Message Icon


Message Icon


Message Icon


Message Icon


Carbon Dioxide in Full Face Masks

Full face snorkel mask  appeared on the snorkelling scene around 2015 that combined your mask and snorkel into a single piece of kit that kept all your face dry and allowed you to breathe through both your nose and mouth.



Full face masks added a sense of freedom and comfort to many who wanted to go snorkelling but didn’t like the idea of water around their face.  Everything was fine for a while until tragic accidents occurred while snorkelers used full face snorkel masks.

We have had a few comments and concerns from customers reading News Reports about CO₂ build up in Full-Face Snorkel Masks and while there is definitely a problem with some masks there isn’t a problem with all masks.  As long as you buy from a specialist such as ourselves, who have researched the safest masks out there and would never sell dangerous equipment, then you can be assured that your mask is safe to use.


We all know that we breathe out a higher concentration of Carbon Dioxide, CO₂, than we breathe in. Too much CO₂ in our bloodstream can lead to hyperventilation and even death. The human body is well designed to get rid of excess CO₂ though when we breathe out but when you add a snorkel to the equation it gets harder to get rid of the CO₂

Dead Air Space

Every time you breathe out, even right now as you read this, you don’t clear out all of the ‘dirty’ air in your lungs and windpipe. Some ‘dirty’ air remains in your windpipe and lungs but every time you breathe in it mixes with fresh air and gets diluted. If you take nice deep breaths, you breathe in plenty of ‘clean’ air and flush out most of the ‘dirty’ air.


The dead air space normally is only the inside of your windpipe and a small portion of your lungs. If you breathe normally this is fine but when you add a snorkel you’re adding even more dead air space that fills with dirty air when you exhale so you need to breathe quite deeply to get rid of it all.

A Full Face Snorkel adds even more dead air space over your mouth so if it doesn’t get rid of dirty air effectively then CO₂ can start to build up and you’ll feel out of breath if you don’t breathe properly.

Regardless of whether you’re using a traditional snorkel or Full Face Snorkel you need to breathe properly and if you feel out of breath, tired or unwell then stop using the snorkel and get out of the snorkel until you feel better.


The Problem with Full-Face Masks

When the popularity of full-face snorkel masks climbed, cheaper copies started to emerge that just copied the concept, but the copiers didn’t really understand the importance of airways or CO₂ build-up, they were just interested in making masks as cheap and fast as possible.

As you can see from the comparison below, the white mask is a cheaper copy that hasn’t been moulded properly and the exhaust vents that were sealed from the cheap moulding process only have a few crude drill holes to allow dirty air to go out of the mask. Any restriction or addition to the dead air space like this can lead to CO2 build-up, the white mask would be dangerous to use.



The black mask in the image is a SEAC Unica Mask and as you can see all of the bore of the snorkel is the inlet so plenty of fresh air will flood the mask when you breathe in and the exhaust escapes out the side of the mask for better flow and less dead air space.  SEAC invested tens-of-thousands of Euros in specialist testing equipment and checked that their mask met the closest standard available for CO₂ build up. 

Because full face snorkel masks are still fairly new to the market there isn’t actually a standard for them to meet yet so SEAC went for the closest test which was for industrial gas masks to make sure their Unica met even those standards.




Is There Still a Problem?

Yes, but only in certain masks. As a consumer, you need to look for reputable brands and not be tempted by the lowest price tag.  The cheaper the mask is the lower the quality of the materials, build quality and testing will be. More expensive brands such as OceanREEF and SEAC have spent money and time to design and test masks that keep you safe so please avoid cheaper knock-offs as they have led to some pretty serious incidents.

If you do a quick search online there are now thousands of copies flooding the market with appealing prices but for the sake of saving £20 you could get in serious trouble in the water with a cheap knock-off. A cheap Full Face Mask will cover your face and airways so I don’t want the cheapest bit of kit even if it is only for a beach holiday.

For SCUBA diving Full Face Masks like the Neptune or Raptor the same problems can be found in cheaper copies out there but again these big brands have their gear tested before they release them so they’re safe to use and you don’t need to worry. Kirby Morgan a big commercial diving brand released an alert not long ago warning of a copy of one of their masks that looked almost exactly the same but did not perform anywhere near their standards, so only buy from reputable dive centres who know what they’re stocking and selling.

Bottom line; deep breaths and avoid cheap copies.