A decommissioned generating station in Waukegan is pictured in a file photo. (WTTW News)
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Right now, coal combustion residuals – commonly known as coal ash – aren’t subject to EPA regulation at many offline power plants. 

(WTTW News)

Coal ash, the byproduct created when plants burn coal for power, contains potentially dangerous materials like arsenic, mercury and cadmium that can endanger nearby water supplies. Since coal-fired power plants use a lot of water to keep their equipment cool, they’re often near bodies of water like Lake Michigan.

Activists want a date when the 88-year-old Waukegan coal-fired power plant will begin a transition to cleaner power. But NRG Energy says it's poured millions into pollution controls for the plant and has no plans to close.

Not that long ago, air pollution from burning coal made the Windy City more like the Smoggy City. Geoffrey Baer tells us how Chicago cleaned up its act.