ProScale is a Human Toxicity Assessment in Life-cycle-assessments (LCA): ProScale assesses direct hazard and exposure potentials from chemicals along their life cycle. The Hazard Factor, the Exposure Concentration Factor, the Persons-Hours Factor, and the Mass Flows are calculated for each substance and each unit process and then combined to establish the ProScale score. It can be integrated in LCA to compare human toxicity potentials of alternatives. Several companies from the Industrial Sustainability practitioner network (ISPN) were involved in the method development and applying the method in LCA.