Hello Venson:
As I recall, the HEPA filter/bag concept was an outgrowth of the a multi-government agency effort called the Manhattan Project, which many of the old timers are familiar with from having lived through it.
Many vacuum makers used HEPA long before MIELE did, yet some [more] seem to associate HEPA with MIELE due to the HEPA ratings which are European grown measures/standards.
Carmine D.
This message was modified Feb 26, 2009 by CarmineD