Washington (CNN) -- Longer lines at airport checkpoints would result from eliminating a nearly $1 billion Behavior Detection Officers program, the head of the Transportation Security Administration told a congressional committee Thursday.
The Screening of Passengers by Observation Techniques, or SPOT, program trains officers to identify terrorists before they act by looking for passengers showing signs of stress, fear or deception.
The Government Accountability Office investigated and said in a report this week there was no proof it works, and urged Congress to cut funding for it.
Transportation Security Administration administrator John Pistole defended the program as an essential component of a web of protections.
"If we remove one whole layer of security, that being BDOs, who again are the least invasive and are looking for intent rather than items then that gives us an exposure to potential terrorists that we don't currently have," he said.
Behavior Detection Officers also operate a program called Managed Inclusion which evaluates passengers at the checkpoints and allows some to enter the faster Pre-Check lanes.
"Defunding the program is not the answer," Pistole said. "There would be fewer passengers going through expedited screening, there would be increased pat downs, there would be longer lines, and more frustration by the traveling public."
The union representing TSA officers defended the program.
"An imperfect deterrent to terrorist attacks is better than no deterrent at all, " said American Federation of Government Employees National President David Cox, speaking in a conference call after the hearing. "Is it a perfect program? No, but until we have a better program, we shouldn't just trash and burn this program."
But some members of the U.S. House of Representatives Homeland Security Committee saw the Behavior Detection Officer program as troubling.
"We cannot continue to fund programs with the hope that they will work. We must prioritize limited funds for programs that have been proven effective," said Bennie Thompson, D-Mississippi, the committee's ranking Democratic member.
House Committee Chairman Michael McCaul, R-Texas, praised the concept of detecting behavior, but worried the current operation may be flawed.
"I am concerned that TSA will continue to spin its wheels with this program instead of developing a more effective and efficient approach," he said.
The hearing also focused on the recent shooting at Los Angeles International Airport where 23-year-old Paul Ciancia allegedly shot and killed TSA officer Gerardo Hernandez, and injured two others at a security checkpoint.
Los Angeles World Airport Police were on site within four minutes and subsequently shot Ciancia.
Administrator Pistole said agreements with local law enforcement on response times are being reviewed in wake of the incident.
"Under the aviation security program that TSA has with the (330 largest) airports, there is an agreed upon response time which is typically five minutes," he said. "Clearly five minutes was too long in this case and that is something we are looking at as part of our review. "
LAX shooting reignites debate over TSA workers' role in security