Potassium Hydroxide

H302: Harmful if swallowed [Warning Acute toxicity, oral]

H314: Causes severe skin burns and eye damage [Danger Skin corrosion/irritation]

P260, P264, P270, P280, P301+P317, P301+P330+P331, P302+P361+P354, P304+P340, P305+P354+P338, P316, P321, P330, P363, P405, and P501 (click each P-code to see the statement)

This chemical does not meet GHS hazard criteria for < 0.1% (3 of 4709) of reports.

H290 (20.9%): May be corrosive to metals [Warning Corrosive to Metals]

H302 (96.1%): Harmful if swallowed [Warning Acute toxicity, oral]

H314 (99.4%): Causes severe skin burns and eye damage [Danger Skin corrosion/irritation]

H318 (24.7%): Causes serious eye damage [Danger Serious eye damage/eye irritation]

P234, P260, P264, P264+P265, P270, P280, P301+P317, P301+P330+P331, P302+P361+P354, P304+P340, P305+P354+P338, P316, P317, P321, P330, P363, P390, P405, P406, and P501 (click each P-code to see the statement)

Aggregated GHS information provided per 4709 reports by companies from 79 notifications to the ECHA C&L Inventory. Each notification may be associated with multiple companies.

Reported as not meeting GHS hazard criteria per 3 of 4709 reports by companies.

There are 78 notifications provided by 4706 of 4709 reports by companies with hazard statement code(s).

Information may vary between notifications depending on impurities, additives, and other factors. The percentage value in parenthesis indicates the notified classification ratio from companies that provide hazard codes. Only hazard codes with percentage values above 10% are shown. For more detailed information, please visit ECHA C&L website.

H301: Toxic if swallowed [Danger Acute toxicity, oral]

H304: May be fatal if swallowed and enters airways [Danger Aspiration hazard]

H318: Causes serious eye damage [Danger Serious eye damage/eye irritation]

H370: Causes damage to organs [Danger Specific target organ toxicity, single exposure]

H372: Causes damage to organs through prolonged or repeated exposure [Danger Specific target organ toxicity, repeated exposure]

P260, P264, P264+P265, P270, P280, P301+P316, P301+P330+P331, P302+P361+P354, P304+P340, P305+P354+P338, P308+P316, P316, P317, P319, P321, P330, P331, P363, P405, and P501 (click each P-code to see the statement)

P260, P264, P264+P265, P270, P280, P301+P316, P301+P330+P331, P302+P361+P354, P304+P340, P305+P354+P338, P308+P316, P316, P317, P321, P330, P331, P363, P405, and P501 (click each P-code to see the statement)

H290: May be corrosive to metals [Warning Corrosive to Metals]

H402: Harmful to aquatic life [Hazardous to the aquatic environment, acute hazard]

P234, P260, P264, P264+P265, P270, P273, P280, P301+P317, P301+P330+P331, P302+P361+P354, P304+P340, P305+P354+P338, P316, P317, P321, P330, P363, P390, P405, P406, and P501 (click each P-code to see the statement)

Fresh air, rest. Refer immediately for medical attention.

Remove contaminated clothes. Rinse skin with plenty of water or shower for at least 15 minutes. Refer immediately for medical attention.

First rinse with plenty of water for several minutes (remove contact lenses if easily possible), then refer for medical attention.

Rinse mouth. Do NOT induce vomiting. If within a few minutes after ingestion, one small glass of water may be given to drink. Refer immediately for medical attention.

(Act quickly])

EYES: flush with water 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)

EYES: First check the victim for contact lenses and remove if present. Flush victim's eyes with water or normal saline solution for 20 to 30 minutes while simultaneously calling a hospital or poison control center. Do not put any ointments, oils, or medication in the victim's eyes without specific instructions from a physician. IMMEDIATELY transport the victim after flushing eyes to a hospital even if no symptoms (such as redness or irritation) develop.

SKIN: IMMEDIATELY flood affected skin with water while removing and isolating all contaminated clothing. Gently wash all affected skin areas thoroughly with soap and water. IMMEDIATELY call a hospital or poison control center even if no symptoms (such as redness or irritation) develop. IMMEDIATELY transport the victim to a hospital for treatment after washing the affected areas.

INHALATION: IMMEDIATELY leave the contaminated area; take deep breaths of fresh air. If symptoms (such as wheezing, coughing, shortness of breath, or burning in the mouth, throat, or chest) develop, call a physician and be prepared to transport the victim to a hospital. Provide proper respiratory protection to rescuers entering an unknown atmosphere. Whenever possible, Self-Contained Breathing Apparatus (SCBA) should be used; if not available, use a level of protection greater than or equal to that advised under Protective Clothing.

