Before there were full-body scanners, there were puffers. The Transportation Security Administration spent about $30 million on devices that puffed air on travelers to “sniff” them out for explosives residue. Those machines ended up in warehouses, removed from airports, abandoned as impractical.

The massive push to fix airport security in the United States after the attacks of Sept. 11, 2001, led to a gold rush in technology contracts for an industry that mushroomed almost overnight. Since it was founded in 2001, the TSA has spent roughly $14 billion in more than 20,900 transactions with dozens of contractors.

In addition to beefing up the fleets of X-ray machines and traditional security systems at airports nationwide, about $8 billion also paid for ambitious new technologies. The agency has spent about $800 million on devices to screen bags and passenger items, including shoes, bottled liquids, casts and prostheses. For next year, it wants more than $1.3 billion for airport screening technologies.

But lawmakers, auditors and national security experts question whether the government is too quick to embrace technology as a solution for basic security problems and whether the TSA has been too eager to write checks for unproven products.

Time for a collective ‘Duh!”