Popular consumer fireworks contain toxic metals, study finds

You might want to think twice before lighting up the sparklers and firecrackers this weekend.

A new scientific study reports that popular consumer fireworks release large quantities of metal particles into the air, including lead, potentially damaging your lungs. It’s yet another hazard of one of America’s most cherished, and notoriously dangerous, summertime traditions.

Every year, Americans buy more than 200 million pounds of fireworks for home use, according to the American Pyrotechnics Association. Though the sparkles, pops, and bangs of backyard fireworks are exhilarating, their danger is well-documented. According to the US Consumer Product Safety Commission, about 10,000 Americans sought emergency room treatment for fireworks-related injuries in 2019.

“These are unfortunate injuries because they’re completely preventable,” said Dr. Gary Smith, the director of the Center for Injury Research and Policy at Nationwide Children’s Hospital.

Though physical injuries associated with fireworks have been widely recognized, other potential dangers of America’s beloved backyard explosions have remained relatively unexamined.

New research, published this week in the Particle and Fibre Toxicology Journal, offers one of the first glimpses into the health risks of pyrotechnic pollution, and how fireworks manufacturers can offer safer products.

Pollution potential

While watching a documentary about The Walt Disney Company, Dr. Terry Gordon, a professor of environmental medicine at New York University Langone Health, and his teenage son wondered if Disney’s famously massive fireworks displays might pose a health risk.

As an air pollution researcher, it’s a topic that Gordon had often considered, but had never tested.

Burning fireworks releases a variety of chemical particles into the air. Some of the particles are extremely small – 10 microns or less – tiny enough to invade human lungs. Breathing in these minuscule particles, referred to as PM10, can irritate or damage lungs, aggravate asthma, and cause serious sickness in people with heart or lung disease.

Adding to the potential health risk, fireworks contain a lot of metals. These metals give fireworks their distinctive colors as they burn, but they could also make the smoke particularly harmful to human lungs.

Fireworks toxicity testing

To figure out what kind of pollution fireworks emitted, and what the health effects might be, Gordon, his son, and their research team at NYU bought ten different kinds of widely-sold consumer fireworks. They lit the pyrotechnics in a specially-constructed metal chamber filled with purified air and collected the released PM10 (the particles small enough to enter human lungs).

Chemical analysis revealed that many of the fireworks released large quantities of metals as they burned, including copper, aluminum, strontium, and barium. Particles from two of the products tested, Black Cuckoo and Saturn Missiles, were found to contain lead at concentrations between 1.6% and 4%. The researchers measured variation in the PM10composition between different batches of the same product, and their sample size was small, so they weren’t able to make conclusions about the prevalence of lead in consumer fireworks based on this study. Still, Gordon found the measurements concerning.

“There isn’t supposed to be any lead,” Gordon said.

To determine the effects of this metallic pollution on lung tissue without exposing people to potentially harmful substances, the team studied two types of human lung cells grown in the lab. They added the PM10 collected from the different fireworks products to the cells, at a low dose mimicking the amount of PM10 in New York City’s air. The scientists then measured cellular oxidative stress, an estimation of lung cell inflammation.

They found that about half of the fireworks tested released PM10 that caused heightened cell stress, compared to control cells that received a harmless saline solution. The particles high in lead were the most damaging to lung cells, causing almost 10 times as much inflammation as the control.

The scientists also tested the effects of the fireworks pollution in mice by introducing PM10 from some of the fireworks into laboratory mice lungs. The fireworks that were the most toxic to human lung cells also caused the most injury and inflammation to the mice’s lungs, confirming the team’s in vitro findings.

Future testing and health risks

Each type of fireworks tested in the study released a unique combination of metals, making it difficult to discern which metals were responsible for the lung inflammation. Determining which specific metals are the most toxic is a critical next step. This information could help manufacturers choose different, safer metals to produce fireworks color effects.

More thorough testing of consumer fireworks is also necessary to ensure that products containing dangerous amounts of lead don’t hit stores.

“We should be testing different fireworks and make safer fireworks,” said Gordon. “They’re not all created equal.”

Since this study wasn’t conducted on human subjects, it can’t tell us about specific health risks of fireworks exposure.

However, the damaging effect of the fireworks pollution on human lung cells suggests that populations who are particularly vulnerable to respiratory issues, such as people with asthma, emphysema, chronic obstructive pulmonary disease, may want to limit their exposure to consumer fireworks.

At a bare minimum, Gordon, a self-confessed fan of pyrotechnics, advises that people avoid breathing in fireworks smoke by always standing upwind.

Or better yet, stick to firecracker popsicles this year.

This story was originally published July 2, 2020 at 12:49 PM.