Many jobs in toxic environments and in less than ideal surroundings, such as oil spill remediation, require the use of 2 layers of personal protective equipment (PPE) to maximize worker safety. This study was designed to assess physiological and subjective responses while working in a single-layer (SL) or double-layer (DL) ensemble during a continuous work protocol in a hot environment of 31°C WBGT. Eleven men in a repeated-measures design performed 2 counterbalanced work-bouts at a time-weighted work rate of 300 kcal/h. All tests were terminated when a rectal temperature (Tre) of 38.7°C was attained. Total work time was significantly (P < 0.05) shorter in DL (60.5 ± 3.9 versus 66.4 ± 4.6 min in SL), and final microenvironmental temperature (MEt) (35.6 ± 0.9°C vs 37.1 ± 0.3°C) and humidity (MEh) (90.0 ± 4.0% vs 95.4 ± 1.1%) were higher in DL. There were no differences for Tre, mean skin temperature, or sweat rate over time. These data have practical implications in that although the physiological strain on workers in DL was not substantially greater than in SL, worker safety, and productivity can be reduced while working in layered PPE.