Completed in 1973, Harding Street Station's tallest chimneys are 565 feet (172 m) in height.

[3] With its oldest coal-fired unit dating back to 1958, the plant was ranked 12th on the United States list of dirtiest power plants in terms of sulphur dioxide emissions per megawatt-hour of electrical energy produced from coal in 2005.

[citation needed] IPL stopped burning coal at the Harding Street facility in 2016 and retrofitted the units to natural gas.

[5][6] On the south side of the former plant is a sequence of unlined coal ash ponds.

Between 2016 and 2019, 24 of these were polluted above federal advisory levels of molybdenum, boron, lithium, sulfate, arsenic, antimony, selenium, and cobalt.