Screening for Oxygen Intolerance in Navy Divers

5 min read · 8 May 2026

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Screening for oxygen intolerance in U.S. Navy divers is a 1986 publication by Butler Jr and Knafelc in Undersea Biomedical Research. Its subject is the assessment of divers’ responses to oxygen exposure, a central medical concern because oxygen can become toxic under the elevated pressures encountered in diving.

What does oxygen intolerance mean in diving?

Oxygen is essential for metabolism, but breathing oxygen at elevated partial pressure can have harmful effects. In diving, pressure increases the partial pressure of each gas in a breathing mixture, so exposure depends not only on the oxygen concentration but also on depth and duration.

Oxygen toxicity is commonly considered in two broad forms. Central nervous system effects can arise during relatively acute exposure and may include seizures; pulmonary effects are associated with more prolonged exposure and can involve irritation or injury to the lungs.

“Oxygen intolerance” in a screening context refers to concern about an individual’s susceptibility or response during oxygen exposure. It is not a diagnosis that can be inferred from a title alone; the underlying issue is how to recognise and manage risk when oxygen is used in demanding operational conditions.

Why is screening relevant to divers?

Oxygen-rich breathing gases have important uses, including reducing inert-gas exposure in some dive procedures and supporting treatment in hyperbaric settings. Those benefits have to be balanced against the possibility of toxic effects, which can become more consequential when a diver is underwater and cannot immediately leave the exposure.

A seizure underwater can lead to loss of control of the breathing apparatus, aspiration, or drowning. This makes oxygen tolerance a practical safety question as well as a matter of physiology: exposure planning, operational procedures, and the diver’s medical assessment all contribute to managing risk.

Screening is one approach to identifying potential concerns before exposure. In diving medicine, such assessment sits alongside attention to gas composition, depth, exposure time, workload, and a diver’s health history. No screening process can remove every uncertainty from a complex physiological response.

What physiological factors shape oxygen toxicity?

The risk of oxygen toxicity is influenced by the pressure of oxygen reaching the body and by how long exposure continues. Physical exertion, environmental conditions, and individual variation may also matter. A diver’s response is therefore understood in context rather than as a simple property of the breathing gas alone.

Partial pressure: the pressure contribution of oxygen in the breathing mixture, which rises as ambient pressure rises.
Exposure duration: time under elevated oxygen pressure is relevant to both acute and cumulative effects.
Central nervous system effects: potentially sudden manifestations are especially hazardous during immersion.
Pulmonary effects: prolonged oxygen exposure can affect the respiratory system.
Operational setting: workload, depth, gas choice, and the ability to respond to an emergency influence practical risk.

These concepts help explain why research on screening belongs within a broader field that studies oxygen exposure limits, individual susceptibility, and the safe use of breathing gases. They also show why a screening question cannot be separated from the conditions in which a diver is expected to work.

How does screening fit into diving medicine?

Research into screening asks how a medical or physiological assessment might help identify people for whom a particular exposure warrants added caution. In oxygen-related work, that general question connects clinical evaluation with the realities of dive planning and operational safety.

The subject has relevance beyond military diving. Divers, scientific teams, and hyperbaric clinicians may all encounter situations where oxygen exposure is deliberately increased. The balance of benefit and risk differs across settings, but the shared challenge is to anticipate physiological hazards without treating a screening result as a guarantee of safety.

Screening is one part of a layered approach. Appropriate exposure planning, monitoring, training, and emergency readiness remain important, and interpretation of a person’s medical circumstances belongs with a diving-medicine physician or other appropriately qualified clinician.

Frequently asked questions

Why can oxygen become hazardous underwater?

As ambient pressure increases, the partial pressure of oxygen in a breathing mixture also increases. Sufficiently high exposure can affect the nervous system or lungs.

Is oxygen toxicity always predictable?

No. Risk depends on exposure conditions and individual factors, and a screening assessment cannot guarantee that a diver will avoid an adverse response.

Who should interpret a diver’s oxygen-related medical risk?

A diving-medicine physician should assess individual health concerns and help interpret them in the context of planned diving or hyperbaric exposure.

Citation details

Title: Screening for oxygen intolerance in U.S. Navy divers
Authors: Butler Jr, FK; Knafelc, ME
Year: 1986
Published in: Undersea Biomedical Research 1986 Mar;13(1):91-8
Identifiers: PMID 3705251
Repository record: Rubicon Research Repository, handle 123456789/3046

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.