Internet of Things (IoT), together with fifth-generation (5G) mobile systems and related enabling communication technologies, constantly contributing for the enhancement in various industrial applications and driving towards the vision of complete industrial automation. In this context, both Blockchain and Edge computing are considered as promising technologies to fulfill the vision and requirements for the future Industry 4.0. The integration of these technologies together with massive scale Industrial IoT (IIoT) applications would be vital in addressing several key challenges related to e.g. latency, scalability and security of data processing and sharing, among others. However, such complex IIoT systems are constantly exposed to security threats from various sources. This paper focuses on identifying the major security challenges in the IIoT blockchain-edge related networks. In addition, some potential security solutions are presented in order to overcome these challenges.