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Product Name: Osmium Tetroxide
Chemical Formula: OsO4
Synonyms: Osmium(VIII) oxide
CAS Number: 20816-12-0
Recommended Uses: Chemical reagent, microscopy staining
Manufacturer Information: Contact chemical supplier for updated address and phone
Emergency Contact: Refer to local/national poison control center or emergency telephone
Classification: Acute Toxicity (Oral, Dermal, Inhalation), Skin Corrosion/Irritation, Eye Damage, Specific Target Organ Toxicity
Signal Word: Danger
Hazard Statements: Fatal if inhaled, in contact with skin or swallowed; causes severe skin burns and eye damage; may cause respiratory irritation
Pictograms: Skull and crossbones, Corrosive, Exclamation Mark
Precautionary Statements: Avoid breathing dust or vapors; wear protective gear; use only inside chemical fume hood; keep container tightly closed; wash hands after use
Potential Health Effects: May cause blindness, severe lung injury, systemic toxicity, skin necrosis; chronic exposure may lead to kidney or nervous system damage
Routes of Exposure: Inhalation, skin, eye contact, ingestion
Chemical Name: Osmium Tetroxide
Concentration: 100%
CAS Number: 20816-12-0
Impurities or Stabilizing Additives: None reported in pure form
Inhalation: Remove person to fresh air; provide oxygen if breathing is difficult; seek immediate medical attention; avoid breathing aerosol during rescue
Skin Contact: Remove contaminated clothes; flush skin with plenty of water (15-20 minutes minimum); seek medical attention promptly
Eye Contact: Rinse cautiously with water for several minutes (lifting eyelids); continue rinsing; seek immediate medical help
Ingestion: Rinse mouth thoroughly with water; do not induce vomiting; call a poison control center or physician at once
Most Important Symptoms: Eye and skin burns, coughing, sore throat, shortness of breath, vision loss, headache
Note to Physician: Treat symptomatically; osmium tetroxide has delayed pulmonary and nervous system toxicity
Suitable Extinguishing Media: Use dry chemical, CO2, or foam—do not use water directly on substance; cool containers exposed to flame
Specific Hazards: Emits toxic fumes of osmium oxide and gases under fire; substance itself is not flammable but oxidizes combustible material
Special Protective Equipment: Wear self-contained breathing apparatus and protective gear; isolation from all personnel not involved in firefighting recommended
Fire-Fighting Procedures: Move containers from fire area if possible and safe; prevent runoff from contaminating water supplies
Personal Precautions: Evacuate untrained personnel; ventilate area; avoid breathing vapors or contact with skin and eyes
Protective Equipment: Chemical-resistant gloves (nitrile or neoprene), safety goggles, laboratory coat, full-face shield, positive pressure respirator for high exposures
Spill Cleanup: Absorb with inert, damp (not dry) material; avoid dust; use sealed container for waste; decontaminate area with reducing agent (e.g., sodium thiosulfate)
Environmental Precautions: Prevent substance from entering drains, sewers, or water sources; notify authorities in the event of large spill
Emergency Procedures: Restrict access, air handling shut-off, contain the spread and ventilate
Handling: Always use in chemical fume hood; avoid generating gases or vapors; prohibit eating, drinking, or smoking in area
Storage: Store tightly sealed in cool, dry, well-ventilated, secure area away from organics, combustibles, reducing agents; use resistant containers (glass, metal)
Technical Measures: Use piping and containment resistant to strong oxidizers; implement secondary containment
Safe Transfer: Use tools to minimize handling, avoid static discharge or shaking
Storage Incompatibilities: Strong acids, bases, organics, most metals—reacts violently with many materials
Exposure Limits: OSHA PEL: 0.002 mg/m3 (TWA); ACGIH TLV: 0.0002 ppm (0.0016 mg/m3)
