Might be a regional issue, but everything I have take apart or looked at in my area is caked with the fine black powdery substance.
Likely something coming from the tank farms in our area??
The pumps are also supposed to have spin on oil filter looking post filters, but how often do these get changed and how fine are they.
I think I calculated about 2500-3000 gallons goes through the average filter in 60k miles???