Strathcona County RCMP responded to multiple collisions on Highway 21 this morning. 

Police reported at least two multi-vehicle collisions on the highway near Township Road 520 just before 7 a.m. 

Police say that heavy smoke from wildfires causing low visibility was a factor in the collisions. 

The highway was closed for a time but has since reopened. 

Two drivers were taken to hospital with non-life-threatening injuries, and the other drivers were taken by the county bus to Millennium Place in Sherwood Park.