The dogs identify scent which escapes from air pockets within the rubble. In some cases the dogs are capable of indicating whether or not the subject is alive or deceased. The dogs are usually trained to stay at the point of detection and signal their partner. The most commonly used signal is the bark alert. In many cases the dog never makes contact with the subject who may be buried under tons of rubble.
Specialized equipment is required to conduct the rescue.
These teams must be aware of hazardous materials and unsafe conditions in the area of search.