Experimenting with hazardous substances and experimental competence - a legal statement

Safe experimentation with hazardous substances is a key competence for chemistry teachers. Thus, it is important for education and advanced training of chemistry teachers to promote and maintain the professionally competence to experiment. In this contribution, the example of chlorine and bromine is used to present methods for carrying out safe school experiments in spite of high and very high material hazards and the importance of being able to legally develop, document and perform the experimental lessons on the basis of one ' s own risk assessment.