Exploding oxygen tanks fueled a massive fire that destroyed a UK ambulance station and several vehicles.
The metal building in Thurrock eventually collapsed.
Essex County Fire and Rescue Service Incident Commander Al Green told BBC News they found a "relatively small fire but it escalated very quickly."
He said the exploding oxygen tanks enhanced the blaze, and additional crews were dispatched to assist at the Elite Event Medical Services building.
Nearby residents were urged to stay inside and close windows to avoid exposure to the dense smoke as firefighters worked to control the blaze that broke out about 4:50 a.m.
