Here’s What Makes Them Go Boom! in the Night Sky

Some fireworks facts:

How they work: The basic ingredient in fireworks is old-fashioned gunpowder. The black powder, as it is known, is what lifts a rocket shell. The loud “boom” comes from flash powder.

Visual effects occur when certain chemicals are burned. Strontium salts, for instance, produce a red light, copper oxide creates blue, barium nitrate gives off green and charcoal or iron radiate orange.

Chemical powders are compressed into small pellets called “stars,” each of which leaves a trail of color upon explosion. A typical shell can have several hundred stars.

The design seen in the sky depends largely on the shape of the shell. Oriental shells are round, limited to one color and one explosion, or break. Italian shells are a cylinder shape, often with several breaks and colors.

Where they come from: The Chinese invented fireworks about 2,000 years ago and continue to dominate the world market.

China produces about 75% of the consumer fireworks used in the United States.

Who regulates them: Several government agencies, among them the Department of Transportation; Bureau of Alcohol, Tobacco and Firearms; Consumer Product Safety Commission, and the Occupational Safety and Health Administration.

Some fireworks like cherry bombs and M-80s are banned by the federal government. Several states prohibit all types of street fireworks, such as firecrackers, Roman candles, skyrockets, revolving wheels, cylindrical fountains and sparklers.