The term ?man?s best friend? is certainly true when it comes to the canine?s ability to detect over 1,900 explosives. Homeland Security Secretary Michael Chertoff visited a Virginia training facility for police dogs, calling them a “state-of-the-art anti-terrorist tool.” Deep in the bowels of Washington DC?s Metro transit system, canine officers from four local agencies conducted a ?sweep,? investigating trashcans and orange cones, ticket machines, and trains. These specially-trained animals are more effective than any means of pro-active security — including random passenger searches and high tech cameras. Their ability to smell out these dangerous chemicals has become a necessity since the July attacks against London?s transit infrastructure .

However, experts believe that the use of special canines is still spotty. Some 14 million people use our nation’s transit systems each day, and there are too few dogs and officers trained in this specialty to make a dent. In addition, canine sniffing is based on the quantity and proximity of the explosive product as well as the strength of odor and direction of the wind. So, even with their keen skills to locate explosive products, the number of dogs available cannot be expected to make a significant difference in protecting transit infrastructures across the country. Moreover, canines cannot be expected to be fail-proof. Animal temperaments come into play. They can only be worked for 30-minute periods before they need a break before their keen olfactory senses become dulled.