Beryllium-Copper: How safe?

Geez, I have a set of beryllium copper golf irons that I don't use, maybe I should visit e-bay.

As stated in Albert's reference, it is my understanding that some years ago, stricter environmental controls increased costs related to manufacturing items with this material.

The information about beryllium dust vs the beryllium/copper alloy is correct.

Take a ride with me in my way-back machine. Decades ago when I worked in environmental control one of the sites I inspected was a beryllium smelter. I think it was the only one in the United States. Since I was told the ore came from South America, I always thought it was funny that the plant was located in my territory in a small town in northwestern Ohio.

The smelting and machining processes required strict environmental controls and personal protection including respirators and skin protection. The finished beryllium/copper alloy products (non-sparking hand tools)were safe to use without gloves. In fact I saw their non-sparking drum wrenches in use at many of the other sites I inspected.

Bottom line, don't worry about the alloy.

Though it is commonly believed that Copper Beryllium alloys are safe to handle, evidence suggests this is not true.  There are many factors that make copper beryllium dangerous such as corrosion, microscopic amounts of dust on the copper beryllium that can enter through open pores or cuts and product specific problems, such as shaving from a copper beryllium tool slipping and causing exposure to beryllium particles that can be breathed in.  OSHA has recently reduced exposure limits to beryllium to 0.2ug/m3.  

Here is a study in the Chest Journal outlining a case study of two women who developed Chronic Beryllium Disease from just handling Copper Beryllium products. https://journal.chestnet.org/article/S0012-3692(15)38252-0/fulltext#cesec10

Apple, the tech giant, has removed all Beryllium including Copper Beryllium.  https://www.apple.com/environment/safer-materials/

As long as we're on this subject, how about Beryllium tweets?

Keep in mind that beryllium copper connectors are generally plated with either gold, silver or rhodium (sometimes very heavily plated - as in the case with Furutech).  So, even though beryllium alloy may have a slight risk of being toxic, you would really never get to that "beryllium" metal through the plating, unless you used a grinder or scraper against that metal (which is highly unlikely unless you just wanted to ruin your connector).