According to this web page http://holysmoke.org/hho/the-facts.html , "the EPA tested two dozen HHO units and they were all found to be ineffective". Googling a few variations of EPA HHO evaluation and searching the EPA website turned up nothing. Was these ever such an evaluation done?  I should think DOE would be more likely to sponsor such an evaluation rather than the EPA.

This article also says that if HHO were such a great idea, all the car companies would be using it.  Well, let me tell you a story. A company called Arvin Meritor developed a fuel reformer system that produced hydrogen which would be injected back into the cylinder. Actually, the principle is not that different from HHO.  They said it could improve mileage by as much as 30%.  http://www.greencarcongress.com/2005/11/hydrogenenhance.html/

Well, by and by, the division that developed this technology was sold off to "an equity investment firm based in New York" for $310 million. http://www.greencarcongress.com/2007/02/arvinmeritor_to.html/  As far as I know, nothing ever became of this great technology. Are there any 2012 cars or trucks that will be using it?  Not that I know of. Sort of seems like this great technology was buried - killed and buried.  If it was a scam, why did they pay out $310 million?  (btw holysmoke, notice how I use links to refer the reader to more information about something I am referring to.)

Many engineers who have worked for big companies can tell you stories about great ideas that somehow got lost, killed or ignored for all kinds of reasons. The Dilbert comic strip is exagerated for purposes of humor but being an engineer who has worked for big companies, I can tell you, it is not much of an exageration.