Caledon OPP and emergency crews are on scene of a serious five vehicle collision on Highway 10.
Two have been taken to hospital in Toronto with life-threatening and critical injuries.
The road is closed from Olde Base Line Road to Charleston Sideroad.
Police say it will remain closed for several hours and likely into the afternoon rush hour.
Police recommend any commercial vehicle traffic should take the recommended routes which include, Charleston Sideroad to Airport Road for southbound traffic, and King Street to Airport Road for northbound traffic.
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