After a firework explodes, its pellets ignite, burn and generate color as they float through the sky. If that initial burst is too powerful, however, the stars shatter and “you really lose the whole color effect,” Dr. Conkling said. The most explosive fireworks, in other words, have only a hint of color.

The real promise behind quiet fireworks, however, is the possibility that they could reduce the harmful effects of traditional fireworks, which include stress on animals and damage to people’s hearing.

Fireworks can cause birds to panic and flee en masse, said Judy Shamoun-Baranes, a geoecologist at the University of Amsterdam who has studied the effects of fireworks on birds. In 2011, 5,000 red-winged blackbirds fell out of the sky in Beebe, Ark., after fireworks celebrations on New Year’s Eve, possibly because the loud noises led them to fly into chimneys, houses and trees.

Loud fireworks also scare larger mammals like deer and coyotes out into roads, where they can get hit by cars, said Lisa Horn, the executive director of West Sound Wildlife Shelter in Washington State.

Ms. Horn’s shelter sees an influx of animals after July 4 each year. July 5 is “always all hands on deck,” she said. Pet shelters also claim to take in the most runaway dogs each year on July 5.

For people, loud fireworks can lead to hearing loss. The World Health Organization lists 120 decibels as the pain threshold for sound, including sharp sounds such as thunderclaps. Fireworks are louder than that.

“They’re typically above 150 decibels, and can even reach up to 170 decibels or more,” said Nathan Williams, an audiologist at Boys Town National Research Hospital in Nebraska.