Fire officials said the backhoe/tractor hit a 4-inch gas main in the 5800 block of N. Shoup Avenue shortly after 1 p.m.
An unknown number of homes in the area were evacuated, authorities said. There were also buildings exposed on three sides of the blaze, but it was not known if those structures were also evacuated.
Firefighters worked to keep the flames from spreading.
Crews with Southern California Gas Company were headed to the scene to shut off the gas line. Authorities said they anticipated the gas line to be turned off shortly.
Traffic was closed on N. Shoup Avenue at Tiara Street due to the firefight.