The accident happened around 10:37 p.m. and set off a chain reaction of explosions at the Palmyra Middle School campus."This accident occurred after one of the firework charges misfired, causing an explosion, sending firework material into a nearby crowd located near the games and ride area ... This accident also propelled fireworks material across the football field and beyond," a Palmyra Borough Police Department news release stated.Eleven people suffered burns contusions and abrasions. Four of them were minors, aged 11, 14, 15 and 17. One of the injured was a fireworks employee. All of the patients were taken to Hershey Medical Center.