If you don’t see them, you hear them. On any July Fourth or New Year’s Eve, it’s common to experience the loud pop of a firework or see it colorfully explode into the sky and hang there briefly.

Pyrotechnic amusements from sparklers to Roman candles have long been a staple of celebrations in the U.S. and beyond, helping to mark national holidays, sporting events and more.

“They have become a global phenomenon, and they have become almost, if you like, the accepted way in which big events are celebrated,” said John Withington, author of the upcoming book, A History of Fireworks from Their Origins to the Present Day.

But the elaborate, computer-controlled displays of contemporary fireworks shows are a long way from the medium’s simpler beginnings in ancient China.

Fireworks began in ancient China before spreading West

The thinking goes that someone living in China around the first century B.C. threw a piece of bamboo on a fire and it exploded with a bang. Bamboo stalks contain air pockets that can expand and blow up in extreme heat. According to Withington, Chinese travelers would carry bamboo on journeys in case they needed to create a loud noise to scare away wild animals.

The next major development came around the ninth century, when gunpowder was invented. Chinese fabricators loaded up bamboo stalks with gunpowder to create perhaps the world’s first manufactured fireworks, and later began using paper tubes as well, History.com said. These were deployed to ward off evil spirits and celebrate births and weddings, according to the Smithsonian.

By the 12th century, fireworks were being lit for entertainment purposes in China’s imperial court, Withington said. Rudimentary fireworks then made their way to Europe around the 14th century, where Italian artists constructed displays resembling theatrical sets called “machines” and set off fireworks inside them.

Fireworks became even more complex thanks to advances in chemistry. The 19th century saw potassium chlorate used to elicit brilliant colors in fireworks, such as red and green, and enhance their brightness, according to Withington.

Over the years, innovations in technology led to some curious suggestions for how fireworks could help solve modern problems. Whalers experimented with rocket-powered harpoons in the late 1800s, and inventor Gerhard Zucker attempted to use pyrotechnic rockets to deliver mail in the 1930s.

A July Fourth tradition

Europeans who made their way to the Americas brought fireworks with them. It’s possible that Capt. John Smith, who was saved by Pocahontas according to legend, set off fireworks in Jamestown in 1608.

On July 3, 1776, the day after the Continental Congress voted for independence from Great Britain, John Adams wrote a letter to his wife, Abigail, imagining future celebrations of the occasion. (Though Congress voted for the Declaration of Independence on the 2nd, it was approved, signed and printed on the 4th.) Adams suggested those observances should include “illuminations,” or fireworks.

“It ought to be solemnized with Pomp and Parade, with Shews, Games, Sports, Guns, Bells, Bonfires and Illuminations from one End of this Continent to the other from this Time forward forever more,” Adams wrote.

The following year, one of the first organized July Fourth celebrations was held in Philadelphia and included a fireworks display. “The evening was closed with the ringing of bells, and at night there was a grand exhibition of fireworks (which began and concluded with thirteen rockets) on the Commons, and the city was beautifully illuminated,” a story in the Pennsylvania Evening Post reported.

To critics, however, fireworks weren’t just a flashy racket — they were also deadly. On Independence Day of 1903, more than 460 people were killed in fireworks accidents, according to Withington.

A Pennsylvania attorney named Charles Pennypacker wrote in a letter to the Philadelphia Inquirer that year that Americans should hold a “quiet and sane observance” of the holiday. They could take a trolley ride, sit under a tree or bake a cake, Pennypacker suggested.

It didn’t go over too well with some. “On July 3, 1904, so the day before Independence Day,” Withington said, “some local young people gathered outside his house and started letting off fireworks and generally creating mayhem.”

Still, the “Safe and Sane” movement gained traction among some city officials who hoped to create calmer July Fourth celebrations. Chicago’s mayor outlawed the discharge of fireworks, while Santa Fe held a beauty pageant in place of the typical festivities, according to Smithsonian Magazine.

Fireworks today

The interest in fireworks never fizzled out, and they remain available across almost the entire U.S. today.

Only Massachusetts bans all forms of consumer fireworks, according to the American Pyrotechnics Association (APA). Every other state and the District of Columbia permit the sale of some or all types of fireworks.

According to the APA, fireworks remain popular. Consumers bought 246.5 million pounds of fireworks last year and 436.4 million pounds the year before that, industry figures show.

Yet they continue to pose a safety risk both to professionals working with commercial-grade fireworks and those lighting the odd firecracker for fun.

According to a recent report by the Consumer Product Safety Commission, 9,700 people were treated in emergency rooms for fireworks injuries last year, eight of whom died. Two-thirds of the injuries occurred in the weeks before and after July 4.

But safety experts say there are some best practices people can follow to have a blast without getting hurt, such as lighting fireworks outside, not holding lit fireworks in your hand and not using fireworks when impaired by alcohol or drugs.

According to KCUR, fireworks can also pose a risk to human health by producing particulate matter and other pollutants and harm the environment by releasing carbon dioxide into the atmosphere.