Drug users, alcohol abusers, and the financially questionable have all been granted high-level security clearances as Defense Department employees. A study done by the General Accounting Office reveals many of the Defense Department's workers have checkered pasts and have not been called on to explain their behavior during security checks. The study also found back group checks were incomplete 90% of the time.
See "Clearances Granted to Many Troubled Workers", Edward T. Pound, USA Today, May 31, 2001