by Eric Howard
On July 26, 2016 the North Carolina Department of Environmental Quality UST Section announced that the State Action Levels for Total Petroleum Hydrocarbons (TPH) had been changed. The previous TPH Action Limits of 10 mg/kg for hydrocarbons in both the gasoline range (GRO) and the diesel range (DRO) have been increased to 50 mg/kg for GRO and 100 mg/kg for DRO, respectively. TPH is defined as the concentration of petroleum fuel constituents present as carbon chains in the range of C6 through C35.
The Action Level is defined as the concentration of a contaminant that (if exceeded) may require further regulatory action, such as cleanup or monitoring. Per the NCDEQ, "The North Carolina Action Level of 10 mg/kg has been observed to produce MADEP hydrocarbon ranges and constituent specific analyses of less than the reporting limit in the majority of cases." Essentially, the previous Action Limits were determined to be too strict, and resulted in unnecessary expense when assessing a site for clean-up.
Previously, a site with soil TPH concentration values above 10 mg/kg (either GRO or DRO, or both) would be subject to further assessment, monitoring, and/or remediation. The most obvious benefit from this rule change is that sites where the NCDEQ required additional assessment or remediation under the previous regulatory action may be spared. Additionally, remediation standards of active sites have relaxed, potentially making clean-up faster and less expensive.