Death and the Full-Face Snorkel Masks

Undercurrent's October story about the recent deaths of another two snorkelers in Hawaii while using full-face snorkeling masks prompted David Concannon (Sun Valley, ID), an Undercurrent subscriber and attorney at law specializing in diving litigation, to write. Here is what he said (with our editing for brevity).

"In 2019, I assisted HEAD in its dealings with Hawaiian authorities conducting an epidemiology study of FFSMs to assess their impact on drownings in the state. HEAD voluntarily tested its FFSM products as well as other manufacturers' FFSMs to see if they could pose a risk to users. The results were alarming.

"Originally, FFSMs sold by HEAD with brand Mares were supplied by Ocean Reef and badge-engineered. "This arrangement ceased in 2019 when, writes Concannon," HEAD designed its own FFSM and, in the process of testing to meet EN standards, realized that 90 percent of the products on the market could not meet the standard and were wildly unsafe (including the Ocean Reef model). The timing coincided with the epidemiology study in Hawaii, which originated because FFSMs were getting pilloried in the press.

"At that time, there were only two ANSTI Breathing Machines in the entire world [designed] to test FFSMs, one at Dive Lab in Panama City, Florida, and the other at Mares headquarters in [Genoa], Italy. I would be surprised if any of the manufacturers other than HEAD does any testing of its FFSMs.

"For use underwater (diving), the corresponding norm is set out in European standard EN250 for work-of-breathing with scuba regulators. There is no norm defining the performance requirements for full-face masks used in snorkeling.

"What is at the heart of EN250 norms? One aspect deals with carbon dioxide build-up. During normal breathing, a person at rest converts around 4-5 percent of the inhaled air into carbon dioxide.

"The exhaled carbon dioxide (CO2) is not an issue in an open and ventilated environment; it is dispersed so that the next inhaled breath does not contain any CO2 above background levels. If the content of CO2 in the inhaled breath starts to rise, the human body experiences hypercapnia: a rise in CO2 in the body and consequently its accumulation in the bloodstream, which leads to shallow breathing and the feeling of shortness of breath.

"Shallow breathing increases hypercapnia because it does not get rid of the CO2 in the lungs since the lungs are only partially emptied. So, whereas hypercapnia can start because of external CO2 build-up, it can quickly worsen due to the addition of internal CO2 build-up [within the mask]. This snowball effect can quickly make a bad situation worse."

[Other symptoms of hypercapnia include distress, anxiety, confusion, and even seizures.]

Concannon concluded, "HEAD would like to encourage [U.S.] authorities to develop safety standards for Full Face Snorkel Masks and restrict careless manufacturers and distributors from bringing unsafe products to the market."