Okla. Stat. tit. 4, § 4-504: Carbon monoxide chambers - Equipment required

Carbon monoxide chambers shall be equipped with:

1. Internal lighting and a viewport providing direct visual

observation of any animal within the chamber;

2. Compressed cylinder gas of commercial grade adequate to

achieve a uniform carbon monoxide gas concentration throughout the

chamber that induces unconsciousness within three (3) minutes after

any animal is placed in the chamber;

3. A suitable gauge or gas concentration indicator or recording

device making possible easy and instantaneous visual determination

of the carbon monoxide concentration in the chamber;

4. A means of keeping the animals in the chamber in separate

compartments;

5. An exhaust fan connected by a gas-tight duct to the

outdoors, capable of completely evacuating the gas from the chamber

before it is opened after each use, for protection of personnel.

There shall also be a gas analyzer located in the room that is

capable of warning personnel of hazardous concentrations while the

chamber is being used. Small carbon monoxide chambers without

exhaust fan or warning bell may be placed outdoors, provided they

are placed under a shelter with a roof for protection of equipment

and personnel, but open at the sides for ventilation.