Sodium Hydroxide — Safety & Hazards

GHS Classification

GHS (Globally Harmonized System of Classification and Labelling of Chemicals) is a United Nations system to identify hazardous chemicals and to inform users about these hazards. GHS has been adopted by many countries around the world and is now also used as the basis for international and national transport regulations for dangerous goods. The GHS hazard statements, class categories, pictograms, signal words, and the precautionary statements can be found on the PubChem GHS page.

Source/Guidance

Hazard Classes and Categories

The Hazard Classes and Categories are aligned with GHS (Globally Harmonized System of Classification and Labelling of Chemicals) hazard statement codes. The percentage data in the parenthesis from ECHA indicates that the hazard classes and categories information are consolidated from multiple companies. Also, see the detailed explanation from the above GHS classification section.

Source/Guidance

Met. Corr. 1 (47.5%)

Skin Corr. 1A (> 99.9%)

Eye Dam. 1 (44.1%)

Eye Irrit. 2 (36.6%)

Met. Corr. 1 (100%)

Skin Corr. 1B (100%)

Eye Dam. 1 (100%)

Specific target organ toxicity (single exposure) - category 3

Skin corrosion - category 1A

Skin corrosion/irritation - Category 1

Serious eye damage/eye irritation - Category 1

Specific target organ toxicity - Single exposure - Category 1 (respiratory system)

Hazardous to the aquatic environment (Acute) - Category 3

Skin corrosion/irritation - Category 1A-1C

Serious eye damage/eye irritation - Category 1

Specific target organ toxicity - Single exposure - Category 1 (respiratory system)

Hazardous to the aquatic environment (Acute) - Category 3

Corrosives, Reactive agents - 1st degree

Skin Corr. 1A

NFPA Hazard Classification

The National Fire Protection Association (NFPA) Hazard Classification (also known as NFPA 704) provides a simple, readily recognized, easily understood system for identifying the specific hazards of a material and the severity of the hazard that would occur during an emergency response. The system addresses the health, flammability, instability, and special hazards presented from short-term, acute exposures that could occur as a result of a fire, spill, or similar emergency.

Source/Guidance

DOT Hazard Classification

The U.S. Department of Transportation (DOT) categorizes hazardous materials into nine hazard classes for transportation purposes. This section provides the summary from the Hazardous Materials Table of the 49 eCFR § 172.101. For details, please visit https://www.ecfr.gov/current/title-49/subtitle-B/chapter-I/subchapter-C/part-172

Source/Guidance

EPA Safer Chemical

EPA labels products so that consumers can easily choose ones that are safer for people and the environment. When consumers see the Safer Choice label on a product, they can be confident that the ingredients have been through a rigorous EPA review. The label means that EPA scientists have evaluated every ingredient in the product to ensure it meets Safer Choice's stringent criteria. When people use Safer Choice products, they are protecting their families and the environment by making safer chemical choices.

Source/Guidance

Health Hazards

Description of the chemical's health hazards (e.g., toxicity, corrosivity, and flammability) that can have negative impacts on our short- or long-term health.

Causes severe burns of eyes, skin, and mucous membranes. (USCG, 1999)

Strong corrosive action on contacted tissues. INHALATION: dust may cause damage to upper respiratory tract and lung itself, producing from mild nose irritation to pneumonitis. INGESTION: severe damage to mucous membranes; severe scar formation or perforation may occur. EYE CONTACT: produces severe damage. (USCG, 1999)

Fire Hazards

Fire hazard means any situation, process, material or condition which may cause a fire or explosion or provide a ready fuel supply to increase the spread or intensity of the fire or explosion and which poses a threat to life or property. This section provides information on fire hazards involving this chemical.

Excerpt from ERG Guide 154 [Substances - Toxic and/or Corrosive (Non-Combustible)]:

Non-combustible, substance itself does not burn but may decompose upon heating to produce corrosive and/or toxic fumes. Some are oxidizers and may ignite combustibles (wood, paper, oil, clothing, etc.). Corrosives in contact with metals may evolve flammable hydrogen gas. Containers may explode when heated. For electric vehicles or equipment, ERG Guide 147 (lithium ion or sodium ion batteries) or ERG Guide 138 (sodium batteries) should also be consulted. (ERG, 2024)

Excerpt from ERG Guide 154 [Substances - Toxic and/or Corrosive (Non-Combustible)]:

Non-combustible, substance itself does not burn but may decompose upon heating to produce corrosive and/or toxic fumes. Some are oxidizers and may ignite combustibles (wood, paper, oil, clothing, etc.). Corrosives in contact with metals may evolve flammable hydrogen gas. Containers may explode when heated. For electric vehicles or equipment, ERG Guide 147 (lithium ion or sodium ion batteries) or ERG Guide 138 (sodium batteries) should also be consulted. (ERG, 2024)

Not combustible. Contact with moisture or water may generate sufficient heat to ignite combustible materials. Risk of fire and explosion on contact with incompatible substances. See Chemical Dangers.

Hazards Summary

This section provides an overview of the key hazards information of this compound.

At room temperature, sodium hydroxide is a white crystalline odorless solid that absorbs moisture from the air. It is a manufactured substance. When dissolved in water or neutralized with acid it liberates substantial heat, which may be sufficient to ignite combustible materials. Sodium hydroxide is very corrosive. It is generally used as a solid or a 50% solution. Other common names include caustic soda and lye. Sodium hydroxide is used to manufacture soaps, rayon, paper, explosives, dyestuffs, and petroleum products. It is also used in processing cotton fabric, laundering and bleaching, metal cleaning and processing, oxide coating, electroplating, and electrolytic extracting. It is commonly present in commercial drain and oven cleaners.

Liquid causes second or third degree burns after short contact; [CHRIS] In studies using rabbits, instillation by oral intubation caused within 10 seconds: erosion into the stomach muscle with 12% solutions; perforation with 28% solutions; and no damage with 1% solutions. Application to the skin of a 5% solution caused severe necrosis after 4 hours. Application of a 1% solution to the eyes caused no damage if the eyes were immediately irrigated. [ACGIH] Solutions > 30% are highly corrosive to skin. [Quick CPC] Inhalation of the aerosol can cause pulmonary edema. [ICSC]

Fire Potential

This section describes fire potential of this chemical (e.g., whether it is combustible or flammable).

