Analyses of the air made to determine the concentrations of various toxic compounds used in the mix formulas, have shown that phthalate plasticiters occupy a leading position among them. The highest concentrations were determined at the work sites of the roll mill operators, calendar machine operators and coating machine operators. Carbon monoxide, hydrogen chloride, vinyl chloride and also polyvinyl chloride resin dust, lead and cadmium compounds were detected in small amounts in the air at the production areas along with the plasticiters. In addition, the air temperature in the production sites mentioned (in the vicinity of the roll mills and calendar machines) is higher during the operations, while the physical stress varies. The toxicity of a group of phthalate plasticiters (dimethyl-, diethyl-, dibntyl- and dioctyl phthalates) along the various paths through which they enter the organism was investigated along with the studies made in vivo in the plant.