The highway has been closed in northwestern Ontario between Kenora and Vermillion Bay since 2 a.m.
According to the Ontario Provincial Police (OPP), black ice caused two semis to collide near Nixon Lake at about 1 a.m. That led to a chain reaction on the dark, twisting patch of road.
Damage to some of the trucks is extensive but there are only minor injuries, police said, adding that no passenger vehicles were involved.
The OPP say all the semis were loaded and it will likely take some time before the highway reopens.
Drivers are advised to take Highway 71 east of Kenora as an alternate route.