Wet activated carbon has been confirmed as removing oxygen from air. In confined spaces, such as adsorber vessels, this can produce an oxygen-deficient atmosphere which is hazardous to human health, and can cause death unless the proper safety precautions are initiated.
The phenomenon occurs with all types of activated carbons, the rate of oxygen uptake varying with the degree of the exposure of the wet activated carbon. The rate of oxygen uptake is realtively rapid in a drained bed.
All confined spaces containing activated carbon should be regarded as being hazardous; the appropriate regulatory safety measures, particularly with respect to respiratory protection, must be taken before entering, and working in, such spaces.