I heard the $4000 Focal Utopia Headphones yesterday

Very nice. Very expensive. Beryllium drivers.  Reviews a bit hyped I think. Who would pay that premium otherwise? Not sure I could live just with any headphones still.

4b9c724a 509c 4bb1 a384 a61b6782a9d0Ag insider logo xs@2xmapman
OK that would seal it.  No beryllium headphones for me then. :^)
I have worked extensively with using beryllium-copper alloy in various components and don't recall any special handling procedures in the factory for such materials. We used them in designing the casings for components that were exposed directly to salt water in under-sea telecom cable applications. I don't think anyone uses pure beryllium in any consumer product applications. I have little doubt Focal has done enough research to make sure it is harmless. This is of course all moot (for me) since I would never ever pay that much for headphones unless that was the only method I could listen to music for the rest of my life....

I personally wouldn't get too paranoid about it, The women I referred to worked in an electro-plating plant handling and wiring components all day long. There are many potentially toxic materials in all our lives that are potentially worse. The beryllium domes used in transducers are always covered often due to their fragility as seen on Yamaha NS1000 monitors. Beryllium may be toxic if handled directly over extended periods but it's not exactly radioactive. Some people swear by beryllium drivers and some swear at them , at the end in this hobby it's all about subjective implementation and I'm certain Focal have done their homework and sound wonderful as they should for the money..

I belive beryllium is dangerous during the manufacturing process but left alone is stable.  It is brittle and can be poked with a finger which is  why there is a metal grill over the beryllium mid/tweeter of my TAD's.   
Beryllium is toxic, period. Skin contact usually only raises a rash, but forming the stuff is always left to specialty shops, which is why you can't just buy some to play with. Beryllium copper alloy is mostly copper, which is why it is safe to use.