If the diver forgets to insert the canister or uses an already exhausted canister or has a defective absorbent, he may suffer from carbon dioxide poisoning. The symptoms may begin with increased respiratory activity. If the CO2 partial pressure increases, anxiety and feelings of panic, sweating, headaches and fatigue normally occur. Mental effects may occur and this manifests itself in the form of confusion and the inability to think clearly.

In the same way, CO2 poisoning can occur in improperly mounted full face masks, see “Mask assembly” or in the absence of a non-return valve in the breathing hoses see “Preparation” Section “Mask and Mouthpiece.

Action:Action: By-pass continuously and abort the dive and return to the surface.