Firefighters responded to an explosion at a school construction site in Newark Thursday.

Fire officials say a crane backed into a propane tank, causing it to ignite at the site on Bloomfield Avenue and North 6th Street. Four cars in a parking lot caught fire. Hazmat trucks were also called to the scene, which is in a mostly residential area.

Firefighters flooded the tank with water to dilute the fuel and prevent any explosions. Officials say no injuries were reported in the incident. The school under construction suffered minor damage. Fire officials are calling the incident an accident.