The areas affected by thallium pollution include surroundings of cement plants producing Portland cement and clinker, as well as zinc and lead mills. The high toxicity of this element has beer, known for a long time, but no attention has been devoted to it. The symptoms of thallium poisoning are difficult to identify or distinguish from other illnesses, and accurate diagnosis is seldom possible. Although the problem exists in Poland, studies on thallium pollution and its effects generally have not been carried out.