Carbon Monoxide Poisoning in Recreational Diving

6 min read · 8 July 2026

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Carbon Monoxide Poisoning in Recreational Diving: an Uncommon But Potentially Fatal Problem is a 1998 meeting abstract by Caruso and colleagues, published in Undersea & Hyperbaric Medicine. It addresses carbon monoxide exposure in recreational diving—a subject that matters because this invisible gas can impair oxygen delivery during a dive and become a medical emergency.

Why is carbon monoxide a concern underwater?

Carbon monoxide is a colourless, odourless gas produced by incomplete combustion. A diver may breathe it when breathing gas is contaminated, including through problems involving a source of compressed air. Because the gas cannot be detected by smell or taste, a diver cannot reliably identify exposure from the breathing mixture itself.

Carbon monoxide binds to haemoglobin, the blood protein that carries oxygen. This reduces the blood’s capacity to transport oxygen and can also interfere with its release to tissues. The resulting oxygen deficit may affect the brain, heart and other organs, while underwater the diver also faces the demands and consequences of being in an environment where immediate assistance may be difficult.

How can exposure affect a diver?

Possible effects include headache, dizziness, nausea, weakness, confusion and impaired coordination. Severe poisoning can cause loss of consciousness, heart injury or death. These symptoms are not unique to carbon monoxide: they can overlap with other diving-related illnesses and ordinary causes of feeling unwell, making the circumstances and clinical assessment important.

At depth, a diver may not be able to recognise or communicate a change in mental state promptly. Confusion or poor coordination can compromise buoyancy control, safe ascent and the ability to respond to a buddy. A suspected exposure therefore raises both a medical concern and an immediate operational safety concern.

What should a diving-medicine assessment consider?

Clinical evaluation considers the possibility of exposure alongside symptoms, the dive and breathing-gas history, and other potential explanations. Ordinary oxygen measurements may not, on their own, reliably exclude carbon monoxide poisoning; appropriate testing and interpretation depend on the clinical setting. A diving-medicine physician or emergency clinician should assess suspected exposure.

Exposure: whether the diver may have breathed contaminated gas and whether others shared the same source.
Neurological and cardiac effects: changes in awareness, coordination or consciousness, as well as symptoms that may indicate heart involvement.
Dive context: when symptoms began and how they relate to breathing gas, exertion and the dive profile.
Urgency: suspected poisoning warrants prompt medical assessment rather than continued diving or reliance on symptoms alone.

These are general clinical considerations, not a substitute for individual medical care. Treatment decisions, including whether hyperbaric oxygen is appropriate, require assessment by qualified clinicians; the choice depends on the patient and circumstances.

How does this topic fit into diving and hyperbaric medicine?

Carbon monoxide poisoning sits at the intersection of breathing-gas quality, dive safety and emergency medicine. Diving medicine examines not only the direct effects of pressure and immersion, but also hazards carried into the underwater environment by the breathing supply. Gas contamination can turn a routine recreational dive into a medical incident without providing an obvious warning.

Hyperbaric medicine is relevant because oxygen is central to the management of carbon monoxide poisoning, and clinicians may consider oxygen delivered at increased pressure in selected cases. That does not mean every exposure requires the same treatment. The subject calls for careful recognition, appropriate testing and coordination between emergency care and clinicians familiar with diving.

What practical lessons follow for divers and operators?

Prevention depends on maintaining the integrity of the breathing-gas supply and taking suspected contamination seriously. If more than one diver using a shared source becomes unwell, a common exposure deserves consideration. A diver who develops concerning symptoms should stop diving and seek urgent professional assessment; suspected breathing-gas contamination also needs appropriate attention before the supply is used again.

Caruso and colleagues’ meeting abstract belongs to a continuing area of inquiry into uncommon but potentially severe diving hazards. For divers, physicians and hyperbaric clinicians, the key concepts are the silent nature of the gas, its disruption of oxygen transport, the overlap between symptoms and other conditions, and the importance of prompt evaluation.

Frequently asked questions

Why is carbon monoxide difficult to detect during a dive?

It has no colour or smell, so a diver cannot reliably detect it by looking at or smelling the breathing gas.

Can symptoms be mistaken for another diving problem?

Yes. Headache, dizziness, nausea and confusion can have several causes, so suspected exposure requires clinical assessment in the context of the dive and breathing gas.

Does every case require hyperbaric oxygen?

No single treatment applies to every exposure. Clinicians assess the individual and decide what care is appropriate; suspected poisoning warrants prompt medical attention.

Citation details

Title: Carbon Monoxide Poisoning in Recreational Diving: an Uncommon But Potentially Fatal Problem
Authors: Caruso, JL; Hobgood, JA; Uguccioni, DM; Dovenbarger, JA
Year: 1998
Published in: Undersea & Hyperbaric Medicine 1998
Record type: Meeting abstract
Repository record: Rubicon Research Repository, handle 123456789/734

This page is an original summary written by the Rubicon editors from the publication’s bibliographic record. It does not reproduce the paper, its abstract or its data; consult the publication itself for its methods and findings.