The gopher tortoise (Gopherus polyphemus) is a declining species found on many military installations in the Southeastern states.  The tortoise is federally listed as threatened in its westernmost distribution and considered to be at risk everywhere else.  On installations where troop readiness training is conducted, an important component of realistic troop readiness training is the generation of obscurant material and the conduct of maneuvers under obscurant cover.  Fog oil has long been deployed for visual obscuration training, and the effect of such obscurants on these species is unknown. The question presented itself however, as to whether or not the tortoise, in its long underground burrow tunnel, was actually exposed to the obscurant under field conditions. As a preliminary step prior to instituting toxicological studies, a laboratory simulation was performed of the capability of the fog oil smoke to penetrate the living space of this species.  In this series of studies, the fog oil smoke did not enter the simulated tortoise burrow in significant concentrations. This suggests that tortoise burrows do not need to be studied in situ, and that tortoises may be considered protected while in the burrow.