From what I can read from google, the answer is absolutely not.
From seeing graphite guys grinding it for 30 years and having no adverse effects, it seems safe.
And from personal use, in very confined areas I feel nothing out of the ordinary.
Yet...we had a safety meeting and they say wear a good mask or lose lung capacity. I disagreed. (how dare me question experts)
The stuff is made of carbon, and its graphitized. Kinda like heat treating steel, it just changes the structure, not the contents. And carbon is harmless considering ALL living things are riddled with the stuff.
But is the dust harmless?
My theory, in lower doses its proberbly good for you, absorbing crap in your lungs and then absorbed or coughed out.
So now we have all these people walking around with masks to block the carbon.
What do you guys think? I bet is worse to live near a beach with the silica in the air.