Highway 401 eastbound in Napanee, Ont., had yet to fully reopen early Thursday following a massive pileup early Wednesday.
Nine people were taken to hospital after at least 20 transport trucks and several other vehicles crashed in whiteout conditions between Napanee and Deseronto.
Police say the collisions occurred over a three-kilometre stretch of the highway.
Westbound lanes were reopened a few hours after the 8 a.m. pileup, but provincial police said only one eastbound lane had been opened to traffic by early Thursday.
Of the nine people taken to a local hospital, three were later transferred to Kingston General Hospital with serious injuries.
A bus sent to the scene transferred 19 people to an emergency shelter.
Police advise motorists to drive slowly through this area as crews work on the south shoulder of the highway removing contaminated soil from a diesel spill.