Wow, the EPA needs to centralize all their GIS data downloads. They have download sites all over the place.
I found region 6 and 9 from this site. EPA Environmental Dataset Gateway
Guess I'll keep looking around
EDIT: Found a KML for NPL that was current to 2008, it covers the contiguous US. If you save out only the polygon KML, you can convert it to a shapefile. http://www.google.com/url?sa=t&rct=j&q=&esrc=s&frm=1&source=web&cd=5&cad=rja&uact=8&ved=0CDoQFjAEahU...
Disregard that, it only covered one region, got a bit hasty.
while not what you were looking for, this may be of use to you, ATSDR Hazardous Waste Site Polygons (copy/paste)
I haven't examined the data yet, but it could be useful