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Potassium Hydroxide

PubChem CID
14797
Structure
Potassium Hydroxide_small.png
Molecular Formula
Synonyms
  • POTASSIUM HYDROXIDE
  • 1310-58-3
  • Caustic potash
  • Potash lye
  • Potassium hydrate
Molecular Weight
56.106 g/mol
Computed by PubChem 2.2 (PubChem release 2021.10.14)
Dates
  • Create:
    2005-03-27
  • Modify:
    2025-01-18
Description
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.
Potassium hydroxide is an alkali metal hydroxide.

1 Structures

1.1 2D Structure

Chemical Structure Depiction
Potassium Hydroxide.png

1.2 3D Status

Conformer generation is disallowed since MMFF94s unsupported element, mixture or salt

1.3 Crystal Structures

2 Names and Identifiers

2.1 Computed Descriptors

2.1.1 IUPAC Name

potassium;hydroxide
Computed by Lexichem TK 2.7.0 (PubChem release 2021.10.14)

2.1.2 InChI

InChI=1S/K.H2O/h;1H2/q+1;/p-1
Computed by InChI 1.0.6 (PubChem release 2021.10.14)

2.1.3 InChIKey

KWYUFKZDYYNOTN-UHFFFAOYSA-M
Computed by InChI 1.0.6 (PubChem release 2021.10.14)

2.1.4 SMILES

[OH-].[K+]
Computed by OEChem 2.3.0 (PubChem release 2024.12.12)

2.2 Molecular Formula

HKO
Computed by PubChem 2.2 (PubChem release 2021.10.14)
KOH

2.3 Other Identifiers

2.3.1 CAS

1310-58-3

2.3.2 Deprecated CAS

2226392-06-7, 29857-72-5, 71769-53-4
29857-72-5

2.3.3 European Community (EC) Number

215-181-3

2.3.4 UNII

2.3.5 UN Number

2.3.6 ChEBI ID

2.3.7 ChEMBL ID

2.3.8 DrugBank ID

2.3.9 DSSTox Substance ID

2.3.10 HMDB ID

2.3.11 ICSC Number

2.3.12 KEGG ID

2.3.13 NCI Thesaurus Code

2.3.14 Nikkaji Number

2.3.15 RTECS Number

2.3.16 RXCUI

2.3.17 Wikidata

2.3.18 Wikipedia

2.4 Synonyms

2.4.1 MeSH Entry Terms

  • potassium hydroxide
  • potassium hydroxide monohydrate
  • potassium hydroxide tetrahydrate
  • potassium hydroxide, 39K-labeled
  • potassium hydroxide, 41K-labeled

2.4.2 Depositor-Supplied Synonyms

3 Chemical and Physical Properties

3.1 Computed Properties

Property Name
Molecular Weight
Property Value
56.106 g/mol
Reference
Computed by PubChem 2.2 (PubChem release 2021.10.14)
Property Name
Hydrogen Bond Donor Count
Property Value
1
Reference
Computed by Cactvs 3.4.8.18 (PubChem release 2021.10.14)
Property Name
Hydrogen Bond Acceptor Count
Property Value
1
Reference
Computed by Cactvs 3.4.8.18 (PubChem release 2021.10.14)
Property Name
Rotatable Bond Count
Property Value
0
Reference
Computed by Cactvs 3.4.8.18 (PubChem release 2021.10.14)
Property Name
Exact Mass
Property Value
55.96644614 Da
Reference
Computed by PubChem 2.2 (PubChem release 2021.10.14)
Property Name
Monoisotopic Mass
Property Value
55.96644614 Da
Reference
Computed by PubChem 2.2 (PubChem release 2021.10.14)
Property Name
Topological Polar Surface Area
Property Value
1 Ų
Reference
Computed by Cactvs 3.4.8.18 (PubChem release 2021.10.14)
Property Name
Heavy Atom Count
Property Value
2
Reference
Computed by PubChem
Property Name
Formal Charge
Property Value
0
Reference
Computed by PubChem
Property Name
Complexity
Property Value
2
Reference
Computed by Cactvs 3.4.8.18 (PubChem release 2021.10.14)
Property Name
Isotope Atom Count
Property Value
0
Reference
Computed by PubChem
Property Name
Defined Atom Stereocenter Count
Property Value
0
Reference
Computed by PubChem
Property Name
Undefined Atom Stereocenter Count
Property Value
0
Reference
Computed by PubChem
Property Name
Defined Bond Stereocenter Count
Property Value
0
Reference
Computed by PubChem
Property Name
Undefined Bond Stereocenter Count
Property Value
0
Reference
Computed by PubChem
Property Name
Covalently-Bonded Unit Count
Property Value
2
Reference
Computed by PubChem
Property Name
Compound Is Canonicalized
Property Value
Yes
Reference
Computed by PubChem (release 2021.10.14)

3.2 Experimental Properties

3.2.1 Physical Description

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.
Pellets or Large Crystals; Pellets or Large Crystals, Liquid, Other Solid; NKRA; Other Solid; Liquid, Other Solid; Dry Powder; Water or Solvent Wet Solid; Liquid
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.]

3.2.2 Color / Form

White or colorless, orthorhombic, deliquescent pieces, lumps, or sticks having crystalline fracture
Lewis, R.J. Sr. (ed) Sax's Dangerous Properties of Industrial Materials. 12th Edition. Wiley-Interscience, Wiley & Sons, Inc. Hoboken, NJ. 2012., p. 3730
White or slightly yellow lumps, rods, pellets
O'Neil, M.J. (ed.). The Merck Index - An Encyclopedia of Chemicals, Drugs, and Biologicals. Cambridge, UK: Royal Society of Chemistry, 2013., p. 1420
White rhombic crystals
Haynes, W.M. (ed.). CRC Handbook of Chemistry and Physics. 95th Edition. CRC Press LLC, Boca Raton: FL 2014-2015, p. 4-82

3.2.3 Odor

Odorless
NIOSH. NIOSH Pocket Guide to Chemical Hazards. Department of Health & Human Services, Centers for Disease Control & Prevention. National Institute for Occupational Safety & Health. DHHS (NIOSH) Publication No. 2010-168 (2010). Available from: https://www.cdc.gov/niosh/npg

3.2.4 Boiling Point

greater than 266 °F at 760 mmHg (USCG, 1999)
U.S. Coast Guard. 1999. Chemical Hazard Response Information System (CHRIS) - Hazardous Chemical Data. Commandant Instruction 16465.12C. Washington, D.C.: U.S. Government Printing Office.
2408 °F at 760 mmHg (NTP, 1992)
National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina.
1,320
MSDS
1327 °C
Haynes, W.M. (ed.). CRC Handbook of Chemistry and Physics. 95th Edition. CRC Press LLC, Boca Raton: FL 2014-2015, p. 4-82
1324 °C
2408 °F
2415 °F

3.2.5 Melting Point

680 °F approximately (NTP, 1992)
National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina.
405
MSDS
about 360 °C; about 380 °C when anhydrous
O'Neil, M.J. (ed.). The Merck Index - An Encyclopedia of Chemicals, Drugs, and Biologicals. Cambridge, UK: Royal Society of Chemistry, 2013., p. 1420
Melting point: 406 °C
Haynes, W.M. (ed.). CRC Handbook of Chemistry and Physics. 95th Edition. CRC Press LLC, Boca Raton: FL 2014-2015, p. 4-82
90-92% KOH; MP: about 250 °C; heat of fusion: about 6.7 kJ/mol /Technical potassium hydroxide/
Schultz H et al; Potassium Compounds. Ullmann's Encyclopedia of Industrial Chemistry. 7th ed. (1999-2015). New York, NY: John Wiley & Sons. Online Posting Date: a5 Jun 2000
380 °C
680 °F
716 °F

3.2.6 Solubility

107 g/100 cc at 59 °F (NTP, 1992)
National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina.
Soluble
MSDS
Very soluble in water. Freely soluble in ethanol
Solubility in water, 121 g/100 g water at 25 °C
Haynes, W.M. (ed.). CRC Handbook of Chemistry and Physics. 95th Edition. CRC Press LLC, Boca Raton: FL 2014-2015, p. 4-82
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
Schultz H et al; Potassium Compounds. Ullmann's Encyclopedia of Industrial Chemistry. 7th ed. (1999-2015). New York, NY: John Wiley & Sons. Online Posting Date: a5 Jun 2000
Soluble in 0.9 part water, about 0.6 part boiling water
O'Neil, M.J. (ed.). The Merck Index - An Encyclopedia of Chemicals, Drugs, and Biologicals. Cambridge, UK: Royal Society of Chemistry, 2013., p. 1420
Soluble in ethanol, methanol
Haynes, W.M. (ed.). CRC Handbook of Chemistry and Physics. 95th Edition. CRC Press LLC, Boca Raton: FL 2014-2015, p. 4-82
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%

