According to Suffolk County Police, the incident happened in Copiague around 9:10 p.m. on Thursday, July 4.
The man, a 21-year-old resident of the town of Eastchester, was lighting a firework at a party in front of a house on the 200 block of Trouville Road when it exploded in his hand.
The explosion severed three fingers on his left hand and damaged the other two. He also suffered a burn to one leg.
Responding First Precinct Patrol officers applied a tourniquet to stem the bleeding before the man was transported to Good Samaritan University Hospital in West Islip for the treatment of serious but non-life-threatening injuries.
Detectives are asking anyone with information on the incident to contact the First Squad at 631-854-8152.
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