North Carolina Administrative Code › Title 15A - Environmental Quality › Chapter 02 - Environmental Management › Subchapter L - GROUNDWATER CLASSIFICATION AND STANDARDS › Section .0400 - RISK-BASED ASSESSMENT AND CORRECTIVE ACTION FOR PETROLEUM UNDERGROUND STORAGE TANKS › Section 02L .0407 - 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) 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 and
				  15A NCAC
				  02N .0706 and
				  02N .0707. 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 shall be used to the maximum extent possible, 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.
(d) 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 and
				  15A NCAC
				  02N .0706. 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 and
				  15A NCAC
				  02N .0707. 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 .0406(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 shall be used to the maximum extent possible, if
					 the benefits of its use do not increase the risk to the environment and human
					 health.