3.2.7 Density

1.45 to 1.50 at 68 °F (USCG, 1999)
U.S. Coast Guard. 1999. Chemical Hazard Response Information System (CHRIS) - Hazardous Chemical Data. Commandant Instruction 16465.12C. Washington, D.C.: U.S. Government Printing Office.
2.04 at 59 °F (USCG, 1999) - Denser than water; will sink
U.S. Coast Guard. 1999. Chemical Hazard Response Information System (CHRIS) - Hazardous Chemical Data. Commandant Instruction 16465.12C. Washington, D.C.: U.S. Government Printing Office.
2.044 g/cu cm
Haynes, W.M. (ed.). CRC Handbook of Chemistry and Physics. 95th Edition. CRC Press LLC, Boca Raton: FL 2014-2015, p. 4-82
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/
Schultz H et al; Potassium Compounds. Ullmann's Encyclopedia of Industrial Chemistry. 7th ed. (1999-2015). New York, NY: John Wiley & Sons. Online Posting Date: a5 Jun 2000
2.04 g/cm³
2.04

3.2.8 Vapor Pressure

1 mmHg at 1326 °F ; 5 mmHg at 1497 °F (NTP, 1992)
National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina.
1 MM HG @ 714 °C
Sax, N.I. Dangerous Properties of Industrial Materials. 6th ed. New York, NY: Van Nostrand Reinhold, 1984., p. 1047
1 mmHg at 1326 °F; 5 mmHg at 1497 °F
(1317 °F): 1 mmHg

3.2.9 Autoignition Temperature

Not flammable (USCG, 1999)
U.S. Coast Guard. 1999. Chemical Hazard Response Information System (CHRIS) - Hazardous Chemical Data. Commandant Instruction 16465.12C. Washington, D.C.: U.S. Government Printing Office.
U.S. Coast Guard. 1999. Chemical Hazard Response Information System (CHRIS) - Hazardous Chemical Data. Commandant Instruction 16465.12C. Washington, D.C.: U.S. Government Printing Office.

3.2.10 Decomposition

When heated to decomposition it emits toxic fumes of K2O.
Lewis, R.J. Sr. (ed) Sax's Dangerous Properties of Industrial Materials. 11th Edition. Wiley-Interscience, Wiley & Sons, Inc. Hoboken, NJ. 2004., p. 3034

3.2.11 Corrosivity

Corrosive
Schultz H et al; Potassium Compounds. Ullmann's Encyclopedia of Industrial Chemistry. 7th ed. (1999-2015). New York, NY: John Wiley & Sons. Online Posting Date: 5 Jun 2000

3.2.12 pH

Strongly alkaline (1 % solution)
pH = 13.5 (0.1 Molar aq soln)
O'Neil, M.J. (ed.). The Merck Index - An Encyclopedia of Chemicals, Drugs, and Biologicals. Cambridge, UK: Royal Society of Chemistry, 2013., p. 1420

3.2.13 Other Experimental Properties

Hygroscopic
Haynes, W.M. (ed.). CRC Handbook of Chemistry and Physics. 95th Edition. CRC Press LLC, Boca Raton: FL 2014-2015, p. 4-82
When dissolved in water or alcohol or when the solution is treated with acid, much heat is generated.
O'Neil, M.J. (ed.). The Merck Index - An Encyclopedia of Chemicals, Drugs, and Biologicals. Cambridge, UK: Royal Society of Chemistry, 2013., p. 1420
Readily absorbs moisture and carbon dioxide from air and deliquesces
O'Neil, M.J. (ed.). The Merck Index - An Encyclopedia of Chemicals, Drugs, and Biologicals. Cambridge, UK: Royal Society of Chemistry, 2013., p. 1420
Heat of solution: 53.51 kJ/mol (in water)
Schultz H et al; Potassium Compounds. Ullmann's Encyclopedia of Industrial Chemistry. 7th ed. (1999-2015). New York, NY: John Wiley & Sons. Online Posting Date: a5 Jun 2000
Heat of fusion: 7.5 kJ/mol
Schultz H et al; Potassium Compounds. Ullmann's Encyclopedia of Industrial Chemistry. 7th ed. (1999-2015). New York, NY: John Wiley & Sons. Online Posting Date: a5 Jun 2000

3.3 SpringerMaterials Properties

3.4 Chemical Classes

Other Classes -> Bases

3.4.1 Drugs

3.4.1.1 Animal Drugs
Pharmaceuticals -> UK Veterinary Medicines Directorate List
S104 | UKVETMED | UK Veterinary Medicines Directorate's List | DOI:10.5281/zenodo.7802119

3.4.2 Cosmetics

Cosmetic ingredients (Potassium Hydroxide) -> CIR (Cosmetic Ingredient Review)
Buffering
S13 | EUCOSMETICS | Combined Inventory of Ingredients Employed in Cosmetic Products (2000) and Revised Inventory (2006) | DOI:10.5281/zenodo.2624118

3.4.3 Food Additives

FORMULATION AID, FUMIGANT, PH CONTROL AGENT, PROCESSING AID, STABILIZER OR THICKENER, WASHING OR SURFACE REMOVAL AGENT -> FDA Substance added to food

5 Chemical Vendors

6 Drug and Medication Information

6.1 Drug Indication

Medically, the microscopic examination of potassium hydroxide (KOH) preparations is utilized in the diagnosis of fungal hyphae or trichomonads. Samples from hair, skin, or nail tissue are obtained by scraping with a scalpel, cotton-tipped applicator and are inoculated directly onto the KOH solution. In addition to the above, potassium hydroxide is used as a softener for nail grooves.

6.2 FDA National Drug Code Directory

6.3 Drug Labels

Drug and label
Active ingredient and drug

6.4 Clinical Trials

6.4.1 ClinicalTrials.gov

6.5 Therapeutic Uses

/EXP THER/ The effects of 1% potassium hydroxide aqueous solution and aqueous Teepol, a surfactant, on reducing subsequent development of anthralin inflammation without loss of therapeutic effect are described. Both compounds were effective and the action seemed to have resulted from enhanced oxidation of anthralin to inactive products by potassium hydroxide and from increased solubility and removal of anthralin by Teepol.
Lawrence CM et al; Br. J. Dermatol.; 116 ISS P171-177 (1987)
/EXP THER/ 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.
OECD; Screening Information Data Set (SIDS) Initial Assessment Report for SIDS Initial Assessment Meeting (SIAM) 13, Potassium Hydroxide (CAS 1310-58-3) November 2001. Available from, as of March 18, 2015. https://www.inchem.org/pages/hsg.html/
Potassium hydroxide is a powerful caustic which has been used to remove warts. /Former use/
Reynolds, J.E.F., Prasad, A.B. (eds.) Martindale-The Extra Pharmacopoeia. 28th ed. London: The Pharmaceutical Press, 1982., p. 44
A 2.5% solution in glycerol may be used as a cuticle solvent.
Reynolds, J.E.F., Prasad, A.B. (eds.) Martindale-The Extra Pharmacopoeia. 28th ed. London: The Pharmaceutical Press, 1982., p. 44
Therap. cat (Vet): Caustic. In disbudding calves' horns. In aq solution to dissolve scales and hair in skin scrapings.
Budavari, S. (ed.). The Merck Index - An Encyclopedia of Chemicals, Drugs, and Biologicals. Whitehouse Station, NJ: Merck and Co., Inc., 1996., p. 1315

7 Food Additives and Ingredients

7.1 Food Additive Classes

JECFA Functional Classes
Food Additives -> ACIDITY_REGULATOR;

7.2 FDA Substances Added to Food

Used for (Technical Effect)
FORMULATION AID, FUMIGANT, PH CONTROL AGENT, PROCESSING AID, STABILIZER OR THICKENER, WASHING OR SURFACE REMOVAL AGENT

7.3 Evaluations of the Joint FAO / WHO Expert Committee on Food Additives - JECFA

Chemical Name
CAUSTIC POTASH
Evaluation Year
1965
ADI
NOT LIMITED

8 Pharmacology and Biochemistry

8.1 Pharmacodynamics

The corrosiveness of potassium hydroxide renders it a very useful agent in the decomposition/removal soft tissue and hair removal. It is incorporated into some nail products, shaving creams, and soaps.

8.2 MeSH Pharmacological Classification

Indicators and Reagents
Substances used for the detection, identification, analysis, etc. of chemical, biological, or pathologic processes or conditions. Indicators are substances that change in physical appearance, e.g., color, at or approaching the endpoint of a chemical titration, e.g., on the passage between acidity and alkalinity. Reagents are substances used for the detection or determination of another substance by chemical or microscopical means, especially analysis. Types of reagents are precipitants, solvents, oxidizers, reducers, fluxes, and colorimetric reagents. (From Grant and Hackh's Chemical Dictionary, 5th ed, p301, p499) (See all compounds classified as Indicators and Reagents.)

