The Dowlais Imperial Chemical Industries (ICI) plant at was originally a government 'shadow factory' which opened in 1938, shortly before the outbreak of the Second World War. Merthyr Tydfil was chosen as a location for key wartime industries as it was considered safe from air attack and also because of local availability of manpower, supplies of water and raw materials. The ICI plant produced ammonia, mainly for explosives. In the late 1940s and early 1950s the factory continued to expand but it closed in 1963 and the site became Merthyr Tydfil Industrial Estate.
B.A.Malaws, RCAHMW, 14 November 2007.