Anyone trying to sneak a knife onto an airplane could be fined $250 and a passenger with an explosive could get as much as $10,000 under new guidelines.

Thousands of airline passengers board planes every year carrying banned items such as cuticle scissors, box cutters and guns.

Tom Blank, assistant administrator for transportation security policy, testified before Congress last week that the Transportation Security Administration (search) has intercepted more than 1,650 firearms, more than 3 million knives and more than 57,000 incendiary devices since shortly after the terrorist hijackings on Sept. 11, 2001.

"Fines may help awaken a sleeping population here," said David Stempler, president of the Air Travelers Association (search).

"We have too many examples of people inadvertently bringing a gun in their carry-on."

When Congress created the Homeland Security Department (search) last year, it raised the maximum fine for trying to carry prohibited items through airport security from $1,100 to $10,000. The TSA, which became part of Homeland Security, issued the guidelines on Wednesday spelling out the range of fines applied to each violation.

Mark Hatfield, TSA spokesman, said the new schedule of fines shows that the agency is serious about keeping dangerous items off planes. "'I forgot I had the gun in the bag' is not an acceptable excuse," he said.

The guidelines list aggravating factors, such as "attitude" and "artful concealment," that can bring a heftier fine.

Though bringing a prohibited item to a checkpoint is illegal, fines won't be levied on everyone who inadvertently tries to bring a pair of cuticle scissors or a cigarette lighter through airport security.

The guidelines call for going easy on children, inexperienced flyers or people who disclose that they are carrying something they shouldn't.

"We're looking for weapons, we're not looking for scissors," Hatfield said.

Airline passengers carrying banned items can be prosecuted either for civil or criminal violations.

If TSA screeners catch someone committing a criminal act, such as carrying a concealed weapon or assaulting a screener, they'll call local law enforcement officials.

Those accused of a civil violation will receive a notice of violation and an option sheet in the mail. They get a 50 percent discount on the fine if they pay within 30 days.

Those who want to appeal the fine have several options, including a hearing before a Coast Guard judge.

Hatfield said the TSA can't say how many people have been fined because the databases for its legal department were moved and aren't accessible right now.