Bromine is a chemical element of atomic number 35, it is a dark red fuming toxic liquid with a choking, irritating smell. It is a member of the halogen group and occurs chiefly in the form of salts in seawater and brines. Sea water contains around 65 ppm (parts per million) of bromine and by 1924 the Ethylene Gasoline Corporation in the USA had designed and built a plant to extract bromine.
At Amlwch bromine was recovered from sea water in the Blowing Out Towers (BOT) and further purified in the Steaming Out Towers (SOT). This was then reacted with other materials to make the final products.