Objective: The aim of this work is to describe the operation principle of the TRA ECETOC model developed using the descriptor system, and the utilization of that model for assessment of inhalation exposures to different organic solvents for selected process categories identifying a given application. Method: Measurement results were available for toluene, ethyl acetate and acetone in workplace atmosphere in Poland. The following process categories have been postulated: (1) Paints and lacquers factory: use in closed, continuous process with occasional controlled exposure; (2) Shoe factory: roller or brush application of glues; (3) Refinery: use in closed process, no likelihood of exposure. The next step was to calculate the workplace concentration at chosen process categories by applying the TRA ECETOC model. Results: The selected categories do not precisely describe the studied applications. Very high concentration values of acetone were measured in the shoe factory, mean 443 ppm. The concentration obtained with the aid of the model is underestimated, ranging from 25.47 to 254.7 ppm, for the case with and without activation of the local exhaust ventilation (LEV), respectively. Estimated concentration at a level corresponding to that of the measured concentration would be possible if the process category involving spraying, e.g., PROC 7 was considered. For toluene and ethyl acetate, the measured concentrations are within the predicted ranges determined with the use of the model when we assume the concentration predicted with active ventilation for the beginning, and the concentration predicted with inactive ventilation for the end of the range. Conclusions: Model TRA ECETOC can be easily used to assess inhalation exposure at workplace. It has numerous advantages, its structure is clear, requires few data, is available free of charge. Selection of appropriate process categories related to the uses identified is guarantee of successful exposure assessment.