Fireworks cause tens of thousands of fires every year in the United States. In 2023 alone, fireworks started an estimated 32,302 fires, including 3,760 structure fires, 849 vehicle fires, and more than 27,000 outdoor fires such as grass, brush, and wildland blazes. The risk is real, well documented, and not limited to large aerial displays.
How Fireworks Start Fires
Fireworks ignite fires in a few predictable ways. The most straightforward is falling debris: burning embers, hot shell fragments, and sparks land on dry grass, rooftops, leaves in gutters, or wooden decks. Even a small piece of smoldering cardboard from a spent mortar shell can ignite dry vegetation in seconds.
Manufacturing defects and product malfunctions add another layer of risk. A faulty fuse can ignite the explosive powder in an unintended sequence, causing the firework to detonate at ground level or inside its launch tube. Bottle rockets and other aerial devices sometimes follow erratic, unpredictable flight paths, sending flaming projectiles into vehicles, buildings, or wooded areas far from where they were aimed. Roman candles can tip over mid-firing and shoot flaming balls horizontally across a yard.
Then there’s the temperature factor. Sparklers, often handed to children because they seem tame, burn at up to 1,200 degrees Fahrenheit. That’s hot enough to ignite clothing, dry leaves, paper, and most common building materials on contact. For comparison, wood ignites at roughly 450 to 500 degrees. A single sparkler dropped on a dry lawn or wooden porch carries genuine fire-starting potential.
The Independence Day Spike
Fire activity spikes dramatically around the Fourth of July. Portland Fire & Rescue reported 55 fires on July 4, 2023, compared to just 16 on the same date the year before. Over the eight-day window surrounding the holiday, the city logged 227 fires, with at least 25 on Independence Day alone suspected to be fireworks-related. New Year’s Eve sees a similar, though typically smaller, surge.
This clustering matters because fire departments are already stretched thin on these holidays. When dozens of fires break out in the same few hours, response times slow and small fires have more time to grow. A brush fire that might have been knocked down quickly on an ordinary Tuesday can spread significantly when every crew in the district is already committed.
Which Fires Are Most Common
The vast majority of fireworks-caused fires, roughly 84% in 2023, are outdoor fires: grass, brush, leaves, mulch, and dumpsters. These may sound minor, but in dry or windy conditions, an outdoor fire can reach a home, garage, or fence line within minutes.
Structure fires are less frequent but far more destructive. The 3,760 structure fires in 2023 include homes, sheds, garages, and commercial buildings. A bottle rocket landing in a gutter full of dry leaves, a sparkler discarded near a wooden fence, or a mortar shell that drifts onto a roof can all put a building at risk. Vehicle fires, though the smallest category at 849, typically start when hot debris lands on or near a parked car, igniting upholstery, tires, or spilled fuel.
Conditions That Raise the Risk
Dry weather is the single biggest amplifier. During drought conditions or in arid climates, even a small spark can ignite grass that would shrug off the same ember after a week of rain. Wind compounds the problem by carrying burning debris farther from the launch site and feeding oxygen to any fire that starts.
Proximity to combustible materials matters just as much. Setting off fireworks near dry brush, woodpiles, propane tanks, parked vehicles, or structures with wood shingle roofs dramatically increases the chance of a fire spreading. Urban and suburban settings are particularly tricky because homes, fences, and landscaping are packed closely together, giving fire an easy path from one property to the next.
Reducing the Risk
If you’re using consumer fireworks where they’re legal, distance is your best defense. Launch aerial fireworks on flat, open ground, well away from structures, vehicles, trees, and dry vegetation. Keep a charged garden hose or several buckets of water within arm’s reach, not across the yard.
Disposal is where many fires start hours after the celebration ends. Fireworks that appear spent can retain enough heat or unburned powder to reignite inside a trash can or garage. The safe approach is to fully submerge all used fireworks, including duds, in a bucket of water for at least 15 minutes, though several hours is better. After soaking, wrap them in a plastic bag to prevent them from drying out, then place them in an outdoor trash can away from your home or any other structure. Move the can away from flammable materials until trash pickup.
Never try to relight a firework that failed to ignite. A delayed fuse can go off at any moment, and the resulting misfire is unpredictable. Wait at least 15 to 20 minutes, then soak it with the rest of your spent fireworks.
Sparklers Deserve Extra Caution
Because sparklers burn at 1,200 degrees, they’re not the harmless party favor they appear to be. A spent sparkler wire stays dangerously hot for minutes after the flame goes out. Dropping one on a deck, in dry grass, or into a paper bag of trash is enough to start a fire. The safest practice is to have a bucket of water specifically for used sparkler wires and to drop each one in immediately after it burns out. Bare feet, flip-flops, and sparkler debris on the ground are a predictable combination for burns as well.