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Chemical Name: Sodium Metarsenite
Synonyms: Sodium Arsenite, Disodium Arsenite
Chemical Formula: NaAsO2
Appearance: White to grayish, crystalline powder or lumps, slightly soluble in water
Odor: Faint, not easily detectable under normal use
Intended Use: Primarily used in chemical synthesis, wood preservation, sometimes in laboratory research
Hazard Classification: Highly toxic and dangerous to human health and the environment
Hazard Categories: Acute toxicity (oral, dermal, inhalation), carcinogenicity, environmental toxicity
Main Health Risks: High risk of poisoning through skin contact, swallowing, or breathing dust; can cause severe organ damage, especially to liver, kidneys, nervous system
Physical Hazards: Dust can form explosive mixtures in air; reacts dangerously with acids producing poisonous gases
Label Symbols: Skull and Crossbones, Health Hazard (carcinogen), Environment (aquatic toxicity)
Warning Statements: Fatal if inhaled, swallowed, or in contact with skin; causes cancer; highly toxic to aquatic life with long-lasting effects
Main Component: Sodium Metarsenite, usually above 97% purity in commercial stock
Hazardous Impurities: Arsenic trioxide, sodium arsenate may be present as contaminants in trace amounts, raising risk for extra toxicity
Stabilizers/Additives: Typically manufactured pure, without stabilizers
Inhalation: Move exposed person to fresh air right away; respiratory distress can follow with little warning; oxygen or artificial respiration may be necessary
Skin Contact: Remove contaminated clothing and wash skin with large amounts of water and soap, monitoring for burns or allergic reactions
Eye Contact: Rinse eyes for at least 15 minutes with gentle, continuous water flow, keeping eyes wide open
Ingestion: Medical emergency — do not induce vomiting; seek professional help immediately; activated charcoal sometimes used
General Comments: Medical intervention often required due to life-threatening toxicity; close observation for delayed symptoms is crucial; rescuers must avoid exposure
Suitable Extinguishing Media: Use dry chemical powder, foam, or carbon dioxide extinguishers; water spray only in small quantities to avoid toxic runoff
Specific Hazards: Highly poisonous arsenic fumes can form in fire; avoid using direct jets of water which spread contamination
Protective Equipment for Firefighters: Full protective gear and positive pressure self-contained breathing apparatus needed to prevent exposure to toxic smoke
Combustion Products: Arsenic oxides and sodium compounds, both extremely hazardous if inhaled or settled on surfaces
Personal Precautions: Wear chemical resistant clothing, gloves, goggles, and suitable mask (P3/P100 level filtration); keep unprotected people away
Environmental Precautions: Prevent entry into sewers, ground water, or natural waterways because of irreversible contamination risk
Cleanup Methods: Use HEPA-filtered vacuums or wet dust suppression methods; never sweep dry powder; contain and collect spilled material in sealed, labeled containers for disposal
Decontamination: Avoid using strong acids or bases during cleanup as hazardous gases may form
Disposal: All collected material and used personal protective equipment require handling as hazardous waste
Safe Handling Advice: Only work with the substance in well-ventilated areas or fume hoods; avoid skin and eye contact at all costs; never eat, drink, or smoke near handling zones
Incompatible Materials: Keep away from acids, strong oxidizers, and reducing agents because of highly toxic gas risk
Storage Requirements: Store in sealed, tightly-closed containers made from resistant materials like polyethylene or glass; label storage units clearly with toxic hazard warnings; keep separate from food and drink
Access Control: Only trained and authorized people should access storage or work areas; always use spill trays and containment measures
Storage Location: Keep entirely away from watercourses, basements, and uncontrolled public areas
Exposure Limits: OSHA and ACGIH set low permissible exposure limits (e.g., 0.01 mg/m³ for arsenic compounds, as respirable dust)
Engineering Controls: Must use local exhaust ventilation, closed systems, or glove boxes when handling even small quantities
Personal Protection: Chemical-resistant gloves (not simple latex), barrier aprons, goggles or face shields, and respiratory protection rated for particulates and gases (P3/P100 or better); keep personal protective equipment in good repair, and replace immediately after contamination
Hygiene Measures: Wash hands and exposed skin thoroughly after handling; do not reuse contaminated gloves or clothing; keep workspaces clean and decontaminated
Physical State: Crystalline powder or solid, sometimes slightly granular
Color: White to gray, can take on yellowish tint with impurities
Solubility: Slightly soluble in water, forms a toxic, basic solution
Melting Point: Decomposes on heating rather than melting cleanly
Odor: Barely perceptible
Other Noteworthy Properties: Dust can become airborne easily, raising inhalation hazard; reacts badly with acids producing arsine or arsenic oxides
Chemical Stability: Stable when stored away from light, moisture, and acids; degrades under humid or warm conditions
Incompatible Materials: Highly reactive with acids, strong oxidizers (risk of arsenic gas evolution), ammonium salts
Hazardous Decomposition Products: Arsenic oxides, sodium oxides, arsine (with acid contact); all decomposition products are extremely toxic
Polymerization: Not likely to polymerize
Conditions to Avoid: Dampness, high heat, acidic or oxidative environments
Exposure Symptoms: Nausea, vomiting, stomach pain, diarrhea, muscle weakness, headache, confusion, in severe cases convulsions or coma
Long-Term Effects: Chronic exposure can cause skin lesions, reduced nerve function, anemia, organ damage, cancer (especially lung and skin), possible genetic damage
Routes of Exposure: Main risk by inhalation of dust, but absorption through skin and swallowing are real dangers
Lethal Dose: Extremely low; even less than a gram can be fatal to humans
Carcinogenic Status: Classified as carcinogenic to humans according to major health authorities
Environmental Hazard: Highly toxic to aquatic lifeforms, both in freshwater and marine systems
Persistence: Does not break down quickly in the environment; arsenic compounds can accumulate in soil, water, and biological systems, contaminating food chains and posing long-term ecosystem risks
Bioaccumulation: Tends to concentrate in plants, animals, and eventually people who eat contaminated food
Mobility: Soluble fraction can migrate easily through water systems, contaminating drinking supplies and agricultural soil
Waste Classification: Regarded as hazardous waste everywhere
Disposal Routes: Must go only to approved hazardous waste facilities with incineration or deep secure landfill capacity
Incineration: Should only be carried out in controlled settings with scrubbing and absorption of arsenic-laden exhaust gases
Don’ts of Disposal: Never pour or dump down drains, soil, or regular trash, due to severe water and food chain risks
Containers: All bags, gloves, and packaging contaminated with the substance must be handled by trained hazardous waste handlers
Shipping Classification: Classified as dangerous goods under major transport regulations (UN 1685)
Packing Instructions: Must use sealed, clearly labeled, robust containers resistant to breaking or leaking; no mixed loads with foodstuffs or incompatible chemicals
Transport Requirements: Trucking or rail movement often needs advance notification and special documentation; accidental release poses emergency response risks
Accident Procedures: Transporters must carry spill management gear and know emergency contacts for hazardous material response
Occupational Health Guidelines: Exposure must remain below national or regional limits due to arsenic’s carcinogenic risk; workplace air must be monitored regularly; workers involved in production or handling report for health checks
Environmental Limits: Discharge to environment strictly forbidden by environmental regulators; water supplies must test below strictest arsenic limits (often 10 μg/L)
Labeling Laws: Packaging must feature clear warnings in line with global hazard systems (e.g., GHS, CLP); inclusion of skull + crossbones and aquatic hazard signs demanded by law
Special Handling Requirements: Restricted to licensed operations; documentation for every stage of shipping, use, and disposal is mandatory