INGESTION: DO NOT INDUCE VOMITING. Corrosive chemicals will destroy the membranes of the mouth, throat, and esophagus and, in addition, have a high risk of being aspirated into the victim's lungs during vomiting which increases the medical problems. If the victim is conscious and not convulsing, give 1 or 2 glasses of water to dilute the chemical and IMMEDIATELY call a hospital or poison control center. IMMEDIATELY transport the victim to a hospital. If the victim is convulsing or unconscious, do not give anything by mouth, ensure that the victim's airway is open and lay the victim on his/her side with the head lower than the body. DO NOT INDUCE VOMITING. Transport the victim IMMEDIATELY to a hospital. (NTP, 1992)

General First Aid:

· Call 911 or emergency medical service.

· Ensure that medical personnel are aware of the material(s) involved, take precautions to protect themselves and avoid contamination.

· Move victim to fresh air if it can be done safely.

· Administer oxygen if breathing is difficult.

· If victim is not breathing:

-- DO NOT perform mouth-to-mouth resuscitation; the victim may have ingested or inhaled the substance.

-- If equipped and pulse detected, wash face and mouth, then give artificial respiration using a proper respiratory medical device (bag-valve mask, pocket mask equipped with a one-way valve or other device).

-- If no pulse detected or no respiratory medical device available, provide continuous compressions. Conduct a pulse check every two minutes or monitor for any signs of spontaneous respirations.

· Remove and isolate contaminated clothing and shoes.

· For minor skin contact, avoid spreading material on unaffected skin.

· In case of contact with substance, remove immediately by flushing skin or eyes with running water for at least 20 minutes.

· For severe burns, immediate medical attention is required.

· Effects of exposure (inhalation, ingestion, or skin contact) to substance may be delayed.

· Keep victim calm and warm.

· Keep victim under observation.

· For further assistance, contact your local Poison Control Center.

· Note: Basic Life Support (BLS) and Advanced Life Support (ALS) should be done by trained professionals.

Specific First Aid:

· For corrosives, in case of contact, immediately flush skin or eyes with running water for at least 30 minutes. Additional flushing may be required.

In Canada, an Emergency Response Assistance Plan (ERAP) may be required for this product. Please consult the shipping paper and/or the "ERAP" section.

(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.

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

SMALL FIRE: Dry chemical, CO2 or water spray.

LARGE FIRE: Dry chemical, CO2, alcohol-resistant foam or water spray. If it can be done safely, move undamaged containers away from the area around the fire. Dike runoff from fire control for later disposal.

FIRE INVOLVING TANKS, RAIL TANK CARS OR HIGHWAY TANKS: Fight fire from maximum distance or use unmanned master stream devices or monitor nozzles. Do not get water inside containers. Cool containers with flooding quantities of water until well after fire is out. Withdraw immediately in case of rising sound from venting safety devices or discoloration of tank. ALWAYS stay away from tanks in direct contact with flames. (ERG, 2024)

In case of fire in the surroundings, use appropriate extinguishing media.

Suitable extinguishing media: Use water spray, alcohol-resistant foam, dry chemical or carbon dioxide.

Wear self-contained breathing appartus for firefighting if necessary.

· CALL 911. Then call emergency response telephone number on shipping paper. If shipping paper not available or no answer, refer to appropriate telephone number listed on the inside back cover.

· Keep unauthorized personnel away.

· Stay upwind, uphill and/or upstream.

· Ventilate closed spaces before entering, but only if properly trained and equipped.

· 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.

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)

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.

· For highlighted materials: see Table 1 - Initial Isolation and Protective Action Distances.

· For non-highlighted materials: increase the immediate precautionary measure distance, in the downwind direction, as necessary.

· 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.

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.

Personal precautions, protective equipment and emergency procedures: Wear respiratory protection. Avoid dust formation. Avoid breathing vapors, mist or gas. Ensure adequate ventilation. Evacuate personnel to safe areas. Avoid breathing dust...

Pick up and arrange disposal without creating dust. Sweep up and shovel. Keep in suitable, closed containers for disposal.

Prevent further leakage or spillage if safe to do so. Do not let product enter drains. Discharge into the environment must be avoided.

SRP: 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 air, soil or water; effects on animal, aquatic and plant life; and conformance with environmental and public health regulations. If it is possible or reasonable use an alternative chemical product with less inherent propensity for occupational harm/injury/toxicity or environmental contamination.

Neutralization & discharge to sewer: Carefully dissolve in water and neutralize with dilute acetic acid. Flush to sewer with lots of water, regulations permitting or dispose of through a licensed contractor. Consider use of waste caustic for neutralizing plant acid wastes.

Precautions for safe handling: Further processing of solid materials may result in the formation of combustible dusts. The potential for combustible dust formation should be taken into consideration before additional processing occurs. Avoid contact with skin and eyes. Avoid formation of dust and aerosols. Provide appropriate exhaust ventilation at places where dust is formed.

