In their normal state the crystals are non-hazardous.

 In the unlikely event that breakage occurs, with crystal material spilling
 outside the packaging, the following precautions should be
 taken:
      1) Do not touch crystal dust
      2) Do not breath crystal dust
      3) Do not swallow crystal dust
      4) Sweep dust/crystal fragments carefully into a plastic bag or other sealed container
      5) Return dust/fragments to Mmme E Auffray at CERN.