Not combustible.

Skin, Eye, and Respiratory Irritations

Skin, eye and respiratory irritations caused by exposure to this chemical.

Liquid or solid sodium hydroxide is a severe skin irritant. It causes second and third degree burns on short contact and is very injurious to the eyes.

HAZARD WARNING: The irritating nature of the aerosol on the mucous membranes is presumed to be adequate warning to maintain air concn at tolerable levels.

Irritating to skin, eyes, and respiratory system.

EPA Hazardous Waste Number

Identifier for hazardous waste containing this chemical.

Source/Guidance

D002; A waste containing sodium hydroxide may (or may not) be characterized a hazardous waste following testing for corrosivity characteristics as prescribed by the Resource Conservation and Recovery Act (RCRA) regulations.

Flammable Limits

The flammable limits (or the flammability limits) are the minimum and maximum concentrations of fuel vapor or gas in a fuel vapor or gas/gaseous oxidant mixture (usually expressed in percent by volume) defining the concentration range (flammable or explosive range) over which propagation of flame will occur on contact with an ignition source. Also called explosive (or explosivity) limits.

OSHA Standards

Occupational Safety and Health Administration (OSHA) standards are rules that describe the methods that employers must use to protect their employees from hazards. These standards limit the amount of hazardous chemicals workers can be exposed to, require the use of certain safe practices and equipment, and require employers to monitor hazards and keep records of workplace injuries and illnesses.

Source/Guidance

Permissible Exposure Limit: Table Z-1 8-hr Time Weighted Avg: 2 mg/cu m.

Vacated 1989 OSHA PEL Ceiling limit 2 mg/cu m is still enforced in some states.

NIOSH Recommendations

The National Institute for Occupational Safety and Health (NIOSH) recommendations for chemical safety concerning this compound.

Source/Guidance

Recommended Exposure Limit: 15 Minute Ceiling Value: 2 mg/cu m.

First Aid

First aid measures for exposure to this chemical through various routes (for example, ingestion, inhalation, skin contact, and eye contact).

(Act quickly)

EYES: flush with water at once for at least 15 min.

SKIN: flush with water, then rinse with dilute vinegar (acetic acid).

INGESTION: give water and milk. Do NOT induce vomiting. Call physician at once, even when injury seems to be slight. (USCG, 1999)

Excerpt from NIOSH Pocket Guide for Sodium hydroxide:

Eye: IRRIGATE IMMEDIATELY - If this chemical contacts the eyes, immediately wash (irrigate) the eyes with large amounts of water, occasionally lifting the lower and upper lids. Get medical attention immediately.

Skin: WATER FLUSH IMMEDIATELY - If this chemical contacts the skin, immediately flush the contaminated skin with water. If this chemical penetrates the clothing, immediately remove the clothing and flush the skin with water. Get medical attention promptly.

Breathing: RESPIRATORY SUPPORT - If a person breathes large amounts of this chemical, move the exposed person to fresh air at once. If breathing has stopped, perform artificial respiration. Keep the affected person warm and at rest. Get medical attention as soon as possible.

Swallow: MEDICAL ATTENTION IMMEDIATELY - If this chemical has been swallowed, get medical attention immediately. (NIOSH, 2024)

(General first aid procedures)

Eye: Irrigate immediately - If this chemical contacts the eyes, immediately wash (irrigate) the eyes with large amounts of water, occasionally lifting the lower and upper lids. Get medical attention immediately.

Skin: Water flush immediately - If this chemical contacts the skin, immediately flush the contaminated skin with water. If this chemical penetrates the clothing, immediately remove the clothing and flush the skin with water. Get medical attention promptly.

Breathing: Respiratory support

Swallow: Medical attention immediately - If this chemical has been swallowed, get medical attention immediately.

Fire Fighting Procedures

This section provides information on the actions to be taken in the event of a fire emergency involving this chemical, to prevent the spread of and extinguish fires.

Extinguish fire using agent suitable for surrounding fire. Use water spray to keep fire-exposed containers cool.

If material on fire or involved in fire: Extinguish fire using agent suitable for type of surrounding fire. (Material itself does not burn or burns with difficulty.) Use "alcohol" foam, dry chemical or carbon dioxide. Keep run-off water out of sewers and water sources.

Isolation and Evacuation

Isolation and evacuation measures to take when a large amount of this chemical is accidentally released in an emergency.

Excerpt from ERG Guide 154 [Substances - Toxic and/or Corrosive (Non-Combustible)]:

IMMEDIATE PRECAUTIONARY MEASURE: Isolate spill or leak area in all directions for at least 50 meters (150 feet) for liquids and at least 25 meters (75 feet) for solids.

SPILL: Increase the immediate precautionary measure distance, in the downwind direction, as necessary.

FIRE: If tank, rail tank car or highway tank is involved in a fire, ISOLATE for 800 meters (1/2 mile) in all directions; also, consider initial evacuation for 800 meters (1/2 mile) in all directions. (ERG, 2024)

Excerpt from ERG Guide 154 [Substances - Toxic and/or Corrosive (Non-Combustible)]:

IMMEDIATE PRECAUTIONARY MEASURE: Isolate spill or leak area in all directions for at least 50 meters (150 feet) for liquids and at least 25 meters (75 feet) for solids.

SPILL: Increase the immediate precautionary measure distance, in the downwind direction, as necessary.

FIRE: If tank, rail tank car or highway tank is involved in a fire, ISOLATE for 800 meters (1/2 mile) in all directions; also, consider initial evacuation for 800 meters (1/2 mile) in all directions. (ERG, 2024)

Spillage Disposal

Methods for containment and safety measures to protect workers dealing with a spillage of this chemical.

Personal protection: chemical protection suit including self-contained breathing apparatus. Do NOT let this chemical enter the environment. Sweep spilled substance into covered plastic containers. Carefully collect remainder. Then store and dispose of according to local regulations.

