Free fatty acids are one of the substances produced by the breakdown of neutral fats. This dataset includes major raw and auxiliary materials, energy use, and atmospheric emissions from the production process; however, infrastructure such as production equipment and facility construction are not within the system boundary of the dataset. The life cycle inventory data were sourced from literature and optimized based on the best available information from 2022. The process of producing biodiesel from waste edible oil collection, treatment, and processing involves filtration and pretreatment, esterification, neutralization, separation, decolorization and purification, dehydration and deacidification, distillation, and refining. Among these steps, impurities and water in the oil are separated through heating followed by sedimentation. Free fatty acids are generated during this process. co-products of the process.