Different types of dust are used in a variety of industries today. This industrial dust can be categorized as raw material, finished product, or waste. It is certainly necessary to carefully and safely handle dust-like materials. In general, it can be said that dust is any material with a granulation that does not exceed 500 μm in size. In all branches of industry where dust-like materials are used (food, pharmaceutical, petrochemical, wood processing, metal processing...), dust explosions cannot be excluded. In order for a dust explosion to occur a series of conditions must be created, which is not impossible. The obligation of the plant owner is to ensure plant safety with regard to personnel and the environment. Dust is very dangerous, and the awareness of its hazards is very low because dust is not considered to be as dangerous as gases. However, practical experience contradicts this. One method of preventing explosions of dust mixtures is inertization. Inertization is the process of reducing oxygen concentrations in explosive mixtures. The question is, which percentage of oxygen concentration should be achieved, and by which means could this be accomplished in the best and quickest way possible. The answers to these questions are provided by experimental research. The objective of this paper is to research the effect of two inert gases in an explosion of coal dust. CO2 and N2 are used as the inert substance. The experiment is performed in a sealed container of 20 dm3 in volume with the dust of high quality coal, with a granulation size of 71 μm. Ignition of the dispersed dust and air mixture is achieved with two chemical igniters, each with 5 kJ energy. Tests are performed on three different concentrations of coal dust: 250 gm-3, 500 gm-3 and 750 gm-3. Before everything the maximum explosion pressure without reduction of oxygen content was determined (in the mixture of air and dust for each concentration). After that reduction began of the oxygen percentage in the mixture in steps of 2 %, right up to the limit of 12 % oxygen. A total of 30 explosions were created and the explosion pressure curve was recorded. The time needed to ignite the mixture was measured and the maximum increase in pressure per time was determined. The effects of two inert gases on the maximum explosion pressure were observed through research. Analyses were performed based on these results, yielding curves of the movement of explosion pressures depending on the concentrations of dust and oxygen in the mixtures. Because of the occurrence of combustion gases in certain cases, there was an increase in explosion pressures even with relatively low percentages of oxygen (explosion pressures greater than those in conditions with 21 % oxygen). This fact indicates that when designing protection measures all the parameters of each process must be taken into consideration, and most important is extensive knowledge of the characteristics of the substances that occur in the process.