Around the 1860s, at the height of the iron and steel era, a pier and a deep-water dock were built, at Portishead, by the Bristol & Portishead Pier and Railway to accommodate the large ships that had difficulty in reaching Bristol Harbour. The Portishead power stations were coal-fed power stations built next to the dock. Construction work started on Portishead "A" power station in 1926. It began generating electricity in 1929 for the Bristol Corporation's Electricity Department. In 1951, Albright and Wilson built a chemical works on the opposite side of the dock from the power stations. The chemical works produced white phosphorus from phosphate rock imported, through the docks, into the UK. The onset of new generating capacity at Pembroke (oil-fired) and Didcot (coal-fired) in the mid-1970s brought about the closure of the older, less efficient "A" Station. The newer of the two power stations ("B" Station) was converted to burn oil when the Somerset coalfields closed. Industrial activities ceased in the dock with the closure of the power stations. The Port of Bristol Authority finally closed the dock in 1992, and it has now been developed into a marina and residential area.