Cleanup Methods

Procedures for cleanup of chemical spill or hazardous waste

On/in soil (solid): Construct barriers to convert or divert to impervious surface. Promptly shovel into steel containers.

Soil, Liquid: Absorb small amounts of spill with sand, vermiculite or other inert absorbant material; Shovel into steel containers. May also remove material with vacuum equipment.

Environment considerations - Land spill:: Dig a pit, pond, lagoon, or holding area to contain liquid or solid material. Dike surface flow using soil, sand bags, foamed polyurethane, or foamed concrete. Absorb bulk liquid with fly ash of cement powder.

Environmental considerations - Water spill: Use natural barriers or oil spill control booms to limit spill travel. Neutralize with dilute acid.

For more Cleanup Methods (Complete) data for SODIUM HYDROXIDE (6 total), please visit the HSDB record page.

Disposal Methods

Disposal methods or procedures for this chemical or hazardous waste containing it.

SRP: The most favorable course of action is to use an alternative chemical product with less inherent propensity for occupational harm/injury/toxicity or environmental contamination. Recycle any unused portion of the material for its approved use or return it to the manufacturer or supplier. Ultimate disposal of the chemical must consider: the material's impact on air quality; potential migration in soil or water; effects on animal and plant life; and conformance with environmental and public health regulations.

Following neutralization either at the spill site or at a waste management facility, the resultant sludge can be disposed of in a secure landfill.

SRP: Wastewater from contaminant suppression, cleaning of protective clothing/equipment, or contaminated sites should be contained and evaluated for subject chemical or decomposition product concentrations. Concentrations shall be lower than applicable environmental discharge or disposal criteria. Alternatively, pretreatment and/or discharge to a permitted wastewater treatment facility is acceptable only after review by the governing authority and assurance that "pass through" violations will not occur. Due consideration shall be given to remediation worker exposure (inhalation, dermal and ingestion) as well as fate during treatment, transfer and disposal. If it is not practicable to manage the chemical in this fashion, it must be evaluated in accordance with EPA 40 CFR Part 261, specifically Subpart B, in order to determine the appropriate local, state and federal requirements for disposal.

Put into large vessel containing water. Neutralize with HCL /hydrochloric acid/. Discharge into the sewer with sufficient water. Recommendable methods: Neutralization & discharge to sewer. Peer review: Dilute greatly (< pH 9) before discharge. (Peer-review conclusions of an IRPTC expert consultation (May 1985))

Preventive Measures

Preventive measures to take to avoid suffering negative health effects from this chemical.

SRP: The scientific literature for the use of contact lenses by industrial workers is inconsistent. The benefits or detrimental effects of wearing contact lenses depend not only upon the substance, but also on factors including the form of the substance, characteristics and duration of the exposure, the uses of other eye protection equipment, and the hygiene of the lenses. However, there may be individual substances whose irritating or corrosive properties are such that the wearing of contact lenses would be harmful to the eye. In those specific cases, contact lenses should not be worn. In any event, the usual eye protection equipment should be worn even when contact lenses are in place.

Nickel is the preferred metal for handling caustic soda at all concentrations and temperatures. However, the high cost and limited availability of nickel precludes its use for most applications. Mild steel is adequate for almost all caustic-handling applications. Plastics and plastic-lined steel are now available as construction materials. Fiberglass reinforced plastic tanks of Derakane vinyl ester resin are suitable for many applications. Polypropane is commonly used for lining pipe for protection against mechanical damage.

Any dilutions of caustic from concentrations greater than 25% should be done cautiously.

Personnel protection: Keep upwind. Avoid breathing vapors. ... Avoid bodily contact with the material.

For more Preventive Measures (Complete) data for SODIUM HYDROXIDE (11 total), please visit the HSDB record page.

Nonfire Spill Response

Emergency response measures to take in the event of a chemical spill (without a fire).

Excerpt from ERG Guide 154 [Substances - Toxic and/or Corrosive (Non-Combustible)]:

ELIMINATE all ignition sources (no smoking, flares, sparks or flames) from immediate area. Do not touch damaged containers or spilled material unless wearing appropriate protective clothing. Stop leak if you can do it without risk. Prevent entry into waterways, sewers, basements or confined areas. Absorb or cover with dry earth, sand or other non-combustible material and transfer to containers. DO NOT GET WATER INSIDE CONTAINERS. (ERG, 2024)

Excerpt from ERG Guide 154 [Substances - Toxic and/or Corrosive (Non-Combustible)]:

ELIMINATE all ignition sources (no smoking, flares, sparks or flames) from immediate area. Do not touch damaged containers or spilled material unless wearing appropriate protective clothing. Stop leak if you can do it without risk. Prevent entry into waterways, sewers, basements or confined areas. Absorb or cover with dry earth, sand or other non-combustible material and transfer to containers. DO NOT GET WATER INSIDE CONTAINERS. (ERG, 2024)

Safe Storage

Measures to take for safe storage of this chemical.

Source/Guidance

Separated from food and feedstuffs, strong acids and metals. Store only in original container. Dry. Well closed. Store in an area without drain or sewer access.

Storage Conditions

Conditions for safe storage of this compound, including any incompatible chemicals and specific storage requirements (e.g., ventilation requirements).

CONTAINERS SHOULD BE STORED IN ROOMS WITH TRAPPED FLOOR DRAINS TOWARDS WHICH FLOORS SHOULD BE SLANTED. WHERE FLOOR DRAINS ARE NOT PROVIDED, CURBS OR DRAINED GUTTER, COVERED WITH ... GRILL, SHOULD BE CONSTRUCTED @ DOOR OPENINGS.

Volumetric sodium hydroxide soln used in laboratory must be protected from air to avoid formation of carbonate.

Store in a cool, dry, well-ventilated location. Separate from organic and oxidizing materials, acids, metal powders. Immediately remove and properly dispose of any spilled material.

