Mass balance describes the relationship between input and output of a specific substance within a system in which the output from the system cannot exceed the input into the system. First attempts were made by plastic raw material producers to claim their products renewable (plasticsMaterials with large molecular chains of natural or fossil raw materials, produced by chemical or biochemical reactions. More) based on a certain input of biomassMaterial of biological origin excluding material embedded in geological formations and material transformed to fossilised material. This includes orga... More in a huge and complex chemical plant, then mathematically allocating this biomassMaterial of biological origin excluding material embedded in geological formations and material transformed to fossilised material. This includes orga... More input to the produced plastic. These approaches are at least controversially disputed. [bM 04/14, 05/14, 01/15]