OAKLAND, Calif. (KRON) –Two ladder trucks with Oakland Fire Department (OFD) collided Sunday around 8 a.m. on the way to a structure fire, according to a statement from OFD.

Each of the ladder trucks carries five personnel on board. Four firefighters on the trucks were taken to the hospital but have since been released. Two other firefighters were approved to head back to work Sunday at their fire station.

This accident is currently under investigation by OFD.