Plymouth County authorities have released the names of the two LeMars residents who were killed in a fiery crash Monday afternoon in northwest Iowa. 46-year-old Douglas Berkenpas was driving a Wells Dairy semi-tanker truck. 27-year-old Sheila Cost was driving a car. Both were killed. Authorities say the car slid out of control and crossed the center line, into the path of the truck. Berkenpas went onto the shoulder and came back on the road, crossing the center line and hitting another semi, rupturing a fuel tank that caught fire. The driver of that second truck, a Wisconsin man, had minor injuries. The wreck closed Highway 60 for about ten hours for a full investigation and cleanup.