WASHINGTON - It has been almost 10 years since the September 11, 2001, terror attacks, and US airports still are not as secure as they need to be. More than 14,000 people have found their way into sensitive areas, and about 6,000 travelers have made it past government screeners without proper scrutiny, according to a congressman who is leading an inquiry into the deficiencies.

Since November 2001, more than 25,000 security breaches have occurred at US airports, despite the extra security measures put in place over the past 9 { years, said Republican Rep. Jason Chaffetz, citing government statistics. That is an average of slightly more than five security breaches a year at each of the 457 commercial airports, and "these are just the ones we know about," said Chaffetz, who is overseeing a congressional hearing Wednesday on security shortcomings. "I think it's a stunningly high number."

The Transportation Security Administration said these numbers represent "a tiny fraction of 1 percent" of the more than 5.5 billion people that have been screened across the country since 9/11. "These events were reported, investigated and remedied," agency spokesman Greg Soule said.

The 25,000 figure is misleading because a security breach is broadly defined to include instances when a checked bag was misplaced after it had gone through security screening to a person who was caught in the act of breaching security and immediately apprehended, Soule said.

The congressional interest comes amid the busy midyear travel season and growing criticism of some of the TSA's screening policies, like security pat-downs for children and travelers in their 90s. The TSA has defended its policies, citing terrorists' persistent interest in attacking commercial aviation. For instance, early this month, counterterror officials saw intelligence about some terrorists' renewed interest in surgically implanting bombs in humans to evade airport security like full-body imaging machines. The TSA and FBI are even testing this theory on pigs' carcasses to see how viable the threat is, said a law enforcement official who spoke on condition of anonymity to discuss sensitive security matters.

Since the 2001 attacks, the airport screening work force has been entirely revamped and billions of dollars have been spent on technology that has been deployed across the country. But despite all the enhancements, travelers have made it past security when they should not have. Most recently, a cellphone-sized stun gun was found aboard a plane operated by JetBlue Airways Corp. Officials do not believe the stun gun was intended for use in some type of attack, but the FBI is investigating how and why it was on the airplane. Earlier this month, a Nigerian American was accused of breaching three layers of airport security while getting on a cross-country flight with an expired boarding pass.

Chaffetz also worries that airports have issued more than 900,000 special credentials to workers for access to secure and restricted areas in airports, including 16,000 secure badges to Washington Dulles International Airport in Northern Virginia alone, he said.

The government has long been aware and concerned about the "insider threat" in which someone who wishes to do harm has access to secure areas such as those in airports. Terrorists have used such insiders to access overseas targets and collect sensitive information to aid terror operations, including hotel bombings in Indonesia in 2009 when a florist working in one of the hotels helped facilitate the attacks.