One of the critical trustworthiness requirements for industrial control systems is safety. Existing functional safety systems are not originally designed to provide protection against malicious intentional parties but only against accidents and errors. In this talk, first, fundamental trustworthiness aspects with regards to 5G-connected industrial networks will be given. Then, a generic smart manufacturing use case will be analyzed from a combined perspective of security and functional safety by an investigation of security vulnerabilities and threats on the safety-related system. Finally, some best practices based on related standards and security features of 5G mobile technology will be presented to explain how to mitigate effects of these security threats on safety.