Material Safety Data Sheet: Caustic Soda (Sodium Hydroxide)

Identification

Product Name: Caustic Soda
Chemical Name: Sodium Hydroxide
Synonyms: Lye, Soda Lye, NaOH, White Caustic
CAS Number: 1310-73-2
Recommended Use: Chemical manufacturing, soap production, water treatment, cleaning products
Manufacturer: Listed on product packaging or company records
Emergency Contact Info: Provided by supplier or manufacturer, usually found on the product label

Hazard Identification

Classification: Corrosive to metals, causes severe skin burns and eye damage, hazardous to the environment
Hazard Symbols: Corrosive (GHS05), Exclamation Mark (GHS07)
Signal Word: Danger
Hazard Statements: Causes severe skin burns and eye damage; may cause respiratory irritation; contact with water releases heat
Precautionary Statements: Avoid breathing dust or mist, wash skin thoroughly after handling, wear protective gloves, eye and face protection, ensure good ventilation

Composition / Information on Ingredients

Chemical Identity: Sodium Hydroxide
Concentration: 98-100% for solid, 20-50% for solutions depending on commercial grade
Impurities: Trace amounts of sodium chloride, sodium carbonate, iron oxide (depending on manufacturing process)
Other Information: Contains no additives or stabilizers in commercially pure form

First Aid Measures

Inhalation: Remove person to fresh air immediately, keep at rest, seek medical attention if breathing is difficult
Skin Contact: Remove contaminated clothing, rinse skin thoroughly with water for at least 15 minutes, get medical help
Eye Contact: Flush eyes with running water for at least 30 minutes, lifting eyelids, seek immediate medical attention
Ingestion: Rinse mouth, do not induce vomiting, give water to dilute if conscious, seek emergency medical care
Self-Protection: Avoid direct exposure, always use personal protection equipment while administering first aid

Fire-Fighting Measures

Suitable Extinguishing Media: Dry chemical, carbon dioxide, alcohol-resistant foam, do not use water directly on caustic soda spills as it reacts vigorously
Specific Hazards: Not flammable but reacts exothermically with water and some metals, produces toxic fumes
Protective Equipment: Wear self-contained breathing apparatus, chemical-resistant suit, avoid skin and eye contact
Advice for Firefighters: Keep upwind, evacuate area, prevent runoff from entering drains or water sources

Accidental Release Measures

Personal Precautions: Use full personal protection including gloves, eye protection, and face shield
Environmental Precautions: Prevent large spills from entering drains and waterways, contain spill using suitable absorbent material
Cleanup Methods: Sweep up solid material; for solution, neutralize with dilute acid, collect residues with non-combustible absorbent, keep waste in labeled containers for disposal
Disposal: Handle as hazardous waste, observe all regional regulations during cleanup and disposal

Handling and Storage

Safe Handling: Avoid formation of dust or aerosols, do not inhale vapors or contact skin, keep containers closed when not in use, use dedicated equipment, never mix with acids or incompatible substances
Storage Recommendations: Store in a dry, cool, well-ventilated place, separate from acids, flammables, and reducing agents, use corrosion-resistant containers, keep away from moisture, label containers clearly
Storage Temperature: Room temperature, avoid extremes of heat or cold
Incompatible Materials: Avoid aluminum, tin, zinc, copper, strong acids, ammonium salts

Exposure Controls and Personal Protection

Occupational Exposure Limits: OSHA PEL: 2 mg/m³ (ceiling level); ACGIH TLV: 2 mg/m³ (ceiling level)
Engineering Controls: Use local exhaust ventilation, process enclosures, or other engineering controls to prevent airborne exposure
Personal Protection: Chemical-resistant gloves (neoprene, PVC, nitrile), goggles or face shield, long-sleeved clothing, impervious footwear
Respiratory Protection: Use appropriate masks or respirators if exposure likely
Hygiene Measures: Wash hands before eating or drinking, remove contaminated clothing promptly

Physical and Chemical Properties

Appearance: Solid: white, odorless, crystalline pellets or flakes; Solution: clear to slightly cloudy liquid
Molecular Formula: NaOH
Molecular Weight: 40.00 g/mol
Odor: Odorless
pH: Strongly alkaline (pH 12-14 in water)
Solubility: Freely soluble in water with heat release, soluble in ethanol, insoluble in ether
Melting Point: 318°C
Boiling Point: 1,388°C
Density: 2.13 g/cm³ (solid)
Vapor Pressure: Not applicable (non-volatile solid)
Other Properties: Reacts exothermically with water, highly hygroscopic, absorbs CO₂ from air

Stability and Reactivity

Chemical Stability: Stable under normal use and storage conditions
Hazardous Reactions: Vigorous exothermic reaction with water, reacts with acids to form heat and sodium salts, attacks aluminum and zinc to release hydrogen gas
Incompatible Materials: Acids, ammonium salts, halogenated organics, certain metals
Hazardous Decomposition Products: None under normal conditions; contact with metals releases hydrogen, may form toxic fumes with chlorinated compounds

Toxicological Information

Routes of Entry: Inhalation, skin and eye contact, ingestion
Acute Effects: Burns to skin, eyes, and mucous membranes; inhalation causes coughing, shortness of breath, possible pulmonary edema; ingestion results in severe pain, vomiting, possible perforation of digestive tract
Chronic Effects: Long-term exposure may cause dermatitis, chronic respiratory irritation, scarring of eyes or esophagus
Toxicity Data: Oral LD₅₀ (rat): 325 mg/kg; severe irritant and corrosive properties
Carcinogenicity: Not classified as a human carcinogen by IARC, NTP, or OSHA

Ecological Information

Aquatic Toxicity: Highly toxic to aquatic organisms due to extreme alkalinity; disruption of pH in water bodies
Persistence and Degradability: Not persistent, rapidly dissociates in water
Bioaccumulative Potential: Low, does not bioaccumulate
Mobility in Soil: High solubility leads to mobility in soil; may alter soil pH rapidly
Other Adverse Effects: Alters ecosystem balance, may cause fish kills and damage to aquatic vegetation

Disposal Considerations

Waste Treatment Methods: Neutralize with dilute acid under controlled conditions, dilute further and discharge according to local regulations if permitted
Disposal of Packaging: Rinse containers thoroughly, dispose of according to hazardous waste guidelines
Special Precautions: Never dispose of in household waste, avoid release to environment
Regulatory Requirements: Follow all federal, state, and local disposal regulations, consult environmental authority for guidance

Transport Information

UN Number: UN1823 (solid), UN1824 (solution)
Proper Shipping Name: Sodium Hydroxide, Solid or Sodium Hydroxide, Solution
Transport Hazard Class: 8 (Corrosive)
Packing Group: II
Label Requirements: Corrosive label (Class 8), proper placarding on vehicles
Special Transport Precautions: Protect from moisture, separate from acids and incompatible materials, use leak-proof, corrosion-resistant containers

Regulatory Information

Workplace Regulation: Subject to OSHA Hazard Communication Standard, requires Safety Data Sheet availability and worker training
Environmental Regulation: Covered under Clean Water Act and CERCLA due to potential environmental hazard
International Regulation: Covered by REACH in EU, includes restrictions and registration requirements
Labeling: Required GHS symbols, precautionary statements, emergency number
Other Information: Listed on TSCA Inventory, subject to SARA Title III reporting for large quantities