Just after midnight this morning, Knoxville Rural Metro Fire responded to a tractor trailer fire at the Petro truck stop on N. Watt Road off of I-40. When units arrived they found the truck heavily involved with fire spreading into the trailer, which was carrying foam mattresses. Foam was used on the tractor and multiple resources were assigned to the trailer. The fuel shutoff was activated early. The fire was brought under control just after 2 a.m. and the cleanup was extensive. Petro Truck side will be closed for an extended period of time.