Ronald Reagan Washington National Airport has become the first US airport to test boarding passes for residue from explosives.
Passengers that are selected for secondary screening will now have their boarding passes checked along with the standard checks already carried out. Security agents will use a box with a piece of fabric that picks up microscopic samples to test the passes.
A spokesperson for the Transportation Security Administration said that there is no extra delay for the passenger as long as the test comes back negative. The scanners were recently tested at train stations in Connecticut, reports The Associated Press.