SECTION 1Identification
| Product identifier | Sodium Hydroxide Solution, 50% |
| Other means of identification | Caustic soda solution; lye solution; sodium hydroxide, 50% aqueous solution. CAS No. 1310-73-2. Product code CC-800. |
| Recommended use | Industrial raw material for formulating cleaning products; pH adjustment and neutralization. |
| Restrictions on use | Industrial use only. Not for consumer use. Do not mix with acids. Do not use with aluminum, zinc, tin or galvanized equipment. |
| Supplier (U.S.) | Cyberdyne Caustics, Inc. 1984 Dyson Way, Tech-Noir Industrial District Main office: (555) 555-0193 Regulatory contact: M. Dyson, Product Stewardship |
| Emergency telephone | (555) 555-0194, 24 hours (Cyberdyne emergency line). In a medical emergency, call 911. |
SECTION 2Hazard identification
Classification (29 CFR 1910.1200(d))
- Corrosive to metals, Category 1
- Acute toxicity, oral, Category 4
- Skin corrosion/irritation, Category 1A
- Serious eye damage/eye irritation, Category 1
Label elements
Signal word: DANGER Hazard statements:
|   Corrosion | Exclamation mark |
| Precautionary statements: Prevention | Keep only in original packaging. Do not breathe mists. Wash hands and any exposed skin thoroughly after handling. Do not eat, drink or smoke when using this product. Wear protective gloves, protective clothing, eye protection and face protection. |
| Response | If swallowed: Rinse mouth. Do NOT induce vomiting. If on skin (or hair): Take off immediately all contaminated clothing. Rinse skin with water or shower. Wash contaminated clothing before reuse. If inhaled: Remove person to fresh air and keep comfortable for breathing. 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. Specific treatment: see Section 4. Absorb spillage to prevent material damage. |
| Storage | Store locked up. |
| Disposal | Dispose of contents and container in accordance with federal, state and local regulations (see Section 13). |
| Hazards not otherwise classified | None identified. Note: adding water to the solution, or mixing it with acids, releases heat that can boil and spatter the liquid (see Sections 7 and 10). |
| Hazards classified under 1910.1200(d)(1)(ii) (reaction products) | Contact with aluminum, zinc or tin releases hydrogen, a flammable gas (see Section 10). |
| Ingredients of unknown acute toxicity | None. |
SECTION 3Composition/information on ingredients
Substance (aqueous solution).
| Chemical name | Common name and synonyms | CAS No. | Concentration (wt %) |
|---|---|---|---|
| Sodium hydroxide | Caustic soda; lye | 1310-73-2 | 50 |
| Water | Water | 7732-18-5 | 50 |
Impurities and stabilizing additives: none that are classified or contribute to the classification.
SECTION 4First-aid measures
| Inhalation | Move the person to fresh air. If breathing is difficult, trained personnel give oxygen. If not breathing, give rescue breathing. Get medical attention. |
| Skin contact | Flush skin immediately with plenty of water for at least 15 minutes while removing contaminated clothing and shoes. Use the safety shower. Get medical attention immediately. |
| Eye contact | Flush immediately with water for at least 15 minutes, holding eyelids open. Remove contact lenses if easy to do. Continue rinsing on the way to medical care. Get medical attention immediately. |
| Ingestion | Rinse mouth. Do NOT induce vomiting. If the person is conscious, give a small amount of water. Get medical attention immediately. |
| Most important symptoms and effects, acute and delayed | Severe burns of eyes and skin; permanent eye injury; burns of mouth, throat and stomach if swallowed. Mist irritates the eyes, nose and throat and can cause pneumonitis. Temporary loss of hair. |
| Immediate medical attention and special treatment | Immediate medical attention is required for any eye contact, skin burns or ingestion. Continue flushing the eyes on the way to medical care. |
SECTION 5Fire-fighting measures
| Suitable extinguishing media | The solution does not burn. Use media suitable for the surrounding fire. Water spray to cool containers exposed to fire. |
| Unsuitable extinguishing media | Do not spray water into open or leaking containers; dilution releases heat and can spatter the solution. |
