Some studies were conducted on the analysis of environmental impact of chemical pretreatment technologies. For instance, the life-cycle assessment (LCA) was used to evaluate the impact of chemical pretreatment technologies on the environment. LCA is a conceptual framework and methodology for the assessment of environmental impacts of product systems on a cradle-to-grave basis [158]. Analysis of a system under LCA encompasses the extraction of raw materials and energy resources from the environment, the conversion of these resources into the desired products, the utilization of the product by the consumer, and finally the disposal, reuse, or recycle of the product after its service life [159]. The LCA approach is an effective way to introduce environmental considerations in process and product design or selec­tion. Based on LCA studies, the chemical pretreatment for bio-ethanol production technologies can be compared. Energy production and utilization cycles based on cellulosic biomass have near-zero greenhouse gas emissions on a life-cycle basis [160]. Biomass utilization into ethanol production offers environmental benefits in terms of nonrenewable energy consumption and global warming impact [161].