This Report describes a study conducted at Yuma Proving Ground, Arizona. Trained acclimated soldiers conducted simulated combat missions in a stationary M-1 tank, while wearing Chemical Biological (CB) clothing. Physiological measurements, skin temperature, rectal temperature, heart beat rate and sweat production were continuously monitored. In addition, the environmental parameters of wet bulb, dry bulb, and wet bulb globe temperature and wind velocity and relative humidity were recorded.