Twenty-two year old Alessio Di Giacomo, the son of the factory's owner, died, according to a report in La Repubblica. His father, Mauro, and uncle, Federico, along with another relative, Roberto, are missing. Rescuers said the chances of finding them alive are slim.
Gianmarco, Alessio's brother, is in hospital.
The blast also struck nearby homes in the town of Città Sant'Angelo, sparking a huge fire.