Sodium Hydroxide

Classification

Skin corrosion, Category 1A

Hazard statements

• H314 Causes severe skin burns and eye damage.

Key precautionary statements

• P260 Do not breathe dust or mist.
• P264 Wash hands thoroughly after handling.
• P280 Wear protective gloves, protective clothing, eye protection and face protection.
• P301+P330+P331 IF SWALLOWED: Rinse mouth. Do NOT induce vomiting.
• P303+P361+P353 IF ON SKIN (or hair): Take off immediately all contaminated clothing. Rinse skin with water or shower.
• P304+P340 IF INHALED: Remove person to fresh air and keep comfortable for breathing.
• P305+P351+P338 IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continue rinsing.
• P310 Immediately call a POISON CENTER or doctor.

The OSHA PEL is an 8-hour TWA of 2 mg/m³, but NIOSH and ACGIH both set 2 mg/m³ as a ceiling that should not be exceeded at any time during the workday. Airborne exposure comes mainly from dust and from mists of caustic solutions. No skin notation is assigned, but direct contact with the solid or strong solutions causes burns. NIOSH advises providing an eyewash and quick drench shower where it is handled. State OSHA plans may set different limits.

• Appearance: Colorless to white solid (flakes, beads, granular form). Commonly handled as a water solution.
• Odor: Odorless
• Molecular weight: 40.0
• Boiling point: 2534°F (1390°C)
• Melting point: 605°F (318°C)
• Flash point: Not applicable (noncombustible solid)
• Explosive limits: Not applicable
• Vapor pressure: 0 mmHg (approx.)
• Specific gravity: 2.13
• Water solubility: 111%; dissolving releases a lot of heat
• pH: 14 (5% solution)

Inhalation

Dust or mist irritates the nose, throat and mucous membranes and can cause pneumonitis. High exposure can cause fluid buildup in the lungs (pulmonary edema), which may be delayed by hours.

Skin

Causes severe chemical burns. Burns may not be painful right away, so damage can be deep before it is noticed. NIOSH also lists temporary hair loss.

Eyes

Causes severe burns and can cause permanent eye damage, including blindness.

Ingestion

Causes burns of the mouth, throat and stomach. Get medical attention immediately.

Target organs

Eyes, skin, respiratory system

Long-term effects

Repeated exposure to dust or mist can cause bronchitis and lasting lung damage. Sodium hydroxide is not classified as a carcinogen.

Gloves

For solutions, the New Jersey Department of Health lists butyl, nitrile, neoprene, PVC, Viton and Silver Shield/4H as suitable glove materials. Check the glove maker's data for the concentration you use.

Eyes and face

Chemical splash goggles, plus a face shield when handling solutions or large amounts of solid.

Respiratory

Not normally needed with good ventilation. Where dust or mist exceeds limits, NIOSH lists a full-facepiece respirator with N100, R100 or P100 filters, or a powered air-purifying respirator with HEPA filters, up to 10 mg/m³. Use a pressure-demand SCBA for emergencies or unknown concentrations.

Clothing

Chemical-resistant apron, sleeves and boots; full chemical suits for large spills. Remove clothing promptly if wet or contaminated, and change daily. Keep an eyewash and quick drench shower nearby.

Store in tightly closed containers in a cool, dry, well-ventilated corrosives area. The solid absorbs moisture and carbon dioxide from the air, so keep containers sealed.

Avoid creating dust. When making solutions, add sodium hydroxide slowly to cold water while stirring, never water to the solid, because the mixing releases a lot of heat. Wash hands after handling.

Keep away from

• Water and moisture (heat release)
• Acids
• Flammable liquids
• Organic halogens
• Metals such as aluminum, tin and zinc (release flammable hydrogen gas)
• Nitromethane

• Evacuate the area and keep unprotected people away.
• Wear gloves, goggles, face shield and protective clothing; use respiratory protection for dust.
• For solid spills, collect the material without raising dust (use a vacuum, do not dry sweep) and place it in sealed containers.
• For solution spills, soak up with dry sand, earth or similar inert material and place in sealed containers.
• Keep out of drains, sewers and waterways.
• For larger incidents, refer to ERG Guide 154.

Suitable extinguishing media

• Use the agent best suited to the surrounding fire (sodium hydroxide does not burn)
• Water spray to cool fire-exposed containers, keeping water out of the containers

Special hazards

Noncombustible, but contact with water can release enough heat to ignite nearby combustible materials. Reacts with aluminum, tin and zinc to release flammable hydrogen gas. Fires produce corrosive sodium oxides. Firefighters should wear SCBA and full protective gear.

• OSHA Hazard Communication (29 CFR 1910.1200): Hazardous chemical; labels, safety data sheets and worker training required.
• OSHA Air Contaminants (29 CFR 1910.1000 Table Z-1): PEL 2 mg/m³ TWA.
• CERCLA hazardous substance (40 CFR 302.4): Reportable quantity 1,000 lb (454 kg).
• EPCRA Section 302 (40 CFR 355): Not listed as an extremely hazardous substance.
• EPCRA Section 313 / TRI (40 CFR 372.65): Not listed.
• Clean Air Act 112(r) RMP (40 CFR 68.130): Not listed.
• DOT Hazardous Materials (49 CFR 172.101): UN1823 Sodium hydroxide, solid, Class 8, PG II. Solutions ship as UN1824.

• NIOSH Pocket Guide: Sodium hydroxide
• PubChem: Sodium hydroxide GHS classification
• Fisher Scientific SDS: Sodium hydroxide
• NJ Department of Health Hazardous Substance Fact Sheet: Sodium hydroxide
• OSHA Annotated PELs Table Z-1