Michael Rios, owner of Liberty Fireworks and Pyrotechnics in San Antonio, Texas, said the fireworks technology is excellent and the effects continue to get better but there is always room to improve quality control.

"I understand it's fireworks; man's making it, and anytime you get man's hands involved, you know there's mistakes and errors unfortunately with fireworks, and it's not a good thing when you have those kinds of mistakes and then something blows," he said.

Rios said he is still waiting for enough supply so that all four stands of his business can open. Only two are selling fireworks now.

The shortage of fireworks supply is a result of "a chain reaction", as storage inventory of the US was depleted because of record sales last year, the initial lockdown in China early last year following the pandemic, and the backup in the US ports, he said.

"Right now we have a container in Long Beach that's been sitting there for two months because of the backup at the port," Rios said in a telephone interview.

"Now you know China, they did their job in getting us the fireworks, however, we're not receiving it (the shipment) because of some other problem that's on the US side," he said.

Rios said that the shipping costs have more than doubled, but his company is trying to "absorb that cost".

"If this is just a seasonal thing, and we're going to go back to normal freight prices next year, then we're willing to absorb that cost during this season, this year," he said.

US imports of fireworks increased 65 percent from $99.92 million to $164.83 million through the first four months of 2021 when compared with the same period the previous year, according to WorldCity analysis of the latest US Census Bureau data.