... Exercise great care in handling potassium hydroxide, as it rapidly destroys tissue. Do not handle with bare hand.

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.

SRP: Contaminated protective clothing should be segregated in a manner such that there is no direct personal contact by personnel who handle, dispose, or clean the clothing. The completeness of the cleaning procedures should be considered before the decontaminated protective clothing is returned for reuse by the workers. Contaminated clothing should not be taken home at the end of shift, but should remain at employee's place of work for cleaning.

For more Preventive Measures (Complete) data for POTASSIUM HYDROXIDE (8 total), please visit the HSDB record page.

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)

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.

Keep container tightly closed in a dry and well-ventilated place. Absorbs carbon dioxide (CO2) form air. Air sensitive. Strongly hygroscopic. Storage class (TRGS 510): Non-combustible, corrosive hazardous materials.

· Wear positive pressure self-contained breathing apparatus (SCBA).

· Wear chemical protective clothing that is specifically recommended by the manufacturer when there is NO RISK OF FIRE.

· Structural firefighters' protective clothing provides thermal protection but only limited chemical protection.

0.18 [mg/m3]

2.0 [mg/m3]

54 [mg/m3]

C 2 mg/m3

none See Appendix G

See: IDLH INDEX

Ceiling Limit: 2 mg/cu m

2 mg/m³ [1992]

Small Fire

· Dry chemical, CO2 or water spray.

Large Fire

· Dry chemical, CO2, alcohol-resistant foam or water spray.

· If it can be done safely, move undamaged containers away from the area around the fire.

· Dike runoff from fire control for later disposal.

Fire Involving Tanks, Rail Tank Cars or Highway Tanks

· Fight fire from maximum distance or use unmanned master stream devices or monitor nozzles.

· Do not get water inside containers.

· Cool containers with flooding quantities of water until well after fire is out.

· Withdraw immediately in case of rising sound from venting safety devices or discoloration of tank.

· ALWAYS stay away from tanks in direct contact with flames.

Australia: peak limitation 2 mg/cu m (1990); United Kingdom: 10 min STEL 2 mg/cu m (1991)

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

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

Repeated or prolonged contact with skin may cause dermatitis.

Residues of potassium 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.

Residues of potassium 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: Meeting Food Chemicals, Codex specifications.

Wide-brimmed hat and close-fitting safety goggles equipped with rubber side shields; long-sleeved cotton shirt or jacket with buttoned collar and buttoned sleeves; rubber or rubber-coated canvas gloves. (Shirt sleeves should be buttoned over the gloves so that any spilled material will run down the outside.) Rubber safety-toe-shoes or boots and cotton coveralls. (Trouser cuffs should be worn outside of boots.) Rubber apron. (USCG, 1999)

Excerpt from NIOSH Pocket Guide for Potassium 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)

Wear appropriate personal protective clothing to prevent skin contact.

Potassium hydroxide, solution appears as an clear aqueous solution. Corrosive to metals and tissue. Noncombustible. Used in chemical manufacturing, petroleum refining, cleaning compounds.

Potassium hydroxide, [dry solid, flake, bead, or granular] appears as a white solid. Corrosive to metals and tissue. Used in soap manufacture, bleach, as an electrolyte in alkaline batteries, and as a food additive.

Liquid; Dry Powder; Liquid; Liquid; Other Solid; Dry Powder; Large Crystals; Large Crystals; CBI; Dry Powder; Other Solid

White or nearly white pellets, flakes, sticks, fused masses or other forms

Odorless, white or slightly yellow lumps, rods, flakes, sticks, or pellets. [Note: May be used as an aqueous solution.]; [NIOSH]

WHITE HYGROSCOPIC SOLID IN VARIOUS FORMS.

White, odorless solid or clear aqueous solution.

Odorless, white or slightly yellow lumps, rods, flakes, sticks, or pellets. [Note: May be used as an aqueous solution.]

White or colorless, orthorhombic, deliquescent pieces, lumps, or sticks having crystalline fracture

White or slightly yellow lumps, rods, pellets

White rhombic crystals

Odorless

greater than 266 °F at 760 mmHg (USCG, 1999)

2408 °F at 760 mmHg (NTP, 1992)

1327 °C @760 [mm Hg]

680 °F approximately (NTP, 1992)

about 360 °C; about 380 °C when anhydrous

Melting point: 406 °C

90-92% KOH; MP: about 250 °C; heat of fusion: about 6.7 kJ/mol /Technical potassium hydroxide/

107 g/100 cc at 59 °F (NTP, 1992)

Very soluble in water. Freely soluble in ethanol

Solubility in water, 121 g/100 g water at 25 °C

Solubility in water (g KOH/100 g H2O): 97 at 0 °C; 103 at 10 °C; 112 at 20 °C; 126 at 30 °C; 178 at 100 °C

Soluble in 0.9 part water, about 0.6 part boiling water

Soluble in ethanol, methanol

For more Solubility (Complete) data for POTASSIUM HYDROXIDE (6 total), please visit the HSDB record page.

