Some fireworks are made with lead. You can't tell which by looking.
Independent lab testing has found lead packed into common backyard fireworks, a few of them at extreme levels. Here is what the science actually says, and what it means for the Fourth.
Sources: NYU School of Medicine (2020) · U.S. Consumer Product Safety Commission
40,000
ppm of lead in one consumer firework ("Black Cuckoo"). That is 4% lead by weight.
NYU School of Medicine, Particle & Fibre Toxicology, 2020
2 of 12
common fireworks tested carried high lead. Researchers said it looked added on purpose, not as contamination.
Same NYU study, 12 products sampled
2,667x
more lead in that one loaded product than in the trace-level fireworks I measured on my own bench (15 ppm).
My XRF reading vs the NYU Black Cuckoo
The danger you see, and the one you don't
We all know fireworks are dangerous.
Burns, blown-off fingertips, an ER visit somewhere every July. That danger is loud, and people respect it. They stand back. They keep the kids away from the fuse.
Lead is another thing entirely.
No bang, no burn, no trip to the ER. Lead works on a developing brain slowly and quietly, and you cannot see, smell, or feel the dose. That is the whole problem with it, and the whole reason the rest of this page is about how much is actually there, and where it comes from.
Illustrative radiograph and neuroimaging renders, not real patient scans.
The honest version
It is not every firework. It is the ones you can't pick out.
Lead salts make certain colors and crackle effects brighter and cheaper to produce. Most fireworks carry only a trace. But in the NYU study, the worst offender held 40,000 ppm of lead, and there is no warning label, no smell, no color that tells you which box on the shelf is the bad one.
So the real question is not "do fireworks contain lead." Some do. The question is how much of it you actually breathe, and whether that number matters. That part you can calculate. So let's calculate it.
Let's actually do the math
Set off some fireworks. Watch the dose.
"No safe level of lead" is true as a principle. It does not mean every whiff of smoke is a meaningful dose. Dose is the whole game, and dose depends entirely on how much lead was in the product to begin with.
The backyard exposure calculator
Pick a product, light a few, and see how much lead actually reaches your lungs over a night, against the FDA daily reference levels for a child and an adult.
1. Which firework are you lighting?
Trace15 ppm · my XRF reading
Saturn Missiles1,600 ppm · NYU
Black Cuckoo40,000 ppm · NYU
2. How many over the night?
3. Where are you standing?
On the lawn~10 m back
Right over itlighting it yourself
0.08
micrograms of lead inhaled over the whole night
child limit 2.2
adult limit 8.8
Negligible. You would have to inhale far more than this to reach a child's daily reference level.
Rough order-of-magnitude model, on purpose. Assumes 30 g of composition per device, half of the lead going airborne as inhalable fine particles, outdoor dispersion (~2,000 m³ near-field watching, ~120 m³ standing in the smoke), a 0.02 m³/min breathing rate, and a few minutes in the plume per device. Reference levels are the FDA Interim Reference Levels: 2.2 µg/day for a child, 8.8 µg/day for an adult. The point is not the decimal. The point is the size of the gap.
Light a dozen trace-level fireworks from the lawn and you inhale a fraction of a microgram, a tiny slice of a child's daily reference level, for one night. Light the 40,000 ppm outlier while standing over it and the same model hands you a number that should stop you cold. Same activity. The product is the whole difference.
Know what you're lighting
The common types, and where the metal hides
Heavy metals in fireworks aren't only lead. Barium makes green, strontium makes red, copper makes blue, and titanium and aluminum make the white sparks. Here's how the everyday categories stack up.
Sparklers
Burns hot, held by handThe fuel-and-oxidizer coating can include barium and aluminum. The bigger issue is heat (they burn near 1,800°F) and that a child holds the residue, then touches their mouth. Wash hands after.
Fountains & cones
Heavy local smokeSit on the ground and spray sparks for 30 to 60 seconds, dumping a concentrated cloud of metal-bearing smoke right at ground level where kids and pets are. The spent casing and ash stay on your driveway.
Firecrackers & "cuckoo" novelties
Highest measured leadThe single product that tested at 40,000 ppm lead in the NYU study was a spinning "Black Cuckoo" novelty. Cheap imported crackle and spin effects are where lead salts most often turn up.
Aerial shells & cakes
Color = metal saltsEvery color is a metal: barium green, strontium red, copper blue. The burst happens high up, but the particles drift down over whoever is watching, which is how July 4 air monitors pick up metal spikes.
Roman candles & rockets
Lower residue, real hazardLower on settled residue than ground effects, but the injury risk is high and they scatter unburned chemical pellets across a wide area that kids find later.
Professional displays
Best of the bunchHeld to tighter chemical standards, fired far from the crowd and high overhead, so dilution does most of the work. Watching a town show from a distance is the lowest-exposure way to celebrate.
What actually makes them safer
The rule most people have never heard of
There is real regulation here, and it is the reason American-made and certified product cleaned up while the lead keeps turning up in cheap imports. It is worth knowing before you buy.
The standard that bans lead
Lead tetroxide and other lead compounds are prohibited under APA Standard 87-1, the fireworks industry's consensus standard, which the federal government incorporates by reference into the hazmat transport rules (49 CFR). Lead once made the crackle effect, but because it is toxic the trade switched to bismuth. The CPSC proposed its own consumer-product lead ban in 2017 and then did not finalize it, so today the binding prohibition is the industry standard, not a CPSC rule.
AFSL certification
The American Fireworks Standards Laboratory tests and certifies product, including imports, against those chemical limits. An AFSL stamp means a lab actually screened it. No stamp means nobody did.
Where the lead still gets through
Roughly 31% of imported fireworks tested by federal inspectors in one recent year were noncompliant, including prohibited chemicals. The gap is uncertified product slipping past the standard, not the standard itself.
What it means for your cart
Buy from a real distributor, look for AFSL certification, and skip the no-name novelty crackers and spinners. That single habit avoids the category where the 40,000 ppm outlier lived.
The part nobody cleans up
The morning after, the lawn is covered in spent casings and gray ash. That ash carries whatever metals were in the fireworks, and it sits exactly where kids crawl, play, and put their hands in their mouths. For trace-level product the amount is small, but the hand-to-mouth path is the one exposure worth actually managing. Rake it up, bag it, and rinse hard surfaces before anyone goes barefoot.
I tested fireworks on the Fourth of July
Two years ago I put my XRF analyzer on the fireworks I had on hand. About 15 ppm lead in some, not all. That reading is the "trace" line in the calculator above. Here is what that looked like.
You can't test a firework. You can test everything else.
Fireworks are one day a year, and for most products the dose is tiny. The lead your kid actually lives with is in dishes, toys, painted decorations, and old paint, every day. Fluoro-Spec finds it in seconds, at home, no lab.
Get the test kit Take the 2-minute lead check