BOSTON (AP) — A Pennsylvania fireworks company had its license suspended in Massachusetts after workers mowing lawns inadvertently set off unexploded shells from Fourth of July displays, shaking machine operators, Massachusetts Fire Marshal Stephen Coan said Wednesday.

The size of the commercial lawnmowers protected the workers from the exploding shells in Ware, Waltham and Stoughton (STOH’-tuhn) days after the shows, Coan said. Unexploded shells were also found in Wilmington and Worcester.