Solubility in water, g/100ml at 25 °C: 110 (very good)

(59 °F): 107%

1.45 to 1.50 at 68 °F (USCG, 1999)

2.04 at 59 °F (USCG, 1999) - Denser than water; will sink

2.044 g/cu cm

Colorless, strongly basic, soapy, caustic liquid whose density depends on the concentration (g/cu cm at wt%): 1.092 at 10; 1.188 at 29; a.291 at 30; a.395 at 40; 1.514 at 50 /Aqueous potassium hydroxide/

2.04 g/cm³

2.044 @25 °C

1 mmHg at 1326 °F ; 5 mmHg at 1497 °F (NTP, 1992)

1 MM HG @ 714 °C

1 mmHg at 1326 °F; 5 mmHg at 1497 °F

(1317 °F): 1 mmHg

Not flammable (USCG, 1999)

When heated to decomposition it emits toxic fumes of K2O.

Forms crusts on exposure to air (from absorption of carbon dioxide). Water soluble. Dilution of concentrated solutions generates heat.

Hydrolysis generates enough heat to ignite adjacent combustible material [Haz. Chem. Data 1966]. Dissolves in water (with liberation of heat, may steam and spatter. Solution is basic (alkaline). Deliquescent

Bases, Strong

Water and Aqueous Solutions

Water-Reactive

CSL00052

ACETONE + POTASSIUM HYDROXIDE + CALCIUM HYDROXIDE + CHLOROFORM

Chloroform and acetone interact vigorously and exothermally in presence of solid potassium hydroxide or calcium hydroxide to form 1,1,1-trichloro-2-hydroxy-2-methylpropane.

Explosive

Bretherick's

CSL00113

POTASSIUM HYDROXIDE + ACETONITRILE

Acetonitrile can be hydrolyzed exothermally in the presence of strong aqueous base, such as NaOH or KOH, starting at ~60oC. The reaction can potentially escalate into a runaway reaction if the generated heat is not removed (such as during a loss of cooling incident).

User-Reported

CSL00141

POTASSIUM HYDROXIDE + PROPARGYL ALCOHOL

Propargyl alcohol can polymerize explosively. Strong bases such as KOH appear to lower the onset temperature of this event.

acetylene

ARC experiment of a reaction mixture in neat propargyl alcohol with KOH catalyst ruptured a hastelloy ARC bomb. Onset temperature was 75 degrees C.

CSL00202

1,3,5-Benzenetriol, 2,4,6-trinitro-, potassium salt + Water + Acetic Acid + Potassium nitrite + Potassium hydroxide + Ethanol

"The potassium salt of 2,4,6-trinitroso-1,3,5-benzenetriol, prepared in our laboratory precisely according to the literature procedure of R. Benedikt (Chem. Ber. 1878, 11, 1374), unexpectedly exploded. 1,3,5-Benzenetriol (1 g, 7.9 mmol) dissolved in 30 mL of H2O and 3 mL of glacial acetic acid was cooled at 6-9 °C and 3 equivalents of potassium nitrite (2 g, 23.7 mmol) in 2 mL water was added. The reaction mixture immediately became brownish and was stirred an additional 30 minutes. Potassium hydroxide (1.4 g, 23.7 mmol) was added, followed by 10 mL of ethanol. The precipitate of dark green crystals was filtered off to give the potassium salt (48%), which was stored in a covered flask on the bench. An hour and a half later, it exploded spontaneously, damaging some glass containers. According to the original report, 2,4,6-trinitroso-1,3,5-benzenetriol decomposes on heating at 130 °C." (reprint of full text)

Response by Neal Langerman" "Nitroso compounds are well documented as energetic and frequently spontaneously decompose (“Bretherick’s Handbook of Reactive Chemical Hazards,” P. G. Urben, editor, 7th Ed., Academic Press, 2007, and “Explosives,” Rudolf Meyer, Josef Köhler, Axel Homburg, 6th Ed., Wiley-VCH, 2007). The compound being synthesized by Katritzky is very similar to the known explosive compound 2,4,6-trinitrobenzene-1,3-diol and the unstable compound 2,4,6-trinitrobenzene-1,3,5-triol (see Bretherick’s). The metal salts of the latter are explosive. Given this literature information, it is reasonable to expect the trinitroso compound to be unstable and explosive. Under these circumstances, synthetic chemistry should be conducted with appropriate controls to prevent an explosion and to limit the size of an energetic event, should one occur." (reprint of full text). Literature citation: Langerman, Neal. esponse to an unexpected explosion. Chem. Eng. News 2008, 86 (40), 5. DOI: 10.1021/cen-v086n040.p004. (Letters: chemical safety)

10.1021/cen-v086n040.p004

Literature Reference

10/20/2022

POTASSIUM HYDROXIDE, SOLUTION is a strong base dissolved in water. Reacts exothermically with all acids. Slowly dissolves glass. Attacks aluminum and zinc to generate flammable hydrogen gas. Ignited a polyethylene container liner when mixed with potassium persulfate by release of heat and oxygen [MCA Case History 1155. 1955].

