8:30 p.m. update
The westbound lane and shoulder of Highway 17 remains blocked but the eastbound lane opened to traffic at about 8:20 p.m.
Traffic is still backed up but moving slowly through the area.
Original story: 7:40 p.m.
A cattle tractor trailer fire has forced closure of Highway 17 in both directions between the east entrance of the Alona Bay Lookout and Highway 101 to Wawa.
Witnesses at the scene west of Montreal River say cattle are running loose in the area and traffic is backed up in both directions.
The cattle truck was in the eastbound lane when it caught fire at about 6:30 p.m. It is unknown when the highway might be reopened.