Towards Practical Safety Contracts in Industry 4.0: Challenges, Examples, and Enabling Properties

Industry 4.0 (I4.0) envisions production systems with high adaptability, autonomy, and dynamic reconfiguration. However, this dynamism conflicts with established safety assurance practices, which rely on static certification of predefined system configurations. Safety contracts have been proposed to manage the safety challenges of I4.0 use cases such as Plug and Produce and Lot Size 1, yet they may leave residual risks arising from insufficient or incorrect implementation of safety functions. This paper analyzes these limitations and conceptualizes them as residual integration risks (RIR)—the risks that persist despite successful contract compliance checks. Through three motivating examples involving cobots, we illustrate how RIR can emerge in practice and discuss their technical and regulatory implications. We identify key properties and techniques that support RIR management, providing researchers with a conceptual framework and vocabulary for reasoning about the limits of contract-based safety. This work lays the foundation for the development of concrete mitigation strategies for managing RIR in industrial settings.