P2OASys provides a way for companies to assess the potential environmental, worker, and public health impacts of alternative technologies aimed at reducing toxics use. The tool offers a comprehensive and systematic method for thinking about the potential hazards posed by current and alternative processes identified during the TUR planning process. The tool allows the user to examine the potential environmental and worker impacts of options, while looking at the total impacts of process changes, rather than simply those of chemical changes alone. Comparison can be made by inputting both quantitative and qualitative data on the chemical toxicity, ecological effects, physical properties, and changes in work organization likely as a result of the proposed option. Embedded formulae in P2OASys provide a numerical hazard value for the company's current process and identified options.These values should then be combined with other information sources and professional expertise to make decisions on adoption of alternatives.