A match is a short splint of wood or cardboard having a head that can be ignited by friction, used to kindle fire. Early matches were complex, unreliable, and somewhat dangerous (e.g., dipping a match treated with potassium chlorate and sugar into a bottle of concentrated sulfuric acid). Friction matches of the modern type were first produced in 1827, containing antimony (III) sulfide and potassium chlorate. Soon white phosphorus was introduced for strike-anywhere matches. This, however, caused the disease "phossy jaw" in match-factory workers, and was banned from about 1900, being replaced by potassium sesquisulfide (P₄S₃) and potassium chlorate, with iron (III) oxide, ground glass, and glue. Safety matches have in the head potassium chlorate, manganese (IV) oxide, sulfur, iron oxide, ground glass, and glue. They ignite only when struck on the mixture on the side of the box, which consists of red phosphorus, antimony (III) sulfide, and an abrasive. The matchstick is coated with paraffin wax to give a better flame.