Flare guns can be quite dangerous. They can kill if fired at a person. Flare guns have also, in the past, been modified to take real ammunition. Such "converted" weapons are a real concern in countries with tight gun control laws, such as European nations [source: Bilefsky]. Timothy McVeigh, the man convicted and later executed for the deadly terrorist bombing of the Oklahoma City Federal Building, once claimed to be capable of converting a flare gun into a rocket launcher to shoot down government helicopters [source: Kifner].
A flare can also cause a fire that may lead to serious injury, death or damage. In 2009, two brothers were sentenced to 90 days in jail, three years probation and 500 hours of community service for firing a flare as part of a Fourth of July celebration two years earlier. The flare caused a fire in a Milwaukee meatpacking plant, which led to four buildings being destroyed and $50 million in damages [source: AP]. Another flare-gun-induced fire, in 1989, caused a fire in New York that injured seventeen firefighters [source: New York Times].
The compounds in flares have sometimes raised concerns of possible toxicity. Perchlorate oxidizers are found in many signal and decoy flares used by the military. But when perchlorate gets into the water supply, it can hinder the thyroid's ability to take in iodine [source: SERP]. For that reason, the military has, in recent years, tested possible replacement flares with some success, likely leading to new, safer flares.
You can get a kit containing a flare gun and flares for anywhere from fifty to several hundred dollars. Make sure to educate yourself on your community's laws surrounding their use and, when possible, talk to experts, such as someone from the Coast Guard or an experienced firearms dealer.
For more information about flares, signals and other maritime matters, take a look at the links on the following page.