A 4,600-strong contingent of the popular paintball league was injured on Saturday, when a paintball gun exploded in a car in New Jersey, killing a person and injuring at least 4,500 others.
The blast was reported at about 10:40pm (AEDT), according to the New York State Police, and was reported by a New Jersey Fire Department spokesman.
A total of 1,400 people were treated at a hospital for injuries from the explosion, which took place in the Garden State.
No other injuries were reported.
It was the second explosion in a week.
In January, another explosion at a paintballs event in New Hampshire killed at least one person and injured more than 300.
Authorities have not yet named the person who was killed.
New Jersey has a strict paintball rules.