The most dangerous fireworks legally available to consumers are reloadable mortar shell kits, which launch aerial shells from tubes and account for some of the most severe injuries and deaths each year. But the full picture is more nuanced than a single category. Illegal explosive devices like M-80s carry even greater risk, and sparklers, often dismissed as harmless, injure thousands of people annually, many of them children.
Reloadable Mortar Kits: The Highest-Risk Consumer Firework
Reloadable mortar kits consist of a launch tube and separate aerial shells that the user drops in by hand. They’re the closest thing to professional-grade fireworks sold to consumers, and they’re involved in a disproportionate share of serious injuries and deaths. In the 2023 peak season around the Fourth of July, reloadable shells and multiple-tube devices together accounted for roughly 12 percent of firework injuries treated in emergency departments, but their injuries tend to be far more severe than those from smaller devices.
The main danger comes from what pyrotechnics enthusiasts call a “flowerpot,” where a shell fails to launch and instead detonates inside or just above the tube. A tube can also tip over after ignition, sending a shell horizontally into a crowd. Loading a shell upside down, a common beginner mistake, can destroy the entire rack and scatter burning debris. Several of the 11 firework-related deaths reported in the U.S. in 2024 involved device malfunctions or misuse of this type.
Consumer fireworks are classified as 1.4G explosives, meaning the hazard is supposed to stay confined to the package. Professional display fireworks carry a 1.3G classification, which allows for fire and minor blast effects. Reloadable mortar kits sit right at the upper edge of what’s legal for consumers, and in practice, the line between the two categories can feel thin.
Illegal Explosives Like M-80s
If you include illegal devices, the answer shifts. M-80s, M-100s, and quarter sticks contain far more explosive material than any legal consumer firework. A legal firecracker is limited to 50 milligrams of flash powder. An M-80 contains roughly 3,000 milligrams. Any salute containing more than 130 milligrams of explosive material is classified as a display firework under federal law, meaning it’s illegal for consumers to buy or use. These devices are powerful enough to amputate fingers or hands on detonation, and they’re a recurring factor in firework fatalities.
Homemade and altered fireworks fall into a similar category. During the 2023 peak season, homemade or altered devices were linked to an estimated 200 emergency room visits. The actual number is likely higher, since nearly half of all firework injuries involve devices that ER staff can’t identify after the fact.
Why Sparklers Are Deceptively Dangerous
Sparklers seem safe enough to hand to a five-year-old, and millions of families do exactly that every summer. They burn at roughly 2,000 degrees Fahrenheit, hot enough to melt some metals. That temperature can cause deep burns on contact with skin and easily ignite clothing. Sparklers caused an estimated 700 emergency department visits during the 2023 peak season, putting them on par with firecrackers as a leading source of injuries.
Children are especially vulnerable. Small kids often don’t understand that the wire remains dangerously hot after the sparkler appears to go out, and they’re more likely to wave sparklers close to their own faces or the faces of other children. The Children’s Hospital of Philadelphia considers sparklers a significant burn risk for kids, not a safe alternative to other fireworks.
Hands, Eyes, and Permanent Damage
The severity of a firework injury depends on what body part takes the hit. Hands and fingers are the most commonly injured area, making up about 35 percent of ER-treated firework injuries. Burns are the most frequent diagnosis overall, accounting for 42 percent of cases. But the injuries that tend to be life-altering involve the eyes.
Fireworks cause nearly 2,000 eye injuries every year in the United States. According to research published in JAMA Ophthalmology, one in six of those injuries results in severe, permanent vision loss. The mechanisms range from chemical and thermal burns to corneal abrasions to outright rupture of the eyeball. These injuries affect not just the people lighting fireworks but bystanders, including people watching from what they assumed was a safe distance.
Head, face, and ear injuries account for another 22 percent of cases, while eye injuries specifically make up 19 percent. Taken together, injuries above the neck represent more than 40 percent of all firework-related ER visits.
The Bigger Picture on Firework Risk
An estimated 9,700 people were treated in U.S. emergency departments for firework injuries in 2023, with 8 deaths that year and 11 in 2024. Five of the eight deaths in 2023 involved misuse, meaning the person was using the firework in a way it wasn’t designed for. Two involved malfunctions. The pattern holds across years: the most dangerous firework is often the one being used incorrectly, whether that means holding a Roman candle at the wrong angle, peering into a mortar tube that didn’t fire, or relighting a device that appears to be a dud.
That said, reloadable mortar kits remain the most objectively dangerous consumer firework by design. They contain the most explosive material, they require the most user skill, and their failure modes are the most violent. If you’re buying fireworks and want to reduce your risk, the single most effective step is avoiding these devices entirely. The gap in injury severity between a ground-based fountain and a reloadable aerial shell is enormous.