Actually, they use a gadget that converts water into breathable oxygen and then hydrogen gas. The chemical equation for water is H2O H= Hydrogen and O=Oxygen. This reaction requires two water molecules to be present so the new equation is 2H2O. Then the water is electrolyzed to break apart the two molecules resulting in 2(H2) and 2(O). The oxygen atoms are attracted to eachother, so a breathable oxygen molecule is formed O2. The oxygen is then inhaled, while the hydrogen is exhaled.