The public debate surrounding the trade-offs between pipeline and rail transportation has been developing over the past decade as the amount of crude oil transported by rail has increased. It was invigorated in 2013 after the deadly Lac-Mégantic disaster in Quebec when a freight train derailed and spilled 5.56 million litres of crude oil, which resulted in explosions and fires that destroyed much of the town's core. That same year, a train carrying propane and crude derailed near Gainford, Alberta, resulting in two explosions but no injuries or fatalities. These rail accidents, among other examples, have raised concerns that the regulation of rail transport is inadequate for large-scale crude oil shipments. Pipeline failures also occur, for instance, in 2015 a Nexen pipeline ruptured and leaked 5 million litres of crude oil over approximately 16,000 m2 at the company's Long Lake oilsands facility south of Fort McMurray. Although both pipeline and rail transportation are generally quite safe, neither mode is without risk. Numerous studies, however, indicate that pipelines are safer, based on the number of occurrences (accidents and incidents) weighed against the quantity of product transported. Between 2004 and 2015, the likelihood of rail accidents in Canada was 2.6 times greater than for pipelines per transported volume of oil equivalents. Natural gas products were 4.8 times more likely to have a rail occurrence when compared to similar commodities transported by pipelines. Critics question if pipelines carrying diluted bitumen from Alberta's oil sands are more likely to corrode and cause incidents, but evidence shows the risk of corrosion being no different than that of other crude oils.