8.3 Absorption, Distribution and Excretion

Absorption
KOH in aqueous solutions completely dissociates into K+ and OH- ions. Because of the neutralization of OH- by gastric HCl and the rapid blood pH regulation action (buffer capacity of extracellular body fluids, respiratory and renal compensation mechanisms), an alkalosis due to the OH- ions after KOH oral dosage in non-irritating conditions is thus prevented. The uptake of potassium, in potassium hydroxide form, is much less than the oral uptake with therapeutic doses of KCl for treating potassium deficiency, of up to 10 g/day. Furthermore, the oral uptake of potassium from food/natural sources or from food additives is likely to be also much higher.
Interesting observations are also that alkalosis promotes renal excretion of K+, and that, for preventing hyperkalemia, extra cellular potassium is taken up by cells in exchange for hydrogen ions (Saxena, 1989). In other words, these compensating effects of K+ and OH- would attenuate the systemic effect of KOH.
OECD; Screening Information Data Set (SIDS) Initial Assessment Report for SIDS Initial Assessment Meeting (SIAM) 13, Potassium Hydroxide (CAS 1310-58-3) November 2001. Available from, as of March 18, 2015. https://www.inchem.org/pages/hsg.html/
...It can also be stated that the substance will neither reach the foetus nor reach male and female reproductive organs in effective toxic concentrations. Therefore, no risk for reproductive toxicity is expected.
OECD; Screening Information Data Set (SIDS) Initial Assessment Report for SIDS Initial Assessment Meeting (SIAM) 13, Potassium Hydroxide (CAS 1310-58-3) (November 2001). Available from, as of March 18, 2015. https://www.inchem.org/pages/hsg.html/
Under normal handling and use conditions (non-irritating) neither the concentration of potassium in the blood nor the pH of the blood will be increased above normal limits and therefore KOH is not expected to cause systemically toxic levels in the blood. The renal excretion of K+ can be elevated and the OH- ion is neutralised by the bicarbonate buffer system in the blood...
OECD; Screening Information Data Set (SIDS) Initial Assessment Report for SIDS Initial Assessment Meeting (SIAM) 13, Potassium Hydroxide (CAS 1310-58-3) (November 2001). Available from, as of March 18, 2015. https://www.inchem.org/pages/hsg.html/
Alkalies penetrate skin slowly. /Alkalies/
Dreisbach, R.H. Handbook of Poisoning. 12th ed. Norwalk, CT: Appleton and Lange, 1987., p. 213
Ammonium hydroxide penetrates fastest, followed by sodium hydroxide, potassium hydroxide, and finally calcium hydroxide.
Sullivan, J.B. Jr., G.R. Krieger (eds.). Hazardous Materials Toxicology-Clinical Principles of Environmental Health. Baltimore, MD: Williams and Wilkins, 1992., p. 433

8.4 Metabolism / Metabolites

KOH in aqueous solution is entirely dissociated into K+ and OH- ions. Due to the neutralization of OH- by gastric HCl and the quick and efficient blood pH regulation mechanisms (buffer capacity of extra cellular body fluids, respiratory and renal compensation mechanisms), an alkalosis due to the OH- ions after KOH oral dosage in non-irritating conditions is prevented.
KOH in aqueous solutions is completely dissociated into K+ and OH- ions. Due to the neutralization of OH- by gastric HCl and the quick and efficient blood pH regulation mechanisms (buffer capacity of extra cellular body fluids, respiratory and renal compensation mechanisms), an alkalosis due to the OH- ions after KOH oral dosage in non-irritating conditions is prevented.
OECD; Screening Information Data Set (SIDS) Initial Assessment Report for SIDS Initial Assessment Meeting (SIAM) 13, Potassium Hydroxide (CAS 1310-58-3) November 2001. Available from, as of March 18, 2015. https://www.inchem.org/pages/hsg.html/
...In every case, it should be realised that aerosols of KOH are not stable. They are rapidly transformed due to an uptake of carbon dioxide from the atmosphere resulting in the formation of potassium bicarbonate and potassium carbonate. Cooper et al. (1979) reported that the transformation of respirable NaOH aerosols into carbonate aerosols could occur in seconds...
OECD; Screening Information Data Set (SIDS) Initial Assessment Report for SIDS Initial Assessment Meeting (SIAM) 13, Potassium Hydroxide (CAS 1310-58-3) November 2001. Available from, as of March 18, 2015. https://www.inchem.org/pages/hsg.html/

8.5 Mechanism of Action

The exact mechanism of action of KOH is not known but the speculated one is that topical application of KOH digests keratin, and induces inflammation. The mechanism of skin injury by alkali substances such as potassium hydroxide is by the saponification of fat, causing fatty tissue to lose its function with increased damage due to a heat reaction. Extraction of water from cells occurs due to the hygroscopic (absorbent) nature of alkali. Dissolution of proteins also occurs, allowing for deeper penetration of OH- ions and resulting in various chemical reactions. The alkali penetrates the skin quickly, saponifies plasma membranes, denatures collagen proteins, and leads to vascular thromboses in the conjunctiva and other parts of the eye. The resulting corneal burns include scarring and opacification of the cornea with resulting in vision loss, corneal neovascularization, ulcer formation, and perforation. Other consequences of untreated or very severe alkali burns include epithelial erosions, secondary glaucoma, and causes the destruction of conjunctival mucus cells, causing dry eyes, trichiasis (misdirected eyelash hairs), and other ocular conditions. In the gastrointestinal tract, after oral ingestion, burns may result. The mechanism of injury is liquefactive necrosis. The thrombosis of gastrointestinal blood vessels also contributes to tissue damage. When the alkali enters the stomach, gastric acid may neutralize the strong base, which can limit the extent of the injury. Perforation of the stomach can sometimes occur with peritonitis and caustic injury to the surrounding organs including the colon, pancreas, liver, and spleen.
The mechanism of injury by alkali skin burns is by saponification of fat, which causes fatty tissue to lose its function with increased damage due to heat reaction; extraction of considerable water from cells due to the hygroscopic nature of alkali; and dissolution of proteins, permitting so deeper penetration of OH- ions and further chemical reactions.
OECD; Screening Information Data Set (SIDS) Initial Assessment Report for SIDS Initial Assessment Meeting (SIAM) 13, Potassium Hydroxide (CAS 1310-58-3) November 2001. Available from, as of March 18, 2015. https://www.inchem.org/pages/hsg.html/
A systemic (non-acute) oral intoxication by KOH is not expected. Regarding the potassium toxicity, the LD50 value in rats of KCl, 3.020 g/kg bw/day is much higher than that of KOH, in the range of 0.273 - 0.365 - 1.230 g KOH/kg bw/day. This demonstrates that the acute toxicity of KOH is probably due to the corrosivity caused by the OH- ion (pH value), and less to systemic toxic effects of the K+ ion. Under non-irritating conditions, the potassium doses are much lower than those used in acute toxicity studies, and therefore not relevant from the point of view of the systemic toxicity of potassium. Furthermore, the uptake of potassium, via exposure to potassium hydroxide, is much less than the oral uptake with therapeutic doses of KCl for treating potassium deficiency, of up to 10 g/day. Moreover, the oral uptake of potassium from food, from natural origin or from food additives, is likely to be also much higher.
OECD; Screening Information Data Set (SIDS) Initial Assessment Report for SIDS Initial Assessment Meeting (SIAM) 13, Potassium Hydroxide (CAS 1310-58-3) November 2001. Available from, as of March 18, 2015. https://www.inchem.org/pages/hsg.html/

9 Use and Manufacturing

9.1 Uses

Cosmetic Ingredient Review Link
CIR ingredient: Potassium Hydroxide
EPA CPDat Chemical and Product Categories
The Chemical and Products Database, a resource for exposure-relevant data on chemicals in consumer products, Scientific Data, volume 5, Article number: 180125 (2018), DOI:10.1038/sdata.2018.125
Sources/Uses
Used to make liquid soaps; it is also used in paint, varnish removers, and drain cleaners; it is used in electroplating, photoengraving, and lithography. [ACGIH] Used as a wet etchant in semiconductor manufacturing at standard concentrations of 50% or 10%; [CSH, p. 46]
ACGIH - Documentation of the TLVs and BEIs, 7th Ed. Cincinnati: ACGIH Worldwide, 2020.
CSH - Baldwin DG, Williams ME, Norman SD. Chemical Safety Handbook: For the Semiconductor, Electronics, and Photovoltaic Industries, 4th Ed. Beverly Farms, MA: OEM Press, 2015., p. 46
Industrial Processes with risk of exposure

Acid and Alkali Cleaning of Metals [Category: Clean]

Electroplating [Category: Plate]

Semiconductor Manufacturing [Category: Industry]

Battery Manufacturing [Category: Industry]

Photographic Processing [Category: Other]

Activities with risk of exposure
Lithography printing [Category: Hobbies]
For potassium hydroxide (USEPA/OPP Pesticide Code: 075602) there are 0 labels match. /SRP: Not registered for current use in the U.S., but approved pesticide uses may change periodically and so federal, state and local authorities must be consulted for currently approved uses./
National Pesticide Information Retrieval System's Database on Potassium Hydroxide (1310-58-3). Available from, as of February 12, 2015: https://npirspublic.ceris.purdue.edu/ppis/
The active ingredient is no longer contained in any registered pesticide products ... "cancelled."
United States Environmental Protection Agency/ Prevention, Pesticides and Toxic Substances; Status of Pesticides in Registration, Reregistration, and Special Review. (1998) EPA 738-R-98-002, p. 325
Manufacturing liquid soap; mordant for wood; absorbing CO2; mercerizing cotton; print and varnish removers; electroplating, photoengraving and lithography; printing inks; in analytical chemistry for alkalimetric titrations; in organic synthesis. Pharmaceutic aid (alkalizer).
O'Neil, M.J. (ed.). The Merck Index - An Encyclopedia of Chemicals, Drugs, and Biologicals. Cambridge, UK: Royal Society of Chemistry, 2013., p. 1420
Soap manufacture, bleaching, manufacture of potassium carbonate and tetrapotassium pyrophosphate, electrolyte in alkaline storage batteries and some fuel cells, absorbent for carbon dioxide and hydrogen sulfide, dyestuffs, liquid fertilizers, food additive, herbicides, electroplating, mercerizing, paint removers, reagent.
Lewis, R.J. Sr.; Hawley's Condensed Chemical Dictionary 15th Edition. John Wiley & Sons, Inc. New York, NY 2007., p. 1032
For more Uses (Complete) data for POTASSIUM HYDROXIDE (10 total), please visit the HSDB record page.