| Specific hazards | Not combustible. Contact with aluminum, zinc or tin, including in a fire area, releases hydrogen, which can form an explosive mixture with air. Containers can rupture when heated. Can give off corrosive fumes when heated. Fire-control water and runoff are caustic. |
| Special protective equipment and precautions for fire-fighters | Positive-pressure SCBA and chemical protective clothing where contact with the product is possible. Cool containers with water spray from a safe distance. Contain runoff. |
SECTION 6Accidental release measures
| Personal precautions, protective equipment and emergency procedures | Keep people away and upwind. Only trained responders wearing the PPE in Section 8 (goggles, face shield, alkali-resistant gloves, boots and suit or apron) enter the spill area. Responders follow the employer's emergency response plan. |
| Methods and materials for containment and cleaning up | Stop the leak if it can be done safely. Dike and contain; keep out of storm drains, sewers and waterways. Do not use aluminum tools or containers. Small spills: absorb with dry sand, earth or absorbent pads rated for caustic. Neutralize the remaining residue cautiously with a dilute weak acid such as acetic or citric acid (neutralization gives off heat), and check with pH paper. Collect in labeled polyethylene or steel containers for disposal. Large spills: dike well ahead of the spill and recover the liquid into polyethylene or steel containers. Rinse the area with water and collect the rinse water. |
| Release reporting | Sodium hydroxide has a CERCLA RQ of 1,000 lb. For this 50% solution, a release of 2,000 lb (about 157 gal) or more in 24 hours must be reported to the National Response Center, 1-800-424-8802 (40 CFR 302.6(a) and (b)). See Section 15. |
SECTION 7Handling and storage
| Precautions for safe handling | Avoid creating mist. Do not get in eyes, on skin or on clothing. When diluting, always add the solution slowly to water while stirring; never add water to the solution. Do not eat, drink or smoke in work areas. Provide eyewash and quick-drench facilities in the work area (29 CFR 1910.151(c)). |
| Conditions for safe storage, including incompatibilities | Store in closed original containers (drums, totes or tanks) in a ventilated area with secondary containment, away from acids and incompatible metals. Keep containers closed; the solution absorbs carbon dioxide from air and forms sodium carbonate crusts. Protect from freezing: the 50% solution freezes at about 54 °F (12 °C). Steel and polyethylene are suitable container materials. Do not use aluminum, zinc, tin or galvanized metal for containers, fittings or tools; aluminum packaging parts in contact with this material are not authorized for transport (49 CFR 172.102, special provision N34). |
SECTION 8Exposure controls/personal protection
Occupational exposure limits
| Ingredient (CAS) | OSHA PEL (Table Z-1) | NIOSH REL | ACGIH TLV | NIOSH IDLH |
|---|---|---|---|---|
| Sodium hydroxide (1310-73-2) | TWA 2 mg/m³ | Ceiling 2 mg/m³ | Ceiling 2 mg/m³ | 10 mg/m³ |
| Appropriate engineering controls | General ventilation is normally adequate. Use local exhaust where mists are produced (heating, spraying or vigorous mixing). Eyewash and quick-drench shower in the work area. |
| Eye/face protection | Chemical splash goggles and a face shield. |
| Skin protection | Alkali-resistant gloves (for example neoprene, nitrile, PVC or natural rubber), apron or chemical-resistant suit, and boots. Confirm breakthrough time with the glove manufacturer's data. Remove clothing that becomes wet or contaminated. |
| Respiratory protection | Use under a written respiratory protection program meeting 29 CFR 1910.134. NIOSH: up to 10 mg/m³, any supplied-air respirator in continuous-flow mode (APF 25), any powered air-purifying respirator with a high-efficiency particulate filter (APF 25), any air-purifying full-facepiece respirator with N100, R100 or P100 filters (APF 50), any SCBA with full facepiece (APF 50), or any supplied-air respirator with full facepiece (APF 50). Above 10 mg/m³ (IDLH) or unknown concentrations: pressure-demand SCBA with full facepiece, or pressure-demand supplied-air respirator with full facepiece and an auxiliary self-contained positive-pressure breathing apparatus. Escape: air-purifying full-facepiece respirator with N100, R100 or P100 filters, or escape-type SCBA. |
SECTION 9Physical and chemical properties
