Eco-friendly fire crackers? That's what a team of scientists is working on - a new generation of 'green' pyrotechnics that produce less smoke and use fewer toxic metals.
Fireworks are fun and exciting, but the flashing displays can harm the environment and pose risks to human health.
According to a report in ABC Science, researchers at the Los Alamos National Laboratory in New Mexico have been developing a new type of pyrotechnic, which should be welcome news for people who operate or watch fireworks on a regular basis.
"Everyone at or downwind of a pyrotechnic display is getting subjected to levels of these metals that aren't natural levels," said David E Chavez, a chemist at Los Alamos National Laboratory. "Whether that really is going to cause health effects is up for debate," he added.
Some of the metals that make fireworks colourful may also be poisonous when heated.
In particular, there are perchlorates, which are oxygen-rich molecules that allow the fuel in fireworks to burn. Perchlorates appear in nuclear missiles, flares and rocket fuel for spacecraft.
Animal studies have linked perchlorates, such as potassium perchlorate and ammonium perchlorate, to thyroid problems.
Repeated pyrotechnic displays, especially ones that occur every day at theme parks, can take their toll.
In a 2007 study, researchers found that perchlorate levels spiked more than 1000 times higher than normal in parts of a small Oklahoma lake within 14 hours after a Fourth of July fireworks show.
It took up to 80 days for levels of the chemical to return to where they started, the team reported in the journal Environmental Science and Technology.
"If you have a place where pyrotechnics are shot over and over again for years and years, you will have a build-up of these toxins in the environment," said Chavez.
In the last two or three years, scientists have come up with some "greener" alternatives.
For example, Hiskey's company has developed fireworks that burn nitrogen-based fuels instead of carbon-based versions, making perchlorate unnecessary.
The result is a cleaner burn, and with less smoke to obscure the colour. These fireworks also contain 10 times less barium than the standard kind.
For now, eco-friendly fireworks are only being used by companies that put on regular displays, especially indoors, where smoke is particularly unacceptable.