N.C. regulators: This is what led to controversial Duke Energy coal-ash classifications

State regulators say a controversial early draft of classifications for Duke Energy’s coal-ash ponds in North Carolina was largely based on incomplete dam safety information and lacking key data about groundwater and soil conditions at the sites. The N.C. Department of Environmental Quality has given its most detailed explanation to date for the significant difference between that early classification draft and the final recommendations made in December. The early draft listed 27 of Charlotte-based…