Selenium Dioxide Material Safety Data Sheet (MSDS)

1. Identification

Product Name: Selenium Dioxide
Chemical Formula: SeO₂
Other Names: Selenium(IV) oxide, Selenium dioxide
Recommended Uses: Laboratory reagent, catalyst in chemical synthesis, glass manufacturing, pigment
Supplier Name: Identify supplier contacts, address, and emergency phone number
Emergency Contact Number: Include local and international lines for chemical accidents

2. Hazard Identification

Classification: Classified as hazardous under GHS
Signal Word: Danger
Hazard Statements: Toxic if swallowed, inhaled, or absorbed through skin; causes severe irritation to eyes, skin, and respiratory system; may cause organ damage after repeated exposure
Pictograms: Skull and crossbones, corrosion, health hazard
Precautionary Statements: Avoid breathing dust or fumes, use only outdoors or in well-ventilated area, wear protective gloves and eye/face protection, wash thoroughly after handling, avoid release to the environment

3. Composition / Information on Ingredients

Chemical Name: Selenium Dioxide
CAS Number: 7446-08-4
EC Number: 231-194-7
Purity: 99% or as specified by the supplier
Hazard Components: Pure compound

4. First Aid Measures

Inhalation: Remove immediately to fresh air, seek medical attention if symptoms develop
Skin Contact: Remove contaminated clothing, rinse skin with plenty of water for fifteen minutes, get medical help for persistent irritation
Eye Contact: Rinse cautiously with water for several minutes, remove contact lenses if present and easy, continue rinsing, seek medical help
Ingestion: Rinse mouth, do not induce vomiting, seek medical attention promptly
Most Important Symptoms/Effects: Burning eyes and throat, cough, nausea, headache, irritation of mucous membranes
Immediate Medical Attention Needed For: Breathing problems, severe eye/skin burns, unconsciousness

5. Fire-Fighting Measures

Suitable Extinguishing Media: Use carbon dioxide, dry chemical, or foam; water may be used for cooling containers, but do not spray directly on substance
Specific Hazards: Produces toxic selenium and oxides fumes upon combustion, non-flammable but supports burning of combustibles
Protective Equipment: Self-contained breathing apparatus, full protective clothing
Advice for Firefighters: Fight fire from safe distance, avoid inhaling fumes, evacuate unnecessary personnel

6. Accidental Release Measures

Personal Precautions: Evacuate area, use personal protective equipment, avoid dust formation, ventilate area
Environmental Precautions: Prevent further leakage or spillage, do not let chemical enter drains or watercourses
Containment and Cleaning: Sweep up and collect in suitable, closed containers, avoid raising dust, ventilate area after clean-up, dispose as hazardous waste

7. Handling and Storage

Safe Handling: Handle in chemical fume hood, minimize dust generation, do not eat or drink in work area, wash hands after use
Storage Conditions: Store in tightly closed containers, keep in cool, dry well-ventilated space, separate from food and incompatible materials like reducing agents or strong acids
Specific Storage Recommendations: Use corrosion-resistant containers, label storage area clearly, maintain spill control measures near storage area

8. Exposure Controls and Personal Protection

Exposure Limits: OSHA PEL for selenium compounds as Se: 0.2 mg/m³ TWA, ACGIH TLV: 0.2 mg/m³ TWA
Engineering Controls: Use fume hood, local exhaust ventilation, keep workspaces clean and uncontaminated
Personal Protective Equipment: NIOSH-approved respirator for airborne concentrations, chemical-resistant gloves, safety goggles, lab coat, and apron
Environmental Controls: Keep material away from drains, install spill kits for selenium compounds

9. Physical and Chemical Properties

Appearance: White to slightly greyish crystalline solid
Odor: Pungent, irritating
Odor Threshold: Not established
pH: Not applicable
Melting Point: 340 °C
Boiling Point: 315 °C (sublimes)
Flash Point: Not applicable
Evaporation Rate: Not applicable
Flammability: Non-flammable
Solubility in Water: Soluble (55 g/100 ml at 25°C)
Vapor Pressure: Negligible at 20°C
Relative Density: 3.95 g/cm³ at 25°C
Partition Coefficient: Not determined
Decomposition Temperature: Decomposes at 315°C

10. Stability and Reactivity

Chemical Stability: Stable under normal conditions
Reactivity: Reactive with strong reducing agents and acids
Hazardous Reactions: Contact with acids forms toxic selenium vapors; reaction with organics may be vigorous
Conditions to Avoid: Moist air, high humidity, sources of ignition, incompatibles
Incompatible Materials: Strong reducing agents, acids, organic materials
Hazardous Decomposition Products: Selenium fumes, oxides of selenium

11. Toxicological Information

Routes of Exposure: Inhalation, skin contact, ingestion, eye contact
Acutely Toxic Effects: LD50 (oral, rat): 68 mg/kg, toxic by all routes; symptoms include nausea, vomiting, headache, metallic taste, abdominal pain, breath and sweat with garlic odor
Chronic Effects: Repeated exposure affects liver, kidneys, nervous system; chronic selenosis from long-term or high-level exposure
Irritation: Severe eye and skin irritation, redness and burns after direct contact
Sensitization: Not classified as sensitizer
Mutagenicity/Carcinogenicity: Not listed as a human carcinogen by IARC, NTP, or OSHA; some evidence of genotoxicity in animal studies

12. Ecological Information

Ecotoxicity: Highly toxic to aquatic life, even at low concentrations
Persistence and Degradability: Not readily biodegradable, persists in environment, risk of bioaccumulation
Bioaccumulative Potential: Can accumulate in organisms and move up food chains
Mobility in Soil: Moderate mobility; can leach to water bodies if released
Other Harmful Effects: Selenium compounds disrupt aquatic and soil ecology, risk to birds and mammals through food chain

13. Disposal Considerations

Waste Disposal Method: Dispose as hazardous chemical waste in accordance with local, regional, national, and international regulations
Contaminated Packaging: Treat as hazardous waste, clean thoroughly before recycling or disposal
Special Precautions: Do not release into sewers, ground, or surface waters; use licensed chemical waste contractors
Recommended Procedure: Collect and transfer material in sealed, clearly labeled containers; incineration under controlled conditions for selenium recovery

14. Transport Information

UN Number: 2657
UN Proper Shipping Name: Selenium dioxide
Transport Hazard Classes: 6.1 (toxic substance)
Packing Group: II
Marine Pollutant: Yes
Special Precautions for Transport: Use approved containers, prevent spillage, transport only by authorized carriers, check for restrictions in destination countries
Labels Required: Toxic, Marine Pollutant

15. Regulatory Information

US Regulations: Listed on TSCA, subject to SARA Title III reporting under Section 313
EU Regulations: Classified under CLP Regulation (EC) No 1272/2008; included in REACH candidate list
Canada: DSL/NDSL listed, subject to WHMIS regulations
Other Regulations: Subject to workplace exposure monitoring, special labeling and control procedures as hazardous substance in most jurisdictions
Restrictions: May require notification or license for import, export, or use in synthesis