Firefighters encounter numerous life-threatening challenges, including exposure to hazardous materials, extreme heat, and high-pressure environments, all of which significantly elevate the risk of fatal cardiac events. This chapter describes a smart undergarment equipped with dry textile electrodes, developed in the scope of the SafeFire project and that aims to reduce these risks by providing continuous real-time monitoring of first responders’ vital signs. Integrated with the ScientISST platform, this system supports electrocardiography (ECG) data acquisition both online via Bluetooth and offline through the use of an SD card. These capabilities pave the way for immediate risk assessment and post-mission health evaluations. Despite challenges such as difficulty in electrode adhesion to the skin and noise induced by movement, our work highlights the potential of wearable technology to enhance the safety and operational performance of firefighters. The chapter focuses on the development and testing of the smart undergarment, emphasizing the importance of material selection and advanced signal processing techniques to ensure reliable data acquisition in adverse conditions.