[bcohen5055]

While in undergrad I spent about 5 years working with carbon fiber in a motorsports setting. I did a lot of cutting and sanding without a mask. There were weeks I would blow my nose 3 days after working on a part and still find black specks. I guess I'll find out in a few years...

[claudius]

According to the article, this is the actually “good” variant: Normally, the dust is getting caught in the nose and does not reach the lungs. However, these fibres break down during a fire at temperatures of 650°C and become much smaller. This smaller size allows them to enter the lungs and potentially cause havoc there.

Put another way, every “black speck” you found did not reach your lungs (although I doubt that this is particularly healthy, either…) :)