Four individuals were critically injured Sunday afternoon when a suspected junk compressor loaded with freon exploded as it was being dismantled by scavengers at the corner of Tayuman and Dagupan streets in Tondo, Manila.

According to an initial report from firefighter-paramedic Jam Mariano, all four victims were male and suffered serious injuries. One reportedly sustained a severed hand and jaw wounds from metal fragments caused by the powerful explosion.

Residents said they heard a loud blast at around 3:30 p.m. and rushed to the scene.

A bystander initially reported it as a grenade blast as one of those wounded allegedly bragged earlier about finding such an explosive device.

Investigators said the victims were extracting metal from a sealed compressor, believed to be from a junk refrigerator, when it suddenly exploded. They were immediately rushed to the Ospital ng Tondo by responding paramedics.

The Manila Police District is now conducting an investigation to determine the cause of the explosion.