Abbeystead disaster

[1] A group of 44 visitors were inside the underground building at the time, attending a public presentation by North West Water Authority (NWWA) to demonstrate the operations of the station.

The official inquiry into the disaster concluded that the methane had seeped from coal deposits 4,000 feet (1,200 m) below ground and had built up in an empty pipeline.

[1] The Abbeystead valve house was constructed as part of NWWA's 'Lancashire conjunctive use scheme', a water-supply project "to help in meeting the region's expected increases in water demand during the 1980s."

Independent geological and seismic surveys commissioned by NWWA later identified the source of the methane gas as coal seams 4,000 feet (1,200 m) below the pipeline.

The gas had collected over millions of years in a natural limestone reservoir, from which it seeped towards the surface through a complex network of geological faults.

[1] In March 1987, at Lancaster High Court, the building's designers Binnie & Partners were found to be 55 per cent liable in negligence for failing to exercise "reasonable care" in assessing the risk of methane.