9.1.1 Use Classification

EPA Safer Chemical Functional Use Classes -> Processing Aids and Additives
Safer Chemical Classes -> Green circle Green circle - The chemical has been verified to be of low concern
Food additives
Food Additives -> ACIDITY_REGULATOR; -> JECFA Functional Classes
Hazard Classes and Categories -> Corrosives, Reactive - 1st degree
Cosmetics -> Buffering
S13 | EUCOSMETICS | Combined Inventory of Ingredients Employed in Cosmetic Products (2000) and Revised Inventory (2006) | DOI:10.5281/zenodo.2624118

9.1.2 Industry Uses

  • Solvents (which become part of product formulation or mixture)
  • Pigment
  • Oxidizing/reducing agents
  • Ion exchange agent
  • Functional fluids (open systems)
  • Etching agent
  • Solvents (for cleaning or degreasing)
  • Other (specify)
  • Laboratory chemicals
  • Surface modifier
  • Intermediates
  • Bleaching agents
  • Intermediate
  • Not Known or Reasonably Ascertainable
  • Adsorbents and absorbents
  • Other
  • Ion exchange agents
  • Soil amendments (fertilizers)
  • Abrasives
  • Process regulators
  • Processing aids, specific to petroleum production
  • Semiconductor and photovoltaic agent
  • Processing aids not otherwise specified
  • Paint additives and coating additives not described by other categories
  • Catalyst
  • Agricultural chemicals (non-pesticidal)
  • Plating agents and surface treating agents
  • Processing aids, not otherwise listed
  • Conductive agent
  • Surface active agents
  • Flotation agent
  • Cleaning agent
  • pH regulating agent

9.1.3 Consumer Uses

  • Solvents (which become part of product formulation or mixture)
  • Plasticizers
  • Pigment
  • Oxidizing/reducing agents
  • Ion exchange agent
  • Laboratory chemicals
  • Other (specify)
  • Solvents (for cleaning or degreasing)
  • Bleaching agents
  • Not Known or Reasonably Ascertainable
  • Adsorbents and absorbents
  • Corrosion inhibitors and anti-scaling agents
  • Solvent
  • Soil amendments (fertilizers)
  • Ion exchange agents
  • Other
  • Processing aids not otherwise specified
  • Processing aids, not otherwise listed
  • Agricultural chemicals (non-pesticidal)
  • Catalyst
  • Paint additives and coating additives not described by other categories
  • Cleaning agent
  • pH regulating agent
  • Anti-freeze agent
  • Conductive agent
  • Surface active agents

9.1.4 Household Products

Household & Commercial/Institutional Products

Information on 291 consumer products that contain Potassium hydroxide in the following categories is provided:

• Auto Products

• Commercial / Institutional

• Home Maintenance

• Inside the Home

• Landscaping/Yard

• Personal Care

• Pesticides

• Pet Care

9.2 Methods of Manufacturing

Potassium hydroxide is produced industrially by the electrolysis of potassium chloride.
Freilich MB, Petersen RL; Potassium Compounds. Kirk-Othmer Encyclopedia of Chemical Technology (1999-2014). John Wiley & Sons, Inc. Online Posting Date: September 15, 2014
Largely water-free, ca. 90-95% potassium hydroxide (caustic potash) is obtained by evaporating potassium hydroxide solution. The residual content of 5-10% H2O is bound as a monohydrate.
Schultz H et al; Potassium Compounds. Ullmann's Encyclopedia of Industrial Chemistry 7th ed. (1999-2014). NY, NY: John Wiley & Sons. Online Posting Date: June 15, 2000

9.3 Impurities

CONSIDINE. CHEMICAL AND PROCESS TECHNOL ENCYC 1974 p.229

9.4 Formulations / Preparations

Grades: Commercial, ground, flake, fused (88-92%), purified by alcohol (sticks, lumps and drops), reagent, highest purity, United States Pharmacopeia, liquid (45%), FCC.
Lewis, R.J. Sr.; Hawley's Condensed Chemical Dictionary 15th Edition. John Wiley & Sons, Inc. New York, NY 2007., p. 1032
Available as 50%-Rayon, 50%-Commercial, 73%-Commercial, and Flake.
CONSIDINE. CHEMICAL AND PROCESS TECHNOL ENCYC 1974 p.229
Marketed as dehydrated solid (90-92% potassium hydroxide) and as a liquor (45-50% potassium hydroxide).
CONSIDINE. CHEMICAL AND PROCESS TECHNOL ENCYC 1974 p.923
2 Liquid grades sold: rayon and commercial.
CONSIDINE. CHEMICAL AND PROCESS TECHNOL ENCYC 1974 p.229
POTASSIUM HYDROXIDE ... CONTAINS NOT LESS THAN 85.0% OF TOTAL ALKALI, CALCULATED AS POTASSIUM HYDROXIDE ... & INCL NOT MORE THAN 3.5% OF POTASSIUM CARBONATE ...
Osol, A. and J.E. Hoover, et al. (eds.). Remington's Pharmaceutical Sciences. 15th ed. Easton, Pennsylvania: Mack Publishing Co., 1975., p. 723

9.5 Consumption Patterns

29% AS A CHEM INT FOR POTASSIUM CARBONATE; 19% AS A CHEM INT FOR SOAPS; 19% AS A CHEM INT FOR TETRAPOTASSIUM PYROPHOSPHATE; 10% AS A CHEM INT FOR OTHER INORG POTASSIUM CHEMICALS; 8% AS A CHEM INT FOR LIQUID FERTILIZERS; 5% IN MFR OF DYESTUFFS; 4% IN MFR OF HERBICIDES; 6% FOR MISC USES (1975)
SRI
Potassium Carbonate, 25%; Liquid Fertilizers, 15%; Soap, 10%; Potassium Phosphates, 9%; Synthetic Rubber, 5%; Pesticides, 3%; Potassium Permanganate, 2%; Exports, 5%; Other Chemicals and Misc uses, 26% (1984)
CHEMICAL PROFILE: Caustic Potash, 1984
Potassium carbonate, 25%; potassium phosphates (including TKPP), 10%; liquid fertilizers, 8%; soaps, 7%; potassium chemicals (including potassium silicate, permaganate and cyanide), 30%; miscellaneous (including oil and gas, metal treatment, batteries and water treatment), 18%; exports, 2%.
Kavaler AR; CHEMICAL PROFILE: Caustic potash. Chemical Marketing Reporter 231 (20): 50 (1987)
Potassium chemicals (including potassium acetate, cyanide, permanganate and silicate), 35%; potassium carbonate, 25%; liquid fertilizer, 12%; soaps, 12%; potassium phosphates (including tetrapotassium pyrophosphate), 7%, miscellaneous, 9%.
Kavaler AR; Chemical Profile: Caustic Potash. Chemical Marketing Reporter, Jan. 22, 1996

9.6 U.S. Production

Aggregated Product Volume

2019: 1,000,000,000 - <5,000,000,000 lb

2018: 1,000,000,000 - <5,000,000,000 lb

2017: 1,000,000,000 - <5,000,000,000 lb

2016: 1,000,000,000 - <5,000,000,000 lb

(1972) 1.54X10+11 GRAMS
SRI
(1975) 1.91X10+11 GRAMS
SRI
(1984) 2.25X10+11 G. /88 to 92% POTASSIUM HYDROXIDE - LIQUID/
BUREAU OF THE CENSUS. CURRENT INDUSTRIAL REPORTS: INORGANIC CHEMICALS 1984 p.2
Demand: 1986: 245,000 tons; 1987: 250,000 tons; 1991 /projected/: 270,000 tons. (Includes imports; 16,000 tons were imported in 1986.)
Kavaler AR; CHEMICAL PROFILE: Caustic potash. Chemical Marketing Reporter 231 (20): 50 (1987)
For more U.S. Production (Complete) data for POTASSIUM HYDROXIDE (8 total), please visit the HSDB record page.

