Wildfires and Breathing-Gas Contamination

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WITH WILDFIRES RAGING IN CANADA, ITALY, GREECE, THE U.S., and elsewhere, divers and dive operators have called DAN Medical Services and DAN Safety Services with concerns about whether the smoke from wildfires may contaminate breathing gas. 

When similar concerns were raised in 2018, DAN sent a team to investigate the impact on air quality in and around 17 dive shops ranging from San Diego, California, to Eugene, Oregon, all exposed to wildfire smoke. The findings did not identify any apparent increased risk to divers.

Analyzing both environmental air and compressed air, DAN’s team measured concentrations of carbon monoxide (CO), carbon dioxide (CO2), and particulate matter in the air near the dive shops and the fires as well as in recently filled scuba cylinders.

What the team found was reassuring: When analyzing the air outside, even when smoke was present and particulate levels were unacceptably high, the handheld monitor did not show elevated environmental levels of CO or CO2

Next the team evaluated cylinders. In most cases they found that dive store owners were using filters that included a catalyst called hopcalite, which causes CO to convert to CO2 in the presence of gases containing oxygen (such as air). As an additional safeguard, these owners were not filling cylinders on extremely smoky days. Some operators filled their storage banks on clear days so they could continue to fill cylinders even when the air quality index was unacceptably high. Most of the dive operators had adapted their practices to ensure safe air and safe diving for their clients, and their level of safety awareness is commendable.

In conclusion, visible smoke in surrounding areas, even when it can be detected by the human nose, should not compromise air quality in scuba cylinders. Dive operators should appropriately maintain their compressor and filtration systems, utilize filters fitted with CO removal agents, preferably draw air from inside their buildings, and heed basic safety practices when it comes to nearby fires. 

Concerned divers should ask the fill station if it uses CO removal agents, and they can smell their air before diving to ensure there is no residual particulate matter.

For more information, call the DAN Risk Mitigation information line at +1-919-684-2948, or send an email to . AD

© Alert Diver — Q4 2023