The black spots I am talking about is hard, loose, and very tiny. That's the activated carbon from the filter. No big deal. Just don't inhale them into your lungs.
My dad worked where they made the carbon stuff. He died of lung disease at age 63 and he out lived all his co-workers who started around the same time he did. In short, no body made it to retirement there. The new guys work under strick safety requirements now.
Stush