Dataset associated with the publication "Assessing the Environmental Potential of Hydrogen from Waste Polyethylene" by Cecilia Salah, Selene Cobo, and Gonzalo Guillén-Gosálbez, available at https://doi.org/10.1016/B978-0-323-85159-6.50322-5. The dataset includes the numeric data used both in Figure 2 and Table 1 of the manuscript, in a machine-readable format. The structure of the dataset is here elucidated sheet by sheet: Fig2-endpoint-results-breakdown: numerical values associated with the total endpoint environmental impacts of the different technologies per impact category, broken down by process component. These values are used to generate Figure 2 of the main manuscript. Tab1-endpoint-results-total: numerical values associated with the total endpoint environmental impacts of the different technologies per impact category. These values as displayed in Table 1 of the main manuscript.