North Carolina Administrative Code › Title 15A - Environmental Quality › Chapter 02 - Environmental Management › Subchapter L - GROUNDWATER CLASSIFICATION AND STANDARDS › Section .0500 - RISK-BASED ASSESSMENT AND CORRECTIVE ACTION FOR PETROLEUM RELEASES FROM ABOVEGROUND STORAGE TANKS AND SOURCES › Section 02L .0507 - RECLASSIFICATION OF RISK LEVELS

Current through Register Vol. 39, No. 2, July 15, 2024
(a)
				  Each responsible party shall have the continuing obligation to notify the
				  Department of any changes that may affect the level of risk assigned to a
				  discharge or release by the Department if the change is known or should be
				  known by the responsible party, including changes in zoning of real property,
				  use of real property, or the use of groundwater that has been contaminated or
				  is expected to be contaminated by the discharge or release.
(b) The Department shall reclassify the risk
				  posed by a release if warranted by further information concerning the potential
				  exposure of receptors to the discharge or release or upon receipt of new
				  information concerning changed conditions at the site. After initial
				  classification of the discharge or release, the Department may require limited
				  assessment, interim corrective action, or other actions that the Department
				  believes will result in a lower risk classification.
(c) Remediation of sites with off-site
				  migration shall be subject to the provisions of
				  G.S.
				  143-215.104AA.
(d) If the risk posed by a discharge or
				  release is determined by the Department to be high risk, the responsible party
				  shall comply with the assessment and cleanup requirements of Rule .0106(c),
				  (g), and (h) of this Subchapter. The goal of a required corrective action for
				  groundwater contamination shall be restoration to the level of the groundwater
				  standards set forth in Rule .0202 of this Subchapter, or as closely thereto as
				  is economically and technologically feasible. In a corrective action plan
				  submitted pursuant to this Paragraph, natural attenuation may be used when the
				  benefits of its use do not increase the risk to the environment and human
				  health. If the responsible party demonstrates that natural attenuation prevents
				  the further migration of the plume, the Department may approve a groundwater
				  monitoring plan.
(e) If the risk
				  posed by a discharge or release is determined by the Department to be an
				  intermediate risk, the responsible party shall comply with the assessment
				  requirements of Rule .0106(c) and (g) of this Subchapter. As part of the
				  comprehensive site assessment, the responsible party shall evaluate, based on
				  site specific conditions, whether the release poses a significant risk to human
				  health or the environment. If the Department determines, based on the
				  site-specific conditions, that the discharge or release does not pose a
				  significant threat to human health or the environment, the site shall be
				  reclassified as a low risk site. If the site is not reclassified, the
				  responsible party shall, at the direction of the Department, submit a
				  groundwater monitoring plan or a corrective action plan, or a combination
				  thereof, meeting the cleanup standards of this Paragraph and containing the
				  information required in Rule .0106(h) of this Subchapter. Discharges or
				  releases that are classified as intermediate risk shall be remediated, at a
				  minimum, to a cleanup level of 50 percent of the solubility of the contaminant
				  at 25 degrees Celsius or 1,000 times the groundwater standard or interim
				  standard established in Rule .0202 of this Subchapter, whichever is lower, for
				  any groundwater contaminant except ethylene dibromide, benzene, and alkane and
				  aromatic carbon fraction classes. Ethylene dibromide and benzene shall be
				  remediated to a cleanup level of 1,000 times the federal drinking water
				  standard as referenced in
				  15A NCAC
				  18C .1518, incorporated by reference
				  including subsequent amendments and editions and available free of charge at
				  http://reports.oah.state.nc.us/ncac/title 15a - environmental quality/chapter
				  18 - environmental health/subchapter c/15a ncac 18c
				  .1518.pdf. Additionally, if a corrective action plan
				  or groundwater monitoring plan is required under this Paragraph, the
				  responsible party shall demonstrate that the groundwater cleanup levels are
				  sufficient to prevent a violation of:
(1) the
				  rules contained in
				  15A NCAC
				  02B;
(2) the standards contained in Rule .0202 of
				  this Subchapter in a deep aquifer as described in Rule .0506(2)(b) of this
				  Section; and
(3) the standards
				  contained in Rule .0202 of this Subchapter at a location no closer than one
				  year time of travel upgradient of a well within a designated wellhead
				  protection area, based on travel time and the natural attenuation capacity of
				  the subsurface materials or on a physical barrier to groundwater migration that
				  exists or will be installed by the person making the request.
In any corrective action plan submitted pursuant to this
					 Paragraph, natural attenuation may be used if the benefits of its use does not
					 increase the risk to the environment and human health and shall not increase
					 the costs of the corrective action.