What is a stated cause of carbon monoxide poisoning in divers?

• A. Carbon Monoxide in the system due to mechanical issues in the compressor
• B. Increased oxygen delivery to tissues
• C. Overhydration of the diver
• D. Exposure to seawater by immersion

Answer: (A)

Carbon monoxide poisoning in divers comes from the breathing gas being contaminated with carbon monoxide, most often due to problems with the air supply equipment. When a compressor or the gas delivery system has mechanical issues, carbon monoxide can slip into the breathing air. CO binds to hemoglobin with a much higher affinity than oxygen, forming carboxyhemoglobin, which prevents oxygen from being carried to tissues. That impaired oxygen delivery, not any change in hydration or seawater exposure, is what causes the symptoms divers experience.

So the statement about carbon monoxide entering the system because of mechanical issues in the compressor is the best fit. The other options don’t describe a mechanism that would cause CO poisoning: simply having more oxygen delivered to tissues would not cause poisoning; overhydration isn’t related to CO exposure; immersion in seawater itself doesn’t introduce CO.