Canines: are still top dog when it comes to finding explosives.

• Author: Magnuson, Stew
• Position: SECURITYBEAT

* The Department of Homeland Security has spent millions trying to develop and refine technologies that can detect bombs in public areas.

Backscatter radiation, millimeter and terahertz waves are among the costly and exotic sensors that have either been tested, or are in use at airports, stadiums and train stations.

The most practical solution may be one that has been employed for years: bomb-sniffing dogs, said the Government Accountability Office.

Congress has allocated $2.5 million to the watchdog agency to produce a new series of "technology assessments." The first of these reports examined the difficult problem of detecting explosives in passenger rail systems such as inter-city trains and subways. GAO investigators did extensive field research and provided a detailed overview of all the technologies that are in the development, or already in use.

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Explosive detection canines "are considered a mature technology," the unclassified version of the report said. (Why dogs are defined as a "technology" is not explained.)

Science does not completely understand how dogs use their sense of smell to detect the chemical compounds found in bombs, nevertheless, "operators also viewed canines as the most effective method currently available for detecting explosives in the rail environment because of their detection capability as well as the deterrent effect that they provide," the report stated.

Dogs aren't perfect. Unlike a machine, they must take frequent breaks, and they usually only spend about three to four hours per day on the job. They generally complete training at about age two and retire at age nine, giving them about seven years of "operational...