This should give you the info you need.

http://www.copperinfo.co.uk/alloys/beryllium-copper/downloads/pub-104-copper-beryllium-health-and-safety-notes.pdf

My company machines beryllium copper. I have a health document I would like to share.

Suffice to say, BC is hazardous if precautions are not taken.

In it's inert form it's fairly benign, but dust, fumes, and particulate are all know carcinogens.