The U.S. federal agency that oversees the safety of oil and gas pipelines is too closely tied to industry and has failed to implement safety measures mandated by Congress, according to a harsh report by the General Accounting Office. Between 1990 and 1998, the proportion of enforcement actions brought by the Office of Pipeline Safety that resulted in fines fell from 49 percent to 4 percent, and over the same period the number of major pipeline accidents increased by 4 percent per year. The report comes a year after a gasoline pipeline spill and explosion in Bellingham, Wash., killed three people. A Senate committee yesterday approved a bill that would significantly tighten pipeline regulation.