Potassium acetate can be used as a deicer instead of chloride salts such as calcium chloride or magnesium chloride. It offers the advantage of being less aggressive on soils and much less corrosive, and for this reason is preferred for airport runways. It is, however, more expensive. Potassium acetate is also the extinguishing agent used in class k fire extinguishers because of its ability to cool and form a crust over burning oils. Potassium acetate is used as a food additive as a preservative and acidity regulator.