Recommended Exposure Limit (REL)

The recommended exposure limit (REL) is the maximum amount or concentration of a chemical that a worker may be exposed to. The RELs are guidelines established and recommended by the NIOSH (National Institute for Occupational Safety and Health). The RELs can be given in three ways. [1] Time-weighted average (REL-TWA): average exposure based on up to10h/day, 40h/week work schedule. [2] Short-term exposure limit (REL-STEL): a 15-minute TWA exposure that should not be exceeded at any time during a workday. [3] Ceiling limit (REL-C): absolute exposure limit that should not be exceeded at any time.

Source/Guidance

C 2 mg/m3

Permissible Exposure Limit (PEL)

The permissible exposure limit (PEL) is the maximum amount or concentration of a chemical that a worker may be exposed to under OSHA regulations. The PEL can be given in three ways. [1] Time-weighted average (PEL-TWA): average exposure based on an 8h/day, 40h/week work schedule. [2] Short-term exposure limit (PEL-STEL): a 15-minute TWA exposure that should not be exceeded at any time during a workday. [3] Ceiling limit (PEL-C): absolute exposure limit that should not be exceeded at any time.

Source/Guidance

2.0 [mg/m3]

TWA 2 mg/m3 See Appendix G

Immediately Dangerous to Life or Health (IDLH)

The Immediately Dangerous to Life or Health air concentration values (IDLH values) characterize high-risk exposure concentrations and conditions and are used as a component of respirator selection criteria. IDLH values are established (1) to ensure that the worker can escape from a given contaminated environment in the event of failure of the respiratory protection equipment and (2) to indicate a maximum level above which only a highly reliable breathing apparatus, providing maximum worker protection, is permitted.

Source/Guidance

10 mg/m3 [From NPG: Sodium hydroxide] (NIOSH, 2024)

10 mg/m3 (NIOSH, 2024)

10.0 [mg/m3]

Excerpts from Documentation for IDLHs: Human data: Workplace concentrations ranging from 2 to 8 mg/m3 have been associated with irritation of the respiratory system [Ott et al. 1977].

10 mg/cu m

10 mg/m³

10 mg/m3

See: 1310732

Threshold Limit Values (TLV)

The threshold limit value (TLV) of a chemical is an airborne concentration at which a worker can be exposed day after day for a working lifetime without adverse effect. There are three types of TLVs for chemicals. [1] Threshold limit value - time-weighted average (TLV-TWA): average exposure on the basis of a 8h/day, 40h/week work schedule. [2] Threshold limit value - short-term exposure limit (TLV-STEL): a 15-minute TWA exposure that should not be exceeded at any time during a workday, even if the 8-hour TWA is within the TLV-TWA. [3] Threshold limit value - ceiling limit (TLV-C): absolute exposure limit that should not be exceeded at any time. TLVs are developed by the American Conference of Governmental Industrial Hygienist. While TLVs are widely accepted occupational exposure limits, they are not standards enforced by the U.S. Government.

Source/Guidance

Ceiling Limit: 2 mg/cu m.

2 mg/m

Emergency Response Planning Guidelines

Emergency Response Planning Guidelines (ERPGs) are air concentration guidelines for single exposures to agents, developed by the American Industrial Hygiene Association (AIHA). They are intended for use as tools to assess the adequacy of accident prevention and emergency response plans, including transportation emergency planning, community emergency response plans, and incident prevention and mitigation. ERPGs estimate the concentrations at which most people will begin to experience health effects if they are exposed to a hazardous airborne chemical for 1 hour. (Sensitive members of the public, such as old, sick, or very young people, aren't covered by these guidelines and they may experience adverse effects at concentrations below the ERPG values.) A chemical may have up to three ERPG values, each of which corresponds to a specific tier of health effects.

Source/Guidance

ERPG-1: 0.5 mg/m3 - one hour exposure limit: 1 = mild transient health effects or objectionable odor [AIHA]

ERPG-2: 5 mg/m3 - one hour exposure limit: 2 = impaired ability to take protective action [AIHA]

ERPG-3: 50 mg/m3 - one hour exposure limit: 3 = life threatening health effects [AIHA]

Other Standards Regulations and Guidelines

Safety and hazard standards, regulations, and guidelines for this this compound that is not shown in other sections.

Australia: 2 mg/cu m, peak limitation (1990); Federal Republic of Germany: 2 mg/cu m, short-term level 4 mg/cu m, 5 min, 8 times per shift (1990); Sweden: 2 mg/cu m ceiling (1990); United Kingdom: 10 min STEL 2 mg/cu m (1991)

Emergency Response Planning Guidlines (ERPGs) for sodium hydroxide: [Table#880]

Inhalation Risk

Risk of exposure to this chemical through inhalation. Note that the terms "risk" and "hazard" have different meanings. A hazard is something that has the potential to cause harm, while risk is the likelihood of harm taking place, based on exposure to that hazard.

A harmful concentration of airborne particles can be reached quickly when dispersed.

Effects of Short Term Exposure

This section provides health effects of short-term exposure to this compound. The short-term exposure (also called acute exposure) is a short contact with a chemical. It may last a few seconds or a few hours. For example, it might take a few minutes to clean windows with ammonia, use nail polish remover or spray a can of paint. The fumes someone might inhale during these activities are examples of acute exposures.

The substance is corrosive to the eyes, skin and respiratory tract. Corrosive on ingestion.

Effects of Long Term Exposure

This section provides health effects of long-term exposure to this compound. The long-term exposure (also called chronic exposure) is continuous or repeated contact with a toxic chemical over a long period of time (months or years). If a chemical is used every day on the job, the exposure would be chronic. Over time, some chemicals, such as PCBs and lead, can build up in the body. Chronic exposures can also occur at home. Some chemicals in household furniture, carpeting or cleaners can be sources of chronic exposure.

Repeated or prolonged contact with skin may cause dermatitis.

Allowable Tolerances

The tolerances of a chemical (usually a pesticide) are the maximum amount of chemical residues allowed to remain in or on fruits, vegetables, grains, and other foods, as part of the process of regulating pesticides. In some countries tolerances are called maximum residue limits (MRLs).

Source/Guidance

Residues of sodium hydroxide are exempted from the requirement of a tolerance when used in accordance with good agricultural practice as inert (or occasionally active) ingredients in pesticide formulations applied to growing crops or to raw agricultural commodities after harvest. Use: neutralizer. Limit: none.

