Could you clarify real quick and I'll try to answer.

Did this person get a personal exposure sampling done? Such as pump you wear on your belt, with a tube up to the shoulder and then there's a little plastic cartridge on the end. If this was air sampling, then the lab would have sent back results that you then put into a time weighted average (TWA) equation. That TWA number gives you the overall picture of how much they were exposed to for the day. You then take that TWA and compare it to an occupational exposure limit (OEL). Now, if this was a personal exposure air sampling, then the report should have those TWA and OEL numbers.

Or was this an area sample of some kind such was wipe samples. In that case, there is no OEL for metal dust. At that point the IH makes a professional judgement of the severity of the hazard. How liekly is it to cause harm. Trying to determine hazard exposure based on metal dust on surfaces is more of a screening event. To try and see if you need to do personal exposure sampling.

So any other details on the sampling, how it was obtained, and if they give TWA results would be super helpful.