Shelter officials immediately removed it from the oven and administered another injection to euthanize the animal, Animal Services Manager Bob Geier said.

Geier said the dog had received a euthanasia shot, and, in keeping with standard procedure, staff members checked its reflexes before putting it into the crematorium last week.

The dog had appeared dead.

Animals react differently to the euthanasia and sedation drugs, Geier said.

''I feel we did our due diligence,'' he said.

Every shelter employee who euthanizes animals goes through an extensive training program, he said.

Geier said the animal was euthanized because it had a history of biting people and had failed a temperament test.

John Paul Fox, chief investigator for the Humane Society of Utah, said some animals, especially ones that are very old or young, or have survived major injuries, can survive standard doses.

He said it is not common for animals to survive euthanasia, but it does happen from time to time.

Some animals can stop showing signs of life for some time before coming back from deep unconsciousness.

Fox said animal handlers need to check a variety of life signs to be sure the animal is dead, which is why there is so much training involved in the practice.

Fox said employees at the shelter plan to invite a doctor to conduct more training on euthanasia procedures.