How much is H&S technical and how much is it about people?
The answer is....yes and no!
I am not much a fan of absolute binaries for describing things, especially when it is clear that most polarities exist on some form of continuum (e.g. MBTI characteristics, situational leadership, etc). Most people will have a "comfort zone" along that continuum, with preferences for a certain aspect that may be more fixed or more flexible - think of it as being a bit like being left-handed, right-handed or ambidextrous; some people can only use one hand and find the other a bit uncoordinated and useless, while others may cheerfully swap from one hand to the other with great ease (I used to watch someone do that on the tennis court to avoid having to hit a backhand shot!).
I have long contemplated the apparent "disconnect" between the concept of health and safety being about "keeping people safe"....and the actual real-world approach adopted by most traditional organisations, in which the primary focus of safety programmes is prevention of incidents in which assets and / or reputation could be damaged, including legal penalties, and people are still generally (if unconsciously) thought of in terms of their work output than as individuals.
Safety management itself could benefit from some meaningful root cause analysis to better understand its failings / shortcomings and opportunities to improve.
The technical requirements, as underscored by both Craig and Derek, are absolutely critical in high hazard workplace environments. And the correct place for these technical skills and competencies is primarily in design, planning, and guidance on risk assessment, communication and training, and supporting development of appropriate management systems.
The people requirements are absolutely vital for conveying critical safety requirements from the design and planning element of the organisation to implementation and BAU activities. Understanding people and the diversity of their values, needs, capabilities, etc is essential for everything from getting the right people for the work to be done safely (ie recruitment and selection, fit for the organisation and task, etc), developing teamwork and communication networks, and particularly for effective development of worker knowledge and skills.
Far too often, "training" is a critical failure point because technical experts are tasked with delivering information, precisely because of their technical expertise, but the technical experts lack the people skills and understanding of effective LEARNING processes and neurological factors, resulting in workers who have been "certified" but are NOT actually genuinely competent in functional ways. This also arises because training has not been designed and developed according to effective instructional design principles, including clarity about the appropriate logical levels of competency to be achieved and how these will be assessed - those paper-based assessments are often not worth much more than the paper they are written on.
There are actually at least 7 types or stages of learning processes, a range of sensory channels and preferences, individual personality types, values world views, and many other individual characteristics and variables, which then also have to consider the context of the organisation's culture and values, the industry in which the business operates, the actual workplace conditions, etc. These will never be addressed in a "one size fits all" approach, and burying one's head in the sand because of its complexity will only perpetuate the problems. Yes, it is complex, and no, it's not really something you can do once and "put on automatic" - that is why we are still struggling with it!
To successfully navigate all these individual human factors, a safety practitioner really needs to have a pretty good grasp of the full spectrum, with the ability to responsively "flex" between technical and people skills according to requirements of the current context. This in turn is likely to vary according to a number of other external factors..... I've often suggested that my role is more like being a bridge between the most technical elements and key requirements, and the people who do the work. I make a point of understanding the purpose of safety requirements, use my skills and experience to develop rapport and trust, and figure out what each person needs. I figure out their obstacles and help them to find solutions that work for them, without taking over and creating more barriers and obstacles!
Ultimately, only an individual can truly keep themselves safe, because I can't be everywhere and I don't have any remote controls for other individuals. All I can do is to help others to become aware, understand, commit and develop constructive mindsets. If I try to impose too much technical requirements without respecting their needs, I will only create resistance and make my job that much harder.