This unlimited release document is an extraction from the original Official Use Only report, Sandia National Laboratories report number SAND2005-1045 and Lawrence Berkeley Lab report number 54973/Rev 2.1. The purpose of the original document is to aid airport planners in defending their facilities against chemical and biological (chem-bio) attack, given the technologies and capabilities available today. With this document, airport planners should gain an understanding of the important issues for chem-bio defense, and should be able to assess the preparedness of their airport, to determine whether to bring in consultant expertise, and to target the most effective upgrades for their facilities. The defenses outlined in this document are intended to accomplish two objectives: (1) to deter some high-consequence attacks through HVAC system physical security, and (2) to mitigate the consequences of an attack through passive protection and active response measures.