text: “Dogs are relatively expensive, a lot of training is required, and there’s a very limited duration that they can work,” said Geoffrey Barrall, a chemist who led a group at General Electric that developed airport screening machines. “When they get tired, you usually have no way of knowing.”
  Homeland security analyst Matthew Farr of the Frost & Sullivan consulting firm said dogs “don’t have enough of a presence to really be a deterrent. There’s a lot of room to expand their use.”
  The TSA uses German shepherds, Belgian Malinois and Vizslas, and trains them at Lackland Air Force Base in San Antonio. Some dogs are bred there, though most are bought from European breeders. The cost of housing a dog for a year and training it and a handler for 10 weeks is $25,000.
  The TSA gives the dogs to airport and transit police, paying $40,000 to $50,000 a year for expenses and part of the handler’s salary. Dogs work 10-12 years.
  The TSA wants to increase spending on dogs from $27 million to $30.5 million next year, using the extra money to supply more rail systems.
  Transit agencies like using dogs but worry about devoting a full-time officer to one, said Greg Hull, security director for the American Public Transportation Association. “There’s a cost involved,” Hull said.
  In airports, dogs sniff cargo, luggage, passengers and planes. In rail stations, they focus on passengers and their bags.