Year after year, fire officials warn the public to use only legal, or “safe and sane,” fireworks for their Fourth of July celebrations.
But what makes one type of fireworks safe for consumers and another a hazard? Is the common sparkler just as dangerous as a Roman candle?
You might be surprised.
California’s limitations on fireworks made for personal use are based on how fireworks operate and what explosive materials are in the product – and how much.
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Legal consumer fireworks are not explosive, and they burn in a slow-moving fashion. Heat from a lit part of fireworks warms up unburned material next to it, causing that segment to catch fire.
The expansion of gases produced as the material burns gives off the same kind of “push” that can fire a bullet and launch a rocket. In fact, the California Health and Safety Code addresses fireworks, model rockets and flamethrowers in the same section because they share similar risks for fire and explosion.
California bans the unlicensed use of fireworks that shoot solid objects into the air, like bottle rockets and Roman candles. Anything that flies above the ground poses an increased fire hazard, according to Sacramento city firefighter Roberto Padilla. Uncontrolled projectiles can also be a source of injury to bystanders.
Because fireworks contain both fuel and an oxidizing agent, they don’t need to be exposed to oxygen in the air to go off.
“Smothering is the worst thing you can do,” said John Conkling, retired technical director for the American Pyrotechnics Association. Smothering holds in heat, making fireworks burn more rapidly. Water puts out fireworks because it absorbs large amounts of energy when it boils, cooling the firework off to below the temperature at which it burns.
High explosives, like picric acid, can be added to fireworks to produce a faster, more powerful reaction. Many high explosives are unstable and can be set off by shaking motions or friction. These materials, along with others that are toxic, are not permitted in California consumer fireworks.
Fireworks that are prohibited under federal law may have large quantities of pyrotechnic material, dangerously short fuses or toxic chemical content. Some of these illegal fireworks, like cherry bombs or M-80s, can be explosive enough to amputate limbs.
Homemade or illegal fireworks caused five of the six U.S. deaths from fireworks reported to the Consumer Product Safety Commission (CPSC) in 2012, with the sixth caused by misuse of a mortar that would not be permitted in California. The safety commission concluded that misuse was the most common cause of fireworks-related injuries, responsible for two-thirds of the estimated 8,700 cases.
Even sparklers can be dangerous. They are the most common cause of fireworks-related injuries in the United States in cases where the type of fireworks is known, according to the safety commission’s 2012 fireworks report.
The simplest sparklers, which are not “safe and sane” and therefore illegal in California, use a mixture that includes aluminum or magnesium applied to a stick. When lit, the metals will burn very brightly and very hot, 1,200 degrees Fahrenheit or higher. Sparklers can cause severe burns or start fires if not handled carefully.
Other sparklers that do not use pure magnesium and do not have a wire or wooden stick are legal.
“All it takes is one spark and off to the races we go,” warned Dennis Mathisen, spokesman for the California Department of Forestry and Fire Protection. Between 2008 and 2012, local fire agencies in California reported an average of 450 fireworks-related fires per year. Mathisen said that because of this year’s severe drought conditions, it is especially important for people to use fireworks responsibly.
Recommendations from the state fire agency include keeping a bucket of water and a hose available, and setting off fireworks only in open areas far from dry vegetation or other flammable items.
Large aerial fireworks may be seen in professional shows, which are run by pyrotechnics operators who are licensed by government agencies. This year’s Fourth of July show at Cal Expo is run by Pyro Spectaculars, a Southern California firm.
Producing a safe fireworks show requires careful evaluation of the site where the display will occur, said Ian Gilfillan, Pyro Spectaculars’ executive vice president. That includes managing nearby hazards, like mowing or watering dry grass.
Similar to recommendations for consumer fireworks, fire technicians wait for a while after a public display is over to check for and dispose of duds. For the general public, CPSC recommends not attempting to relight fireworks that fail and dousing all used fireworks in water.