Here’s a handy guide to the Fireworks laws of the 50 states. Pennsylvania’s fireworks laws are strange because we don’t regulate possession or use, only sale. You can sell fireworks if you have a license to do so, but you can’t sell fireworks, other than the kid’s stuff, to a resident of Pennsylvania. There are a lot of fireworks stores on the Pennsylvania side of the river that specialize in selling fireworks to New Jersey residents, who, of course, ignore their state’s draconian fireworks ban. Buy too much in New Jersey, and it’s possession with intent to sell, and it’s a felony. People have been busted for it. Otherwise possession or use is a petty offense, basically just a fine. New Jersey authorities don’t like you celebrating freedom, comrade.
As Glenn Reynolds noted, fireworks bans “were the entering wedge of nannyism.” Of course, since our federal overlords banned the really fun stuff, I’m not sure how much of this matters anymore.