Argonne (IL) - The BMW Hydrogen 7 Mono-Fuel test vehicle has been rated by the US Department of Energy as a super-ultra low-emission vehicle (SULEV), the highest designation for energy efficiency.

The tests were done at the DOE's National Laboratory in Argonne, Illinois. The man in charge of hydrogen vehicle testing, Thomas Wallner, said the emissions from the Hydrogen 7 vehicle were "only a fraction" of the level required for the SULEV level.

He also noted that the car's 12-cylinder engine sometimes had emission levels that were cleaner than "ambient air" that entered the engine.

The testing center said the car had "near-zero emissions," and it required special technology just to be able to measure it.

BMW commented on the results saying that it is "pushing the boundaries of emissions testing," adding that the next major hurdle is adding more hydrogen fueling stations throughout the US.