Project Fusion was a government funded research project with the goal to develop a device that could separate hydrogen and oxygen atoms in water molecules. The project cost eight billion dollars over five years and although it was feasible, it was impracticable. The difficulty was in finding a practical power source for the device.
The applications of the Project Fusion device were many, but among them was an underwater breathing device. Rudy Wells was able to install a converter in Steve Austin's bionics that powered the Project Fusion underwater breathing device off of the atomic cells in Austin's bionic arm. However, a side effect of using the atomic cells to power the breathing device was the weakening and potential breakdown of Austin's bionics.
(SMDM: H + 2 + O = Death)