It is hardly necessary to say that synthetic materials are often harmful to humans. For example, polyvinyl chloride widely used for the production of plastic windows is not so harmful as it seems. For example, in the production of inexpensive profiles for stabilization of PVC at elevated temperatures, lead, extremely harmful to the human body, are added to it in small amounts. Of course, the amount of lead is insignificant and cannot cause serious harm to health, but suffering from allergic reactions, asthmatics and children can be uncomfortable in the rooms in which there are window blocks made of polyvinyl chloride.
