RCMP northeast of Edmonton believe heavy fog played a significant factor in a massive crash, that eventually involved several vehicles, including an emergency vehicle.

Smoky Lake RCMP, along with fire departments from Smoky Lake, Vilna and Waskatenau, and paramedics, were originally called to a crash involving seven vehicles on Highway 28 about 10 kilometres east of Smoky Lake late Tuesday afternoon.

Police said visibility in the area was still drastically reduced – and as emergency crews were on the scene, four more vehicles became involved in the crash.

In total, eleven vehicles – including a rescue vehicle – were involved.

Most of the people involved in the collisions were not hurt; however, a number of people were taken to area hospitals with non-life threatening injuries.

Investigators are still working to determine the exact cause of the crash – but fog in the area reduced visibility to less than two metres, and that is believed to be a factor in the crash.

The highway was closed for several hours while crews cleaned up the collision.