The aim of this work is to investigate one of the most urgent problems, namely, the health effect of chemical toxicants formed as a result of the professional activities of medical workers. Since classical statistical methods of processing results often do not allow to establish reliably significant connections, it becomes necessary to apply the method of prognosis of changes in the state of health under the influence of factors of industrial harmfulness. In hygienic researches the most effective can be considered the use of a methodology for assessing health risks. In this research medical staff from various sections took part and engaged in the chemical disinfection of Class B (Б) and C (В) waste with chlorine-containing preparations, where the organic agents of chlorine acted as agents of action. The second block of the research is about the impact of a chemical compound, such as methyl methacrylate (which is released during various technological processes of making prostheses), on the health of the dental laboratory staff. Refs 13. Figs 3. Tables 4.