camera." i'm contessa brewer. when you attend a fireworks display, you expect fireworks but not like this. on this night spectators were left scared, scarred and wanting to know what went wrong? ♪ in southeastern pennsylvania, a holiday celebration goes from festive to fearsome in the blink of an eye. >> oh, my god. >> what the -- what the -- >> july 4th, 2010, the town is celebrating more than american independence. the 7,000 residents are celebrating their home town's big birthday. lifelong natives look forward to the evening festivities.