautiously with water for several minutes, remove contact lenses if present and easy to do, continue rinsing, seek immediate medical attention
Ingestion: Rinse mouth with water, give water to drink if conscious and alert, do not induce vomiting, obtain medical advice immediately
Most Important Symptoms: Irritation to respiratory tract, nausea, shortness of breath, redness and pain in eyes or skin

Fire-Fighting Measures

Suitable Extinguishing Media: Water spray, dry chemical, carbon dioxide, foam
Unsuitable Media: Avoid direct water jets, strong oxidizers
Specific Hazards: Emits toxic and irritating sulfur oxides and sodium oxide fumes under fire
Protective Equipment: Self-contained breathing apparatus, full protective fire gear
Firefighting Instructions: Move containers from fire area if it can be done without risk, use water spray to cool fire-exposed containers, prevent run-off from entering drains

Accidental Release Measures

Personal Precautions: Use protective equipment to avoid inhalation or skin and eye contact, ventilate area
Environmental Precautions: Prevent spillage from entering waterways, soil, or drains
Cleanup Methods: Sweep up material carefully to prevent dust formation, place in suitable waste containers, wash spill area with water after material pickup, ventilate the area
Reportable Quantity: Report large releases to environmental authorities in accordance with local, regional, and federal regulations

Handling and Storage

Handling: Minimize dust generation, keep away from moisture, acids, and strong oxidizers, use in well-ventilated areas, practice good industrial hygiene
Storage: Store in original containers, tightly closed, in a cool, dry, and well-ventilated area away from incompatible substances, keep container properly labeled, store away from food and beverages to prevent contamination
Incompatibilities: Acids (releases sulfur dioxide gas), oxidizers, moisture, flammable materials

Exposure Controls and Personal Protection

Occupational Exposure Limits: Sodium Metabisulfite OSHA PEL: 5 mg/m³ (respirable fraction), ACGIH TLV: 5 mg/m³ (TWA)
Engineering Controls: Local exhaust ventilation, process enclosures, eye wash stations
Personal Protective Equipment (PPE): Chemical splash goggles, gloves resistant to chemicals, protective clothing, NIOSH-approved respirator for dust or sulfur dioxide exposure
Hygiene Measures: Wash hands before eating, drinking, and at end of work period, remove contaminated clothing before reuse

Physical and Chemical Properties

Appearance: White or yellowish crystalline powder
Odor: Pungent, sulfurous
Odor Threshold: Approximately 0.3 ppm (as sulfur dioxide)
pH: 4.0–5.0 (1% aqueous solution)
Melting Point: Decomposes above 150°C
Boiling Point: Not applicable (decomposes)
Flash Point: Not flammable
Vapor Pressure: Negligible at ambient conditions
Solubility in Water: 65 g/100 mL at 20°C
Density: 1.48 g/cm³
Partition Coefficient: Not established
Decomposition Temperature: Releases sulfur dioxide gas when heated above 150°C

Stability and Reactivity

Chemical Stability: Stable under dry, cool storage conditions
Conditions to Avoid: Exposure to moisture, heat, acids, oxidizing agents
Incompatible Materials: Acids, oxidizers, reducing agents, water (may release sulfurous gases)
Hazardous Decomposition Products: Sulfur dioxide, sodium oxide
Possibility of Hazardous Reactions: Contact with acids produces toxic gases, contact with oxidizers may ignite or explode

Toxicological Information

Acute Toxicity: LD50 oral (rat): approximately 1,540 mg/kg, symptoms include gastrointestinal distress
Skin Irritation: Can cause skin redness or irritation upon prolonged contact
Eye Irritation: Serious eye irritation, may cause burns
Sensitization: May cause respiratory or skin sensitization, especially in asthmatics or allergic individuals
Chronic Effects: Prolonged inhalation may trigger asthmatic or allergic reactions, possible long-term effects include respiratory system effects
Other Data: Not classified as mutagenic, teratogenic, or carcinogenic by major regulatory agencies for food contact use within established limits

Ecological Information

Aquatic Toxicity: Harmful to aquatic life at elevated concentrations, fish 96-hr LC50: 150 mg/L (Oncorhynchus mykiss)
Persistence and Degradability: Readily reacts with water, biodegradable to sulfate compounds
Bioaccumulation Potential: Low, does not accumulate in organisms
Soil Mobility: Soluble in water, mobile in soil, may affect soil microorganisms at high concentrations
Other Adverse Effects: Acidification of water bodies through sulfur dioxide release, avoid uncontrolled releases to environment

Disposal Considerations

Waste Generation: Gather waste for disposal in compliance with local, regional, and national regulations
Disposal Methods: Dissolve and dilute with large volumes of water, neutralize with base if permissible, send to a licensed waste disposal facility
Packaging Disposal: Rinse containers thoroughly before recycling or disposal, prevent cross-contamination with other chemicals
Sewage Disposal: Not recommended, avoid discharge into sewers or waterways

Transport Information

UN Number: UN 3077
Proper Shipping Name: Environmentally hazardous substance, solid, n.o.s. (contains Sodium Metabisulfite)
Transport Hazard Class: Class 9 (Miscellaneous Dangerous Goods)
Packing Group: III
Marine Pollutant: Yes, if transported in bulk
Special Precautions: Keep packages dry, prevent transport with incompatible substances, follow instructions for emergency response
Labels: Appropriate hazard labels for road, sea, air, and rail transport as per regulations

Regulatory Information

Food Additive Status: Approved food preservative (E223) according to major food standards, subject to maximum allowable levels
OSHA: Regulated as a hazardous chemical
EPA: Classified as hazardous waste under certain conditions
EU Regulations: Listed in Annex II of Regulation (EC) No 1333/2008 for use in food
WHMIS Classification (Canada): D2B (Toxic Material Causing Other Toxic Effects)
SARA Title III: Listed - subject to reporting for quantities over threshold amounts
Labeling Requirements: GHS-compliant, including product identification, signal word, hazard and precautionary statements
Additional Information: Handlers require training in chemical safety; storage, handling, and disposal must align with OSHA, EPA, FDA, and EU guidelines