Four people were injured after an accident on I-94 in Monroe County last night. The Wisconsin State Patrol reports that around 9:00 last night, a minivan was travelling westbound in the eastbound lanes when it struck a passenger vehicle travelling eastbound at mile marker 135 in Warrens. Authorities say a chain reaction crash occurred and two other vehicles were involved in the crash. Two of the passengers in the eastbound vehicle were critically injured and individuals in the other three cars received non-life threatening injuries. No names have been released. The crash remains under investigation by the Wisconsin State Patrol.