An explosion blamed on a gas leak has killed five people in the apartment building where they lived in northwest Italy.

Firefighters say they removed the bodies of four men and a woman from the collapsed building in Arnasco, near Savona, after the pre-dawn blast Saturday. A woman who survived was severely burned.

Arnasco Mayor Alfredo Gallizia says the four-story building, where three families lived, was “saturated with gas and everything came down.”

The cause of the gas leak is being investigated.