Ethylene oxide (EO) is a commodity chemical made by treating ethylene with oxygen over a silver-based catalyst. One of its major applications is for making polyethylene terephthalate (PET) plastics used in water bottles. In the conventional process, up to 15% of the ethylene is simply burned as CO2. This chapter discusses an alternative process that employs methyltrioxorhenium (MTO) as a catalyst and hydrogen peroxide (H2O2) as an oxidant to produce EO with no CO2 as a byproduct. While the capital costs for both processes are similar, the EO production cost for the alternative process is competitive only if the MTO catalyst remains stable for at least one year and the Re leaching is <0.7 ppm. Unexpectedly, cradle-to-gate life cycle assessments (LCA) reveal that the overall environmental impacts on greenhouse gas emissions, air quality and water quality are similar for both processes. In the alternate technology, the carbon footprint associated with H2O2 production reduces the gains made in converting ethylene to EO avoiding CO2 as a byproduct. Direct H2O2 synthesis technology and effective H2O2 utilization are essential to reduce the environmental footprint of the alternate technology.