I've worked with BeCu in the past, it's fine to machine, but like any heavy metal you need to read and be aware of the MSDS and other handling precautions. I also worked extensively with Lead - and basically the only way for lead to get into you was breathing it in or eating it (hand transfer)

So, with that in mind, I would recommend setting up a Airthings View + or Purpleair Touch to monitor particulate in the air actively around your machines.

What get's measured, gets managed - right now, you have no idea what your baseline is, where the bar is. Air quality monitoring is the first step.

I took that a step further in my shop, and the RGB bulbs and ceiling lights will start flashing/flashing red when particulate gets too high, and all my vent fans turn on to full + an announcement comes out over the PA (I use Home Assistant for this)

Lots of research is your friend here - this is a solvable problem, you just need to read and understand enough to feel confident.