IHS

Hi all,
Does anybody work for or know anything about IHS? I've seen some negative comments here about "tribal hires". Mainly, these are non-natives being threated to be fired, for being non-native. I understand that doesn't happen with COSTEP or civil service as those are federal positions.
I've looked at their website and the job announcements show: COSTEP, civil service, or tribal hire. The tribal hire announcements show pay grades, does anyone know where I can find a copy of that pay scale?
Thanks for any information.