POTASSIUM HYDROXIDE absorbs moisture readily forming caustic solution that attacks aluminum and zinc. A piece of potassium hydroxide causes liquid chlorine dioxide to explode [Mellor 2:289. 1946-47]. 1,2-dichloroethylene and potassium hydroxide forms chloroacetylene, which is explosive and spontaneously flammable in air. It is highly toxic [Rutledge 1968. p. 134]. A reaction between n-nitrosomethylurea and potassium hydroxide in n-butyl ether resulted in an explosion due to the formation of diazomethane [Schwab 1972]. Potassium persulfate and a little potassium hydroxide and water ignited a polythene (polyethylene) liner of a container by release of heat and oxygen [MCA Case History 1155. 1955]. Using potassium hydroxide to dry impure tetrahydrofuran, which contains peroxides, may be hazardous. Explosions have occurred in the past. Sodium hydroxide behaves in a similar way as potassium hydroxide [NSC Newsletter Chem. Soc. 1967]. A strong base. Forms caustic solution in water. [Merck 11th ed. 1989].

Acids, water, metals (when wet), halogenated hydrocarbons, maleic anhydride [Note: Heat is generated if KOH comes in contact with water & carbon dioxide from the air].

Above 84 °C it reacts with reducing sugars to form poisonous carbon monoxide gas. Violent, exothermic reaction with water. Potentially explosive reaction with bromoform + crown ethers, chlorine dioxide, nitrobenzene, nitromethane, nitrogen trichloride, peroxidized tetrahydrofuran, 2,4,6-trinitrotoluene. Reaction with ammonium hexachloroplatinate(2-) + heat forms a heat-sensitive explosive product. Violent reaction or ignition under the appropriate conditions with acids, alcohols, p-bis(1,3-dibromoethyl)benzene, cyclopentadiene, germanium, hyponitrous acid, maleic anhydride, nitroalkanes, 2-nitrophenol, potassium peroxodisulfate, sugars, 2,2,3,3-tetrafluoropropanol, thorium dicarbide.

Molten ortho nitrophenol reacts violently with potassium hydroxide (commercial 85% pellets). When solid potassium hydroxide & tetrachloroethane are heated, a spontaneously flammable gas, chloroacetylene, is formed.

/1,2-Dichloroethylene & potassium hydroxide reaction/ produces chloroacetylene, which is ... spontaneously flammable in air.

For more Hazardous Reactivities and Incompatibilities (Complete) data for POTASSIUM HYDROXIDE (13 total), please visit the HSDB record page.

Acids, water, metals (when wet), halogenated hydrocarbons, maleic anhydride [Note: Heat is generated if KOH comes in contact with H2O & CO2 from the air.]

The CIR Expert Panel concluded that ... Potassium Hydroxide is safe in hair straighteners and depilatories under conditions of recommended use; users should minimize skin contact.  These ingredients are safe for all other present practices of use and concentration described in this safety assessment when formulated to be nonirritating.

