"The BMW Hydrogen 7's emissions were only a fraction of SULEV level, making it one of the lowest emitting combustion engine vehicles that have been manufactured," said Thomas Wallner, a mechanical engineer who leads Argonne's hydrogen vehicle testing activities. "Moreover, the car's engine actively cleans the air. Argonne's testing shows that the Hydrogen 7's 12-cylinder engine actually shows emissions levels that, for certain components, are cleaner than the ambient air that comes into the car's engine."

Don Hillebrand, director of Argonne's Center for Transportation Research, said " Argonne's vehicle testing facilities are unique in that they are able to detect even trace levels of emissions. In this case, it was near-zero emissions ... A gross polluter is easy to measure, but the cleaner the car the harder it is to test." Or as was noted by BMW's Wolfgang Thiel, the manager of operating support emissions analysis, "Zero is a very small precise number - we are pushing the boundaries of emissions testing."