The ultimate performance objective of chemical protective clothing is protection of the wearer in his workplace environment. The chemical barrier properties of the materials used in the clothing are of prime importance; however, in fully encapsulated suits, it is mandatory that the total ensemble afford effective protection to the wearer as he performs his normal work routine. A quantitative fit-test booth for respirators was used to determine the protection factors (PF) of total ensembles. The PFs are measured for three exercises simulating typical work activities. A number of suit designs and concepts including limited-use disposable clothing have been tested, and modifications in design have been incorporated to improve performance. Based on the test results, we have been able to proceed to actual on-the-job testing to confirm acceptability with minimum risk to the wearers.