Call On The AVMA To Condemn The Use Of Animal Gas Chambers

Update July 7, 2014: The AVMA’s 2013 Guidelines on Euthanasia of Animals states use of carbon monoxide gas is “not recommended” for “routine euthanasia” of dogs and cats. This statement is buried in a chart on p. 99 of the Guidelines. The AVMA would still find use of a carbon monoxide gas chamber acceptable for dogs and cats as long as it is not used routinely.

Original report:

Despite its own warnings and criticism about animal carbon monoxide gas chambers, the AVMA still finds their use acceptable. The 2007 American Veterinary Medical Association (AVMA) policy report on animal euthanasia states carbon monoxide gas chambers are an acceptable method of killing animals.

But the report does state the "preferred method" for euthanasia is lethal injection by barbiturate sodium pentobarbital: "A primary advantage of barbiturates is speed of action. This effect depends on the dose, concentration, route, and rate of the injection. .. Barbiturates induce euthanasia smoothly, with minimal discomfort to the animal. Barbiturates are less expensive than many other euthanasia agents. The advantages of using barbiturates for euthanasia in small animals far outweigh the disadvantages."

"Intravenous injection of a barbituric acid derivative is the preferred method for euthanasia of dogs, cats, other small animals, and horses. The process of lethal injection is simply more humane. For the animal, it is usually no different than having blood drawn or a shot given by a veterinarian. The animal can be held by an attendant while a veterinarian or technician administers the injection. An attendant can remain with the animal as it loses consciousness which happens very quickly. If the animal is or becomes aggressive, it can be sedated prior to the injection.

"Generally this method causes the animal little or no fear or distress. Shelter workers who use this method are able to comfort and calm the animal. Many spend time talking to and petting the animals first."

The AVMA report on euthanasia emphasizes "[t]he need to minimize animal distress, including fear, anxiety, and apprehension, [in] determining the method of euthanasia. Gentle restraint (preferably in a familiar and safe environment), careful handling, and talking during euthanasia often have a calming effect on animals that are used to being handled. Sedation and/or anesthesia may assist in achieving the best conditions for euthanasia. A route of injection should be chosen that causes the least distress in the animal for which euthanasia must be performed."

The report goes on to note inhalants such as CO gas requires high concentrations in the lungs before they are effective. Until there is sufficient build up of gas in the lungs, the animals experience a "great deal of agitation." Here is how AVMA describes stress reactions of animals: "distress vocalization (this means barking, crying, howling), struggling, attempts to escape, defensive or redirected aggression, salivation, urination, defecation, evacuation of anal sacs, pupillary dilatation, tachycardia, sweating, and reflex skeletal muscle contractions causing shivering, tremors, or other muscular spasms."

AVMA acknowledges "[u]nconscious as well as conscious animals are capable of some of these responses. Fear can cause immobility or playing dead in certain species, particularly rabbits and chickens. This immobility response should not be interpreted as loss of consciousness when the animal is, in fact, conscious. Distress vocalizations, fearful behavior, and release of certain odors or pheromones by a frightened animal may cause anxiety and apprehension in other animals."

There is no question shelter workers have documented the piercing cries, howling, frantic calls, scratching and panic of animals as they are gassed. Just putting them in the chamber is frightening for animals. The chamber is hot, confining and often smells probably like death. They don’t know what is happening and they immediately experience panic and distress. The buildup of gas in an animal’s lungs is slower if there is decreased ventilation, a leaky valve or seal, or more than one animal in the chamber. There may be no way to know how quickly the gas reaches the required concentration of 6% before it can sufficiently build up in an animal’s lungs and result in loss of consciousness. 

The gas may make a hissing noise as it fills the chamber, thus also causing fear and anxiety. AVMA points out animals placed in the chamber together especially if they are of different species become so distressed, they may hurt each other.

AVMA states animals should not be placed in the chamber together. Shelters that still use the gas chamber often put animals together in there, thus increasing their fear, agitation and distress. This is routine at shelters that still use this method. The AVMA report also warns the chamber must be well-lit and have view ports that allow personnel direct observation of animals. This requirement is not followed at most shelters that still use gas chambers.