Residues of sodium hydroxide are exempted from the requirement of a tolerance when used in accordance with good agricultural practice as inert (or occasionally active) ingredients in pesticide formulations applied to animals. Use: neutralizer. Limit: none.

Personal Protective Equipment (PPE)

Personal protective equipment (PPE) to use when handling this chemical.

Wide-brimmed hat; safety goggles with rubber side shields; tight-fitting cotton clothing; rubber gloves under shirt cuffs; rubber boots and apron. (USCG, 1999)

Excerpt from NIOSH Pocket Guide for Sodium hydroxide:

Skin: PREVENT SKIN CONTACT - Wear appropriate personal protective clothing to prevent skin contact.

Eyes: PREVENT EYE CONTACT - Wear appropriate eye protection to prevent eye contact.

Wash skin: WHEN CONTAMINATED - The worker should immediately wash the skin when it becomes contaminated.

Remove: WHEN WET OR CONTAMINATED - Work clothing that becomes wet or significantly contaminated should be removed and replaced.

Change: DAILY - Workers whose clothing may have become contaminated should change into uncontaminated clothing before leaving the work premises.

Provide:

• EYEWASH - Eyewash fountains should be provided in areas where there is any possibility that workers could be exposed to the substances; this is irrespective of the recommendation involving the wearing of eye protection.

• QUICK DRENCH - Facilities for quickly drenching the body should be provided within the immediate work area for emergency use where there is a possibility of exposure. [Note: It is intended that these facilities provide a sufficient quantity or flow of water to quickly remove the substance from any body areas likely to be exposed. The actual determination of what constitutes an adequate quick drench facility depends on the specific circumstances. In certain instances, a deluge shower should be readily available, whereas in others, the availability of water from a sink or hose could be considered adequate.] (NIOSH, 2024)

Hazards from spills and leaks should be minimized by an adequate supply of water for washing-down. ... Adequate ventilation should be provided in areas where caustic ... soda mist or dust is present. ... For the protection of the eyes, safety goggles should be worn, as well as face shields, if complete face protection is necessary. Eyewash fountains and safety showers must be available at any location where eye and/or skin contact can occur. Protection against mist or dust of this compound can be provided by filter or dust-type respiratory protective equipment. ... Safety shoes ... are recommended.

Respirator selection: 100 mg/cu m: a) High-efficiency particulate respirator with a full facepiece, b) Supplied air respirator with a full facepiece, helmet, or hood. , c) Self-contained breathing apparatus with a full facepiece. 200 mg/cu m: a) Powered air-purifying respirator with a high-efficiency filter with a full facepiece, or b) Type C SA with a full facepiece operated in pressure-demand or other positive pressure mode or with a full facepiece, helmet, or hood operated in continuous- flow mode. . Escape: a) Dust and mist respirator, except single-use respirators with full facepiece, or b) Self-contained breathing apparatus with a full facepiece.

Sodium hydroxide: Chemical protective clothing composed of natural rubber, neoprene, nitrile, or styrene/butadiene (SBR)-coated fabric is highly recommended, having break through times greater than one hour. Butyl rubber, neoprene and SBR, polyethylene, chlorinated polyurethane, or polyvinyl alcohol may be used but data suggests break through times of approximately an hour or more.

Sodium hydroxide, 30-70%: Chemical protective clothing composed of natural rubber, neoprene, nitrile, or polyvinyl chloride (PVC) is highly recommended, having break through times greater than one hour. Butyl rubber, nitrile/PVC, polyethylene, chlorinated polyethylene, or styrene/butadiene coated approximately an hour or more. Some data for polyvinyl alcohol (usually from immersion tests) suggest break through times greater than one hour are not likely.

For more Personal Protective Equipment (PPE) (Complete) data for SODIUM HYDROXIDE (12 total), please visit the HSDB record page.

Respirator Recommendations

This section provides a list of allowable respirators to be used for this chemical, according to the NIOSH's Respirator Selection Recommendations.

Source/Guidance

NIOSH/OSHA

Up to 10 mg/m3 :

(APF = 25) Any supplied-air respirator operated in a continuous-flow mode/

(APF = 50) Any air-purifying, full-facepiece respirator with an N100, R100, or P100 filter.

Click here for information on selection of N, R, or P filters.

(APF = 25) Any powered, air-purifying respirator with a high-efficiency particulate filter.

(APF = 50) Any self-contained breathing apparatus with a full facepiece

(APF = 50) Any supplied-air respirator with a full facepiece

Emergency or planned entry into unknown concentrations or IDLH conditions:

(APF = 10,000) Any self-contained breathing apparatus that has a full facepiece and is operated in a pressure-demand or other positive-pressure mode

(APF = 10,000) Any supplied-air respirator that has a full facepiece and is operated in a pressure-demand or other positive-pressure mode in combination with an auxiliary self-contained positive-pressure breathing apparatus

Escape:

(APF = 50) Any air-purifying, full-facepiece respirator with an N100, R100, or P100 filter.

Click here for information on selection of N, R, or P filters.

Any appropriate escape-type, self-contained breathing apparatus

Important additional information about respirator selection

Fire Prevention

Precautionary measures to prevent fires from this chemical.

NO contact with water. NO contact with incompatible materials: See Chemical Dangers

Exposure Prevention

Prevention measures to avoid exposure to this chemical through various routes (for example, ingestion, inhalation, skin contact, and eye contact).

PREVENT DISPERSION OF DUST! AVOID ALL CONTACT! IN ALL CASES CONSULT A DOCTOR!

Inhalation Prevention

Precautionary measures to avoid inhalation of this chemical.

Use local exhaust or breathing protection.

Skin Prevention

Precautionary measures to avoid skin exposure to this chemical.

Protective gloves. Protective clothing.

Eye Prevention

Precautionary measures to avoid eye exposure to this chemical.

Wear face shield or eye protection in combination with breathing protection.

Ingestion Prevention

Precautionary measures to avoid ingestion of this chemical.

Do not eat, drink, or smoke during work.