| Physical state | Liquid (aqueous solution) |
| Color | Colorless |
| Odor; odor threshold | Odorless. Odor threshold not applicable. |
| Melting point/freezing point | 12 °C (54 °F) (50% solution) |
| Boiling point | 140 °C (284 °F) (50% solution) |
| Flammability | Not flammable |
| Lower/upper flammability limit | Not applicable |
| Flash point | Not applicable (not flammable) |
| Auto-ignition temperature | Not applicable (not flammable) |
| Decomposition temperature | No data available |
| pH | About 14 |
| Kinematic viscosity | No data available |
| Solubility | Mixes completely with water; heat is released on dilution |
| Partition coefficient n-octanol/water (log Kow) | Not applicable (inorganic) |
| Vapor pressure; evaporation rate | Sodium hydroxide: about 0 mmHg. Solution: no data available |
| Density/relative density | Relative density 1.53 (50% solution); about 12.8 lb/gal |
| Relative vapor density | Not applicable |
| Particle characteristics | Not applicable (liquid) |
SECTION 10Stability and reactivity
| Reactivity | Reacts rapidly with acids, giving off heat. Attacks aluminum, zinc and tin, releasing hydrogen gas. |
| Chemical stability | Stable in closed containers. Absorbs carbon dioxide from air. |
| Possibility of hazardous reactions | Adding water releases heat that can cause local boiling and spattering. Hydrogen released by contact with aluminum, zinc or tin can form an explosive atmosphere in closed spaces or containers. Violent polymerization on contact with acetaldehyde or acrolein. Can react explosively with maleic anhydride. |
| Conditions to avoid | Contact with incompatible materials; adding water to the solution; freezing. |
| Incompatible materials | Acids, acid anhydrides and acid chlorides; aluminum, tin, zinc and galvanized metal; organic halogens; nitromethane; flammable liquids; acetaldehyde, acrolein and maleic anhydride. |
| Hazardous decomposition products | None under normal conditions of storage and use. Can give off corrosive fumes when heated. |
SECTION 11Toxicological information
| Likely routes of exposure | Skin and eye contact, ingestion, inhalation of mist. |
| Symptoms | Irritation of eyes, skin and mucous membranes; eye and skin burns; pneumonitis from inhaled mist; temporary loss of hair. |
| Target organs | Eyes, skin, respiratory system. |
| Acute toxicity (numerical measures) | Oral LD50 (rabbit), caustic soda solution: 500 mg/kg. Category 4 under Table A.1.1, using test data on the solution. Sodium hydroxide: oral LD50 (rat) 140 to 340 mg/kg; dermal LD50 (rabbit) 1,350 mg/kg. Inhalation: no LC50 data available. |
| Skin corrosion/irritation | Category 1A. Causes second- and third-degree burns on short contact. |
| Serious eye damage/irritation | Category 1. Causes severe eye damage and permanent eye injury. |
| Respiratory or skin sensitization | Not classified. |
| Germ cell mutagenicity; reproductive toxicity | Not classified. |
| Specific target organ toxicity, single exposure | Not classified. Mist irritates the respiratory tract (see Symptoms). |
| Specific target organ toxicity, repeated exposure; aspiration | Not classified. |
| Delayed, immediate and chronic effects | Immediate: burns of eyes, skin and the digestive tract. Delayed: scarring and narrowing of the esophagus after ingestion. Chronic: none known. |
| Interactive effects | No information available. |
| Carcinogenicity | Not listed by NTP (Report on Carcinogens), IARC or OSHA. |
SECTION 12Ecological information
| Ecotoxicity | Harm to aquatic life is mainly from high pH. Sodium hydroxide: goldfish LC50 160 mg/L (24 h); Ceriodaphnia dubia EC50 40.4 mg/L (48 h); mosquito fish TLm 125 ppm (96 h). |
| Persistence and degradability | Not applicable (inorganic). Neutralized in the environment by carbon dioxide and acids. |
| Bioaccumulative potential | Not expected to bioaccumulate. |
| Mobility in soil | Mobile; fully water-soluble. |
| Other adverse effects | Raises the pH of receiving water. |
SECTION 13Disposal considerations
Discarded unused product is a corrosive hazardous waste, D002 (aqueous waste with pH 12.5 or higher by Method 9040C, 40 CFR 261.22(a)(1)). Sodium hydroxide is not a listed P or U waste. Do not discharge to sewers or storm drains. Manage under 40 CFR Parts 260 through 273 and state rules. Manage empty containers under 40 CFR 261.7.
