Wearable sensing applications have attracted much attention in recent years. The aim of the FP6 funded Proetex project is improving safety and efficiency of emergency personnel by developing integrated wearable sensor systems. This paper describes recent developments in the integration of sensing platforms into wearables for the continuous monitoring of environmentally harmful gases surrounding emergency personnel. Low-power miniature CO and CO2 sensors have been successfully integrated in a jacket collar and boot worn by emergency personnel. These sensors need to provide information about the level of gas in the surrounding environment without obstructing the activities of the wearer. This has been achieved by integrating special pockets on the jacket and boot of fire-fighters. Each sensor is attached to a sensing module for signal accommodation and data transfer. The sensor performance has been evaluated by simulation of real-life situations. These wearable gas sensors will dramatically improve personnel awareness of potential hazard and can function as a personal warning system. In this way, fire-fighter’s jacket and boot not only protect the wearer, but have a second function of providing valuable information on external hazards. The authors gratefully acknowledge the financial support of the Science Foundation Ireland (07/CE/I1147) and the EU project FP6-2004-IST-4-026987. We also acknowledge contribution of University of Pisa (Italy), Zarlink Semiconductor (UK), and Diadora/Invicta Group (Italy).