Safe for use in cosmetics, with qualifications

IDENTIFICATION AND USE: Potassium hydroxide (KOH) is commercialized as a solid or as solutions with varying concentrations. It is used in soap manufacture; drain and pipeline cleaners; bleaching agents; manufacture of potassium carbonate and tetrapotassium pyrophosphate, an electrolyte in alkaline storage batteries and some fuel cells, absorbent for carbon dioxide and hydrogen sulfide; dyestuffs; liquid fertilizers; food additive; herbicides; electroplating; mercerizing; and paint removers. HUMAN EXPOSURE AND TOXICITY: Potassium hydroxide causes direct local effects on the skin, eyes and gastrointestinal tract after direct exposure. If KOH aerosols/mists occur, they will cause direct local effects on respiratory tract. Solutions with concentrations higher than 2% are corrosive, while concentrations of about 0.5 to about 2.0 % are irritating. The irritant effects are reported as coughing, wheezing, conjunctivitis, tearing, and irritation. Children may be accidentally exposed to commercial cleaning products. In a retrospective clinical study with 168 children after alkaline substance ingestion, 9 children (5.3%) developed gastric outlet obstruction. The fatal complications from an alkaline battery foreign body (containing potassium hydroxide 45%) in the esophagus of a 2.5 year old male, resulting in corrosive burns of the esophagus, necrosis, perforation, communication between the esophagus and the trachea and subsequent death, is reported. A total of 23 burns of the eye due to NaOH or KOH were admitted to the eye clinic of the RWTH Aachen in Germany from 1985 to 1992. In 17 cases the accident happened during work, while 6 cases occurred at home using NaOH/KOH as drain cleaner. The alkali burns were of special interest because of the rapid and deep penetration of alkali into the ocular tissues. A 4-year old boy who had a button battery lodged in his nose for approx. 24 hrs had local tissue corrosion, with a small perforation, caused presumably by the 25% KOH electrolyte. An epidemiological study about potash mining workers failed to correlate the exposure to potash to a number of diseases evaluated, including lung cancer. However, there is also a strong association between lye stricture of the esophagus and esophageal squamous cell carcinoma, with a long latent period of eventually several decades. ANIMAL STUDIES: In an acute toxicity study for KOH, the LD50 (intubation) of male rats was 365 mg/kg. Hemorrhaging of the stomach and intestine and adhesions of abdominal organs (stomach, pancreas, spleen, liver and small intestine) were seen following administration of both lethal and sub-lethal doses. Surviving animals showed evidence of hyper excitability, followed by apathy and weakness throughout the 14-day post-exposure period. Other clinical signs were increased respiration rate, ruffled fur, eye closing and bloody nasal exudate. All deaths occurred within 72 hours of dosing. KOH has a moderate acute oral toxicity, which is essentially due to its corrosivity. The observed systemic effects could be regarded as secondary effects. Draize skin tests in rabbits, with gauze covering and application of 0.1 mL during 24 hours, qualified a 5% KOH solution as mildly irritating on intact skin and highly irritating on abraded skin. A 10% KOH solution was qualified as corrosive on both intact and abraded skin as the result of a Draize occlusive test on rabbits with 4 hours exposure to 0.5 mL of the solution. The results of an Ames assay study with Salmonella typhimurium TA 97 and TA 102, with and without metabolic activation and up to 1 mg KOH/plate, were negative. The clastogenic activity of KOH was studied in an in vitro chromosomal aberration test using Chinese hamster ovary (CHO) K1 cells. No clastogenic activity was found at KOH concentrations of 0, 8 and 12 mM, which corresponded with initial pH values of 7.3, 9.8 and 10.4, respectively. A long-term study (reliability 3) of 25-46 weeks, consisting of painting 3-6% KOH solutions on mouse skin, has been performed. The results were ca. 15% occurrence of cancer at the application site. An old long-term study (reliability 3) of 25-46 weeks, consisting of painting 3-6% KOH solutions on mouse skin, has been performed. The results were 15% occurrence of cancer at the application site. Doses of 2.35-235 mg/kg bw/day in mice and 3.1-310 mg/kg bw/day in rats were administered to groups of 21-24 animals by single daily oral intubation. Body weights were recorded during 17 days for mice, with a post exposure period of 2 days and during 20 days for rats, with a post exposure period of 5 days. No significant effects were observed on mice and rat's survival and reproductive organs, or on offspring survival, weight, sex ratio and congenital defects.

Serious local effects by all routes of exposure.

inhalation, ingestion, skin and/or eye contact

Cough. Sore throat. Burning sensation. Shortness of breath.

Redness. Pain. Serious skin burns. Blisters.

Redness. Pain. Blurred vision. Severe burns.

Abdominal pain. Burns in mouth and throat. Burning sensation in the throat and chest. Nausea. Vomiting. Shock or collapse.

irritation eyes, skin, respiratory system; cough, sneezing; eye, skin burns; vomiting, diarrhea

Eyes, skin, respiratory system

Dermatotoxin - Skin burns.

Toxic Pneumonitis - Inflammation of the lungs induced by inhalation of metal fumes or toxic gases and vapors.

LD50 Rat oral 363 mg/kg bw/day

LD50 Rat oral 273 mg/kg bw/day

LD50 Rat oral 1230 mg/kg bw/day

Immediate first aid: Remove patient from contact with the material. Ensure that adequate decontamination has been carried out. If patient is not breathing, start artificial respiration, preferably with a demand valve resuscitator, bag-valve-mask device, or pocket mask, as trained. Perform CPR if necessary. Immediately flush contaminated eyes with gently flowing water. Do not induce vomiting. If vomiting occurs, lean patient forward or place on the left side (head-down position, if possible) to maintain an open airway and prevent aspiration. Keep patient quiet and maintain normal body temperature. Obtain medical attention. /Inorganic Bases/Alkaline Corrosives and Related Compounds/

