The remains of Pilkingtons' No 9 Tank House represent a unique survival from the 19th century, a period of rapid development within the glass industry characterized by innovative but short-lived design. These remains are now recognized as the most complete known glass furnace structures of their era. Between 1991 and 1997, Lancaster University Archaeological Unit (now Oxford Archaeology North) conducted a programme of standing building survey, excavation, and oral and documentary research, targeted on the remains on the Hotties site, in St Helens, Merseyside