This is a bit dated, but the first I heard of it was on Global National, tonight.
http://www.washingtonpost.com/wp-dyn/articles/A2576-2005Mar2.html
http://www.washingtonpost.com/wp-dyn/articles/A2576-2005Mar2.html
The CIA wanted the Salt Pit to be a "host-nation facility," an Afghan prison with Afghan guards. Its designation as an Afghan facility was intended to give U.S. personnel some insulation from actions taken by Afghan guards inside, a tactic used in secret CIA prisons in other countries, former and current CIA officials said.