Hawley estimated that about 20 percent of carry-on bags are physically inspected after being screened via various technologies, but did not say how much that would increase. In an effort to better protect travelers against liquid explosives in response to the plot to bomb U.S.-bound airliners foiled in August, TSA also is trying out new detection machines.
"We have ordered additional prototype machines," Hawley said. He did not comment when asked how many machines were ordered. A TSA spokesman did not respond to requests for information.
Lawmakers have been critical of TSA's explosives detection machines in general and of contracts to companies providing them; Rep. John Mica, R-Fla., called failure rates "potentially disastrous" and claimed the agency is overpaying contractors.
The announcements on Monday regarding inspections and explosives detection came as officials made another proclamation that will come as a relief to travelers: TSA is easing its ban on liquids, aerosols and gels that can be taken aboard aircraft.
Beginning Tuesday, small, travel-size toiletries with three ounces or less of liquids or gels will be permitted in carry-on luggage, provided they can collectively fit into a plastic bag that is roughly the size of a sandwich bag.
In addition, travelers will be allowed to carry beverages on board if they purchase the drinks after passing through the security checkpoint.
"A total ban is no longer needed [on liquids in carry-on luggage], from a security point of view," Hawley said.
The decision ease the restriction came after explosives tests were run in collaboration with the FBI that showed three-ounce containers would pose no threat to planes and passengers. U.S. government officials conferred with intelligence officers from the United Kingdom as well, before concluding that the ban on liquids and gels could be relaxed. The Canadian government will make a similar switch to its air travel policy, DHS Deputy Secretary Michael Jackson said.
Jackson said travelers should not consider the threat level against aircraft to be diminished, however. "We are not talking about changing our threat level," which is orange, the second-highest of five color-coded categories, he said.