The objective of this randomized control trial is to compare the effectiveness of Stress Inoculation Training (SIT), a well researched psychological treatment for Post Traumatic Stress Disorder (PTSD), to that of the non-specific standard care provided in primary care settings, called Supportive Counseling (SC), on individuals who were exposed to the September 11, 2001 terrorist attack on the Pentagon, or the immediate aftermath of this attack. Both SIT and SC interventions will each be provided in one 2-hour session with eight weeks of daily systematic web-based follow up to promote self-help. The primary hypothesis of this study is that SIT will reduce the level of PTSD in participants relative to SCand to the pre-treatment levels.