Basic treatment: Establish a patent airway (oropharyngeal or nasopharyngeal airway, if needed). Suction if necessary. Watch for signs of respiratory insufficiency and assist ventilations if necessary. Administer oxygen by nonrebreather mask at 6 to 12 L/min. Monitor for pulmonary edema and treat if necessary ... . Monitor for shock and treat if necessary ... . For eye contamination, flush eyes immediately with water. Irrigate each eye continuously with 0.9% saline (NS) during transport ... . Do not use emetics. For ingestion, rinse mouth and administer 5 mL/kg up to 200 mL of water for dilution if the patent can swallow, has a strong gag reflex, and does not drool ... . Do not attempt to neutralize. Cover skin burns with dry sterile dressings after decontamination ... . /Inorganic Bases/Alkaline Corrosives and Related Compounds/

Advanced treatment: Consider orotracheal or nasotracheal intubation for airway control in the patient who is unconscious, has severe pulmonary edema, or is in severe respiratory distress. Early intubation, at the first signs of upper airway obstruction, may be necessary. Positive-pressure ventilation techniques with a bag valve mask device may be beneficial. Consider drug therapy for pulmonary edema ... . Monitor cardiac rhythm and treat arrhythmias as necessary ... . Start IV administration of D5W /SRP: "To keep open", minimal flow rate/. Use 0.9% saline (NS) or lactated Ringer's (LR) if signs of hypovolemia are present. For hypotension with signs of hypovolemia, administer fluid cautiously. Consider vasopressors if patient is hypotensive with a normal fluid volume. Watch for signs of fluid overload ... . Use proparacaine hydrochloride to assist eye irrigation ... . /Inorganic Bases/Alkaline Corrosives and Related Compounds/

/HUMAN EXPOSURE STUDIES/ Potassium hydroxide (KOH) is a strong alkali that has long been known to digest proteins, lipids, and most other epithelial debris of skin scrapings to identify fungal infections. To our knowledge, KOH has never been used for the treatment of molluscum contagiosum (MC). We evaluated 35 children with MC for the clinical effectiveness of treatment with topical 10% KOH aqueous solution. The solution was applied by the parents of affected children, twice daily, on each MC lesion. The therapy was continued until all lesions underwent inflammation and superficial ulceration. Thirty-two of 35 patients achieved complete clinical cure after a mean treatment period of 30 days. Three children discontinued treatment: two reported severe stinging of the lesions and refused further applications; the other, with giant MC lesions, developed a secondary infection with prolonged treatment. Therapy with KOH was found to be effective and safe in the treatment of MC in children.

/SIGNS AND SYMPTOMS/ Acute poisoning: ... ingestion of alkali is followed by severe pain, vomiting, diarrhea, & collapse. The vomitus contains blood and desquamated mucosal lining. If death does not occur in the first 24 hours, the patient may improve for 2-4 days and then have a sudden onset of severe abdominal pain, boardlike abdominal rigidity, and rapid fall of blood pressure indicating delayed gastric or esophageal perforation. ... Esophageal stricture can occur weeks, months, or even years later to make swallowing difficult. Carcinoma is a risk in later life. /Alkalies/

/SIGNS AND SYMPTOMS/ Acute poisoning: ... alkalies penetrate skin slowly. Extent of damage ... depends on duration of contact. ... Chronic poisoning: (from skin contact) a chronic dermatitis may follow repeated contact with alkalies. /Alkalies/

/SIGNS AND SYMPTOMS/ There are great many accounts of accidental and suicidal ingestion of the sodium and potassium hydroxides... Death results from shock, perforation of the esophagus, aspiration from the esophagus into the trachea, pneumonitis, mediatinitis, or inanition and infection.

For more Human Toxicity Excerpts (Complete) data for POTASSIUM HYDROXIDE (31 total), please visit the HSDB record page.

/LABORATORY ANIMALS: Acute Exposure/ There are no data from which to derive a dose-effect or dose-response relationship for occupational exposure to potassium hydroxide. Eye irritation has been studied in rabbits. A 5% solution was corrosive to the eye, and a 0.1% solution had no effect.

/LABORATORY ANIMALS: Acute Exposure/ In a Draize rabbit test (reliability 3) with gauze covering and application of 0.5 mL of KOH solutions during 4 hours, the 1% solution was not corrosive, whereas the 2% solution was corrosive. There was no post-exposure assessment of the lesion.

/LABORATORY ANIMALS: Acute Exposure/ A 10% KOH solution was qualified as corrosive on both intact and abraded skin as the result of a Draize occlusive test on rabbits with 4 hours exposure to 0.5 ml of the solution. The results with guinea pigs were similar.

/LABORATORY ANIMALS: Acute Exposure/ In a classical rabbit Draize test with gauze covering, application of 0.5 mL of KOH 5% during 4 hours gave a PDII (primary dermal irritation indices) result of 4.8 (moderately irritating). A 10% solution was severely irritating. With 19 mm diameter Hill Top Chamber pad covering during 1 or 4 hours and 0.2 mL applied, the 5 and 10% KOH solutions were qualified as severely irritating.

