Selective electrophilic addition of ozone to sulfur compounds, double bonds of olefins, and pi bonds of aromatics allows these substances to be converted into compounds of other classes that are much more amenable to hydrogenolysis under catalytic hydrotreatment conditions than the parent compounds. An integrated study on the enhancement of the hydrogen treatment process over the industrial catalyst GP-497T by feedstock ozonation was first attempted. Data on the influence of the specific ozone consumption and process parameters on the efficiency of removal of sulfur compounds and polycyclic arenes are presented. Under conditions that simulate the operation of industrial hydrotreating units, representative samples of low-sulfur environmentally benign diesel fuels meeting the requirements of the national and European standards for environmentally clean diesel fuel were obtained.