Introduction. The long-term operation of the chemical enterprise has led to the formation of an area of accumulated harm to public health. The purpose of the study is to investigate the trend in newly identified morbidity in various population groups living in areas of accumulated chemical pollution of the environment. Materials and methods. The primary morbidity rate of the population of Usolye-Sibirskoye was assessed retrospectively according to official statistical reporting – during 1985–1995. and 2016–2022. Relative rates of incidence among children and adults (per 1000 population) were calculated. The trend in the incidence of malignant neoplasms was studied using regression analysis and growth (decrease) rates. Results. Over 2016–2022 there was a gain in the incidence in the population: in 0–14 years children by classes: certain conditions in the perinatal period, blood diseases, neoplasms; in 15–17 years adolescents: by class of disease of the circulatory system, blood, endocrine and genitourinary systems, congenital malformations, neoplasms; in the adult population by classes of diseases including congenital malformations, diseases of the endocrine system, circulatory system, musculoskeletal system and blood diseases, neoplasms. Limitations are due to changes in the structure of statistical reporting forms and various etiological factors for diseases included in one class of diseases. Conclusion. During the post-operation period of the city-forming enterprise, an increase in incidence in children and adults was revealed. Undoubtedly, the formation of pathology was influenced not only by the unfavourable environmental situation in the city, but also by socio-economic conditions. To optimize medical and preventive measures to improve and preserve public health, it is necessary to conduct further studies of the health status in the population in the area of accumulated chemical pollution.