flowsa is a data processing library that attributes resource use, waste, emissions, and loss to economic sectors. flowsa aggregates, combines, and allocates data from a variety of sources. The sources can be found in the GitHub wiki under "Flow-By-Activity Datasets". flowsa helps support USEEIO as part of the USEEIO modeling framework. The USEEIO models estimate potential impacts of goods and services in the US economy. The Flow-By-Sector datasets created in FLOWSA are the environmental inputs to useeior.