It is very important to handle a broken CFL bulb with care.
Yes, it contains mercury. Not a lot, but the mercury is in powder form which is a very dangerous form, especially if inhaled. But if you breath in the powder, how much is a dangerous too much? Nobody seems to want to touch that one.
So is breaking one bulb dangerous?
Well, why risk it?
As to the one in the photo, this is complicated by the fact that hanging this way the interior wiring is exposed to the touch.
So double your danger, double your fun!
How did this bulb break?
Likely by someone trying to screw it in the same way an incandescent bulb is screwed in - by holding the glass.
A CFL bulb should always be held by the base when installing or removing. That is the only part of the assembly that has any integrity.
WHEN INSTALLING, NEVER HOLD A CFL BULB BY THE GLASS!
That is different from the incandescents we all grew up with. But you can see why. It might break!
And on top of that, this one still lights up! So the installer, after breaking it, may have pulled the string, found out it still lights, and left it there anyway! Why not! It still works! Wonderful.
My recommendation: if a CFL bulb breaks away from the base when you are screwing it in, don't leave it there! It's broken! Even if it still lights up - it's broken! And obviously, if the bulb breaks, run for the nearest exit, call 911 and Hazmat, curl up in a fetal position in the front yard, suck your thumb, and wait for help to arrive! Really.
Jay Markanich Real Estate Inspections, LLC
Based in Bristow, serving all of Northern Virginia.
Office (703) 330-6388 Cell (703) 585-7560