On Independence Day, celebrations across the United States depend on China. 
 
 The sparklers, bottle rockets and Roman candles you’ll be using this Fourth of July almost certainly came from there. So did the professional-grade pyrotechnics that’ll be launched above the Washington Monument on Friday night. 
 
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 It’s a quirky exception to “Buy American” sentiments that are otherwise going strong and picking up steam in Washington and corporate America, especially around patriotic events. 
 
 (PHOTOS: 15 historic Independence Day events) 
 
 After all, Congress passed a law this year requiring flags flown by the U.S. military to be made in America. Ralph Lauren, meanwhile, scrambled ahead of this year’s Winter Olympics in Sochi to make sure that Team USA’s uniforms were all manufactured in the United States. And first lady Michelle Obama used U.S.-grown iris and quince blossoms at a state dinner for France in May, departing from the White House’s typical practice of using imported flowers. 
 
 But fireworks? No change there. Over the past 35 years, China has grabbed nearly the entire U.S. market — with 98 to 99 percent of what consumers will buy this year being made there, as well as 75 percent of the “display” fireworks, which are used in big, public shows. 
 
 Fireworks are a big business, with $675 million in sales just to consumers who will shoot off their own products expected this year, said Julie Heckman, the American Pyrotechnics Association’s executive director. Chinese imports are necessary, she said, because it’s “very, very labor-intensive to make fireworks. Basically everything is still made by hand.” 
 
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 Environmental and safety regulations in the United States, she said, would force domestically made versions of the same fireworks to retail for 10 times as much as the Chinese imports, she estimated. 
 
 The industry’s shift to Chinese production came about shortly after the United States and China reestablished trade ties in 1979. By the early 1990s, the country was generating more than $60 million in annual sales from pyrotechnic exports to the United States. By 2013, the United States was importing $213 million worth of fireworks — virtually all from China. 
 
 The trend won’t be changing anytime soon, fireworks industry experts said. 
 
 Thailand accounts for some of the small fraction of fireworks used in the United States that weren’t made in China, as do U.S. companies and European manufacturers of larger pyrotechnics used in professional shows, according to John Rogers, executive director of the American Fireworks Standards Laboratory, which conducts safety inspections before fireworks are shipped from China to U.S. buyers. 
 
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 In the 1980s and early 1990s, Rogers said, the Chinese imports fell short of U.S. Consumer Product Safety Commission and Department of Transportation safety standards, largely because manufacturers there lacked quality control procedures and “because there was nobody really checking — nobody was monitoring to make sure they were meeting U.S. manufacturing and safety standards.” 
 
 The good news, Rogers said, is that the quality of China’s fireworks is improving. Starting in 1994, the American Fireworks Standards Laboratory, which counts nearly all major U.S. fireworks importers among its clients, started inspecting tens of thousands of shipments each year before they left China. 
 
 The group also imposed its own standards, such as a rule intended to prevent sparklers’ particles from falling onto children’s clothing and starting fires, Rogers said. 
 
 U.S. fireworks importers typically make several trips to China each year, and manufacturers there have retooled their production to meet U.S. standards, Heckman said. 
 
 She acknowledged that China has earned a “bad rep” over imported tires, agricultural products and more, but said: “In the fireworks industry, it’s very different. The industry has worked hand in hand with China, and many of these relationships go back four, five, six generations, much like the generational family businesses in the United States.” ||||| When you look up at those Fourth of July fireworks, say hooray for the red and white — but give a special cheer for the blue. 
 
 "People have been trying to make a good blue for 500 years, and they haven't quite perfected it," John Conkling, a chemistry professor emeritus from Washington College in Maryland, told NBC News. "Purples we're getting good at. Pinks are decent. But blues are a big challenge." 
 
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 Conkling should know: He literally wrote the book on the chemistry of pyrotechnics, and is featured in a new video on the subject from the American Chemical Society. The way Conkling sees it, scientists still have a lot to learn about the science of fireworks, thousands of years after the Chinese invented them. 
 
 Even today, the Chinese are setting the pace in the global fireworks industry. "More and more of the product these days is made in China, so if there was a lot of research and development, it'd be going on in China," Conkling said. 
 
 But there's still something to be said for American know-how: Every year, specialty fireworks manufacturers in the United States come up with fresh twists — with a big assist from the U.S. Army. 
 
 "Pyrotechnics is one leg of a four-legged stool in the energetics field," said James Wejsa, chief of the pyrotechnics technology and prototyping division at the Army's Picatinny Arsenal in New Jersey. "We also have the propellants, the explosives and the warheads. The military is the one who really drives the technology in this area, and usually what you have are spin-offs in the commercial sector." 
 