SECTION 14Transport information
| UN number | UN1824 |
| UN proper shipping name | Sodium hydroxide solution |
| Transport hazard class | 8 |
| Packing group | II |
| Basic description (49 CFR 172.202) | UN1824, Sodium hydroxide solution, 8, II. Add "RQ" when one package contains 1,000 lb or more of sodium hydroxide, which is 2,000 lb (about 157 gal) or more of this solution (49 CFR 172.203(c)). A full 275-gal tote holds about 3,500 lb of solution and is shipped as: RQ, UN1824, Sodium hydroxide solution, 8, II. |
| Environmental hazards | Hazardous substance: sodium hydroxide, RQ 1,000 lb (454 kg) per 40 CFR 302.4. Not a marine pollutant (not listed in Appendix B to 49 CFR 172.101). |
| Transport in bulk (IMO instruments) | No information available. |
| Special precautions | Emergency Response Guidebook Guide 154. Special provisions B2, IB2, N34, T7, TP2. Packaging: 49 CFR 173.154 (exceptions), 173.202 (non-bulk), 173.242 (bulk). Vessel stowage A, code 52. |
| Air (IATA Dangerous Goods Regulations) | UN1824, Sodium hydroxide solution, 8, II. Hazard label: Corrosive. Passenger and cargo aircraft: Packing Instruction 851, maximum 1 L net per package. Limited quantity: Y840, maximum 0.5 L net per package. Excepted quantity code E2. Cargo aircraft only: Packing Instruction 855, maximum 30 L net per package. Special provisions A3, A803. ERG code 8L. |
SECTION 15Regulatory information
| TSCA | Listed on the TSCA Inventory (active). |
| CERCLA (40 CFR 302.4) | Sodium hydroxide: RQ 1,000 lb (454 kg). For this 50% solution, 2,000 lb of solution (about 157 gal) contains the RQ (40 CFR 302.6(b)). |
| Clean Water Act 311 (40 CFR 116.4) | Sodium hydroxide is a designated hazardous substance under section 311 of the Clean Water Act (40 CFR 116.4; Table 302.4, statutory code 1). RQ 1,000 lb (454 kg). |
| EPCRA 302 (40 CFR 355, Appendix A) | Not an extremely hazardous substance. |
| EPCRA 311/312 (40 CFR 370) | Hazardous chemical under the OSHA HCS. Reporting threshold 10,000 lb on site at any one time (40 CFR 370.10(a)(2)(i)). |
| EPCRA 313 (40 CFR 372.65) | Not listed. No supplier notification required. |
| Clean Air Act 112(r) (40 CFR 68.130) | Not a listed regulated substance. |
| OSHA Process Safety Management (29 CFR 1910.119) | Not listed in Appendix A. |
| OSHA medical services and first aid (29 CFR 1910.151(c)) | Where the eyes or body of any person may be exposed to injurious corrosive materials, suitable facilities for quick drenching or flushing of the eyes and body must be provided within the work area for immediate emergency use. |
SECTION 16Other information, including date of preparation or last revision
| Date of preparation or last revision | April 14, 2025. Version 3.0. Supersedes May 3, 2022. |
| Revision note | Updated to the Hazard Communication Standard as amended May 20, 2024 (89 FR 44144) and corrected October 9, 2024 (89 FR 81829). |
| Abbreviations | ACGIH: American Conference of Governmental Industrial Hygienists. APF: assigned protection factor. IDLH: immediately dangerous to life or health. LC50/LD50: concentration or dose lethal to 50% of test animals. PEL: permissible exposure limit. REL: recommended exposure limit. RQ: reportable quantity. SCBA: self-contained breathing apparatus. TLm: median tolerance limit. TLV: threshold limit value. TWA: time-weighted average. |