Air and Water Reactions

Special alerts if this chemical reacts with air, water, or moisture.

Slowly absorbs carbon dioxide from the air to give solid products as crusts or precipitates. Water soluble. Dilution with water liberates heat, possibly enough to cause local boiling and spattering.

Soluble in water. Dissolution can liberate enough heat to cause steaming and spattering and ignite adjacent combustible material [Haz. Chem. Data 1966].

Reactive Group

List of reactive groups that this chemical belongs to, according to CAMEO Chemicals at the U.S. National Oceanic and Atmospheric Administration (NOAA).

Source/Guidance

Bases, Strong

Water and Aqueous Solutions

Bases, Strong

Reactivity Alerts

Special alerts if the chemical is especially reactive.

Source/Guidance

Water-Reactive

Reactivity Profile

Description of the chemical's potential reactivity with other chemicals, air, and water. Also it includes any other intrinsic reactive hazards (such as polymerizable or peroxidizable).

SODIUM HYDROXIDE SOLUTION refers to an aqueous solution of sodium hydroxide. Strongly basic. Reacts rapidly and exothermically with organic and inorganic acids, with organic and inorganic acid anhydrides, including oxides of nonmetals such as sulfur dioxide, sulfur trioxide, phosphorus trioxide, phosphorus pentaoxide, and with organic and inorganic acid chlorides. May react explosively with maleic anhydride [MCA Case History 622 1960]. Attacks aluminum and zinc with evolution of hydrogen, a flammable gas. May initiate polymerization in polymerizable organic materials: a violent polymerization results if acetaldehyde contacts alkaline materials such as sodium hydroxide; an extremely violent polymerization results from contact of acrolein with alkaline materials such as sodium hydroxide [Chem. Safety Data Sheet SD-85 1961]. A violent explosion resulted when a quantity of pentol was accidentally brought in contact with a caustic cleaning solution chemically similar to aqueous sodium hydroxide [MCA Case History 363 1964]. Aqueous solutions of reducing sugars other than sucrose, when heated (above 84 °C.), evolve toxic levels of carbon monoxide in the presence of alkalis or alkaline salts, such as sodium phosphate (also potassium hydroxide, sodium hydroxide, calcium hydroxide, etc.) [Bretherick 5th ed. 1995]. Hot and/or concentrated NaOH can cause hydroquinone to decompose exothermically at elevated temperature. (NFPA Pub. 491M, 1975, 385)

SODIUM HYDROXIDE (Caustic Soda) is a strong base. Reacts rapidly and exothermically with acids, both organic and inorganic. Readily absorbs moisture from the air to give caustic semi-solids that attack aluminum and zinc with the evolution of flammable hydrogen gas. Catalyzes the polymerization of acetaldehyde and other polymerizable compounds; these reactions can occur violently, for example, acrolein polymerizes with extreme violence when put in contact with alkaline materials such as sodium hydroxide [Chem. Safety Data Sheet SD-85 1961]. Reacts with great violence with phosphorus pentaoxide when initiated by local heating [Mellor 8 Supp.3:406 1971]. Contact (as a drying agent) with tetrahydrofuran, which often contains peroxides, may be hazardous---explosions have occurred in such a use of the chemically similar potassium hydroxide [NSC Newsletter Chem. Soc. 1967]. Mixing with any of the following substances in a closed container caused the temperature and pressure to increase: glacial acetic acid, acetic anhydride, acrolein, chlorohydrin, chlorosulfonic acid, ethylene cyanohydrin, glyoxal, hydrochloric acid (36%), hydrofluoric acid (48.7%), nitric acid (70%), oleum, propiolactone, sulfuric acid (96%) [NFPA 1991]. Accidental contact between a caustic cleaning solution (probably containing sodium hydroxide) and Pentol caused a violent explosion. [MCA Case History 363(1964)]. Heating with a mixture of methyl alcohol and trichlorobenzene during an attempted synthesis led to a sudden increase in pressure and an explosion [MCA Guide for Safety Appendix 3 1972]. Hot and/or concentrated NaOH can cause hydroquinone to decompose exothermically at elevated temperature. (NFPA Pub. 491M, 1975, 385)

Hazardous Reactivities and Incompatibilities

This compound may undergo hazardous reactions with other chemicals. Therefore, it is considered incompatible with those chemicals and should not be used with them.

GENERATES CONSIDERABLE HEAT WHEN ... SOLN IS MIXED WITH ACID.

CRUDE HYDROQUINONE WAS PUMPED INTO SODIUM HYDROXIDE STORAGE TANK BY MISTAKE. THE HYDROQUINONE LIQUOR AT 85 °C DECOMP RAPIDLY IN THE PRESENCE OF THE SODIUM HYDROXIDE RESULTING IN OVERFLOW OF TANK & EVOLUTION OF CONSIDERABLE AMOUNT OF HEAT.

Much heat is evolved when the solid material is dissolved in water. Therefore, cold water and caution must be used for this process.

Caustic solutions generate heat when further diluted with water. With concentrations of 40% or greater, the heat generated can raise the temperature above the boiling point, resulting in sporadic, dangerous eruptions of the solution.

For more Hazardous Reactivities and Incompatibilities (Complete) data for SODIUM HYDROXIDE (32 total), please visit the HSDB record page.

DOT Emergency Guidelines

U.S. Department of Transportation (DOT) Emergency Guidelines for this chemical. The information in this section is collected from the Hazardous Substances Data Bank (HSDB). For updated emergency guidelines, see the DOT Emergency Response Guidebook.

