Ethyl chloride is a colourless flammable gas at ordinary temperature and pressure. It has a characteristic ether-like odour and a burning taste. Ethyl chloride is used as a chemical intermediate, in solvents, aerosols, and anaesthesia. Currently, chloroethane is largely used as a blowing agent in foamed plastics. In the past, chloroethane was used in the production of tetraethyl lead, an anti-knock additive to leaded gasoline. Chloroethane has also been used in the production of ethyl cellulose and for miscellaneous applications including use as a solvent, for phosphorus, sulfur, fats, oils, resins and waxes; in insecticides; and as an ethylating agent in the manufacture of dyes and drugs, refrigerant, and topical anaesthetic and use in the manufacture of dyes, chemicals, and pharmaceuticals. Other uses of chloroethane are as a pulp vitality tester in dentistry, as a medication to alleviate pain associated with insect burns and stings, as an adjunct in the treatment of tinea lesions and creeping eruptions, and as a counterirritant for relief of myofacial and visceral pain syndromes. Chloroethane is also used as a solvent, as a refrigerant, and in the production of ethyl cellulose, dyes, medicinal drugs, and other commercial chemicals. It is also used to numb skin prior to medical procedures such as ear piercing and skin biopsy, and in sports injuries.