The factory owner, Manuel Diaz, 54, also sustained second-degree burns and shrapnel wounds while trying to save what was left of his P4-million business.
Senior Superintendent Freddie Panen, Rizal police director, told The STAR that the fire was a "plain and simple case of negligence," and not sabotage.
Aside from Diaz, those injured were identified as Rodelio Manamam; Warlito Duena, 34; Eddie Lubat, 51; Narciso Odicto, 14; Paulo Gajo, 12; Edison Pusi, 10; Lunjan Quiosan, 13; Jonathan Vale, 17; and Norman Francisco, 8. Manamam is in critical condition at the Angono District Hospital.
Diaz said the workers of his firecracker factory located at the ground floor of his two-story house along the national road in Barangay Tagpos were making kuwitis and whistle bomb when a spontaneous combustion occurred.
"Bigla na lang nagkaroon ng spark tapos biglang sumabog (There was suddenly a spark and then an explosion)," Diaz said.
The explosion was so powerful that it shattered a glass window of Diaz’s house several meters away.
Shards of glass hit the some of the victims who were just passing by the area, Panen said. The explosion subsequently triggered a fire.
Diaz and his workers tried to save as many equipment and personal belongings, especially the merchandise in his sari-sari store also on the ground floor.
Panen said firefighters from the town and nearby Cardona responded to the blaze, which was contained after an hour.
Diaz told Panen that he had failed to renew the permit of his firecracker factory this year. He had been operating his factory for several years now.
"The factory should maintain a temperature level. But since he had failed to renew his permit, his establishment did not pass through a rigid inspection," Panen said.
Police are readying charges of frustrated homicide through reckless imprudence against Diaz.