9.7 U.S. Imports

(1972) 1.45X10+9 GRAMS
SRI
(1975) 6.53X10+9 GRAMS
SRI
(1984) 1.60X10+10 g.
BUREAU OF THE CENSUS. U.S. IMPORTS FOR CONSUMPTION AND GENERAL IMPORTS 1984 p.1-350
(1994) 55,000 tons
Kavaler AR; Chemical Profile: Caustic Potash. Chemical Marketing Reporter, Jan. 22, 1996

9.8 U.S. Exports

(1972) 6.36X10+9 GRAMS
SRI
(1975) 8.35X10+9 GRAMS
SRI
(1984) 8.99X10+9 g.
BUREAU OF THE CENSUS. U.S. EXPORTS, SCHEDULE E, 1984 p.2-92
(1994) 60,000 tons
Kavaler AR; Chemical Profile: Caustic Potash. Chemical Marketing Reporter, Jan. 22, 1996

9.9 General Manufacturing Information

Industry Processing Sectors
  • All Other Basic Inorganic Chemical Manufacturing
  • Pesticide, Fertilizer, and Other Agricultural Chemical Manufacturing
  • Agriculture, Forestry, Fishing and Hunting
  • All Other Basic Organic Chemical Manufacturing
  • Electrical Equipment, Appliance, and Component Manufacturing
  • Paint and Coating Manufacturing
  • Other (requires additional information)
  • Petroleum Refineries
  • Mining (except Oil and Gas) and support activities
  • Organic Fiber Manufacturing
  • Food, beverage, and tobacco product manufacturing
  • Industrial Gas Manufacturing
  • Miscellaneous Manufacturing
  • Wholesale and Retail Trade
  • Services
  • Construction
  • Oil and Gas Drilling, Extraction, and Support activities
  • Primary Metal Manufacturing
  • All Other Chemical Product and Preparation Manufacturing
  • Not Known or Reasonably Ascertainable
  • Soap, Cleaning Compound, and Toilet Preparation Manufacturing
  • Fabricated Metal Product Manufacturing
  • Computer and Electronic Product Manufacturing
  • Paper Manufacturing
  • Utilities
  • Pharmaceutical and Medicine Manufacturing
EPA TSCA Commercial Activity Status
Potassium hydroxide (K(OH)): ACTIVE
Each year, an estimated 35,000 wells are hydraulically-fractured in the U.S. Although the oil and gas extraction industry as a whole has a relatively higher fatality rate compared to most of the U.S. general industry... there is currently no worker injury/illness or fatality data publicly available for hydraulic fracturing or flowback operations. Regardless of the availability of data, more workers are potentially exposed to the hazards created by hydraulic fracturing and flowback operations due to the large increase in the number of these operations in the past decade. /Hydraulic fracturing/
OSHA; Hydraulic Fracturing and Flowback Hazards Other than Respirable Silica, OSHA 3763-12 (2014). https://www.osha.gov/Publications/OSHA3763.pdf

9.10 Sampling Procedures

Analyte: Hydroxide ion; Matrix: air; Sampler: filter; flow rate: 1 to 4 liter per minute; Sample size: 70 to 1000 liters; interferences: non identified; sample stability: at least 7 days at 25 °C.
U.S. Department of Health and Human Services, Public Health Service. Centers for Disease Control, National Institute for Occupational Safety and Health. NIOSH Manual of Analytical Methods, 3rd ed. Volumes 1 and 2 with 1985 supplement, and revisions. Washington, DC: U.S. Government Printing Office, February 1984., p. 7401

10 Identification

10.1 Analytic Laboratory Methods

Method: NIOSH 7401, Issue 2; Procedure: acid-base titration; Analyte: potassium hydroxide; Matrix: air; Detection Limit: 0.03 mg per sample (as NaOH).
CDC; NIOSH Manual of Analytical Methods, 4th ed. Potassium Hydroxide (1310-58-3). Available from, as of February 20, 2015: https://www.cdc.gov/niosh/docs/2003-154/

10.2 NIOSH Analytical Methods

11 Safety and Hazards

11.1 Hazards Identification

11.1.1 GHS Classification

1 of 6
View All
Note
Pictograms displayed are for > 99.9% (4610 of 4613) of reports that indicate hazard statements. This chemical does not meet GHS hazard criteria for < 0.1% (3 of 4613) of reports.
Pictogram(s)
Corrosive
Irritant
Signal
Danger
GHS Hazard Statements

H290 (19.4%): May be corrosive to metals [Warning Corrosive to Metals]

H302 (96%): Harmful if swallowed [Warning Acute toxicity, oral]

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

H318 (21%): Causes serious eye damage [Danger Serious eye damage/eye irritation]

Precautionary Statement Codes

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

(The corresponding statement to each P-code can be found at the GHS Classification page.)

ECHA C&L Notifications Summary

Aggregated GHS information provided per 4613 reports by companies from 74 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 4613 reports by companies. For more detailed information, please visit ECHA C&L website.

There are 73 notifications provided by 4610 of 4613 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.

11.1.2 Hazard Classes and Categories

Met. Corr. 1 (19.4%)

Acute Tox. 4 (96%)

Skin Corr. 1A (99.4%)

Eye Dam. 1 (21%)

Acute toxicity - category 4

Skin corrosion - category 1A

11.1.3 NFPA Hazard Classification

NFPA 704 Diamond
3-0-1
NFPA Health Rating
3 - Materials that, under emergency conditions, can cause serious or permanent injury.
NFPA Fire Rating
0 - Materials that will not burn under typical fire conditions, including intrinsically noncombustible materials such as concrete, stone, and sand.
NFPA Instability Rating
1 - Materials that in themselves are normally stable but that can become unstable at elevated temperatures and pressures.

11.1.4 EPA Safer Chemical

Chemical: Potassium hydroxide

Green circle Green circle - The chemical has been verified to be of low concern based on experimental and modeled data.

11.1.5 Health Hazards

Causes severe burns of eyes, skin, and mucous membranes. (USCG, 1999)
U.S. Coast Guard. 1999. Chemical Hazard Response Information System (CHRIS) - Hazardous Chemical Data. Commandant Instruction 16465.12C. Washington, D.C.: U.S. Government Printing Office.
U.S. Coast Guard. 1999. Chemical Hazard Response Information System (CHRIS) - Hazardous Chemical Data. Commandant Instruction 16465.12C. Washington, D.C.: U.S. Government Printing Office.
ERG 2024, Guide 154 (Potassium hydroxide, solution; Potassium hydroxide, solid)

· TOXIC and/or CORROSIVE; 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.

· Fire may produce irritating, corrosive and/or toxic gases.

· Runoff from fire control or dilution water may be corrosive and/or toxic and cause environmental contamination.

11.1.6 Fire Hazards

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)

ERG 2024, Guide 154 (Potassium hydroxide, solution; Potassium hydroxide, solid)

· 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, GUIDE 147 (lithium ion or sodium ion batteries) or GUIDE 138 (sodium batteries) should also be consulted.

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.

11.1.7 Hazards Summary

Liquid causes second or third degree burns after short contact. [CHRIS] Potassium hydroxide 30-70% is highly corrosive to skin; [Quick CPC] A corrosive substance that can cause pulmonary edema; [ICSC] See Sodium hydroxicde.
Quick CPC - Forsberg K, Mansdorf SZ. Quick Selection Guide to Chemical Protective Clothing, 5th Ed. Hoboken, NJ: Wiley-Interscience, 2007.

11.1.8 Fire Potential

When wet, attacks metals such as aluminum, tin, lead & zinc to produce flammable hydrogen gas.
U.S. Coast Guard, Department of Transportation. CHRIS - Hazardous Chemical Data. Volume II. Washington, D.C.: U.S. Government Printing Office, 1984-5.

11.1.9 Skin, Eye, and Respiratory Irritations

Dust or mist /is/ irritating to eyes, nose & throat. ...
U.S. Coast Guard, Department of Transportation. CHRIS - Hazardous Chemical Data. Volume II. Washington, D.C.: U.S. Government Printing Office, 1984-5.

11.2 Safety and Hazard Properties

11.2.1 Flammable Limits

Flammability

Noncombustible Solid; however, may react with H2O & other substances

and generate sufficient heat to ignite combustible materials.

11.2.2 OSHA Standards

Vacated 1989 OSHA PEL TWA 2 mg/cu m is still enforced in some states.
NIOSH. NIOSH Pocket Guide to Chemical Hazards. DHHS (NIOSH) Publication No. 97-140. Washington, D.C. U.S. Government Printing Office, 1997., p. 370

11.2.3 NIOSH Recommendations

Recommended Exposure Limit: Ceiling Value: 2 mg/cu m.
NIOSH. NIOSH Pocket Guide to Chemical Hazards. Department of Health & Human Services, Centers for Disease Control & Prevention. National Institute for Occupational Safety & Health. DHHS (NIOSH) Publication No. 2010-168 (2010). Available from: https://www.cdc.gov/niosh/npg

11.3 First Aid Measures

Inhalation First Aid
Fresh air, rest. Refer immediately for medical attention.
Skin First Aid
Remove contaminated clothes. Rinse skin with plenty of water or shower for at least 15 minutes. Refer immediately for medical attention.
Eye First Aid
First rinse with plenty of water for several minutes (remove contact lenses if easily possible), then refer for medical attention.
Ingestion First Aid
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.

11.3.1 First Aid

(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)

U.S. Coast Guard. 1999. Chemical Hazard Response Information System (CHRIS) - Hazardous Chemical Data. Commandant Instruction 16465.12C. Washington, D.C.: U.S. Government Printing Office.

