The objective of the paper was to analyse by means a laser diffraction method, the granulometric composition of dust which settled on various surfaces of factory floors, where pellet was produced. A laser analyser of the size of particles MASTERSIZER 2000 was used in the research. Based on the research, it was found out that the sample of dust contained a limited amount of fractions particularly dangerous for health, i.e. PM4 and PM10 respectively 1.4% and 5.1%. The content of particles of dimension up to 100 μm did not exceed 60% of total volume of the analysed dust. Moreover, a shape of particles was analysed with the use of optic and scanning microscope and NIS –Elements BR software. Values of shape coefficients and histograms of their distribution were determined. Furthermore, relations between the size of particles and its shape were described.