Copperberyllium is typically used to make high-strength, non-sparking, and electrically conductive components that performs well at cryogenic temperatures, since it gains tensile strength and ductility as it cools down.
Even though CuBe is a relatively stable alloy, it can release particulates of beryllium in the air when it is machined or heated. Beryllium is known for its toxicity upon inhalation.
Always remember that some alloys can decompose into their metallic elements, which can be dangerous by themselves even though the alloy is harmless.