Data are presented on the potential danger of harmful substances to the health of chemical production workers and a list of substances that most often cause acute poisoning in industrial conditions is determined. A retrospective analysis of 83 investigation materials into cases of acute poisoning that occurred at a large chemical enterprise located in the Volga Federal District for the period from 1980 to 2023 was carried out. The circumstances and causes of group acute poisoning with a chemical substance (nickel carbonyl) not provided for by production regulations are described in detail. It was established that during the period under review, 83 cases of acute occupational poisoning occurred at the enterprise as a result of exposure to ammonia, carbon monoxide, hydrogen sulfide, styrene and nickel carbonyl, a number of which were of a group nature. In all cases of poisoning, except for nickel carbonyl, the etiological factor was known and adequate therapeutic measures were taken. Difficulties in identifying a harmful substance in case of poisoning with nickel carbonyl were due to the absence in the description of the technological regulations of the possibility of its formation. The causes of acute poisoning were significant violations of the technological regime, non-compliance with labor protection requirements and non-use of personal respiratory protection equipment. The main directions for the prevention of acute occupational poisoning in chemical production conditions are substantiated.