In 1996 the Department of Defense created the Domestic Preparedness Program to assist Federal, State and local agencies in enhancing preparedness for terrorist attacks using weapons of mass destruction. One of the responsibilities of the Domestic Preparedness Program is to enhance emergency and hazardous material response to nuclear, biological, and chemical (NBC) terrorism incidents. An effective response to a terrorist incident includes the use of personal protective equipment to protect wearers from exposure to chemical or biological agents. In some instances, Level B protective suits may be required to enter a contaminated area. Level B suits are chemical resistant clothing that protect the wearer from liquid chemicals. Air is supplied by a pressure-demand full-face-piece self-contained breathing apparatus (SCBA) or pressure-demand supplied-air respirator with escape SCBA. This research examined the ability of Level B suit designs to assess their capability to protect in a chemical warfare (CW) agent or biological environment. Swatches of material from each suit design were tested for resistance to permeation for Sarin (GB) and Mustard (HD). From this data, the researchers calculated the estimated time it would take to permeate the suit with sufficient agent to cause physiological effects in people wearing the suits. Each suit design was tested for its protection factor in an aerosol environment (the researchers used aerosolized corn oil, which may be representative of a chemical or biological agents). Protection factor was defined as the ratio between the challenge concentration outside the suit and the measured concentration inside the suit. The cumulative mass of each agent that permeated each swatch was determined over time, and the findings for all the swatches were used to determine a weighted-average cumulative mass for each suit. These data yielded a breakthrough time that was calculated for each suit for the purposes of comparison. Intact suits were also challenged with corn-oil aerosol to simulate a biological or chemical aerosol. Protection factors were determined for each suit. The report included the following appendices: A) Level B suits chosen for testing; B) modified static diffusion test procedure; C) aerosol simulant test procedure; D) TFR 4 CB protective coverall; E) Kappler Proshield 3 coverall; F) Kappler CP1 coverall; G) Kappler CPF2 coverall; H) Kappler CPF4 coverall; I) Kappler Responder (41255-8-A); J) Kappler Level B CSM Responder (42489); K) Overall test results.