I think this list is a good starting point. On top is IT security. I would add the increased relevance of quality control. https://en.wikipedia.org/wiki/Industry_4.0#Challenges
It is really a nice and interesting topic you discussed.
To answer the question, let's brief the meaning of Industry 4.0.
Industry 4.0 promotes more extensive computerization based on new technologies including cyber-physical systems and the Internet of Things. Intelligence and an ability to communicate are being distributed down to individual machines and components. The goal is the creation of the “Smart Factory,” which uses technology to deliver greater adaptability, resource efficiency and ergonomics, as well as better information exchange among customers and business partners.
Now, coming to the point of safety aspects of the industries. (i) Sensor-based technology helps in automatic detection of accidents or health problems of the workers at work; (ii) Video surveillance system provides an excellent control on the environment that eventually helps in safety of workers; (iii) With the help of IoT devices and hybrid solutions, one can monitor and send across safety information which includes an employee’s biometrics. This, as a result, will help companies reduce their insurance cost through enhancing worksite safety in a smart and effective manner. Since workplace safety is a top concern, development and collaboration of such IoT technologies will be critical for companies to invest in [4]. Apart from this, you may also find some useful references/links given below that would help you extensively.
5. Botti, L., Duraccio, V., Gnoni, M. G., & Mora, C. (2015). A framework for preventing and managing risks in confined spaces through IOT technologies. In Safety and Reliability of Complex Engineered Systems-Proceedings of the 25th European Safety and Reliability Conference, ESREL (pp. 3209-3217).
In my opinion the topic human-robot/machine collaboration needs a special attention to safety aspects. There are several new and emerging technologies and solutions for collaborative robotics - but laws and normatives in various countries are not ready for these new technologies. Further, it depends a lot on the special situation (e.g. a collaborative robot with a cutting tool on the gripper remains unsafe and needs for other safety solutions)
Below you can find a work on safety in human-robot collaboration published and presented on a conference:
http://ieomsociety.org/ieom2018/papers/108.pdf
ROJAS, R.; RAUCH, E.; DALLASEGA, P.; MATT, D.T.: Safe Human-Machine Centered Design of an Assembly Station in a Learning Factory Environment. IEOM 2018 8th International Conference on Industrial Engineering and Operations Management, Dubai, March 6-8, 2018, accepted paper. Scopus indexed. (Best track award).