Material Safety Data Sheet: Sodium Selenite

Identification

Product Name: Sodium Selenite
Chemical Formula: Na2SeO3
Other Names: Disodium selenite, Sodium selenate(IV)
CAS Number: 10102-18-8
Recommended Use: Laboratory reagent, glass manufacturing, supplemental feed additive
Supplier: Information varies by country; locate specific distributor on container
Emergency Contact: Refer to local authority or poison control for urgent support

Hazard Identification

Hazard Class: Acute Toxicity (Oral, Dermal, Inhalation), Aquatic Chronic Hazard
GHS Label: Skull and crossbones, environment, health hazard
Signal Word: Danger
Hazard Statements: Toxic if swallowed, toxic in contact with skin, toxic if inhaled, may cause organ damage through prolonged or repeated exposure, very toxic to aquatic life
Precautionary Statements: Avoid all unnecessary exposure, wear protective gear, do not eat, drink, or smoke when handling, avoid release into environment, use in well-ventilated area, keep away from incompatible substances

Composition / Information on Ingredients

Chemical Name: Sodium Selenite
Common Synonyms: Disodium selenite
Concentration: Pure substance, technical grades available
Impurities: Not significant at standard laboratory grades; refer to certificate of analysis for batch impurities

First Aid Measures

Inhalation: Move person to fresh air immediately, keep at rest, seek medical attention for symptoms of poisoning such as headache, nausea, dizziness, and breathing trouble
Skin Contact: Remove contaminated clothing, flush skin thoroughly with water for at least 15 minutes, seek medical attention for symptoms of redness, swelling, or other irritation
Eye Contact: Rinse cautiously with running water for a minimum of 15 minutes, remove contact lenses if present and easy to do, consult a physician
Ingestion: Rinse mouth, do not induce vomiting, seek medical help without delay, provide information on the compound to emergency responders
Key Symptoms: Gastrointestinal distress, respiratory distress, convulsions, shock, symptoms may appear delayed

Fire-Fighting Measures

Suitable Extinguishing Media: Use water spray, dry chemical, foam, or carbon dioxide for small fires
Unsuitable Extinguishing Media: Avoid water jets that might spread hazardous material
Fire Hazards: Sodium selenite does not combust, but exposure to heat may lead to toxic fume emissions including selenium and sodium oxides
Protective Equipment: Full protective gear, self-contained breathing apparatus, avoid inhaling fumes
Advice for Firefighters: Withdraw if safe fire-fighting becomes impossible; prevent runoff from entering waterways

Accidental Release Measures

Personal Precautions: Evacuate unnecessary personnel, wear chemical-resistant clothing, gloves, goggles, dust mask or respirator
Environmental Precautions: Avoid release into drains, soils, or water bodies, report to relevant authorities if large spill occurs
Clean Up Methods: Sweep up with non-sparking tools, collect for disposal in sealed containers, ventilate area, wash contaminated surfaces thoroughly
Decontamination: Use damp cloths to minimize dust, dispose of material as hazardous waste, wash contaminated clothing separately

Handling and Storage

Handling Precautions: Do not handle without proper training and personal protective equipment, minimize dust generation, keep away from food, beverages, and feed, observe strict hygiene
Safe Storage Conditions: Store in tightly closed containers, in dry, well-ventilated, secure locations away from incompatible materials (acids, strong oxidizers), label storage clearly, keep away from children and unauthorized users
Special Requirements: Maintain inventory control, restrict access, inspect storage containers regularly for signs of corrosion or leakage

Exposure Controls and Personal Protection

Occupational Exposure Limit: OSHA PEL: 0.2 mg/m³ (as selenium compound), ACGIH TLV: 0.2 mg/m³
Engineering Controls: Use enclosures, local exhaust ventilation, fume hoods to prevent exposure
Personal Protective Equipment: Chemically resistant gloves (nitrile or neoprene), safety goggles, lab coat or chemical suit, respirators or dust masks under high dust conditions, safety showers and eyewash stations nearby
Hygiene Measures: Wash hands and face after use, remove contaminated clothing, do not eat, drink or smoke during working
Environmental Controls: Prevent discharge into environment, use containment systems for dust or spills

Physical and Chemical Properties

Appearance: White or slightly off-white crystalline powder
Odor: Odorless
Molecular Weight: 172.94 g/mol
Melting Point: 710 °C (decomposes)
Solubility: Soluble in water, insoluble in alcohol
Boiling Point: Decomposes before boiling
pH (10% solution): Approx. 9
Density: 2.6 g/cm³
Vapor Pressure: Not volatile under standard conditions
Flash Point: Not applicable
Oxidizing Properties: Not classified as an oxidizer

Stability and Reactivity

Chemical Stability: Stable under recommended storage and handling conditions
Reactivity: Reacts with acids to release toxic selenium dioxide fumes, reacts with oxidizers and strong reducing agents producing hazardous gases
Conditions to Avoid: Exposure to acids, high humidity, heat
Incompatible Substances: Strong acids, strong oxidizers, reducing agents
Hazardous Decomposition Products: Selenium oxides, sodium oxides, toxic metal fumes in fire

Toxicological Information

Routes of Exposure: Inhalation, ingestion, skin, and eye contact
Acute Toxicity: LD50 (oral, rat): 4 mg/kg (highly toxic), toxic by skin absorption and inhalation
Symptoms: Metal fume fever, garlic breath, nausea, vomiting, abdominal pain, pulmonary edema, possible fatality at high doses
Chronic Effects: Selenosis with symptoms such as hair loss, nail brittleness, skin eruptions, nervous system depression after prolonged high exposure
Carcinogenicity: Not classified as carcinogenic by IARC or EPA, but research continues on chronic effects
Mutagenicity and Reproductive Effects: Animal studies suggest possible developmental toxicity with prolonged high exposure, current workplace limits focus on strict prevention of overexposure

Ecological Information

Aquatic Toxicity: Extremely toxic to aquatic organisms, acute and chronic exposure can disrupt ecosystem balance, cause fish kills
Persistence and Degradability: Not readily biodegradable, can persist in sediments
Bioaccumulative Potential: Accumulates in aquatic life and food chains, entering higher predators
Mobility in Soil: Mobile in moist soils, can migrate to groundwater
Other Adverse Effects: Affects birds and mammals feeding in contaminated areas, not safe for landfill without controls

Disposal Considerations

Disposal Methods: Treat as hazardous waste, use permitted waste contractor, incinerate or chemical treat residue according to local, state, and national regulations
Container Disposal: Rinse thoroughly, triple rinse if possible, return for recycling or dispose through hazardous waste collection
Environmental Precautions: Avoid disposal into sewers or natural environment; do not bury in unlined landfill
Special Precautions: Document all disposal steps for audit and regulatory review

Transport Information

UN Number: UN2630
Proper Shipping Name: Sodium Selenite
Shipping Hazard Class: 6.1 (Toxic substances)
Packing Group: II (Medium danger)
Special Transport Precautions: Secure tightly, segregate from food and feed during transit, ensure placard labels visible, transport staff trained in hazard awareness and spill management
Transport Documentation: Comply with local, national, and international documentation and tracking rules

Regulatory Information

Workplace Safety: Listed as hazardous by OSHA, EU REACH, and other international agencies
USA Regulations: OSHA hazard communication standard, CERCLA hazardous substance, EPA Toxic Release Inventory
EU Regulations: CLP/GHS, REACH Annex III, Environmental Quality standards
Canada: DSL/NDSL status, WHMIS categories
Other Considerations: Many regions require written safety assessments, staff hazard training, environmental impact notifications for use and disposal