Police launched an investigation Wednesday into the previous night's massive explosion at a gunpowder factory in the town of Taketoyo, Aichi Prefecture, that injured 56 people living near the plant.
The explosion occurred at around 10:10 p.m. at a storage unit of the factory run by NOF Corp., a Tokyo-based leading chemical company.
One of the injured, Tomo Kanai, 83, of the neighboring city of Tokoname, suffered a broken hip and other serious injuries, police said.
According to police, of the 56 victims, 25 are men and 31 women. The explosion destroyed three buildings, partially destroyed 33 others and shattered the windows of 60 structures -- all outside the factory.