English: Brunner Mond, Winnington - lime kilns Salt and limestone are the basic building blocks of the chemical industry in the area. Lime is burnt to create quicklime which is then slaked to become calcium hydroxide. This can be combined with sodium carbonate (washing soda)- itself a result of combining salt and limestone - to produce caustic soda; the growth of the salt industry was driven by the use of these two chemicals in the burgeoning soap and cleansing agents industry at the end of the 19th century. Finding uses for the excess Chlorine was one of the driving forces behind the original Brunner Mond company, later ICI, developing uses in the pharmaceutical and plastics fields. This site is where polythene was first developed.