Or if they are in Senior Executive Service (SES) positions they serve at the pleasure of their boss -- Ms Whitman who I would believe is in trouble herself and could can them. I believe that normal Civil Service rules to not apply to SES positions! At least that is how I remember it when these SES positions were created. Some people who were GS-16's chose to stay GS-16's because they didn't want to take a chance on an SES.
The other day I stated that ms. Whitman might want to be looking around as this President NEVER forgets and this one from the EPA is a big foulup!