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Product Name: Selenic Acid
Synonyms: Selenium(VI) oxide solution, Selenium oxyacid
Chemical Formula: H2SeO4
CAS Number: 7783-85-9
Recommended Use: Laboratory reagent, oxidizing agent
Manufacturer Information: Chemical suppliers typically include manufacturing, distribution, and emergency contact details.
Classification: Oxidizer, corrosive, acutely toxic
Hazard Pictograms: Corrosive, Health hazard, Oxidizer
Hazard Statements: Causes severe skin burns and eye damage; Harmful if inhaled; May cause damage to organs through prolonged exposure; Strong oxidizer, may cause or intensify fire
Precautionary Statements: Do not breathe fumes; Use protective gloves and eye protection; Wash hands thoroughly after use; Store locked up and away from incompatible substances
Ingredient: Selenic Acid
Concentration: Typically supplied as 100% or aqueous solution of variable strength
Chemical Formula: H2SeO4
CAS Number: 7783-85-9
Impurities: Trace amounts of other selenium compounds possible depending on synthesis route
Inhalation: Remove to fresh air. Seek immediate medical attention. Give oxygen if breathing is difficult. Symptoms from inhaling fumes can show up fast.
Skin Contact: Quickly flush skin with water for at least 15 minutes. Remove contaminated clothing; keep rinsing skin. Medical help is needed because selenic acid burns deep and keeps hurting.
Eye Contact: Rinse eyes cautiously with water for several minutes, lifting eyelids. Take out contact lenses if present and keep rinsing. Do not delay seeking medical help. Eyes stand very little chance against this acid without help.
Ingestion: Rinse mouth. Do not induce vomiting. Never give anything by mouth to an unconscious person. Emergency medical assistance is mandatory because selenic acid is highly toxic.
Suitable Extinguishing Media: Use water spray, foam, dry chemical, or carbon dioxide, but do not squirt water straight into container due to risk of violent reaction.
Specific Hazards: Strong oxidizer drives risk of explosive combustion with organic materials or reducing agents. During fire, toxic selenium oxides may form.
Special Protective Equipment: Chemical splash suit, self-contained breathing apparatus; smoke and fumes must not be breathed. Isolate hazard area. Approach from upwind.
Personal Precautions: Get everyone out of the spill area who does not need to be there. Ventilate place. Put on acid-resistant gloves, goggles, and a respirator.
Environmental Precautions: Do not let spillage reach drains, soil or water bodies because selenic acid hurts aquatic life even at low concentrations.
Methods for Cleaning Up: Absorb spill with inert, non-combustible material such as dry sand or vermiculite. Place residue in labeled, sealed containers for safe disposal. Rinse area with copious water but collect any rinse to avoid contaminating the environment.
Handling: Only use in well-ventilated laboratory settings with proper training. Wear splash-proof eye protection, gloves, and acid-resistant apron. Do not mix with combustible materials or reducing agents. Wash hands thoroughly after handling.
Storage: Keep container tightly closed in a cool, dry and well-ventilated area. Store away from direct sunlight and sources of ignition. Incompatible with organics, alkalis, powdered metals, sulfur, and most lab solvents. Segregate from food and feedstuffs.
Engineering Controls: Use with fume hood. Provide mechanical exhaust to minimize vapor buildup.
Respiratory Protection: Respirator selected specifically for acid fumes. Cartridge respirators with acid-gas cartridges typically recommended.
Eye Protection: Tight-fitting chemical splash goggles and a face shield.
Skin Protection: Acid-resistant gloves—neoprene or nitrile offer good protection. Lab coats and chemical aprons required. Emergency showers and eyewash stations strongly advised.
Work Practice Controls: Lock up acid in secured cabinet. Spill control materials within arm’s reach. Staff get regular safety training, and keep records up to date.
