Serious fireworks injuries doubled after Michigan law changed Author Sharpest rise seen in patients harmed by mortar-launched shells, and in amputations. Getty Images Ten years ago, Michigan’s legislature loosened restrictions on fireworks in the state, allowing Michiganders to launch their own displays into the air legally. Almost all of the increase came from a jump in injuries caused by large airborne fireworks launched from tubes called mortars. That’s the same type that killed a professional hockey player who was visiting Michigan over the recent July 4 holiday weekend. And while the study shows no significant changes in the age, gender, race or health care patterns of the fireworks-injured patients, it does show a significant increase in a specific type of injury called traumatic amputation, which could involve fingers, hands, or limbs.