A 55-year-old Westville man was injured in a four-semi crash that closed westbound US 30 near Plymouth for about two hours Monday. Indiana State Police say a 36-year-old semi driver from Illinois apparently fell asleep then woke up moments before colliding with the rear of a stopped semi at the intersection of King Road, causing a chain reaction. Troopers say the collision caused a tank full of argon gas to spill from one of the trucks as they came to rest. Police say the argon gas is inert and was not a hazard to the public. The man Injured in the crash was taken to Saint Joseph hospital in Plymouth and treated for injuries to his back and neck, police say.