Sounds like your lead has been burned before, but this question gets at the heart of a misconception about what occupational safety is. I’ll start with this: the role of an occupational safety professional is to support and protect workers. We aren’t Human Resources or management, even if the “safety guy” is titled “Safety Manager”. The purpose of the role is to identify hazards and prevent workers from being exposed to them. When an incident or a near miss occurs, our investigations are about one thing: determining what happened and coming up with ways to prevent it from happening again.
The caveat of course is that people are people. There are trustworthy managers (no, really) and trustworthy Human Resources people (I assume), and there are shitty safety guys. At the end of the day, though, a serious safety professional is going to take investigation data and focus on identifying the root cause of an incident and how to correct it. When I’m investigating an incident and find that the worker(s) involved fucked up, I’m not going to be thinking, “Well! If we fire Steve, problem solved!” I’m going to figure out what actually caused the fuck up. Was it fatigue? Overwork? Absent or insufficient training? Whatever the answer is, my concern isn’t going to be getting rid of Steve. Maybe we need to train better. Maybe we need to staff better to prevent overwork. Maybe we need to work with Steve to sort out fatigue issues. Whatever the root cause, that’s what I’m after.
Now, HR and management? They’re the ones who’ll think that shit-canning Steve will fix things. They want to find the simplest, cheapest way to stop seeing a problem.
If you really don’t think you can trust any of them, report shit to OSHA (or the governmental body in your country that oversees occupational safety).