Although petcoke is not classified as hazardous, it contains heavy metals and inhaling the fine particles can cause respiratory problems.
Shepherd said residents worry because "there's already lot of asthma, cancer and other illnesses around here."
Chicago's southeast side is an area where heavy industry and working-class residents have coexisted for generations — one neighborhood is even called Slag Valley. Immigrants came to work in the steel mills along Lake Michigan and many families stayed after the mills began closing.
They now dream of a renewal, including a city plan for a huge park at a former steel mill site, but worry that petcoke will "overtake the entire area and we'll have nothing but black mountains for miles and miles along the river," Shepherd said.
The stage is set for more. Petcoke production at the BP refinery is expected to triple next year, from 700,000 tons a year to 2.2 million tons, after a $4.2 billion upgrade scheduled for completion next month, spokesman Scott Dean said.
The company that handles BP's petcoke storage, KCBX, said it's spending more than $10 million on upgrades, including improved "dust-suppression capabilities."
But Emanuel spokesman Bill McCaffrey said the mayor is considering requiring that piles be completely or partially enclosed. Some states, such as California, have such requirements.