Major Canadian oil pipelines that move nearly 1 million barrels per day (bpd) of Alberta oil-sands crude, much of it to the United States, remained closed Monday after a spill on a smaller line was discovered over the weekend, a spokesman for operator Enbridge Incorporated said. Enbridge, Canadaâ€™s biggest pipeline company, said Saturday that 750 barrels of synthetic oil had spilled from the 17-kilometer Line 37, which serves Chinese CNOOCâ€™s Long Lake oil-sands project in northern Alberta. The spill, which may have been caused by the heavy flooding that has paralyzed Calgary, Albertaâ€™s energy headquarters, threatens a serious disruption in the flow of oil-sands crude. The 345,000 bpd Athabasca pipeline, which carries blended crude to the Hardisty terminal in Alberta, and the Waupiso line, which can carry up to 600,000 bpd depending on crude viscosity to Edmonton, Alberta, were both shut. They are two of the biggest lines that carry crude form the northern production centers to the storage and pipeline hub in Hardisty, connecting to Enbridgeâ€™s main export pipeline that runs south into the United States. An Enbridge spokesman said Monday he was unable to provide a timetable for resuming flows. The spill threatens to fuel growing criticism of the safety of the North American pipeline network and of expanding production of oil-sands crude. A series of accidents in recent years has drawn new attention to oil shipments, particularly of oil-sands crude, which is more abrasive on pipelines.