
Beauty Above, Burden Below: The Hidden Cost of Fireworks on Our Waters
Natalie Marcin
June 21, 2026
Imagine a barge anchored just offshore, lighting up the night sky with color as crowds cheer below. Now imagine what comes down after the spectacle ends: charred shells, tangled wires, plastic fragments, and a fine residue of toxic metals, drifting through the water and washing up the next morning onto the same sand where children, families, and dogs play. These nightly displays — beautiful from a distance — are emerging as an overlooked source of heavy-metal and microplastic pollution in our lakes, bays, and oceans.
In addition to this article, check out EarthSpotter's YouTube video: Fireworks & Water Pollution: The Dark Side of Celebrations. The video investigates the pollution at the SeaWorld San Diego fireworks barge, dives into the science of what fireworks leave behind, and runs a hands-on demonstration to see how these explosives interact with water.
What is in a fireworks show?
A single fireworks display launches hundreds to thousands of pounds of explosives into the atmosphere. The colors and brightness that make them beautiful come from metals — commonly aluminum, barium, antimony, and strontium — along with perchlorate, the oxidizer that makes them burn. A shell is also built from plastic pieces or plastic lined cardboard, wires, and paper packaging.
The assumption is that all of this combusts cleanly in the sky. It does not. After detonation, a significant amount of material falls back down into the launch area as burning particulates, spent shells, wires, igniters, plastic pieces, and other components — much of it still carrying a residue of the heavy metals used in the display.
Scale of the problem
The numbers add up quickly. The fireworks barge at SeaWorld San Diego alone launches up to 150 shows per year, often nightly through the summer, directly over Mission Bay. Each show sends its fallout into the water below, night after night, season after season.
The industry itself acknowledges that material comes down. When fireworks are launched over water, operators typically enforce a 100-foot exclusion zone around the barge during the show — a radius where no person is allowed to swim or boat, in part because of the falling debris. In other words, the very water deemed unsafe for people during the show is the habitat that fish, birds, and invertebrates cannot leave.

Image 1: Shows wires found under the SeaWorld fireworks barge.
Why are fireworks so problematic?
1. They deposit toxic metals directly into fragile ecosystems
A display fired over a lake or bay introduces its pollutants straight into the water, with no barrier between the falling debris and the animals below. Each metal carries its own danger:
- Aluminum can impair a fish's ability to breathe and accumulate in its body until it dies.
- Barium interferes with the ability of marine animals to reproduce.
- Antimony stunts the growth of young fish and limits their capacity to take up oxygen.
- Strontium causes digestive problems.
- Perchlorate disrupts neurological function.
In the air, the same compounds degrade local air quality and have been linked to adverse pregnancy outcomes and neurological disease in people.
2. They add to the microplastic crisis
Fireworks shells are full of plastic, and over time that plastic breaks down into microplastics — fragments small enough to look like food to birds, sea turtles, and fish. When an animal eats them, its body cannot break them down, leading to blocked digestive tracts, false satiation, starvation, and death. Scientists have documented harmful impacts from microplastics in at least 663 marine species. These plastics do not stay in the ocean, either: microplastics have been found in the fish we eat, in our food, and in human blood, where they may accumulate and carry health consequences of their own.
3. The pollutants persist and accumulate
These metals and plastics do not simply disappear after a show. Residue settles into sediment and builds up over repeated displays, so a launch site used night after night carries a growing pollutant burden rather than a one-time hit.
Pathways: how the pollution reaches the water
Where does the contamination come from? Unlike a single spill, fireworks pollution arrives through the display itself:
- Falling debris: burning embers, particulates, and physical shell components drop into the launch area during and after the show.
- Misfires and malfunctions: even experts who defend fireworks concede roughly one malfunction per show, sending material into the water that was never meant to reach it.
- Dispersal by water: once pollutants enter the water, tides and currents carry and dissolve them across a dynamic ecosystem, spreading the impact well beyond the barge.
The controversy: do fireworks really harm the water?
An honest investigation has to sit with disagreement. Dr. John Steinberg, a fireworks expert, argues that a display operating exactly as intended is unlikely to send burning stars or embers into the receiving water at all — in theory, the material combusts in the air. SeaWorld San Diego, which is required to test the water after its shows, reports data showing little to no impact on water quality or sediment.
Yet spectators regularly watch burning particles fall from the sky and strike the water, and scientific literature documents real impacts on water quality. Part of the discrepancy may come down to timing. Commercial operators often do not sample the water until 10, 12, or even 24 hours after a show. Water is dynamic — moving with tides and currents — and any particulates and embers that fall in are dissolving and dispersing the entire time. A clean reading the next morning does not prove the water was clean when the last shell fell.