Appearance: Clear, colorless liquid or white needles in solid form, often emits strong, stinging acid smell
Odor: Acidic, pungent
pH: <1 (very acidic)
Melting Point: 26–28°C (solidifies at room temperature)
Boiling Point: Decomposes above 140°C
Solubility: Highly soluble in water, generates heat and fumes
Vapor Pressure: Low at room temperature, but fumes may irritate nose and throat
Density: 2.5 g/cm³ (solid); aqueous solution density varies
Other Propeties: Decomposes in strong heat or light; strong dehydrating agent
Chemical Stability: Stable under recommended storage conditions, but decomposition starts quickly with heat or poor ventilation.
Reactivity: Reacts strongly with organic matter, combustibles, reducing agents, alkalis, and metals. Creates selenium compounds and toxic gases.
Incompatible Materials: Flammable solvents, ammonium compounds, sulfides, powdered metals, bases.
Hazardous Decomposition: Emits highly toxic selenium oxides and potentially explosive gases during fire or strong heat.
Acute Toxicity: Highly toxic even at small doses. Inhalation and skin contact can cause burns, corrosion, and toxic absorption. Swallowing proves rapidly poisonous and demands emergency medical care.
Chronic Effects: Prolonged exposure leads to selenium buildup in tissues, causing hair loss, nerve damage, skin eruptions, and risk of organ damage.
Symptoms of Exposure: Breathing problems, corrosive burns, vomiting, diarrhea, metallic taste, garlic odor in breath, convulsions.
Carcinogenicity: No proven human carcinogenic link, but studies suggest selenium compounds need cautious handling.
Mutagenicity: Some evidence in lab tests; selenic acid must never contact broken skin or eyes. High-risk chemical.
Ecotoxicity: Very toxic for aquatic life, even small traces suffocate fish and damage aquatic food chains.
Mobility: Spreads rapidly in water, doesn’t degrade fast, so it travels far and sticks around.
Persistence and Degradability: Not easily broken down. Tends to bioaccumulate, especially in sediments and living things.
Bioaccumulative Potential: Builds up in animal and plant tissue, putting anyone eating affected food at risk.
Other Adverse Effects: Selenium poisoning from runoff can knock out birds, fish, and micro-organisms, leading to major ecosystem collapse if released.
Waste Treatment: Selenic acid counts as hazardous waste. Collection and neutralization must only happen by trained professionals using proper acid neutralization procedures.
Disposal Methods: Seal liquid or solid residues in approved acid-resistant containers. Label waste clearly for hazardous collection. Approved incinerators with specialized filters cut down toxic releases.
Do Not: Pour selenic acid down drains, onto soil or into regular trash. Contaminated containers need to be cleaned by acid-neutralization specialists before discarding.
UN Number: UN1831
Proper Shipping Name: Selenic Acid, solution
Hazard Class: 8 (Corrosive), 5.1 (Oxidizer)
Packing Group: I (high danger – strict controls required)
Labels: Corrosive, Oxidizer
Special Precautions: Emergency transport instructions carry big penalties for mistakes. Drivers use full chemical PPE and follow approved routes only. Containers must not leak nor ride near food shipments.
Environmental Hazards: Spill kits and emergency response protocols travel with every shipment.
OSHA Status: Selenic acid meets criteria for hazardous chemical under OSHA regulations. Workers receive special training and hazard communication materials specifics.
TSCA Status: Selenic acid listed in the US Toxic Substances Control Act inventory.
International Inventory: Selenic acid appears on Canadian DSL, European EINECS/ELINCS, and Japanese ENCS lists.
Labeling Requirements: Product containers must carry recognized danger symbols, detailed handling instructions, and emergency contact details.
Reportable Quantities: Major spills require reporting to national and local EPA authorities. Documentation of storage and disposal required and regularly audited.
Other Regulations: Extra controls often come from local fire, environmental, and workplace safety agencies. End users check with all relevant agencies before buying, using, or discarding selenic acid.