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)

National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina.
ERG 2024, Guide 154 (Potassium hydroxide, solution; Potassium hydroxide, solid)

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 ingestedor 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 continuouscompressions. 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.

(See 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.

11.4 Fire Fighting

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.

11.4.1 Fire Fighting Procedures

Suitable extinguishing media: Use water spray, alcohol-resistant foam, dry chemical or carbon dioxide.
Sigma-Aldrich; Material Safety Data Sheet for Potassium Hydroxide, Product Number: 484016, Version 4.15 (Revision Date 02/26/2015). Available from, as of February 27, 2015: https://www.sigmaaldrich.com/safety-center.html
Wear self-contained breathing appartus for firefighting if necessary.
Sigma-Aldrich; Material Safety Data Sheet for Potassium Hydroxide, Product Number: 484016, Version 4.15 (Revision Date 02/26/2015). Available from, as of February 27, 2015: https://www.sigmaaldrich.com/safety-center.html

11.5 Accidental Release Measures

Public Safety: ERG 2024, Guide 154 (Potassium hydroxide, solution; Potassium hydroxide, solid)

· 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.

Spill or Leak: ERG 2024, Guide 154 (Potassium hydroxide, solution; Potassium hydroxide, solid)

· 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.

11.5.1 Isolation and Evacuation

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)

Evacuation: ERG 2024, Guide 154 (Potassium hydroxide, solution; Potassium hydroxide, solid)

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

· 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.

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.

11.5.2 Spillage Disposal

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.

11.5.3 Cleanup Methods

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...
Sigma-Aldrich; Material Safety Data Sheet for Potassium Hydroxide, Product Number: 484016, Version 4.15 (Revision Date 02/26/2015). Available from, as of February 27, 2015: https://www.sigmaaldrich.com/safety-center.html
Pick up and arrange disposal without creating dust. Sweep up and shovel. Keep in suitable, closed containers for disposal.
Sigma-Aldrich; Material Safety Data Sheet for Potassium Hydroxide, Product Number: 484016, Version 4.15 (Revision Date 02/26/2015). Available from, as of February 27, 2015: https://www.sigmaaldrich.com/safety-center.html
Prevent further leakage or spillage if safe to do so. Do not let product enter drains. Discharge into the environment must be avoided.
Sigma-Aldrich; Material Safety Data Sheet for Potassium Hydroxide, Product Number: 484016, Version 4.15 (Revision Date 02/26/2015). Available from, as of February 27, 2015: https://www.sigmaaldrich.com/safety-center.html

11.5.4 Disposal Methods

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.
United Nations. Treatment and Disposal Methods for Waste Chemicals (IRPTC File). Data Profile Series No. 5. Geneva, Switzerland: United Nations Environmental Programme, Dec. 1985., p. 266

11.5.5 Preventive Measures

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.
Sigma-Aldrich; Material Safety Data Sheet for Potassium Hydroxide, Product Number: 484016, Version 4.15 (Revision Date 02/26/2015). Available from, as of February 27, 2015: https://www.sigmaaldrich.com/safety-center.html
... Exercise great care in handling potassium hydroxide, as it rapidly destroys tissue. Do not handle with bare hand.
Osol, A. and J.E. Hoover, et al. (eds.). Remington's Pharmaceutical Sciences. 15th ed. Easton, Pennsylvania: Mack Publishing Co., 1975., p. 723
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.

11.6 Handling and Storage

11.6.1 Nonfire Spill Response

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)

11.6.2 Safe Storage

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.

11.6.3 Storage Conditions

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.
Sigma-Aldrich; Material Safety Data Sheet for Potassium Hydroxide, Product Number: 484016, Version 4.15 (Revision Date 02/26/2015). Available from, as of February 27, 2015: https://www.sigmaaldrich.com/safety-center.html

11.7 Exposure Control and Personal Protection

Protective Clothing: ERG 2024, Guide 154 (Potassium hydroxide, solution; Potassium hydroxide, solid)

· 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.

11.7.2 Permissible Exposure Limit (PEL)

11.7.3 Immediately Dangerous to Life or Health (IDLH)

N.D.

See: IDLH INDEX

11.7.4 Threshold Limit Values (TLV)

TLV-Ceiling
2.0 [mg/m3]
Ceiling Limit: 2 mg/cu m
American Conference of Governmental Industrial Hygienists. Threshold Limit Values for Chemical Substances and Physical Agents and Biological Exposure Indices. ACGIH, Cincinnati, OH 2014, p. 50
2 mg/m
TLV-C (Ceiling)
2 mg/m³ [1992]

11.7.5 Emergency Response Planning Guidelines

Emergency Response: ERG 2024, Guide 154 (Potassium hydroxide, solution; Potassium hydroxide, solid)

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.

11.7.6 Other Standards Regulations and Guidelines

Australia: peak limitation 2 mg/cu m (1990); United Kingdom: 10 min STEL 2 mg/cu m (1991)
American Conference of Governmental Industrial Hygienists, Inc. Documentation of the Threshold Limit Values and Biological Exposure Indices. 6th ed. Volumes I, II, III. Cincinnati, OH: ACGIH, 1991., p. 1284

11.7.7 Inhalation Risk

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

11.7.8 Effects of Short Term Exposure

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

11.7.9 Effects of Long Term Exposure

Repeated or prolonged contact with skin may cause dermatitis.

11.7.10 Allowable Tolerances

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.
40 CFR 180.910 (USEPA); U.S. National Archives and Records Administration's Electronic Code of Federal Regulations. Available from, as of February 4, 2015: https://www.ecfr.gov
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.
40 CFR 180.930 (USEPA); U.S. National Archives and Records Administration's Electronic Code of Federal Regulations. Available from, as of February 4, 2015: https://www.ecfr.gov

11.7.11 Personal Protective Equipment (PPE)

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)
U.S. Coast Guard. 1999. Chemical Hazard Response Information System (CHRIS) - Hazardous Chemical Data. Commandant Instruction 16465.12C. Washington, D.C.: U.S. Government Printing Office.

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.
NIOSH. NIOSH Pocket Guide to Chemical Hazards. Department of Health & Human Services, Centers for Disease Control & Prevention. National Institute for Occupational Safety & Health. DHHS (NIOSH) Publication No. 2010-168 (2010). Available from: https://www.cdc.gov/niosh/npg
Wear appropriate eye protection to prevent eye contact.
NIOSH. NIOSH Pocket Guide to Chemical Hazards. Department of Health & Human Services, Centers for Disease Control & Prevention. National Institute for Occupational Safety & Health. DHHS (NIOSH) Publication No. 2010-168 (2010). Available from: https://www.cdc.gov/niosh/npg
Eyewash fountains should be provided in areas where there is any possibility that workers could be exposed to the substance; this is irrespective of the recommendation involving the wearing of eye protection.
NIOSH. NIOSH Pocket Guide to Chemical Hazards. Department of Health & Human Services, Centers for Disease Control & Prevention. National Institute for Occupational Safety & Health. DHHS (NIOSH) Publication No. 2010-168 (2010). Available from: https://www.cdc.gov/niosh/npg
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. NIOSH Pocket Guide to Chemical Hazards. Department of Health & Human Services, Centers for Disease Control & Prevention. National Institute for Occupational Safety & Health. DHHS (NIOSH) Publication No. 2010-168 (2010). Available from: https://www.cdc.gov/niosh/npg

(See personal protection and sanitation codes)

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

Remove: When wet or contaminated

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

Provide: Eyewash, Quick drench

11.7.12 Respirator Recommendations

11.7.13 Preventions

Fire Prevention
NO contact with water. NO contact with incompatible materials: See Chemical Dangers
Exposure Prevention
PREVENT DISPERSION OF DUST! AVOID ALL CONTACT! IN ALL CASES CONSULT A DOCTOR!
Inhalation Prevention
Use local exhaust or breathing protection.
Skin Prevention
Protective gloves. Protective clothing.
Eye Prevention
Wear face shield or eye protection in combination with breathing protection.
Ingestion Prevention
Do not eat, drink, or smoke during work.

11.8 Stability and Reactivity

11.8.1 Air and Water Reactions

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

11.8.2 Reactive Group

Bases, Strong

Water and Aqueous Solutions

Bases, Strong

11.8.3 Reactivity Alerts

Water-Reactive
11.8.3.1 CSL Reaction Information
1 of 4
CSL No
Reactants/Reagents
ACETONE + POTASSIUM HYDROXIDE + CALCIUM HYDROXIDE + CHLOROFORM
Warning Message
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.
GHS Category
Explosive
Reference Source
Bretherick's
Modified Date
5/31/18
Create Date
1/6/17
2 of 4
CSL No
Reactants/Reagents
POTASSIUM HYDROXIDE + ACETONITRILE
Warning Message
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).
Reference Source
User-Reported
Modified Date
2/27/18
Create Date
9/1/18
3 of 4
CSL No
Reactants/Reagents
POTASSIUM HYDROXIDE + PROPARGYL ALCOHOL
Warning Message
Propargyl alcohol can polymerize explosively. Strong bases such as KOH appear to lower the onset temperature of this event.
Functional Group
acetylene
Additional Information
ARC experiment of a reaction mixture in neat propargyl alcohol with KOH catalyst ruptured a hastelloy ARC bomb. Onset temperature was 75 degrees C.
Reference Source
User-Reported
Modified Date
9/26/18
Create Date
8/21/18
4 of 4
CSL No
Reactants/Reagents
1,3,5-Benzenetriol, 2,4,6-trinitro-, potassium salt + Water + Acetic Acid + Potassium nitrite + Potassium hydroxide + Ethanol
Warning Message
"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)
GHS Category
Explosive
Additional Information
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)
Reference Source
Literature Reference
Modified Date
10/20/2022
Create Date
10/20/2022

11.8.4 Reactivity Profile

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].