Our demonstration: the sparkler test
Fireworks are difficult to test directly, so EarthSpotter built a demonstration around their smaller cousin. Sparklers use the same metals as fireworks and combust into the same light, smoke, and particulates — only without launching high into the sky, which made them ideal for watching the water's surface up close.
We clamped sparklers in spring clamps over distilled water, let them sit for an hour, and took a baseline sample. Then we lit them. On camera, embers and sparkler debris drop into the water and the particles bounce as they hit — a sign of solid particulate matter rather than fully combusted material that has dissolved into smoke.
The post-sparkler sample told the story. The once-distilled water was flooded with toxic metals, most notably aluminum, barium, and magnesium — the same elements used in fireworks. This was a demonstration, not a controlled scientific experiment, but the result is hard to dismiss: the burning embers and trash that land in the water at fireworks shows are very likely not innocent, and appear to deposit many of the same heavy metals the fireworks themselves contain.
What the science says
Published research backs up the demo:
- A study over a lake in Orlando, Florida found higher-than-normal concentrations of antimony, barium, and strontium — three common fireworks ingredients — indicating that residue accumulates over time.
- A study tracking perchlorate found levels rose anywhere from 28 to more than a thousand times higher after a fireworks display.
- Local environmental nonprofits sampled the water beneath the SeaWorld barge and compared it to a Mission Bay reference point. Contrary to SeaWorld's own findings, they detected elevated aluminum, strontium, and copper. The same group analyzed physical debris from the Big Bay Boom show in California and found it laced with toxic fireworks-metal residue.
Possible solutions and their challenges
Cleaner alternatives
Drone light shows can deliver the spectacle of a fireworks display without the heavy-metal fallout, offering communities a way to keep the celebration while sparing the water.
Regulation and accountability
Fireworks operators over water are frequently bound by permits requiring cleanup and monitoring. Strengthening enforcement — and ensuring that required testing happens immediately after shows, not a day later — would close the gaps that currently let pollution go undocumented.
Reducing the source
Limiting the number of over-water shows, especially nightly summer runs over sensitive ecosystems, reduces the cumulative pollutant load that builds up at a single launch site.
Human and ecological impact
Beyond the chemistry, the impacts are real.
Wildlife. Fish, seabirds, sea turtles, and invertebrates are exposed to toxic metals and ingest microplastics, leading to impaired breathing and reproduction, stunted growth, blocked digestion, starvation, and death.
Ecosystems. Repeated displays over the same waters deposit metals into sediment and disperse pollutants across the wider bay, so even areas away from the barge are not spared.
Human health and livelihoods. When contaminated plastics and metals enter the marine food chain, they can ultimately affect people who eat fish and shellfish. Microplastics have already been found in human blood. And the debris does not stay offshore — it washes up on public beaches where families and children play.
How EarthSpotter Fights Pollution
The brief beauty of a fireworks show can obscure a lasting environmental cost. From the barge to the beach, these displays deposit heavy metals and plastics that travel, persist, and entangle themselves in natural systems, wildlife, and human lives.
For more on fireworks pollution, check out EarthSpotter's YouTube video: Fireworks & Water Pollution: The Dark Side of Celebrations.
Recognizing the lack of enforcement and public awareness around pollution sources, EarthSpotter was created as a platform focused on educating the public and holding companies accountable for environmental harm. EarthSpotter works through three main mechanisms:
- Environmental journalism: EarthSpotter investigates pollution sources and publishes articles on how these pollutants harm ecosystems. The platform also educates the public on simple ways to protect the environment.
- Public access to data: EarthSpotter provides the public with access to data on companies in their area and the types of pollutants being discharged, encouraging transparency and informed decisions about how to hold polluters accountable.
- Reporting environmental threats: The platform enables the public to report environmental threats, from air pollution to poor water management. Your report may be used to hold polluters accountable through legal action.
A Call to Action
Fireworks pollution is a threat to our waters, and it is one we all have the power to help prevent. If you are concerned about fireworks where you live, talk to your local government about cleaner alternatives like drone shows. If you suspect a fireworks operator near you is not following the terms of its permit, let EarthSpotter know — we can investigate.
The show in the sky lasts a few minutes. What it leaves in the water lasts far longer. Remember, the best solution to pollution is prevention — before it's too late.







