City staff charged with reviewing a proposal to move coal ash from basins around Charlotte to the airport said Monday that they've issued a counter proposal to Duke Energy. The details of the plan were withheld, however, to allow Duke time to assess the plan's details and respond, assistant City Manager Hyong Yi told City Council's Environmental Committee during a meeting Monday.

Though the counter proposal does include the airport, it will presumably ax a plan to move the coal ash under runways, which city staffers deemed unsafe, no matter how small the risk may be of a spill, Yi said.

"As small as that risk might be that something might happen to the encapsulation, the risk is still there," Yi said. "It's still too great for the airport consider given what the consequences would be if such an event would ever occur," such as a leak. "Tomorrow, 50 years from now, 100 years from now."

Staffers were given 60 days to perform a "due diligence review" of a proposal by Duke Energy and a company that specializes in repurposing coal ash to fill that would have moved coal ash in basins around the Charlotte area to the Charlotte Douglas International Airport. "Just like we need time from Duke to do our due diligence, staff's counter proposal to Duke was not what they anticipated, nor what they were prepared for," Yi said.

Options are limited as to where the coal ash could go, he said. Besides moving it to another part of the airport, Duke Energy could build a landfill to house the toxic material, which would require regulatory permits.

Yi said he will present the counter proposal to the environmental committee in August.