For more Non-Human Toxicity Excerpts (Complete) data for POTASSIUM HYDROXIDE (10 total), please visit the HSDB record page.

LC50; Species: Gambusia affinis (mosquito fish); Concentration: 80 mg/L for 96 hr /Conditions of bioassay not specified in source examined/

TLm Mosquito fish 80 ppm/24 hr fresh water. /Conditions of bioassay not specified/

This substance may be hazardous to the environment. Special attention should be given to aquatic organisms.

According to the 2012 TSCA Inventory Update Reporting data, 38 reporting facilities estimate the number of persons reasonably likely to be exposed in manufacturing, processing, or use of potassium hydroxide in the United States may be as low as <10 workers and as high as 9999 workers per plant; the data may be greatly underestimated due to confidential business information (CBI) or unknown values(1).

NIOSH (NOES Survey 1981-1983) has statistically estimated that 1,966,611 (800,041 of these were female) were potentially exposed to potassium hydroxide in the US(1). Occupational exposure to potassium hydroxide may occur through inhalation and dermal contact with this compound at workplaces where potassium hydroxide is produced or used(SRC).

LC50; Species: Gambusia affinis (mosquito fish); Concentration: 80 mg/L for 96 hr /Conditions of bioassay not specified in source examined/

TLm Mosquito fish 80 ppm/24 hr fresh water. /Conditions of bioassay not specified/

This substance may be hazardous to the environment. Special attention should be given to aquatic organisms.

According to the 2012 TSCA Inventory Update Reporting data, 38 reporting facilities estimate the number of persons reasonably likely to be exposed in manufacturing, processing, or use of potassium hydroxide in the United States may be as low as <10 workers and as high as 9999 workers per plant; the data may be greatly underestimated due to confidential business information (CBI) or unknown values(1).

NIOSH (NOES Survey 1981-1983) has statistically estimated that 1,966,611 (800,041 of these were female) were potentially exposed to potassium hydroxide in the US(1). Occupational exposure to potassium hydroxide may occur through inhalation and dermal contact with this compound at workplaces where potassium hydroxide is produced or used(SRC).

SRP: 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 air, soil or water; effects on animal, aquatic and plant life; and conformance with environmental and public health regulations. If it is possible or reasonable use an alternative chemical product with less inherent propensity for occupational harm/injury/toxicity or environmental contamination.

Neutralization & discharge to sewer: Carefully dissolve in water and neutralize with dilute acetic acid. Flush to sewer with lots of water, regulations permitting or dispose of through a licensed contractor. Consider use of waste caustic for neutralizing plant acid wastes.

/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. For UN3171, if Lithium ion batteries are involved, also consult GUIDE 147. /Caustic potash, dry, solid; Potassium hydroxide, dry, solid; Potassium hydroxide, flake; Potassium hydroxide, solid; Caustic potash, liquid; Caustic potash, solution; Potassium 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. /Caustic potash, dry, solid; Potassium hydroxide, dry, solid; Potassium hydroxide, flake; Potassium hydroxide, solid; Caustic potash, liquid; Caustic potash, solution; Potassium hydroxide, solution/

/GUIDE 154 SUBSTANCES - TOXIC and/or CORROSIVE (Non-Combustible)/ Public Safety: CALL Emergency Response Telephone Number on Shipping Paper first. If Shipping Paper not available or no answer, refer to appropriate telephone number listed on the inside back cover. 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. /Caustic potash, dry, solid; Potassium hydroxide, dry, solid; Potassium hydroxide, flake; Potassium hydroxide, solid; Caustic potash, liquid; Caustic potash, solution; Potassium 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. /Caustic potash, dry, solid; Potassium hydroxide, dry, solid; Potassium hydroxide, flake; Potassium hydroxide, solid; Caustic potash, liquid; Caustic potash, solution; Potassium hydroxide, solution/

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

1813 154(dry, solid)

1814 154(solution)

UN 1813; Potassium hydroxide, solid

UN 1814; Potassium hydroxide. solution

IMO 8; Potassium hydroxide solution; potassium hydroxide solid

49 352 25; Potassium hydroxide, dry solid, flake, bead, or granular

49 352 30; Potassium hydroxide, liquid or solution

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. Potassium hydroxide, solid and potassium hydroxide solution are included on the dangerous goods list.

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. Potassium hydroxide, solid and potassium hydroxide solution are included on the dangerous goods list.

Corrosive

Do not transport with food and feedstuffs.

Symbol: C; R: 22-35; S: (1/2)-26-36/37/39-45

UN Hazard Class: 8; UN Pack Group: II