Experienced fire fighters with Hazardous Materials training participated in field tests using procedures described in ASTM F-1154 to evaluate the fit and function of fully encapsulated and disposal type chemical protective ensembles. These evaluations were performed outside under various climatic conditions at the Sacramento, CA; Phoenix, AZ; Prince George's County, VA; and, Del Ray Beach, FL Fire Departments. Initial trials at the first test site in Sacramento showed that tasks described in either Procedure A and B of the ASTM standard were not rigorous enough by themselves to evaluate these ensembles. So all the tasks (16) were combined and used to assess the physiologic responses of the fire fighters. Based on these findings, a different suit integrity test was formulated and the disposable type chemical protective clothing was evaluated under field test conditions. This evaluation quickly identified several weak areas in the suits' construction and is reported in this study.