#27: Dangerous Air Pockets

This survival fact isn’t super obvious, but it’s invaluable. Avoid swimming into underwater caves with air pockets. The idea might seem fun on the surface, but those air pockets can actually be toxic or fatal. You can’t tell if an air pocket will have enough oxygen in it, making them dangerous.

Some people have arrived in an air pocket expecting to take a deep breath of fresh air, only to find that they can’t. The idea of not being able to breathe is absolutely terrifying. This phenomenon happens when an air pocket in an underwater cave doesn’t have a regular source of fresh air. The air pocket could be full of CO2 or toxic fumes, which can cause serious harm.