The aim of the article is to build up qualitative evidence that CBRN training, which requires quick and prompt reactions from first responders, should involve simulation. The authors rely on a case study, the European Sensor System for CBRN Applications - EU-SENSE project, which has to provide an adaptable and multipurpose hazard detection solution for enhancing situational awareness. A dedicated training mode on how to use the device by CBRN practitioners assumes that life-threatening substances are present in a real-life operation. Therefore, in order to provide lifelike experiences in a controlled environment, a simulation-based activities can be proposed. The analysis of CBRN training requirements and sample hypothetical scenarios, which complement the case study, proves that CBRN mission-specific training requires the design of a range of simulation-based activities that help learners acquire safe behavioural competences and at the same time examine their performance. They will be also conducive to developing decision-making and communication skills and improving situational awareness. In a contaminated environment, these skills are necessary for survival. This study contributes to the growing body of research on CBRN training concerning newly developed devices, which enhance the work of CBRN practitioners.