11.8.5 Hazardous Reactivities and Incompatibilities

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].
NIOSH. NIOSH Pocket Guide to Chemical Hazards. Department of Health & Human Services, Centers for Disease Control & Prevention. National Institute for Occupational Safety & Health. DHHS (NIOSH) Publication No. 2010-168 (2010). Available from: https://www.cdc.gov/niosh/npg
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.
Lewis, R.J. Sr. (ed) Sax's Dangerous Properties of Industrial Materials. 11th Edition. Wiley-Interscience, Wiley & Sons, Inc. Hoboken, NJ. 2004., p. 3034
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.
National Fire Protection Association; Fire Protection Guide to Hazardous Materials. 14TH Edition, Quincy, MA 2010, p. 491-160
/1,2-Dichloroethylene & potassium hydroxide reaction/ produces chloroacetylene, which is ... spontaneously flammable in air.
National Fire Protection Association; Fire Protection Guide to Hazardous Materials. 14TH Edition, Quincy, MA 2010, p. 491-160
For more Hazardous Reactivities and Incompatibilities (Complete) data for POTASSIUM HYDROXIDE (13 total), please visit the HSDB record page.

11.9 Transport Information

11.9.1 DOT Emergency Guidelines

/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/
U.S. Department of Transportation. 2012 Emergency Response Guidebook. Washington, D.C. 2012
/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/
U.S. Department of Transportation. 2012 Emergency Response Guidebook. Washington, D.C. 2012
/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/
U.S. Department of Transportation. 2012 Emergency Response Guidebook. Washington, D.C. 2012
/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/
U.S. Department of Transportation. 2012 Emergency Response Guidebook. Washington, D.C. 2012
For more DOT Emergency Guidelines (Complete) data for POTASSIUM HYDROXIDE (8 total), please visit the HSDB record page.

11.9.2 DOT ID and Guide

11.9.3 Shipping Name / Number DOT/UN/NA/IMO

UN 1813; Potassium hydroxide, solid
UN 1814; Potassium hydroxide. solution
IMO 8; Potassium hydroxide solution; potassium hydroxide solid

11.9.4 Standard Transportation Number

49 352 25; Potassium hydroxide, dry solid, flake, bead, or granular
49 352 30; Potassium hydroxide, liquid or solution

11.9.5 Shipment Methods and Regulations

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)./
49 CFR 171.2 (USDOT); U.S. National Archives and Records Administration's Electronic Code of Federal Regulations. Available from, as of December 9, 2015: https://www.ecfr.gov
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.
International Air Transport Association. Dangerous Goods Regulations. 55th Edition. Montreal, Quebec Canada. 2014., p. 293
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.
International Maritime Organization. IMDG Code. International Maritime Dangerous Goods Code Volume 2 2012, p. 91

11.9.6 DOT Label

Corrosive

11.9.7 Packaging and Labelling

Do not transport with food and feedstuffs.

11.9.8 EC Classification

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

11.9.9 UN Classification

UN Hazard Class: 8; UN Pack Group: II

11.10 Regulatory Information

The Australian Inventory of Industrial Chemicals
Chemical: Potassium hydroxide
REACH Registered Substance
New Zealand EPA Inventory of Chemical Status
Potassium hydroxide: HSNO Approval: HSR001546 Approved with controls

11.10.1 Clean Water Act Requirements

Potassium 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.
40 CFR 116.4 (USEPA); U.S. National Archives and Records Administration's Electronic Code of Federal Regulations. Available from, as of February 4, 2015: https://www.ecfr.gov

11.10.2 CERCLA Reportable Quantities

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).
40 CFR 302.4 (USEPA); U.S. National Archives and Records Administration's Electronic Code of Federal Regulations. Available from, as of February 4, 2015: https://www.ecfr.gov

11.10.3 FIFRA Requirements

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.
40 CFR 180.910 (USEPA); U.S. National Archives and Records Administration's Electronic Code of Federal Regulations. Available from, as of February 4, 2015: https://www.ecfr.gov
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.
40 CFR 180.930 (USEPA); U.S. National Archives and Records Administration's Electronic Code of Federal Regulations. Available from, as of February 4, 2015: https://www.ecfr.gov
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 safety 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. Potassium 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): Potassium hydroxide; AI Status: The active ingredient is no longer contained in any registered pesticide products ... "cancelled."
United States Environmental Protection Agency/ Prevention, Pesticides and Toxic Substances; Status of Pesticides in Registration, Reregistration, and Special Review. (1998) EPA 738-R-98-002, p. 325

11.10.4 FDA Requirements

Substance added directly to human food affirmed as generally recognized as safe (GRAS).
21 CFR 184.1631 (USFDA); U.S. National Archives and Records Administration's Electronic Code of Federal Regulations. Available from, as of February 4, 2015: https://www.ecfr.gov
Potassium 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.
21 CFR 582.1631 (USFDA); U.S. National Archives and Records Administration's Electronic Code of Federal Regulations. Available from, as of February 4, 2015: https://www.ecfr.gov

11.11 Other Safety Information

Chemical Assessment

IMAP assessments - Potassium hydroxide: Human health tier II assessment

IMAP assessments - Potassium hydroxide: Environment tier I assessment

11.11.1 Toxic Combustion Products

Gives off hydrogen by reaction with metals.
Sigma-Aldrich; Material Safety Data Sheet for Potassium Hydroxide, Product Number: 484016, Version 4.15 (Revision Date 02/26/2015). Available from, as of February 27, 2015: https://www.sigmaaldrich.com/safety-center.html

12 Toxicity

12.1 Toxicological Information

12.1.1 Toxicity Summary

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.

12.1.2 NIOSH Toxicity Data

12.1.3 Exposure Routes

Serious local effects by all routes of exposure.
inhalation, ingestion, skin and/or eye contact

12.1.4 Symptoms

Inhalation Exposure
Cough. Sore throat. Burning sensation. Shortness of breath.
Skin Exposure
Redness. Pain. Serious skin burns. Blisters.
Eye Exposure
Redness. Pain. Blurred vision. Severe burns.
Ingestion Exposure
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

12.1.5 Target Organs

Eyes, skin, respiratory system

12.1.6 Adverse Effects

Dermatotoxin - Skin burns.

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

12.1.7 Acute Effects

12.1.8 Antidote and Emergency Treatment

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/
Currance, P.L. Clements, B., Bronstein, A.C. (Eds).; Emergency Care For Hazardous Materials Exposure. 3rd revised edition, Elsevier Mosby, St. Louis, MO 2007, p. 191
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/
Currance, P.L. Clements, B., Bronstein, A.C. (Eds).; Emergency Care For Hazardous Materials Exposure. 3rd revised edition, Elsevier Mosby, St. Louis, MO 2007, p. 191-2
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/
Currance, P.L. Clements, B., Bronstein, A.C. (Eds).; Emergency Care For Hazardous Materials Exposure. 3rd revised edition, Elsevier Mosby, St. Louis, MO 2007, p. 192

12.1.9 Human Toxicity Excerpts

/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.
OECD; Screening Information Data Set (SIDS) Initial Assessment Report for SIDS Initial Assessment Meeting (SIAM) 13, Potassium Hydroxide (CAS 1310-58-3) November 2001. Available from, as of March 18, 2015. https://www.inchem.org/pages/hsg.html/
/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/
Dreisbach, R.H. Handbook of Poisoning. 12th ed. Norwalk, CT: Appleton and Lange, 1987., p. 211
/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/
Dreisbach, R.H. Handbook of Poisoning. 12th ed. Norwalk, CT: Appleton and Lange, 1987., p. 211
/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.
American Conference of Governmental Industrial Hygienists. Documentation of the TLVs and BEIs with Other World Wide Occupational Exposure Values. 7th Ed. CD-ROM Cincinnati, OH 45240-1634 2013., p. 1
For more Human Toxicity Excerpts (Complete) data for POTASSIUM HYDROXIDE (31 total), please visit the HSDB record page.

