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Chemical Name: Sodium Hydroxide
Common Names: Lye, Caustic Soda
Formula: NaOH
Color/Appearance: Clear, colorless, odorless liquid
Main Use: Cleaning agent, pH adjustment, industrial processing, wastewater treatment
Recognized By: Highly corrosive label and strong alkaline properties
Main Hazards: Causes severe burns on skin and eyes, respiratory irritation, possible permanent injury
Signal Word: Danger
How It Harms: Eats through tissue quickly, even short exposure to skin can lead to deep burns; eye contact risks blindness; inhalation can damage airways
GHS Classification: Skin Corrosion/Irritation (Category 1A), Serious Eye Damage (Category 1)
Environmental Note: Harmful to aquatic life due to high alkalinity, can upset water chemistry
Major Component: Sodium Hydroxide: typically 30-50% by weight in solution
Impurities: Trace metals, sodium carbonate from manufacturing
Water: Used as solvent for the caustic soda
No notable stabilizers or additives: Just water and sodium hydroxide in most commercial mixes
Eyes: Rinse at once with plenty of water, keep eyelids apart, go straight to a doctor; delays can spell vision loss
Skin: Strip contaminated clothing, flush skin under running water for at least 15 minutes; seek immediate medical attention
Inhalation: Get into fresh air, stay calm; if breathing troubles begin, call emergency services
Ingestion: Do not induce vomiting; rinse mouth with plenty of water and rush to the hospital
Key Tip: Immediate action gives the best chance to minimize permanent injury
Not Flammable: Sodium hydroxide won’t catch fire
Reacts With Metals: Can release hydrogen gas when it touches some metals, and hydrogen will burn or explode if ignited
Protective Gear: Full chemical suit and self-contained breathing device needed for responders, even if flames aren’t the biggest threat
Extinguishing Media: Use powder, foam, or carbon dioxide to douse fires near caustic soda; water may cause splattering
Fire Byproducts: Potential for toxic fumes if mixed with organic materials
Containment: Isolate spill zone, keep unprotected people far from the scene
Personal Protection: Suit up with chemical-proof gloves, boots, face shield, and goggles
Cleanup: Neutralize spill (if safe) with dilute acid or lots of water; collect gently with non-metal tool; avoid splashing
Ventilation: Keep air moving to clear vapors
Avoid Drains: Do everything possible to keep sodium hydroxide away from sewers and water bodies, since it can devastate aquatic habitat
Storage Containers: Use high-density polyethylene or other alkali-resistant materials
Keep Tightly Sealed: Sodium hydroxide loves grabbing water and carbon dioxide from the air, which can mess with its potency
Cool, Dry, Ventilated Place: Overheating or contact with moisture ramps up risk of leaks or container failure
Segregate: Keep far from acids, metals, and organic peroxides
Label Clearly: No one should grab a jug by mistake; make sure every container screams “corrosive” on the label
Engineering Controls: Local exhaust fans, splash guards, closed systems to keep fumes away
Respiratory Protection: Wear an NIOSH-approved respirator if vapor could form
Eye Protection: Full-seal goggles, no shortcuts, shield if risk of splash
Skin Protection: Impermeable gloves, suit, boots made for chemical resistance
Workplace Hygiene: No eating/drinking/smoking in work zones, wash up before breaks or leaving — caustic burns can come from surprise smears on your hands
Appearance: Clear, colorless, slippery liquid
Odor: No strong smell, but your nose will sting if vapors are high
pH: Extremely high, over 13
Boiling Point: 135°C for concentrated solutions
Melting Point: Not relevant for liquid form
Solubility: Dissolves easily in water, releases heat fast on mixing
Density: Around 1.5 g/cm³ for 50% solution
Vapor Pressure: Low at room temperature, but rising fast with heat
Chemical Stability: Holds stable under normal storage, but reacts madly with acids
Reactivity: Eats through aluminum, tin, and some plastics; attacks body tissues on contact
Hazardous Reactions: Intense heat and splatter from adding water too fast; hydrogen gas formed with metals
Incompatible Materials: Keep far from acids, ammonium salts, organic chlorinated solvents, and sugars
Hazardous Byproducts: Hydrogen gas and caustic mists in certain conditions
Main Route of Damage: Burns to eyes, skin, airways, and digestive tract on contact
Acute Effects: Painful burning, tissue destruction, in severe cases permanent loss of function (like blindness or scarring)
Long-Term Effects: Chronic respiratory issues, scarring, sensitivity of affected skin patches
Not Linked to Cancer: No proof of it being a carcinogen, but irreversible injury from careless handling cannot be overstated
LD50 (oral, rat): Estimated around 140-340 mg/kg, but for people, focus on avoiding exposure altogether
Aquatic Toxicity: Large spills flip pH fast, wipe out fish and aquatic insects
Persistence: Not persistent—breaks down in environment, but can do massive pH damage before dilution
Bioaccumulation: Doesn’t build up in animal tissues
Key Risk: Alkalinity, not chemical buildup
Practical Point: Any leak to sewer or river should spark urgent response; water bodies recover, but not if huge volumes hit at once
Neutralization: Dilute and neutralize using a compatible acid with good ventilation and slow addition
Waste Codes: Depends on local regulations for corrosive wastes
Treatment: Neutralized solution may be discharged if permitted, strict compliance with discharge authorities needed
Do Not Dump: Pouring raw caustic soda down the drain without approval endangers both sewers and waterways
Container Disposal: Triple-rinse, neutralize residues, destroy or return to proper waste facility
UN Number: UN1824 (for liquid sodium hydroxide)
Hazard Class: 8 (Corrosive)
Packing Group: II or III depending on concentration
Labels Required: Corrosive, no room for guesswork
Segregation: Keep away from acids and foodstuffs during transit
Transport Conditions: Secure, upright drums or totes, protected from bumps and leaks; emergency spill kit required on board
Occupational Limits: Most regulatory agencies cap workplace exposure (OSHA PEL: 2 mg/m³ ceiling)
Hazard Symbols: Corrosive pictogram on all labels
Transport Rules: International and national regulations demand clear labeling and strict container specs
Environmental Laws: Restrictions for discharge to water bodies; reporting required for major spills
Worker Rights: Every worker must receive proper training before handling sodium hydroxide, including full explanation of risks and protective steps
