An updated environmental review released by a state agency in the U.S. on Monday found no serious threat to Lake Superior if crude oil ever leaked from a new pipeline to replace Enbridge's aging Line 3 across northern Minnesota.

Enbridge says the cost of its Line 3 replacement project has risen nine per cent from its original estimate when it was sanctioned in 2014.

13 cars of a CN Rail train derailed in northeastern Minnesota early Wednesday but without causing a spill or injury.