Engineering Controls: Laboratory fume hood; exhaust ventilation; glovebox use for dry transfer
Personal Protective Equipment: Safety goggles, face shield, impervious gloves, chemical apron; powered respirator or air-supplied mask for high concentrations
Hygiene Measures: Remove and wash contaminated clothing before reuse; thorough hand and face washing after handling
Monitoring: Regular air monitoring for vapor in work areas strongly advised
Appearance: Colorless to pale yellow crystals or solid
Odor: Sharp, chlorine-like, pungent
Molecular Weight: 254.23 g/mol
Melting Point: 40°C (104°F)
Boiling Point: 130°C (266°F)
Solubility: Moderately soluble in water; soluble in organic solvents (chlorinated hydrocarbons, alcohols)
Vapor Pressure: 7 mm Hg at 21°C
Density: 4.9 g/cm3
pH: Acidic in aqueous solution
Partition Coefficient: Data unavailable
Flash Point: Not applicable (not flammable); oxidizer
Evaporation Rate: Data not available
Chemical Stability: Stable under recommended conditions; sublimes easily at room temperature
Incompatibility: Reacts explosively with most organic materials, strong reducing agents, some plastics; avoid amines, alkali metals
Hazardous Decomposition Products: Releases osmium fumes and oxides
Polymerization: Will not occur
Conditions to Avoid: Heat, light, shock, contamination, any incompatible materials
Acute Toxicity: Highly toxic if swallowed, inhaled or absorbed through skin; estimated lethal dose orally in humans is below 1 mg/kg
Skin Corrosion / Irritation: Causes severe skin burns, blisters, necrosis
Eye Damage / Irritation: May cause permanent vision loss, severe eye burns
Respiratory Effects: Extreme irritation, chemical pneumonitis, delayed lung injury
Sensitization: Not well established; rare allergy reports
Chronic Toxicity: Kidney and nervous system effects after repeated exposure
Carcinogenicity: Not classified by IARC/NTP; insufficient evidence
Mutagenicity: Data limited; not confirmed as mutagenic
Signs of Exposure: Sore throat, bronchitis, nosebleeds, skin rash, ocular damage, pulmonary edema, confusion, convulsions
Aquatic Toxicity: Extremely hazardous to aquatic organisms; highly toxic to fish, invertebrates
Persistence and Degradability: Not readily degraded; remains in soils and sediments
Bioaccumulation Potential: High potential to bioaccumulate in aquatic food chains
Mobility: Migrates in both soil and water; high vapor pressure increases atmospheric transport
Other Harmful Effects: Mobile and persistent heavy metal oxide; possible risk to drinking water sources
Disposal Methods: Collect as hazardous waste; containerize in sealed, appropriately labeled drums; follow all federal, state, and local regulations; professional incineration in equipped facility
Prevent Release: Never dispose in ordinary trash, sink, or landfill; never dilute intentionally
Disposal of Contaminated Containers: Rinse with sodium thiosulfate solution, neutralize, triple rinse, label and dispose as hazardous waste
UN Number: UN 2471
Proper Shipping Name: Osmium Tetroxide
Transport Hazard Class: 6.1 (Toxic substances)
Packing Group: I (highest danger)
Labels: Toxic, Corrosive
Special Provisions: Emergency response guide must be accessible; immediate reporting requirements for spills
Environmental Hazards: Marine pollutant; prohibited on passenger aircraft
Transport in Bulk: Special packaging and shipment documentation required
OSHA: Regulated as a highly hazardous material
EPA: Listed as an extremely hazardous substance; subject to spill reporting under CERCLA
SARA Title III: Extremely hazardous, significant thresholds apply for reporting
TSCA: Listed
International Regulations: Subject to strict European REACH, GHS classifications; Canadian, Japanese, and Australian law restrictions
State Regulations: California Proposition 65—Not listed; state worker safety agencies may have stricter policies
Workplace Controls: Exposure monitoring, written hazard communication, medical surveillance, emergency protocols
