Document GzDNZekZnRwNdq6ZOkpaX0xpV

K OH Toxic tips: Potassium hydroxide Toxic Tips INTRODUCTION Chemical Description Potassium hydroxide (KOH) (CAS Number 1310-58-3), also known as caustic potash, potassium hydrate, or lye, is found as white or slightly yellow lumps, rods, or pellets. It is an odorless, noncombustible solid. It is soluble in water, alcohol, and glycerin and slightly soluble in ether. It rapidly absorbs moisture and carbon dioxide and deliquesces. When dissolved in water or alcohol or the solution is treated with an acid, sufficient heat can be generated to ignite combustible materials. It has a molecular weight of 56.11.1,2 Uses and Typical Exposure Situations This compound has applications in industry and in the laboratory. It has been used extensively in the manufacture of soft and liquid soaps, as well as fertilizers and pesticides.3,4 It is also used to make potassium carbonate, for use in the manufacture of glass. It is used in paint, varnish removers, and drain cleaners. In addition, it is used in electroplating, photoengraving, and lithography.5 It has been used therapeutically to remove warts.4 It is used in teaching laboratories as a reagent in analytical chemistry and organic syntheses.1 PATHOPHYSIOLOGY Determinants of Toxicity The concentration of the airborne dust or mist, the respiratory rate of the exposed individual, and the time of exposure to the dust or mist will determine the amount of toxicant reaching the lungs for absorption into the body. Mechanism of Action Since potassium hydroxide is a highly corrosive alkali, it causes liquefaction necrosis when it makes direct contact with any tissue. This chemical can gelatinize tissue by saponification of lipids and it can solubilize proteins and collagen, resulting in deep and painful injuries to the skin, eyes, and respiratory tract.4 CLINICAL PRESENTATION Effects Following Skin Exposure Acute mild exposure causes dermal irritation and partial thickness burns. Prolonged mild exposure or acute high exposure can cause full thickness burns. The effects following skin exposure may be delayed.4 Effects Following Inhalation Potassium hydroxide can irritate the nose, throat and lungs, causing coughing, wheezing and/or shortness of breath, as well as sores in the nose.6 Fortunately, since it is strongly irritating to the upper respiratory tract, severe injury is usually avoided by self-limiting sneezing, coughing, and discomfort.3 In addition, mild exposure can cause bronchospasm. Severe exposure through inhalation can cause upper airway edema and burns with stridor. The effects following inhalation may also be delayed.4 Eye Effects Direct eye contact can cause severe conjunctival irritation, corneal epithelial defects, permanent loss of vision, and in severe cases, perforation of the eyeball.4 Carcinogenicity There is no evidence of carcinogenicity in humans or in experimental animals.6 FIRST AID The primary response to potassium hydroxide exposure is to reduce the exposure, whether by changing into uncontaminated clothes, washing the affected skin thoroughly with soap and water, removing the victim from the contaminated air, or flushing the eyes with water from an eyewash station for at least 15 minutes. HANDLING AND STORAGE Accidental Release Measures The first action that should be taken in the case of any accidental release of hazardous chemicals is to evacuate all people who are not wearing adequate protection. After this has been accomplished, collect any solid potassium hydroxide and place it in a sealable container. If it is a liquid, absorb it in vermiculite, dry sand, earth, or a similar material and deposit it in sealable containers. Do not touch damaged containers or spilled material unless wearing proper gloves, protective clothing, and respirator. Do not allow water to make contact with spilled material. The spill area should be thoroughly washed with dilute acetic acid to neutralize any remaining traces of potassium 54 Division of Chemical Health and Safety of the American Chemical Society Elsevier Inc. All rights reserved. 