How pipeline bitumen fares on water—does it float or sink?—when it spills is the big, sticky question at the heart of the debate over the environmental dangers of resource development.

Bitumen is a thick oil product similar to molasses at room temperature, according to Alberta Energy. At one time, it was used for roofing and paving, like tar.

News Energy Environment Bitumen Doesn’t Float Study debunks Enbridge claims that oil sands crude spill is standard clean-up.

Natural Resources Canada research shows that diluted bitumen will float, helping to answer a key question in B.C.'s debate around pipelines.