Sodium Hypochlorite

Classification

Classification shown is for industrial solutions of about 4–30%; household bleach products are classified by each maker and can differ. Corrosive to metals, Category 1; Skin corrosion, Category 1; Serious eye damage, Category 1; STOT single exposure, Category 3 (respiratory irritation); Acute aquatic hazard, Category 1; Chronic aquatic hazard, Category 2

Hazard statements

• H290 May be corrosive to metals.
• H314 Causes severe skin burns and eye damage.
• H335 May cause respiratory irritation.
• H400 Very toxic to aquatic life.
• H411 Toxic to aquatic life with long lasting effects.

Never mix with

Contact with acids (including acid-based toilet and rust cleaners) releases chlorine gas. Contact with ammonia, ammonium salts or amines releases toxic chloramine gases. Both can cause serious lung injury in an enclosed room.

Key precautionary statements

• P234 Keep only in original packaging.
• P260 Do not breathe mist or vapors.
• P264 Wash hands thoroughly after handling.
• P271 Use only outdoors or in a well-ventilated area.
• P273 Avoid release to the environment.
• P280 Wear protective gloves, protective clothing, eye protection and face protection.
• P301+P330+P331 IF SWALLOWED: Rinse mouth. Do NOT induce vomiting.
• P305+P351+P338+P310 IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continue rinsing. Immediately call a POISON CENTER or doctor.

There is no OSHA PEL, NIOSH REL or ACGIH TLV for sodium hypochlorite itself. The only occupational guideline is the AIHA workplace environmental exposure level (WEEL) of 2 mg/m³ as a 15-minute limit. Because the main airborne danger is usually chlorine released from the solution, the New Jersey Department of Health also points to the NIOSH chlorine ceiling of 0.5 ppm (15 minutes). If bleach is mixed with acids or ammonia, measure and control for the gases produced, not the bleach. Check the product's safety data sheet for the exact concentration you use. State OSHA plans may set different limits.

• Appearance: Clear, slightly yellow or greenish liquid (sold only as a water solution)
• Odor: Chlorine-like
• Molecular weight: 74.4
• Boiling point: Decomposes on heating
• Flash point: Not applicable (noncombustible, but an oxidizer)
• Explosive limits: Not applicable
• Specific gravity: 1.1 (5% solution)
• Water solubility: Soluble
• pH: 10.8–11.4 (5.25% solution); 12–14 for industrial grades
• Stability: Breaks down over time, faster with heat, sunlight and metal contamination

Inhalation

Mist and released chlorine irritate the nose, throat and lungs, causing coughing and shortness of breath. High exposure can cause fluid buildup in the lungs (pulmonary edema), which may be delayed by up to 48 hours. Headache, dizziness, nausea and vomiting can also occur.

Skin

Strong solutions cause chemical burns. Repeated contact with dilute bleach irritates and dries the skin.

Eyes

Causes burns and can permanently damage the eyes.

Ingestion

Burns the mouth, throat and stomach. Get medical attention immediately.

Target organs

Eyes, skin, respiratory system

Long-term effects

Repeated exposure may cause bronchitis. The New Jersey Department of Health lists it as not classifiable as to cancer risk, and it has not been tested for reproductive effects.

Gloves

The New Jersey Department of Health lists butyl, nitrile, neoprene, natural rubber and Viton, with more than 8 hours of breakthrough time for 30–70% solutions.

Eyes and face

Indirect-vent, splash-resistant chemical goggles, plus a face shield for strong solutions or large transfers. NJDOH advises against wearing contact lenses.

Respiratory

Use good general or local ventilation. Above 2 mg/m³, NJDOH lists a full-facepiece respirator with acid gas cartridges and N100 prefilters; above 20 mg/m³ (or 5 ppm chlorine), a supplied-air respirator; and above 30 ppm, an SCBA. Use under a written respiratory protection program.

Clothing

Chemical-resistant apron, sleeves and boots for industrial strengths; NJDOH lists Tychem SL, CPF 3 and Responder suits. Remove clothing promptly if wet.

Store in tightly closed, vented, corrosion-resistant containers in a cool, dark, well-ventilated area. Heat and light speed up decomposition. Avoid stainless steel, aluminum and carbon steel equipment.

Never mix bleach with other cleaners. Keep it physically separated from acids and ammonia products, and label secondary containers clearly.

Keep away from

• Acids such as hydrochloric, sulfuric, nitric and phosphoric acid, and acid-based cleaners (release chlorine gas)
• Ammonia, ammonium salts, quaternary ammonium compounds and amines (release chloramine gases)
• Organic materials such as solvents, fuels, alcohols and glycols
• Hydrogen peroxide and metals such as copper, nickel, cobalt and iron (release oxygen and can burst containers)
• Reducing agents such as sodium bisulfite and sodium thiosulfate (heat release)

• Evacuate the area and keep unprotected people away; ventilate.
• Make sure no acids or ammonia products can reach the spill.
• Wear goggles, face shield, chemical-resistant gloves and clothing.
• Neutralize with sodium bisulfite or cover with soda ash, then collect into covered containers, or absorb with inert material.
• Keep out of drains, sewers and waterways; it is toxic to aquatic life.
• For larger spills, refer to ERG Guide 154.

Suitable extinguishing media

• Dry chemical
• Carbon dioxide (CO₂)
• Water spray
• Foam

Special hazards

Noncombustible, but it is an oxidizer that can ignite wood, paper and oil. Heat speeds decomposition, and fires release toxic gases including chlorine and sodium oxides. Use water spray to cool fire-exposed containers. 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): No PEL established.
• CERCLA hazardous substance (40 CFR 302.4; Clean Water Act list at 40 CFR 117.3): Reportable quantity 100 lb (45.4 kg).
• EPCRA Section 302 (40 CFR 355): Not listed as an extremely hazardous substance.
• EPCRA Section 313 / TRI (40 CFR 372.65): Not listed.
• DOT Hazardous Materials (49 CFR 172.101): UN1791 Hypochlorite solution, Class 8. Packing group depends on strength; commercial 4–30% solutions are commonly shipped as PG III.

• NJ Department of Health Hazardous Substance Fact Sheet: Sodium hypochlorite
• ERCO Worldwide SDS: Sodium hypochlorite solution 4–30%
• 40 CFR 117.3: Reportable quantities of hazardous substances