Source/Guidance

/GUIDE 154: SUBSTANCES - TOXIC AND/OR CORROSIVE (NON-COMBUSTIBLE)/ Fire or Explosion: Non-combustible, substance itself does not burn but may decompose upon heating to produce corrosive and/or toxic fumes. Some are oxidizers and may ignite combustibles (wood, paper, oil, clothing, etc.). Contact with metals may evolve flammable hydrogen gas. Containers may explode when heated. /Sodium hydroxide, bead; Sodium hydroxide, dry; Sodium hydroxide, flake; Sodium hydroxide, granular; Sodium hydroxide, solid; Sodium hydroxide solution/

/GUIDE 154: SUBSTANCES - TOXIC AND/OR CORROSIVE (NON-COMBUSTIBLE)/ Health: TOXIC; inhalation, ingestion, or skin contact with material may cause severe injury or death. Contact with molten substance may cause severe burns to skin and eyes. Avoid any skin contact. Effects of contact or inhalation may be delayed. Fire may produce irritating, corrosive and/or toxic gases. Runoff from fire control or dilution water may be corrosive and/or toxic and cause pollution. /Sodium hydroxide, bead; Sodium hydroxide, dry; Sodium hydroxide, flake; Sodium hydroxide, granular; Sodium hydroxide, solid; Sodium hydroxide solution/

/GUIDE 154: SUBSTANCES - TOXIC AND/OR CORROSIVE (NON-COMBUSTIBLE)/ Public Safety: CALL Emergency Response Telephone Number ... As an immediate precautionary measure, isolate spill or leak area in all directions for at least 50 meters (150 feet) for liquids and at least 25 meters (75 feet) for solids. Keep unauthorized personnel away. Stay upwind. Keep out of low areas. Ventilate enclosed areas. /Sodium hydroxide, bead; Sodium hydroxide, dry; Sodium hydroxide, flake; Sodium hydroxide, granular; Sodium hydroxide, solid; Sodium hydroxide solution/

/GUIDE 154: SUBSTANCES - TOXIC AND/OR CORROSIVE (NON-COMBUSTIBLE)/ Protective Clothing: Wear positive pressure self-contained breathing apparatus (SCBA). Wear chemical protective clothing that is specifically recommended by the manufacturer. It may provide little or no thermal protection. Structural firefighters' protective clothing provides limited protection in fire situations ONLY; it is not effective in spill situations where direct contact with the substance is possible. /Sodium hydroxide, bead; Sodium hydroxide, dry; Sodium hydroxide, flake; Sodium hydroxide, granular; Sodium hydroxide, solid; Sodium hydroxide solution/

For more DOT Emergency Guidelines (Complete) data for SODIUM HYDROXIDE (8 total), please visit the HSDB record page.

DOT ID and Guide

U.S. Department of Transportation (DOT) identification (ID) number and the corresponding guide number. The DOT ID, also called the North American (NA) number, is identical to the United Nations (UN) number, except that some substances without a UN number may have a DOT ID/NA number.

Source/Guidance

1823 154 (dry, solid)

1824 154 (solution)

Shipping Name/ Number DOT/UN/NA/IMO

When dangerous goods are transported/shipped, one of the proper shipping names (along with corresponding identification numbers) shown in Dangerous Goods List of the applicable transport regulations (e.g., IATA-DGR, IMO-IMDG code, and 49 CFR 171-180) must be used to meet labelling, marking, and documentation requirements. This section provides this chemical's appropriate shipping names and identification numbers, such as the U.S. Department of Transportation (DOT) identification number (also known as "United Nations (UN) number" or "North America (NA) number") and the International Maritime Organization (IMO)'s International Maritime Dangerous Goods (IMDG) Code.

IMO 8.0; Sodium hydroxide solid; Sodium hydroxide solution

UN 1823; Sodium hydroxide, solid

UN 1824; Sodium hydroxide solution

Standard Transportation Number

This section provides the Standard Transportation Commodity Code (STCC) for this chemical. The STCC is a seven digit numeric code representing 38 commodity groupings and used on waybills and other shipping documents. If the first two digits of an STCC are 48 or 49, the STCC is also called the Hazardous Materials Response Code (HMRC) or Hazmat STCC, and is used when transporting a hazardous material or dangerous good by rail in North America.

Source/Guidance

49 352 35; Dry

49 352 40; Liquid

49 352 43; 52% Solution

Shipment Methods and Regulations

Shipment methods and regulations of this compound. The information in this section includes the U.S. Hazardous Materials Regulations (49 CFR Subchapter C), the International Air Transport Association (IATA) Dangerous Goods Regulations, the International Maritime Dangerous Goods (IMDG) Code, and other regulations.

Source/Guidance

No person may /transport,/ offer or accept a hazardous material for transportation in commerce unless that person is registered in conformance ... and the hazardous material is properly classed, described, packaged, marked, labeled, and in condition for shipment as required or authorized by ... /the hazardous materials regulations (49 CFR 171-177)./

The International Air Transport Association (IATA) Dangerous Goods Regulations are published by the IATA Dangerous Goods Board pursuant to IATA Resolutions 618 and 619 and constitute a manual of industry carrier regulations to be followed by all IATA Member airlines when transporting hazardous materials.

The International Maritime Dangerous Goods Code lays down basic principles for transporting hazardous chemicals. Detailed recommendations for individual substances and a number of recommendations for good practice are included in the classes dealing with such substances. A general index of technical names has also been compiled. This index should always be consulted when attempting to locate the appropriate procedures to be used when shipping any substance or article.

DOT Label

U.S. Department of Transportation (DOT) hazard warning label for the chemical (such as flammable liquid or corrosive). This label must be displayed on shipped packages, railroad tank cars, and tank trucks according to specifications described in 49 CFR 172.

Source/Guidance

Corrosive

Corrosive

Packaging and Labelling

Warnings and instructions for packaging and labelling of chemical products. The information in this section is from the International Labour Organization (ILO)'s International Chemical Safety Cards (ICSC).

Source/Guidance

Do not transport with food and feedstuffs.

EC Classification

European Commission (EC) classification for hazardous material.

Source/Guidance

Symbol: C; R: 35; S: (1/2)-26-37/39-45

UN Classification

Classification of this chemical, according to the Agreement concerning the International Carriage of Dangerous Goods by Road (ADR). ADR is a United Nations treaty that governs transnational transport of hazardous materials.

