3 A B C D E F G H I J K L M N O P Q R S T U V W Y

Benzene

Benzene is a colourless liquid used in production of many chemicals including polystyrene. It is a volatile hydrocarbon which can be extracted from coal but since 1950 is mainly extracted from crude oil. It is toxic and  a known carcinogen, so there are strict controls on benzene emissions.