Piles of dusty, black waste from coal and petroleum processing have been piling up on Chicago’s southeast side, angering residents and prompting Mayor Rahm Emanuel to weigh in on the contentious environmental issue.

The Sun-Times has reported that Emanuel will introduce an ordinance at next month’s City Council meeting banning new storage facilities for so-called petcoke—a byproduct of the oil refinery process that can be sold overseas. It’s a step back from an outright ban proposed in December by Alderman Edward Burke, whose constituents were outraged by black dust clouds wafting from uncovered piles of petcoke along the Calumet River.

Southeast side communities like Calumet, South Chicago, and South Deering are no strangers to industrial zoning. The Illinois-Indiana border has long been a pastiche of brownfields, residential communities, natural areas, and heavy industry. But the swirling black dust incited a class-action lawsuit filed against three storage sites last year.

Chicago’s Department of Public Health shares area residents’ concerns. “We know that petcoke is a respiratory irritant and the main concern is if the petcoke is inhaled,” Commissioner of Public Health Dr. Bechara Choucair told the Sun-Times. “If you have somebody with asthma or other respiratory problems, inhaling petcoke would really lead to more problems…We are advancing this ordinance to protect our residents.”

The anticipated zoning ordinance would prevent new petcoke storage facilities from entering the city, and would keep current outfits from expanding. KCBX, the largest such facility in the area, says the ordinance is unjustified, a sentiment shared by some business groups:

Mark Denzler, vice president of the Illinois Manufacturers’ Association called the ordinance “a solution in search of a problem.”

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The Illinois Chamber of Commerce is also questioning the ordinance, calling it an “overreaction.”

“We don’t understand what the mayor is trying to accomplish here. Petcoke and coal have been handled and stored in Chicago for decades with few issues. This seems like an overreaction to one incident – good policy rarely comes from overreacting,” Doug Whitley, Illinois Chamber of Commerce CEO said.

KCBX is an affiliate of Koch Industries, the business empire of brothers Charles and David H. Koch. Their company, Koch Carbon, came under fire last year for storing the same material along the Detroit River.