Source/Guidance

UN Hazard Class: 8; UN Pack Group: II

Clean Water Act Requirements

The Clean Water Act (CWA) of 1972 establishes the basic structure for regulating discharges of pollutants into the waters of the United States and regulating quality standards for surface waters. Under CWA, the U.S. Environmental Protection Agency (EPA) developed the Toxic Pollutant List (40 CFR Part 401.15) and the Priority Pollutant List (40 CFR Part 423, Appendix A). These lists are to be used by EPA and States to develop the Effluent Guidelines regulations and ensure water quality criteria and standards.

Source/Guidance

Sodium hydroxide is designated as a hazardous substance under section 311(b)(2)(A) of the Federal Water Pollution Control Act and further regulated by the Clean Water Act Amendments of 1977 and 1978. These regulations apply to discharges of this substance. This designation includes any isomers and hydrates, as well as any solutions and mixtures containing this substance.

CERCLA Reportable Quantities

The CERCLA reportable quantity for a hazardous substance is the minimum quantity of the substance which, if released, must be reported, under the Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA, also commonly known as Superfund).

Source/Guidance

Persons in charge of vessels or facilities are required to notify the National Response Center (NRC) immediately, when there is a release of this designated hazardous substance, in an amount equal to or greater than its reportable quantity of 1000 lb or 454 kg. The toll free number of the NRC is (800) 424-8802. The rule for determining when notification is required is stated in 40 CFR 302.4 (section IV.D.3.b).

FIFRA Requirements

The Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) is the Federal statute that governs the registration, distribution, sale, and use of pesticides in the United States.

Source/Guidance

Residues of sodium hydroxide are exempted from the requirement of a tolerance when used in accordance with good agricultural practice as inert (or occasionally active) ingredients in pesticide formulations applied to growing crops or to raw agricultural commodities after harvest. Use: neutralizer. Limit: none.

Residues of sodium hydroxide are exempted from the requirement of a tolerance when used in accordance with good agricultural practice as inert (or occasionally active) ingredients in pesticide formulations applied to animals. Use: neutralizer. Limit: none.

The Agency has completed its review of all available information, and has determined that the data are sufficient to support reregistration of products containing sodium hydroxide. ... The Agency therefore finds that products containing sodium hydroxide as an active ingredient are eligible for reregistration. ... Although the Agency has found that certain products containing sodium hydroxide are eligible for registration, it should be understood that the Agency may take appropriate regulatory action, and/or require the submission of additional data to support the registration of products containing sodium hydroxide, if new information comes to the Agency's attention or if the data requirements for reregistration (or the guidelines for generating such data) change.

As the federal pesticide law FIFRA directs, EPA is conducting a comprehensive review of older pesticides to consider their health and environmental effects and make decisions about their continued use. Under this pesticide reregistration program, EPA examines newer health and safety data for pesticide active ingredients initially registered before November 1, 1984, and determines whether the use of the pesticide does not pose unreasonable risk in accordance to newer saftey standards, such as those described in the Food Quality Protection Act of 1996. Pesticides for which EPA had not issued Registration Standards prior to the effective date of FIFRA '88 were divided into three lists based upon their potential for human exposure and other factors, with List B containing pesticides of greater concern than those on List C, and with List C containing pesticides of greater concern than those on List D. Sodium hydroxide is found on List D. Case No: 4065; Pesticide type: fungicide, herbicide, antimicrobial; Case Status: RED Approved 09/92; OPP has made a decision that some/all uses of the pesticide are eligible for reregistration, as reflected in a Reregistration Eligibility Decision (RED) document .; Active ingredient (AI): sodium hydroxide; Data Call-in (DCI) Date(s): 09/30/92; AI Status: OPP has completed a Reregistration Eligibility Decision (RED) document for the case/AI.

FDA Requirements

FDA requirements regarding this chemical and products containing it. FDA Requirements means any requirements of the Federal Food, Drug and Cosmetic Act (FDCA), as amended, and any rules or regulations promulgated thereunder which are or may be applicable to the manufacture, sale, labeling or distribution of the products regulated by FDA (e.g., drugs, biologics, dietary supplements, foods, cosmetics, tobacco products, etc.).

Source/Guidance

Substance added directly to human food affirmed as generally recognized as safe (GRAS).

Sodium hydroxide used as a general purpose food additive in animal drugs, feeds, and related products is generally recognized as safe when used in accordance with good manufacturing or feeding practice.

Other Hazardous Reactions

Other hazardous reactions involving this compound.

Corrosion is a problem at temperatures above 60 degrees C, therefore, the use of steel for caustic-handling is not recommended at elevated temperatures. Stress cracking may also occur when caustic soda solution concentrations exceed 20% at temperatures in excess of 60 degrees C.

History and Incidents

The history and incidents involving the chemical safety and hazards of this compound.

This article reports a chemical burn incident that occurred on August 7th, 2005, when a Matsa typhoon hit Shanghai, China. This is the largest chemical burn incident reported in the literature for 20 years in China, involving 118 alkali burn patients who were rescued by the Burn Department of Shanghai Changhai Hospital independently.The scene of the incident was investigated, and the clinical, emergency and hospitalized data of the patients were summarized.The main injurious chemical was a water solution of sodium hydroxide and ammonium chloride. The 118 victims were mostly young men with 5%TBSA deep thickness burn of both lower extremities, including 31 patients who had additional light coughing. Of 58 patients who were finally hospitalized, 42 patients received surgical treatment. Most of these patients recovered within 1 month. There were no deaths. ...

Over a six-month period, the New Jersey Poison Information System received 61 calls related to exposures to alkaline corrosives. Seven of these calls related to a new oven-cleaner product, oven-cleaner pads. These pads are sealed in a protective plastic wrap and contain lye in excess of 5%. ... Five of the callers sustained injuries from their exposure, and three of these sustained burns, one in the oral cavity and one in the eye. None suffered permanent sequelae, but the potential for such is considerable. The method of application, concn of base, and prolonged exposure to a widely covered area may make this product particularly hazardous. /Alkaline corrosives/

Special Reports

Special reports on the safety and hazard of this chemical. Most of them are government documents and review articles.

Environment Canada; Tech Info for Problem Spills: Sodium Hydroxide (Draft) (1981)

NIOSH; Criteria Document: Sodium Hydroxide (1975) DHEW Pub. NIOSH 76-105