This is the scientific White Paper explaining in detail the new element HHO. It seems to be legit.
http://hytechapps.com/science/Santilli.htm
A first basic feature in the production of Aquygen™ Gas is that there is no evaporation process at all, and, in any case, the electric energy available is basically insufficient for evaporation. This feature alone establishes that the H2O Model 1500 Aquygen™ Gas Generator produces a "new form of water" that is gaseous and combustible! This is the first identification on record of the unknown chemical composition of Aquygen™ Gas, its relationship with the H2O Model 1500 Aquygen™ Gas Generator, and some of its applications.
The second important feature of Aquygen™ Gas is that it exhibits a widely varying energy content in BTU's, ranging from a relatively cold flame in open air, to large releases of thermal energy, depending on its use. This is additional evidence of fundamental novelty in the structure of Aquygen™ Gas. In fact, all known fuels have a fixed value of energy content in BTU/scf. Also, the variable character of the energy content of the Aquygen™ Gas is clear evidence that the gas has a structure other than a molecular structure, namely, that its chemical composition includes bonds beyond those of valence type.
The third important feature of Aquygen™ Gas is that it does not require any oxygen for its combustion, since it contains in its interior all oxygen needed for combustion. By recalling that other fuels require atmospheric oxygen for their combustion, thus causing a serious environmental problem know as oxygen depletion, the capability to have combustion without any oxygen depletion renders the Aquygen™ Gas particularly important on environmental grounds.
The fourth important feature of Aquygen™ Gas is its anomalous adhesion to gases, liquids and solids.
The fifth important feature of Aquygen™ Gas is that it does not follow the fundamental PVT law for gases.
The sixth important feature of the Aquygen™ Gas is that it bonds to gaseous fuels (such as natural gas, magnegas fuel, and others) and liquid fuels (such as diesel, gasoline, liquid petroleum, and others), thus significantly improving their thermal content as well as the environmental quality of their exhaust.
The seventh and most important feature of Aquygen™ Gas is that it instantaneously melts tungsten, bricks, and other highly refractive substances. In particular, measurements have established the remarkable capability of combusted Aquygen™ Gas instantaneously reaching temperatures up to 9,000 degrees C, under which virtually all substances on Earth can be sublimated.
It's far from being a legit paper. It is pure nonsense. It's technical terms wrapped around meaningless, pretty graphs and isn't even in the format of a scientific paper. Nowhere are the test methods even recorded. I wonder if all the firms he cites appreciate the publicity from his work!