Now that the 2013 edition of the AVMA Guidelines for the Euthanasia of Animals has been issued, the debate over the use of gas chambers for euthanasia of unwanted dogs and cats in animal shelters is likely to take center stage once again.
In previous editions of the guidelines, the use of carbon monoxide (CO) or carbon dioxide (CO2) gas was considered ‘acceptable’ for euthanasia of dogs and cats. In the 2013 Guidelines, the classification for use of these gases has been changed to ‘acceptable with conditions’. Techniques that are ‘acceptable with conditions’ may have greater potential for operator error or safety hazard, are not well documented in the scientific literature, or may require a secondary method to ensure death. The use of these techniques requires that specific conditions be met to ensure that death is achieved in a humane way. When ALL of the conditions are met, ‘acceptable with conditions’ methods are equivalent to ‘acceptable’ methods. And, if all conditions are not met, they are not considered ‘acceptable.’
This means that the use of CO or CO2 for euthanasia of dogs and cats is ONLY considered acceptable when ALL of the following criteria are met. For more details, consult the full Guidelines.
- Personnel must be instructed thoroughly in the gas’s use and must understand its hazards and limitations;
- The gas source and chamber must be located in a well-ventilated environment, preferably out-of-doors;
- The gas must be supplied in a precisely regulated and purified form without contaminants or adulterants, typically from a commercially supplied cylinder or tank;
- The gas flow rate must allow operators to achieve known and appropriate gas concentrations within the recommended time;
- The chamber must be of the highest-quality construction and should allow for separation of individual animals. If animals need to be combined, they should be of the same species, and, if needed, restrained or separated so that they will not hurt themselves or others. Chambers should not be overloaded and need to be kept clean to minimize odors that might distress animals that are subsequently euthanized;
- The chamber must be well lighted and must allow personnel to directly observe the animals;
- If the chamber is inside a room, monitors must be placed in the room to warn personnel of hazardous concentrations of gas; and
- It is essential that the gas and the chamber be used in compliance with state and federal occupational health and safety regulations.
In the 2013 Guidelines, euthanasia by intravenous injection of an approved euthanasia agent remains the preferred method for euthanasia of dogs, cats, and other small companion animals. Gas chambers are not recommended for routine euthanasia of cats and dogs in shelters and animal control operations. The guidelines state that “alternate methods with fewer conditions and disadvantages are recommended for companion animals where feasible.”
We understand that some people believe these chambers should be banned for use for dogs and cats. Unfortunately, there are still shelters and animal control operations that do not have access to controlled substances and/or the personnel authorized by the Drug Enforcement Administration (DEA) to administer them. This limits these facilities’ options for euthanizing animals. If your local shelter or animal control operation uses a gas chamber to euthanize dogs and cats and you strongly believe its use should be discontinued, we recommend you work with the facility to develop a realistic plan to phase out the use of the chamber. Reducing the population of unwanted animals reduces the number of animals that may need to be euthanized, so efforts to reduce pet relinquishments and increase adoptions are the best long-term solutions.