It all started around 8 p.m. on Tuesday night.
"We had a car went through the Pizza Hut lot and hit the gas regulator," Streets Superintendent Gary Leftin said.
Crews shut down roadways surrounding the intersection and evacuated businesses and homes in the area.
"Natural gas is very explosive and the amount of gas that was being expelled from the pipes was enormous," Battalion Chief Russell Moore said.
Firefighters said a small spark could have caused the entire area to go up in flames.
Gas companies were called to the scene where they used special equipment to remove the car. The crash created an eight inch gash in the line.
The fire department was on the scene until 1:30 in the morning when the gas company was able to stop the leak.
Crews also worked on a bypass in order to keep service to areas on the east side of St. Joseph.
Investigators are still trying to determine what caused the driver to hit the gas line.