Multiple school buses caught fire at a lot on Thursday afternoon, sending thick, black smoke around the Northwest Dallas area. Crews battled the fire at a lot near Interstate 35E and Manana Drive. It's unclear what led to the fire. Dallas Fire-Rescue (DFR) said it responded around 3:30 p.m. after receiving calls about a tractor on fire and that other tractors were around it. When crews arrived, they found that the fire had spread to other vehicles. An aerial view of the scene showed crews putting out flames that engulfed multiple school buses. Employees where the vehicles were stationed told WFAA that the company converts diesel vehicles to natural gas.