Cincinnati/North Kentucky International Airport is the third major facility to join a U.S. government program to test explosives detection screening at air cargo facilities.

The U.S. Department of Homeland Security launched the $30 million Air Cargo Explosives Detection Pilot Program last summer at San Francisco International Airport and expanded it to Seattle-Tacoma International Airport.

In San Francisco, DHS and the Lawrence Livermore Laboratory are researching ongoing cargo handling processes and how use of existing technology may affect the movement of goods.

That program includes tests in which government screeners tear down pallets, load single boxes on belts that push shipments through explosives detection machines and then re-build the pallets at the other end. Research officials say the process takes about 15 minutes per pallet, but cargo executives who are skeptical of that timing say even that sort of speed would cripple air freight operations of any scale.

In Seattle, DHS is testing devices designed to detect a heartbeat and excess carbon dioxide, warnings of the possible presence of a stowaway or terrorists on an all-cargo flight.

At Cincinnati/Northern Kentucky, the tests will determine the flow of air cargo and how quickly it must be screened.

In a statement, DHS said it is seeking data that illustrates the "economic and operational impacts" to airlines from increased screening levels.