With regard to process safety of technological processes, chemical reactions were assumed to be single reactions After st typical runaway incident (IC-MESA. Seveso/Italy 1976), the technical trichlorophenol synthesis was investigated thoroughly. Using analytical, reaction-kinetic and thermodynamic data obtained in cooperating with Boehringer Ingelheim, the authors have established a kinetic model for the TCP synthesis to illustrate simulations of the normal-operating semibatch reactor as well as of other selected incidents.