A gas pipeline explosion has ripped through a San Francisco suburb, killing at least four people and destroying fifty three homes.
The explosion in San Bruno sparked a massive fire, which damaged another one hundred and twenty houses.
At least 30 have been injured.
They are being treated at hospitals across the San Francisco Bay Area, some with severe burns.
Doctors have appealed for blood donations.
Firefighters and water bombing aircraft battled to bring the flames under control for most of the night.
The area has now been declared a disaster zone.
Residents in the nearby districts have been advised to evacuate the area.
Those who have left their homes are being put up in local shelters.
Officials want survivors to contact them to put together a list of the missing.
The local utlity provider that owns the ruptured pipeline has promised to carry out an investigation into the cause of the blast.