An environmental tracking system provides facilities for modeling the processes of an organization that have an impact on the environment. The environmental tracking system allows each process to be modeled by its input substances and its resulting output substances. The environmental tracking system allows links to be established between the processes, such as indicating a source process and a destination process for a substance. Each process performs a conversion of input substances to output substances in accordance with conversion parameters specified for the process. Once the model of the processes of an organization is established, the environmental tracking system can track the flow of substances through the organization based on the model.