12.1.10 Non-Human Toxicity Excerpts

/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.
Arbete och Halsa Vol:22 (2000) pp 15-17 (2000).
/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.
OECD; Screening Information Data Set (SIDS) Initial Assessment Report for SIDS Initial Assessment Meeting (SIAM) 13, Potassium Hydroxide (CAS 1310-58-3) (November 2001). Available from, as of March 18, 2015. https://www.inchem.org/pages/hsg.html/
/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.
OECD; Screening Information Data Set (SIDS) Initial Assessment Report for SIDS Initial Assessment Meeting (SIAM) 13, Potassium Hydroxide (CAS 1310-58-3) (November 2001). Available from, as of March 18, 2015. https://www.inchem.org/pages/hsg.html/
/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.
OECD; Screening Information Data Set (SIDS) Initial Assessment Report for SIDS Initial Assessment Meeting (SIAM) 13, Potassium Hydroxide (CAS 1310-58-3) (November 2001). Available from, as of March 18, 2015. https://www.inchem.org/pages/hsg.html/
For more Non-Human Toxicity Excerpts (Complete) data for POTASSIUM HYDROXIDE (10 total), please visit the HSDB record page.

12.1.11 Non-Human Toxicity Values

LD50 Rat oral 363 mg/kg bw/day
OECD; Screening Information Data Set (SIDS) Initial Assessment Report for SIDS Initial Assessment Meeting (SIAM) 13, Potassium Hydroxide (CAS 1310-58-3) (November 2001). Available from, as of March 18, 2015. https://www.inchem.org/pages/hsg.html/
LD50 Rat oral 273 mg/kg bw/day
OECD; Screening Information Data Set (SIDS) Initial Assessment Report for SIDS Initial Assessment Meeting (SIAM) 13, Potassium Hydroxide (CAS 1310-58-3) (November 2001). Available from, as of March 18, 2015. https://www.inchem.org/pages/hsg.html/
LD50 Rat oral 1230 mg/kg bw/day
OECD; Screening Information Data Set (SIDS) Initial Assessment Report for SIDS Initial Assessment Meeting (SIAM) 13, Potassium Hydroxide (CAS 1310-58-3) (November 2001). Available from, as of March 18, 2015. https://www.inchem.org/pages/hsg.html/

12.2 Ecological Information

12.2.1 Ecotoxicity Values

LC50; Species: Gambusia affinis (mosquito fish); Concentration: 80 mg/L for 96 hr /Conditions of bioassay not specified in source examined/
OECD; Screening Information Data Set (SIDS) Initial Assessment Report for SIDS Initial Assessment Meeting (SIAM) 13, Potassium Hydroxide (CAS 1310-58-3) (November 2001). Available from, as of March 18, 2015. https://www.inchem.org/pages/hsg.html/
TLm Mosquito fish 80 ppm/24 hr fresh water. /Conditions of bioassay not specified/
U.S. Coast Guard, Department of Transportation. CHRIS - Hazardous Chemical Data. Volume II. Washington, D.C.: U.S. Government Printing Office, 1984-5.

12.2.2 ICSC Environmental Data

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

12.2.3 Probable Routes of Human Exposure

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).
(1) US EPA; Chemical Data Reporting (CDR). Non-confidential 2012 Chemical Data Reporting information on chemical production and use in the United States. Available from, as of Mar 2, 2015: https://www.epa.gov/cdr/pubs/guidance/cdr_factsheets.html
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).
(1) NIOSH; NOES. National Occupational Exposure Survey conducted from 1981-1983. Estimated numbers of employees potentially exposed to specific agents by 2-digit standard industrial classification (SIC). Available from, as of Mar 2, 2015: https://www.cdc.gov/noes/

13 Associated Disorders and Diseases

14 Literature

14.1 Consolidated References

14.2 NLM Curated PubMed Citations

14.3 Springer Nature References

14.4 Thieme References

14.5 Wiley References

14.6 Chemical Co-Occurrences in Literature

14.7 Chemical-Gene Co-Occurrences in Literature

14.8 Chemical-Disease Co-Occurrences in Literature

15 Patents

15.1 Depositor-Supplied Patent Identifiers

15.2 WIPO PATENTSCOPE

15.3 Chemical Co-Occurrences in Patents

15.4 Chemical-Disease Co-Occurrences in Patents

15.5 Chemical-Gene Co-Occurrences in Patents

16 Interactions and Pathways

16.1 Chemical-Target Interactions

16.2 Drug-Drug Interactions

17 Biological Test Results

17.1 BioAssay Results

18 Classification

18.1 MeSH Tree

18.2 NCI Thesaurus Tree

18.3 ChEBI Ontology

18.4 KEGG: Drug

18.5 KEGG: JP15

18.6 KEGG: Risk Category of Japanese OTC Drugs

18.7 EPA Safer Choice

18.8 ChemIDplus

18.9 CAMEO Chemicals

18.10 UN GHS Classification

18.11 EPA CPDat Classification

18.12 NORMAN Suspect List Exchange Classification

18.13 EPA DSSTox Classification

18.14 Consumer Product Information Database Classification

18.15 EPA TSCA and CDR Classification

18.16 EPA Substance Registry Services Tree

18.17 MolGenie Organic Chemistry Ontology

19 Information Sources

  1. Australian Industrial Chemicals Introduction Scheme (AICIS)
  2. CAMEO Chemicals
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    https://cameochemicals.noaa.gov/help/reference/terms_and_conditions.htm?d_f=false
    POTASSIUM HYDROXIDE, [DRY SOLID, FLAKE, BEAD, OR GRANULAR]
    https://cameochemicals.noaa.gov/chemical/9484
    CAMEO Chemical Reactivity Classification
    https://cameochemicals.noaa.gov/browse/react
  3. CAS Common Chemistry
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    https://creativecommons.org/licenses/by-nc/4.0/
  4. ChemIDplus
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  5. DrugBank
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  7. EPA Chemicals under the TSCA
    Potassium hydroxide (K(OH))
    https://www.epa.gov/chemicals-under-tsca
    EPA TSCA Classification
    https://www.epa.gov/tsca-inventory
  8. EPA DSSTox
    CompTox Chemicals Dashboard Chemical Lists
    https://comptox.epa.gov/dashboard/chemical-lists/
  9. European Chemicals Agency (ECHA)
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    https://www.fda.gov/about-fda/about-website/website-policies#linking
  11. Hazardous Substances Data Bank (HSDB)
  12. ILO-WHO International Chemical Safety Cards (ICSCs)
  13. New Zealand Environmental Protection Authority (EPA)
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  14. NJDOH RTK Hazardous Substance List
  15. Occupational Safety and Health Administration (OSHA)
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  17. EU Food Improvement Agents
  18. Emergency Response Guidebook (ERG)
  19. Haz-Map, Information on Hazardous Chemicals and Occupational Diseases
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  20. ChEBI
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  22. ChEMBL
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  23. ClinicalTrials.gov
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  24. Comparative Toxicogenomics Database (CTD)
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    https://www.whatsinproducts.com/contents/view/1/6
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    https://www.whatsinproducts.com/
  26. Cosmetic Ingredient Review (CIR)
  27. EPA Chemical and Products Database (CPDat)
  28. NORMAN Suspect List Exchange
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    https://creativecommons.org/licenses/by/4.0/
    Potassium Hydroxide
    NORMAN Suspect List Exchange Classification
    https://www.norman-network.com/nds/SLE/
  29. Crystallography Open Database (COD)
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    https://creativecommons.org/publicdomain/zero/1.0/
  30. DailyMed
  31. EPA Safer Choice
    EPA Safer Chemical Ingredients Classification
    https://www.epa.gov/saferchoice
  32. Joint FAO/WHO Expert Committee on Food Additives (JECFA)
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  33. Hazardous Chemical Information System (HCIS), Safe Work Australia
  34. NITE-CMC
    Potassium hydroxide - FY2006 (New/original classication)
    https://www.chem-info.nite.go.jp/chem/english/ghs/06-imcg-0591e.html
    Potassium hydroxide - FY2017 (Revised classification)
    https://www.chem-info.nite.go.jp/chem/english/ghs/17-mhlw-2117e.html
  35. Regulation (EC) No 1272/2008 of the European Parliament and of the Council
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    https://eur-lex.europa.eu/content/legal-notice/legal-notice.html
    potassium hydroxide; caustic potash
    https://eur-lex.europa.eu/eli/reg/2008/1272/oj
  36. FDA Substances Added to Food
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    http://www.hmdb.ca/citing
  38. Japan Chemical Substance Dictionary (Nikkaji)
  39. KEGG
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    https://www.kegg.jp/kegg/legal.html
    Therapeutic category of drugs in Japan
    http://www.genome.jp/kegg-bin/get_htext?br08301.keg
    Drugs listed in the Japanese Pharmacopoeia
    http://www.genome.jp/kegg-bin/get_htext?br08311.keg
    Risk category of Japanese OTC drugs
    http://www.genome.jp/kegg-bin/get_htext?br08312.keg
  40. National Drug Code (NDC) Directory
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  42. NIOSH Manual of Analytical Methods
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    https://www.nlm.nih.gov/research/umls/rxnorm/docs/termsofservice.html
  44. Pistoia Alliance Chemical Safety Library
    ACETONE + POTASSIUM HYDROXIDE + CALCIUM HYDROXIDE + CHLOROFORM
    https://safescience.cas.org/
  45. Springer Nature
  46. SpringerMaterials
  47. Thieme Chemistry
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  53. GHS Classification (UNECE)
  54. EPA Substance Registry Services
  55. MolGenie
    MolGenie Organic Chemistry Ontology
    https://github.com/MolGenie/ontology/
  56. PATENTSCOPE (WIPO)
CONTENTS