. >> reporter: from her second floor apartment susannah gomez can see what looks like mounds of black> see how it's much thicker. it's not like regular dust. >> reporter: because of concern about what is in the air, she tries to keep her kids indoors. >> it's hard to breathe around it and it just gets very sticky. in the summertime you can see it stuck on your skin. >> reporter: it turns out that these piles of crumbly black powder are a high sulfur, high carbon by properties of crude oil called pet coke. thousands of pounds of it are being stored on the chicago's southeast eyed. >> the united states is where star sands oil the dirtiest of the dirty oil in the world is being refined. and it's being refined and leaving a waste stream of pet coke. >> reporter: it's shipped from bps writing, indiana oil refining to a company controlled by industrialists charles and david coke. >> reporter: community activists say when the wind blows clouds of black dust blanket their nearby neighborhoods. >> it travels throughout the community. and our concern is that it's in the air we breathe. it affec