15A NCAC 02L .0407      Reclassification of risk levels

(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 .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.

(e)  If the risk posed by a discharge or release is determined to be a low risk, the Department shall notify the responsible party that no cleanup, no further cleanup, or no further action is required by the Department unless the Department later determines that the discharge or release poses an unacceptable risk or a potentially unacceptable risk to human health or the environment. No notification shall be issued pursuant to this Paragraph, however, until the responsible party has:

(1)           completed soil remediation pursuant to Rule .0408 of this Section or as closely thereto as economically or technologically feasible;

(2)           submitted proof of public notification, if required pursuant to Rule .0409(b) of this Section; and

(3)           recorded all required land-use restrictions pursuant to G.S. 143B-279.9 and 143B-279.11.

History Note:        Authority G.S. 143-215.2; 143-215.3(a)(1); 143-215.94A; 143-215.94E; 143-215.94T; 143-215.94V; 143B-282; 1995 (Reg. Sess. 1996) c. 648,s. 1;

Recodified from 15A NCAC 02L .0115(e)-(h);

Amended Eff. December 1, 2005;

Readopted Eff. June 1, 2019.