A U.S. citizen was arrested Tuesday after he caused a bomb scare at Miami Airport: Ammunition primers in his luggage exploded while baggage handlers unloaded it from a plane that had just arrived from Boston. The FBI said the man was a 37-year-old U.S. citizen whose luggage contained several hundred ammunition primers—which are illegal to pack in checked luggage—and he is being charged with traveling without a license to charge ammunition. The explosion was caused by the movement of the bag from the Boston flight to one bound for Jamaica, officials said. The incident is not believed to be terrorism-related. Four other flights were delayed as a result of the explosion, the airport said.