1871-5532/$36.00 doi:10.1016/j.jchas.2009.11.005 hydroxide. Ventilate the area after the clean-up is complete. Contact the state Department of Environmental Protection or the regional office of the Environmental Protection Agency (EPA) for specific guidance for disposal of potassium hydroxide as a hazardous waste.4,6 Storage Guidelines It should always be stored in tightly closed containers in a cool, dry, wellventilated location, separate from acids, water, and metals.4,6 It should be in an area with a corrosion resistant concrete floor.7 Reactivities and Incompatibilities Since it is a strong base, it is corrosive in moist air to metals, such as zinc, aluminum, tin, and lead, forming a combustible/explosive gas, hydrogen.7 Potassium hydroxide is not compatible with strong acids, such as hydrochloric, sulfuric and nitric acids. It is also not compatible with halogenated hydrocarbons, such as trichloroethylene and carbon tetrachloride; maleic anhydride; tetrahydrofuran; acid chlorides; and acid anhydrides.6 EXPOSURE CONTROLS Sampling and Analysis The National Institute for Occupational Safety and Health (NIOSH) method 7401 for alkaline dusts recommends sampling using a 1-mm PTFE membrane filter with an air sampling pump providing a flow rate of 1 to 4 L/ minute. The hydroxide ion (OH) is analyzed using acidbase titration.8 Exposure Guidelines The American Conference of Governmental Industrial Hygienist (ACGIH) has assigned a ceiling limit of 2 mg/M3 with no skin notation, which should not be exceeded at any time.9 The NIOSH recommended exposure limit (REL), which is a 10-hour time weighted average (TWA) concentration, is also 2 mg/M3.2 PERSONAL PROTECTION To guard against accidental exposure to potassium hydroxide, an individual working with or around the substance in the absence of local exhaust ventilation should wear protective clothing, including impervious hand protection made with neoprene or natural rubber, as well as a NIOSH approved supplied-air respirator with a full facepiece operated in a pressuredemand or other positive-pressure mode.6 Contact lenses should not be worn. REFERENCES 1. O'Neil, M. J.; Smith, A.; Heckelman, P. E. The Merck Index, 13th ed Merck & Co.; Whitehouse Station, NY, 2001, p. 136970. 2. National Institute for Occupational Safety and Health (NIOSH). NIOSH Pocket Guide to Chemical Hazards, Information for Potassium Hydroxide, accessed from http://www.cdc.gov/ niosh/npg/npgd0523.html on September 17, 2009. 3. (4th ed.). Patty's Industrial Hygiene and Toxicology. Part A Toxicology; Clayton, G. D., & Clayton, F. Ed.,Patty's Industrial Hygiene and Toxicology. Part A Toxicology; John Wiley & Sons, Inc.: New York, NY, 1993, p. 766768. 4. National Library of Medicine. Hazardous Substances Data Bank (HSDB). Fact Sheet for Potassium Hydroxide, accessed from http://toxnet.nlm.nih. gov/cgi-bin/sis/search/f?./temp/ on September 17, 2009. 5. National Library of Medicine. HazMap: Occupational Exposure to Hazardous Agents. Haz-Map for Potassium Hydroxide, accessed from http:// hazmap.nlm.nih.gov/cgi-bin/hazmap_ generic?tbl=TblAgents&id=606 on September 17, 2009. 6. New Jersey Department of Health and Senior Services. Hazardous Substance Fact Sheet: Potassium Hydroxide. January 1995, assessed from http:// nj.gov/health/eoh/rtkweb/documents/ fs/1571.pdf on September 17, 2009. 7. International Labour Organization (ILO), International Occupational Safety and Health Information Centre (CIS). Information for Potassium Hydroxide (ICSC: 0357), accessed from http:// www.ilo.org/public/english/protection/ safework/cis/products/icsc/dtasht/_ icsc03/icsc0357.htm on September 17, 2009. 8. National Institute for Occupational Safety and Health (NIOSH). Manual of Analytical Methods, 4th ed.; NIOSH, U.S. Public Health Service, Cincinnati, OH, 1994, accessed Method 7401 for Alkaline Dusts from http:// www.cdc.gov/niosh/nmam/pdfs/7401 on September 17, 2009. 9. American Conference of Governmental Industrial Hygienists (ACGIH). 2009 TLVs and BEIs Based on the Documentation of the Threshold Limit Values for Chemical Substances and Physical Agents & Biological Exposure Indices, ACGIH, Cincinnati, OH, 2009, p. 49. 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