During our life’s, both privately and professionally, we exposed to a multitude of hazardous situations. And most of the time we are not (timely) aware of the dangerous situation. One of these silent killers is definitely carbon monoxide poisoning. There is a direct societal need for home and building automation (HABA) systems equipped with ultra-sensitive, reliable gas sensors (for hazardous gases), which are relatively low cost and low power, and presence detection technology which is able to register remaining occupants in an evacuated building.In addition, fire men and other workers who have to enter confined spaces are exposed to great invisible hazards almost each day, such as the possibility of no oxygen, toxic fumes, etc. Therefore, these workers should be equipped with reliable, wearable personal health monitors, which are able to detect both multiple hazardous gases at low concentrations and the person’s health conditions. The SAFESENS project aims at co-integration of gas sensor and presence detection technologies, which should enable an enhanced safety and security of buildings and its occupants. In order to achieve this, different technological building blocks will be developed and where possible co-integrated at least at system level. The final demonstrators should exceed the performance of state-of-the-art devices at the level of form factor, power consumption and reliability (specificity in case of gas detection).