H&S as a function of HR? "Do you ever find you need to take off your HR hat and put on your H&S hat to get the best outcome?"
Short answer is "NO"
I think what we all must constantly remember and recognize is - who it is who is writing out our pay cheque. That is the person we are serving.
I also have an approach which is to "always do the right thing". So if I do the right thing for the person paying my cheque, I will as a consequent be doing the right thing for the "workers" and also abide by whatever law might cover a given situation.
I don't take off one hat and put on the other. I think it is essentially the same hat - that is: what is the best way to manage this particular risk/issue. Its a philosophical / ethical approach - and discussion on that means entering a rabbit hole!.
So for example. We know bullying / violence is a risk. I've put in place a number of preventative steps. But when a guy pulled a box cutter knife and threatened a co-worker I fired him. Reflecting, I can see loads of steps in that total situation and each one I can say I 'did the right thing". One hat, two issues.
(Some people are very mis-guided on what the right thing is. I find a fact based, evidential approach helps)