The trailer of a semi-truck caught on fire on Highway 60 near Lake Crystal Tuesday. Investigators say that the fire was apparently caused by something in the trailer malfunctioning. The truck was reportedly carrying non-flammable limestone, which caused a large cloud of smoke while Lake Crystal firefighters extinguished the flames. The driver, who was from South Dakota, was able to escape without injury. The Lake Crystal Police Department also assisted the State Patrol at the scene.