A thorough qualitative investigation of the relation between exergy losses and the environmental aspect of sustainability has been conducted. It is concluded that almost all environmental effects can be taken into account by studying the waste of feedstocks and energy, and the emission and dispersion of pollutants. On the basis of the results of two case studies, i.e., the production of aluminium and polystyrene, it can be made plausible that exergy losses and environmental impact are related. It is concluded that exergy loss is at least a qualitative measure that can be used in environmental policy making regarding technological processes.