Established in 1844 by Hugh Lee Pattison, Washington Chemical Works became an important site for the development of a range industrial chemical processes, supporting a burgeoning local community.
One of the plant’s more innovative processes was the production of magnesium from water piped directly from the North Sea.
In 1939, Washington Chemical Co (by then part of Turner and Newall Ltd) sought permission from the River Wear Commissioner’s Traffic Committee to build a pumping station on a 20ft by 12ft site near the South-West Breakwater at Sunderland Docks.
The aim was to pump copious quantities of sea water through an 8.5-mile steel pipeline to Washington Chemical Works.
The outbreak of World War Two had disrupted supplies of magnesium previously imported from Greece; now a new process was being developed at Washington involving extraction of magnesium from sea water.
An exiled German scientist in America provided guidance on establishing the new plant, which was completed in 1940.
The pipeline was routed from South Docks to Washington across the east side of the disused Queen Alexandra Bridge rail deck.
Officially opened on June 10, 1909, the bridge had been a joint venture between Sunderland Corporation and the North Eastern Railway Co and comprised lower road and upper rail decks crossing the Wear between Deptford and Southwick.
The railway was intended to facilitate the direct transport of mineral traffic from the coalfields between Washington and Annfield Plain to South Docks as well as future passenger traffic development.
Unfortunately, passenger services never materialised and freight traffic ended in 1921.
Magnesium extracted by Washington Chemical Co made an important contribution to wartime aircraft manufacture and afterwards to the UK’s light metal industries.
Another bi-product was dead-burned magnesite, used as a refractory (material that retains its strength at high temperatures) for steel furnaces.
With each litre of sea water containing only about three grammes of magnesium, some 25,000 tons of brine had to be pumped along the pipeline each week to make the operation commercially viable.
A couple of mishaps involving the pipeline are worthy of mention. On December 22, 1950, a twin-engined RAF Mosquito aircraft overshot the runway at RAF Usworth and breached 50 feet of pipeline.
Then in January, 1952, further disruption was caused to magnesium production when the water pipe crossing Queen Alexandra Bridge burst during freezing conditions.
In 1964, the Turner and Newall subsidiaries Washington Chemical Co and Newalls Insulation Co were amalgamated to form Newalls Insulation and Chemical Co Ltd.
The company officially abandoned extraction of magnesium from sea water in 1970, with the site later being subject of gradual demolition and reclamation.
Today, external public utility pipelines and cables still run alongside the lower edges of Queen Alexandra Bridge’s spans.