February 8, 2021 Snorkel Study Reveals Cause of Many Drownings

In January 2019, the Hawai’i Tourism Authority funded a Snorkel Safety Study in order to “determine the causes and risk factors associated with snorkel-related fatal and non-fatal ocean drownings in Hawai’i and develop appropriate safety messages.”

Primary Cause of Snorkel-Related Drownings

The study showed that Hypoxia Induced by Rapid Onset Pulmonary Edema (ROPE) is the cause of some, if not most, snorkel-related fatal and near-fatal drownings.  Certain factors that increase the risk of ROPE are:

• Snorkel resistance and horizontal immersion are predisposing factors that can contribute to the onset of ROPE
• Certain health issues increase the risk of developing ROPE
• Recent prolonged air travel may be a contributing factor.

Conclusions of the Snorkel Resistance Investigation

Key takeaways from the study include:

• Snorkels and full-face masks have a wide range of airflow resistance
• High resistance adds to the risk of developing ROPE
• The more you exert, the greater the resistance
• You can’t judge a snorkel by its looks
• Some, probably most, fatal and non-fatal drownings were hypoxia-induced by Rapid Onset Pulmonary Edema (ROPE)
• Full face masks may be a risk factor

Furthermore, the survey determined the following regarding full face masks:

• Cannot assess their resistance by visual inspection
• Cannot be removed easily in urgent situations even with quick release features
• Cannot “spit out” mouthpiece in urgent situations
• Cannot clear water from tube with sharp expiratory force maneuver
• Cannot dive beneath the surface safely
• Valve malfunction may lead to serious aspiration consequence

Message to Snorkelers Regarding Safety

Recreational snorkeling is not a benign or low-risk activity.  This is true both for inexperienced and experienced swimmers and snorkelers.

• Always swim with a buddy
• If you can’t swim, don’t snorkel
• The risk of drowning is relatively higher among visitors
• Choose snorkel devices thoughtfully. Avoid constrictions in mouthpiece caliber, which may increase airway resistance to inhalation
• Learn to use the simplest snorkel device safely before trying more complex models and before venturing to depths beyond one that allows standing with water at chest level
• If in doubt about your cardiovascular health – don’t go out!
• It may be prudent to wait several days after air travel to attempt a snorkel venture
• Shortness of breath can be a sign of danger. Stay calm, stand up, remove snorkel, get out of water immediately
• Beware of wind and sea currents which may cause you to drift away