It has been shown that there is an urgent need for emissions data in the chemical sector. Since part of the problem is the confidentiality of this data, it has been proposed to create a set of modules for basic chemical reactions that could be incorporated in software simulation tools. Using mass and energy balances, proper emission calculations in mass units could be determined. An example using polyurethane is used to illustrate the objective of this work. Although theoretical, it is better than non-verifiable data, not to say non-existing data. This tool is a clear need for any type of assessment that requires emissions data such as LCA's, as well as for environmental policy, public awareness, and industry itself.