It’s illegal to buy, sell or possess fireworks in the state of Massachusetts.But that doesn’t stop Massachusetts residents from buying them.”Probably 95 percent of our customers are from Massachusetts, Rhode Island, Connecticut and Maine,” said Shannon Obey, manager for Rockingham Fireworks in Seabrook, N.H.Obey says store owners and fireworks distributors aren’t responsible for the consequences of selling to residents from states where fireworks are prohibited.”Once they leave the store, it’s up to them what to do with them,” she saidThat means area police have to be ready to deal with people setting them off illegally on the North Shore this Fourth of July weekend.Lynn Police Lt. Chris Kelly says officers will use their experience, discretion and common sense that comes this weekend when dealing with fireworks complaints.Kelly said a situation becomes a priority if it’s disturbing a neighborhood or is more malicious, such as when people shoot fireworks at each other.”We take fireworks pretty serious,” said Kelly. “We’ll have extra patrols over the holiday weekend.”The consequence for being caught in the possession of fireworks is a summons to court, which can result in a fine from $10-$1,000.Confiscation of all the fireworks is mandatory, according to Kelly. Intentionally harming another person using fireworks can bring more serious consequences. Depending on the circumstances, setting off fireworks can even bring a charge of disorderly conduct.Accidents can happen when people are using fireworks, according to Saugus Fire Chief James Blanchard, who said problems start when people mix fireworks and alcohol.There was a building fire in Saugus last year caused by a fireworks explosion, he said.”People don’t understand the danger when it comes to fireworks,” said Blanchard. “They have no idea what they could do. They could explode at their feet or explode horizontally and set a house on fire a block away.”