Over at sciencedaily.com is firecracker of an article.

From the rockets' red glare to bombs bursting in air, researchers are developing more environmentally friendly fireworks and flares to light up the night sky while minimizing potential health risks, according to an article scheduled for the June 30 issue of Chemical & Engineering News. Some eco-friendly fireworks may soon appear at a Fourth of July display or rock concert near you.

In the C&EN cover story, Associate Editor Bethany Halford points out that fireworks, flares and other so-called pyrotechnics commonly include potassium perchlorate to speed up the fuel-burning process. But some studies have linked perchlorate, which can accumulate in the soil, air and water, to thyroid damage. Pyrotechnics also contain color-producing heavy metals, such as barium and copper, which have also been linked to toxic effects.

[...]

Some of these fireworks are already being used at circuses, rock concerts, and other events.

So, get out there and celebrate like crazy, my American friends. Many of us on this side of the pond will raise a glass to you at some point during the day. Two hundred and thirty-two years ago that was unthinkable, but now many of us are proud and honoured to call you our friends.