The project CircEl-Paper deals with the development of paper-based high-performance Printed Circuit Boards (PCB) with a special focus on the development of new or enhanced recyclable or biobased materials. The project is designed to close the loop of circular economy. In order to accelerate the modification of materials suitable to realize the circular economy approach for PCBs, the CircEl-Paper Hop-On activity enforces the assessment of (modified) materials with regard to ecotoxicity in an early development stage. This mainly refers to the impact on environment, in case the materials unintendedly leave the recycling loop. Therefore, cost-effective computational methos for the environmental safety assessment are developed. This activity contributes to the SSbD framework (Safe and Sustainability by Design). Based on these assessments, CircEl-Paper partners that deal with material development receive guidance and recommendations. The assessments are based on enhanced computational models for structure-activity relationships designed and operated at QSAR. The work is focused on the material classes that are investigated in the CircEl-Paper project, such as modified paper, electronic inks, adhesives and chemical auxiliaries. The results are also linked to the intensive work of Life Cycle Analysis (LCA) as performed in the mother project since data interfaces between the LCA and other tools are developed. Therefore, an additional task is added to the CircEl-Paper project and supports and guides the consortium activity. It is carried out by QSAR, a polish company.