CALGARY -- Hundreds of kilometres of Lake Michigan and Lake Huron shoreline are at risk of contamination if an Enbridge pipeline that runs between them ruptures, according to a study released Thursday.

The report by the University of Michigan Water Center, and supported by the National Wildlife Federation, is based on 840 computer simulations of possible spills from twin lines that run across the floor of the straits linking the two lakes.

Enbridge says the two lines, which form part of the 63-year-old Line 5 pipeline, has never leaked and remain in good shape.

The study looked at the potential fallout for up to five days after a theoretical leakage and found that along with significant contamination around the pipeline itself in Michigan, oil slick could travel as far as Canada's Manitoulin Island and the South Bruce Peninsula on Lake Huron.

David Schwab, a hydrodynamics expert who directed the study, said that when all simulated spills are plotted on a map, 1,160 kilometres of shoreline in the U.S. and Canada are considered potentially vulnerable.

But the study based these simulations on the assumption that no actions are taken to contain the spread of an oil spill, which it notes is unlikely.

Schwab said the study was designed to look at the worst-case impacts of a spill, and he hopes the information will help in spill response planning and with any government decisions about the pipeline.

Environmentalists are pushing to have them removed, saying the aging pipelines threaten the environment.