The problems of formation of toxic chlororganic compounds during waste incineration in the presence of organic and inorganic chlorine compounds are considered. It is shown that the radical mechanism of pyrolysis leads to different products with different composition of the initial substances. It was found that the greatest environmental danger is the joint burning of chlororganic and aromatic compounds. When burning polyvinyl chloride together with other polymeric materials, especially the aromatic structure, not only light chlororganic compounds are formed, but also highly toxic carbonyl chloride and chlor-furan. The formation of the above compounds represents a potential danger of further chemical conversions and the production of chlorinated dioxin compounds. It is proposed to prevent the formation of highly toxic compounds from the burning of polyvinyl chloride, its mandatory separation from the solid municipal waste stream and its separate processing by flameless methods.