The Health Department says it's only used on dogs deemed vicious. It says those dogs make it dangerous for workers to get near them with a lethal injection.
McLean County Health Department Director Walter Howe says the chamber is only used on dogs deemed vicious.
"The safety of employees is of utmost concern, when tending to menacing dogs. We would not want to put our staff in that condition unless we had to. They become almost impossible to handle by an individual."
But others say a dog's history doesn't warrant this kind of procedure. Animal advocate Marion Willetts says the animal must be in the chamber for 20 minutes.
"That is how long it takes to induce death. There are instances where animals had to be gassed twice or three times before they finally died. This is something that does not need to happen."
The health department says it would consider eliminating the gas chamber but it could come at a cost. It says added staff and extra drugs would be needed to make the switch.