More than a third of all fireworks found stashed illegally in airline luggage nationwide last year involved flights to or from Hawai'i, according to the Federal Aviation Administration, which is warning residents to avoid the dangerous practice as the Fourth of July holiday approaches.

Inspectors found fireworks in luggage 89 times in the FAA Western-Pacific region in fiscal 2006, and in 34 cases, the passengers were flying into or out of Honolulu International Airport.

Between October 2006 and June 8, inspectors seized 35 shipments in the region, 13 of them in Hawai'i.

"It's just common sense: You don't take fireworks and try to put them on an airplane," said Tracy K. Elder, resident agent in charge of the Bureau of Alcohol, Tobacco, Firearms and Explosives' Honolulu office. "If you have a bunch of them in a confined space, they can become a fully explosive material and can cause a lot of damage, injury or death."

Now, the Transportation Security Administration here is starting to warn employees to be especially watchful for both legal and illegal fireworks, TSA officials said.

Screeners are reminded to look for everything from sparklers to firecrackers.

"People buy it (fireworks) here and think it's cheaper here so they buy it here and try to bring it over (to the Mainland)," said Sidney A. Hayakawa, the TSA's security director for Honolulu. "That is illegal."

Because of the popularity and easy availability of fireworks in the state, Hawai'i annually accounts for a large number of firework seizures, said Ian Gregor, communications manager for the FAA Western-Pacific Region.

The availability of fireworks in the Islands and the state's location as a hub for flights coming into and out of Asia and the U.S. Mainland make it an ideal spot for consumers seeking to buy and transport fireworks.

"It's not a matter of people acting maliciously. It's people not thinking about the ramifications of what they are doing," Gregor said. "It is incredibly dangerous because even with the slightest amount of friction, two sparklers can rub together and ignite, and that's definitely not a good thing at 35,000 feet."

The FAA western region handled roughly 4.9 million commercial flights last year. The transportation of fireworks on domestic and international flights is prohibited, according to the FAA, and penalties range from a warning letter to a federal prison sentence of up to five years in prison and a $500,000 fine. Civil penalties range up to $50,000 per violation with a minimum fine of $250.

The FAA's Western-Pacific Region Office of Security and Hazardous Materials proposed $943,000 in fines for violations for carrying hazardous materials including fireworks aboard flights in fiscal year 2006.

Reach Peter Boylan at pboylan@honoluluadvertiser.com.