An explosion that destroyed 20 fireworks warehouses in China three months ago will probably dim night skies in the United States this Fourth of July.

Fireworks vendors said that because of the sudden shortage, fireworks such as bottle rockets, ladyfingers and Roman candles, as well as mortars used in professional displays, will be hard to get and more expensive.

Many of the usual pyrotechnic extravaganzas across the country may have to be curtailed or even canceled.

"Everybody in the industry is scared to death that their orders aren't going to get here in time," said Ken Sprague, president of Hamburg Fireworks Display in Lancaster, Ohio, which choreographs fireworks shows throughout the Midwest.

"I haven't slept a full night in months."

The blast on Feb. 14 in the Chinese port city of Sanshui shook homes miles away, and fireworks soared and burst in midair for more than 24 hours, according to local news reports. It is unclear whether anyone was harmed.

The accident led to a ban on fireworks shipments at all Chinese ports except two that are far from fireworks production areas, resulting in further delays.

"We're not getting much information about what caused the fire," said Julie L. Heckman, executive director of the American Pyrotechnics Association, which represents the $900 million fireworks industry in the U.S.

The result, she says, is that exports of consumer fireworks from China are down 35 percent this year and professional display fireworks are down 40 percent.

Many shipments have not left factories in Liu Yang, a city in Hunan province where more than 95 percent of fireworks sold in the United States are made.

"It's been a perfect storm," said Harry Chang, president of marketing for Black Cat fireworks, a division of Shiu Fung Fireworks in Hong Kong. Wholesale prices for fireworks are up 30 percent this year, he said, because of the limited supply, as well as higher shipping costs and increased prices for chemicals, paper and labor.

"People will need to be prepared to dig deeper," said William A. Weimer, vice president of the B.J. Alan Co. in Youngstown, Ohio, one of the largest importers of fireworks in the United States.

Because Weimer ordered earlier than usual this year, he already has 85 percent of his shipments from China.

"A lot of other guys are in big trouble," he said, adding that he has received frantic calls from competitors hoping to buy some of his inventory. "It looks like some communities aren't going to have shows this year."

No pops for holidays?

If shipments do not leave China in the next two weeks, millions of pounds of fireworks may not make it to the United States in time for the Fourth of July.

Labor Day, Christmas and New Year's fireworks displays are even more doubtful, because the Chinese government announced April 14 that it would ban the transport of 256 types of hazardous or potential explosive materials on dates through October to coincide with planned Olympic events.

This includes not only fireworks and the chemicals used to make them but substances used in some pharmaceuticals, coolants, solvents and cosmetics.

Bob Richard, deputy associate administrator for hazardous material safety with the Department of Transportation, said he was working to get the Chinese government to rethink its directive, considering the "serious impact" it would have on the fireworks industry and the "entire supply chain."

"The last thing we want," Richard said, "is a shortage to force the market underground."