In pursuit of a better bang, two unlikely industries are working to develop greener, cleaner-burning pyrotechnics. Hollywood wants less smoke — and the military doesn't want to contaminate its training sites.
But the new formulations are pricy, and America’s commercial fireworks industry — which made $1.1 billion in revenue last year — is still a long way from changing their decades-old recipes. When the industry’s ready, or when environmental regulations become more stringent, fireworks manufacturers will at least know where to start, says Jesse Sabatini, a scientist with the US Army Research Laboratory who has worked extensively on pyrotechnics. “You’ve got formulations now that are out there, that the companies can take.”
The main ingredient in fireworks hasn’t changed for the last 1,000 years: black powder. Fireworks also contain a fuel (often a powdered metal), an oxidizer that helps that fuel burn, and metals and minerals that emit different colors of light when they’re heated. Copper compounds, for example, throw off blue light, strontium produces red fireworks, sodium makes yellow, and barium glows green.
All of these ingredients are spun or pressed together with a binding ingredient — creating pellets that are also known as stars. These are tightly packed around a black powder core into a papier-mâché or cardboard shell, on top of another compartment that’s filled with black powder only.
To launch the firework, you put it into a long tube called a mortar, and light the long fuse that leads to that bottom compartment. The first black powder explosion launches the firework into the air, and ignites a second, internal fuse. When the flame reaches the shell’s black powder core, another explosion propels the burning stars outward in a burst of color.
Black powder makes a mess when it burns. That can affect air quality, although it’s not completely clear how firework displays stack up against, say, vehicle emissions or wildfires. One recent study found a massive, 370-percent spike in airborne soot in the vicinity of a July 4th pyrotechnics show — and another found a 1,000-fold increase.
Despite the uncertainty about just how bad the emissions are, it’s not a good idea to inhale firework smoke. “Fireworks, cigarettes, woodfires, campfires — there’s no smoke that’s good for the human breathing system,” says John Conkling, professor emeritus of chemistry at Washington College and a former executive director of the American Pyrotechnics Association industry group.
The entertainment industry is pushing to reduce the smoke in pyrotechnics used for film or during live performances. Black powder isn’t just bad for the lungs — it also stinks. That can turn any pyrotechnic event in a closed space — like concerts or sporting events — into an unpleasant experience. Mythbusters’ Kari Byron, who’s a black powder connoisseur, told The Verge in an October 2016 interview that the stuff, in fact, smells like a fart.
Plus, smoke is unattractive. “If the the air in the stadium is just filled with smoke, it’ll just look like hell on TV,” says Darren Naud, a former explosives chemist at Los Alamos National Laboratory. Naud spun off a company with another Los Alamos scientist called DMD Systems that engineers lower-smoke fireworks licensed by Ultratec Special Effects. He also patented a new kind of pyrotechnic device that combusts smaller amounts of black powder, or a smokeless propellant, more efficiently to launch fireworks into the sky.
“You could say that our fireworks are more environmentally friendly, but it’s not our first reason to do that ... we’re trying to find a niche market in an industry that requires it,” Naud says. “Am I doing that for Mother Nature? No, I’m trying to make a buck.”
Conkling says Naud is working in the right area for that — because cleaner, pricier ingredients matter for the entertainment industry. “For the special effects industry, that’s a higher ticket item — so you’re able to recoup the investment in the chemicals to get a clean burning material,” he says. Independence Day fireworks displays, by contrast, are more about cheap, awe-inspiring quantity than quality.
Another ingredient in fireworks, called perchlorate, helps the fuel combust and makes the colors shine more brightly. But it’s also thought to be toxic, which is why the Environmental Protection Agency regulates how much of the stuff can seep into drinking water.
As with air pollution, it’s not completely clear the extent to which fireworks displays contaminate water systems with perchlorate. But a 2007 study conducted by EPA scientists found that perchlorate levels in Oklahoma surface waters increased by between 24 to over 1,000 times baseline levels after an Independence Day display — and it took from 20 to 80 days to go back down.
Scientists with the US Army’s Armament Research, Development, and Engineering Center (ARDEC) are trying find a cheap, effective replacement for perchlorate. For the military, which uses pyrotechnics to mimic actual battlefield conditions in training simulations, perchlorate contamination of groundwater can shut down training operations. “When soldiers get deployed to real combat theaters, they are less prepared,” says Jared Moretti, a scientist with ARDEC who specializes in pyrotechnics.
That’s why he and his colleagues — including Jesse Sabatini — are working hard to develop compounds to replace perchlorates; some of them are now being used in red, green, and yellow signal flares. There’s also a push to find new coloring agents that still shine brightly without perchlorate’s added boost. These advances could eventually trickle down into commercial fireworks, Conkling says — especially if the military winds up needing a lot of perchlorate-free pyrotechnic material made.
“The industry wants to sell as much of it as they can, so they start looking at other customers. And it could very well evolve to the fireworks industry using their same materials to produce their colors in a greener fashion,” he says. “Many of the advances over the last hundred years have been things coming out from military research, to get brighter colors in the sky, to get safer colors in manufacturing.”
Still, the best perchlorate replacements are expensive to make — which is why these advances, like the entertainment industry’s smokeless fireworks, are still limited to niche markets. But they may not stay that way forever. Fireworks used to incorporate mercury, arsenic, and lead compounds for effects about 75 years ago, Conkling says. They’re gone now.
So while we might not see new recipes at this year’s July Fourth show, these new formulations may be the future of fireworks. As the military and entertainment industries begin using new compounds, and as we learn more about the environmental and health hazards of fireworks, other markets are likely to follow suit — including the one stocking your local firework display.