Is it humane to use dogs for detection?

There are some very specific rules and regulations for any dog that is trained to do search and rescue or drug detection. From my understanding the dog doesn't usually get close enough to drugs to really even be effected by them, they just alert near where the drugs are stashed and will sit down or bark but not go digging for the drugs. I've seen a drug sniffing dog given the option of drugs to sniff or a ball to play with and the ball won hands down. For rescue dogs there are many dangers like chemicals that the dog might be exposed to, so rescue dogs have to have a trainer who knows what to look for and to keep the dog as safe as possible. It is hard to know if it really is humane, but the dogs have been trained for their work and usually are very happy once they find their target. I'm sure most people aren't as satisfied with their work as those rescue dogs are.