The AVMA report states, "Reptiles, amphibians, and diving birds and mammals have a great capacity for holding their breath". The report goes on to state in these animals which include dogs and cats, the time to lose consciousness may be "greatly prolonged". A study has shown baby animals take longer to die in gas chambers. AVMA reported, "Dogs, at 1 week old, survived for 14 minutes compared with a 3-minute survival time after a few weeks of age. Guinea pigs survived for 4.5 minutes at 1 day old, compared with 3 minutes at 8 days or older. Rabbits survived for 13 minutes at 6 days old, 4 minutes at 14 days, and 1.5 minutes at 19 days and older."

CO gas is not recommended by AVMA or any other group for animals under 16 weeks of age. The same effects have been reported for old or sick animals as well. Yet these are the animals most likely to end up in a gas chamber. It is not uncommon for these animals to be gassed a second or third time before they finally succumb.

The AVMA report also states, "The CO chamber must be of the highest quality construction. The equipment used to deliver and maintain this high concentration must be in good working order and in compliance with state and federal regulations. Leaky or faulty equipment may lead to slow, distressful death and be hazardous to other animals and to personnel." Remember CO is an odorless, colorless gas. You may not know if it is leaking. In Tennessee a shelter worker died while destroying an animal in a gas chamber. He died of CO poisoning. As a result Tennessee has banned the use of gas chambers. Tenn. Code §44-17-303 Many state have banned the use of CO gas chambers.

The AVMA report warns, "Most of these agents are hazardous to personnel because of the risk or health effects resulting from chronic exposure". The long term effects of exposure of shelter workers to this dangerous gas is just now being studied.

The Humane Society of the United States reports, "Carbon monoxide is a hazardous substance considered especially dangerous because it is odorless, tasteless, colorless, and explosive. Repeated exposure to CO, even at low levels, can result in many serious long-term effects including (but not limited to) cancer, infertility, and heart disease."A JAMA study found heart disease can result from exposure to CO gas. Researchers recommended avoiding CO gas altogether. Attached below is a list of experts that have documented the dangers to humans from even low level exposure to CO gas.  

As for cost, a study conducted by the Western Pennsylvania Humane Society in September 2000 concluded that to euthanize 10,000 animals per year, cost of gassing averages $13,230 (excluding the cost of intravenous injection as a back-up method) while lethal injection averages $12,700. Many other studies have found negligible cost differences between the two methods of euthanasia. A 2009 study of North Carolina shelters by the American Humane Association confirmed use of lethal injection costs less per animal than use of a CO gas chamber.  (Find a copy of the study under Animal Law Coalition Downloads)

The Association of Shelter Veterinarians has issued a statement that "the use of carbon monoxide for individual or mass companion animal euthanasia in shelters is unacceptable due to significant humane, operational and safety concerns…[C]arbon monoxide euthanasia should be banned in shelters." In Sept., 2010, the National Animal Control Association issued its statement rejecting use of carbon monoxide gas chambers.

So why does the AVMA with all of its own warnings and criticisms still endorse the use of animal gas chambers? Because the AVMA still says, for whatever reason and despite the cruelty of these devices, that use of carbon monoxide gas chambers is acceptable, many public shelters still use them. Many public shelters point to the AVMA’s acceptance of carbon monoxide gas chambers as a reason to continue using them. Call on the AVMA to condemn the use of animal gas chambers. Then shelters that still use gas chambers may reconsider their use of these inhumane, medieval devices. At least they won’t be able to say the AVMA accepts the use of carbon monoxide gas chambers as a means to kill animals.

Contact: Dr. Larry Kornegay, President AVMA, 1931 North Meacham Road, Suite 100 Schaumburg, IL 60173 Phone: 800.248.2862 Fax: 847.925.1329 E-mail:

One thought on “Call On The AVMA To Condemn The Use Of Animal Gas Chambers”

  1. The AVMA is primarily a trade body for vets. It has little compunction to support true progress in animal welfare nor even to stand by it’s own policies. Ever seen their policy on declawing of cats? It recommends declawing as a very last ditch attempt to stop serious scratching behaviour, yet does not enforce this policy on the majority of American vets who happily mutilate kittens with this vile procedure. Kittens of four months old, who have not yet even learned how to use their claws.

    Expect nothing of the AVMA. The only thing they care about is the constant flow of dollars via subscription to their own brand of hypocrisy.

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