 'Greener' fireworks from the Army 
 
 For example, Picatinny has been working on more environmentally friendly ingredients for the pyrotechnics that produce colored signals as a means of non-verbal communication on the battlefield. 
 
 "Getting new dyes and new ways to burn the formulations with different fuels is a challenge," Wejsa said. "The last thing you want is to have a soldier saying, 'Is that red smoke or violet smoke?' It could be the difference between 'shoot me' and 'don't shoot me,' you know what I'm saying?" 
 
 It turns out that the new formulations just might improve your neighborhood Fourth of July fireworks show as well. The Army has been working on a spin-off with Fireworks by Grucci, one of the biggest companies in the business. 
 
 "These formulations burn brighter and they burn clearer because there's less smoke," Wejsa said. "It's almost like going to high definition, because you don't have the smoke obscuring the color." 
 
 Wejsa and his team are making fireworks "greener" in more ways than one: They've developed a technique to produce a bright green flare using boron carbide rather than toxic barium compounds, a smoke grenade that emits less hazardous smoke, timing fuses and other pyrotechnics that don't leave potentially toxic perchlorate residues, and explosive primers that don't use lead. 
 
 "Our goal is to spin this off to commercial applications," Wejsa said. 
 
 The future of fireworks 
 
 So what's next? "The newest thing has been to try to perfect colors that normally people don't see in fireworks," Conkling said. Like a bright true blue, or really good orange. 
 
 "All the blues we see now have a copper compound that's at the heart of the reaction," Conkling explained. "The battle you're fighting here is that colored fireworks are brightest at high temperatures, but the copper emitter is not stable at high temperatures. So you have to play a game of 'The Price Is Right.'" 
 
 To produce an especially orange blast, chemists try blending run-of-the-mill sodium yellow-orange with red, but the job requires a lot of experimentation. The resulting recipes are closely held. "The old U.S. fireworks makers used to say there were some formulas they wouldn't even tell their grandmothers," Conkling said. 
 
 NBC News file 
 
 Another frontier for fireworks has to do with creating shapes in the sky. "It's common to see the heart pattern, the five-pointed star, multiple rings," Conkling said. "The logical extension of that would be letters, and being able to orient the letter up in the sky so you could spell out 'NBC' or something like that." 
 
 Fireworks by Grucci is already experimenting with a couple of technologies called PixelBurst and SkyEtching to create complicated patterns, letters and numbers. The technique was used for the countdown in Grucci's Dubai New Year's Eve display — and although the numbers are a bit hard to read, Conking is confident pyrotechnicians will work out the bugs. "It isn't like putting a man on the moon to do that," he said. 
 
 Will your fireworks be rained out? A guide for East Coasters 
 
 Besides the military, theme parks are the main drivers for innovation in fireworks displays — and sometimes it's not strictly about the fireworks. For example, the "Frozen" spectacular that's due to make its debut at Disney's Hollywood Studios in Florida this week will supplement the evening sky show with a video projection of social-media "selfies" submitted by parkgoers during the day. 
 
 When Conkling attends the Fourth of July festivities with his four grandchildren in Chestertown, Maryland, he'll be watching for the blues in the red-white-and-blue. But like most fans of the Fourth, he recognizes that a fireworks display isn't just a chemistry experiment. The winning formula also requires a healthy dose of flag-waving — and a flair for drama. 
 
 "One thing I like is a well-paced show," he told NBC News. "There should be no dead spots in it, and there should be some variety in it. It's not just the same thing over and over again." 
 
 IN-DEPTH 
 
 First published July 4 2014, 8:45 AM
– Ah, Independence Day fireworks: What could be more ... Chinese? Yep, despite strong "Buy American" sentiments in other fields (the US military must fly made-in-America flags, for example), China still manufactures at least 98% of consumer fireworks and 75% of "display" fireworks (for big shows) sold in America, Politico reports. The US needs them because fireworks production is "very, very labor-intensive," says a pyrotechnics expert. "Basically everything is still made by hand." What's more, she says, US safety and environmental regulations would make home-made fireworks about 10 times costlier for consumers. China began grabbing the US fireworks market after Washington reestablished trade ties in 1979; by last year, the US was importing $213 million in fireworks, nearly all from China. Federal authorities grew alarmed in the 1980s and early 1990s over the lack of safety standards in Chinese fireworks, but now the American Fireworks Standards Laboratory has imposed stricter rules and says it inspects fireworks shipments before they leave China. Despite all this Chinese know-how, the US Army is making "greener" pyrotechnics that produce less hazardous smoke and leave behind fewer possibly toxic residues, NBC News reports. "Our goal is to spin this off to commercial applications," says an Army pyrotechnics chief. (Read about the connection between fireworks and war.)