A nationwide class-action lawsuit against Shell Oil Co. and Hoechst Celanese Corporation was filed on behalf of owners of houses, mobile homes and other structures with Polybutylene (PB) piping installed between Jan. 1, 1978 and July 31, 1995. Shell and Hoechst Celanese supplied raw materials used in the manufacture of the pipes, which plaintiffs claimed were defective and prone to leaking. The lawsuit was settled in November 1995. Under the settlement, the defendants committed over $1 billion to a settlement fund to compensate those who sustained property damages or repair costs as the result of using PB plumbing.