Due to increasing demand for wood even the wooden residues and old wood are gaining importance. The raw material is then used for energy purposes and the production of splinter plates. It is often contaminated with various chemicals (surface coatings, biocides, residues from construction or transport, etc.). Wanting to shed some light on the presence of inorganic pollutants in old wood and wooden residues in a wood processing company (Novoles), we took 20 samples of disused wood and wooden residues, and 2 samples of willow tree clones from plantations, and analysed their quantity with an x-ray fluorescent spectrometer (XRF). We compared the values with the allowed values set by EU legislation, and tried to find reasons for the presence of pollutants in wood. Using the XRF method we determined the presence of the following chemical elements: Cl, Cu, Fe, Pb, Zn, Cr, Br. We discovered that quantity of chloro compounds in most cases exceeded the allowed value prescribed by the Regulation on the processing of innocuous waste into solid fuel.