Chicago health officials say huge mounds of petroleum coke along the Calumet River must be enclosed within two years to ease health and environmental concerns.
The Chicago Health Department issued regulations on Thursday to try to control a growing public outcry over "petcoke."
The grainy black byproduct of petroleum refining has been piling up along shipping channels in the Midwest, including Chicago's southeast side.
Residents have complained about soot from the piles blowing into their neighborhoods and fear it could cause health and environmental problems.
The regulations also will require air monitors, paved roads at the storage sites and daily sweeping.
KCBX Terminals Co. operates two storage sites in Chicago. A spokesman says the company is evaluating its ability to comply with the regulations but hopes to stay in business.