Editor's note: This story has been updated to correctly reflect the cause of the explosion at a West Philadelphia apartment complex. Police initially said it was caused by a mixture of dynamite and gun powder, but later confirmed that it was caused by a firework. In addition, police retracted their statement that additional explosives were found inside the apartment of the man who caused the blast.

Police say a man lit a firework that sparked an explosion inside a West Philadelphia apartment complex Saturday night.

Police responded to the 5-story complex on the 4900 block of Spruce Street shortly around 11 p.m. When they arrived, they found a 56-year-old man with cuts to his face caused by glass, Philadelphia Police Capt. Drew Techner said.

Authorities initially said they found live explosives and ammunition in the apartment, but later retracted that statement and said no additional explosives were found.

The blast happened after the man got into an argument with two acquaintances, PPD spokeswoman Tanya Little said. During the course of the argument, the man told authorities, he lit a "quarter stick of dynamite" that he bought at a fireworks store.

The man told police that the firework went off quicker than he expected, which caused the explosion, Little said. Damage was contained to only the man's apartment.

Authorities initially said the blast was caused by a mixture of dynamite and gunpowder, but later confirmed that it was caused by the firework going off.

The PPD bomb squad cleared the scene before allowing some 20 or so evacuated residents to return to their homes.

The man who set off the explosion was taken to Penn Presbyterian Medical Center to be treated for cuts to his face, broken ribs and "several other injuries," Little said.

Authorities continue to investigate the blast and the man has not been formally charged.