15A NCAC 02L .0405. REQUIREMENTS FOR LIMITED SITE ASSESSMENT

If the required showing cannot be made under 15A NCAC 02L .0404 of this Section, submit within 120 days of the discovery of the discharge or release, or within such other greater time limit approved by the Department, a report containing information needed by the Department to classify the level of risk to human health and the environment posed by a discharge or release under 15A NCAC 02L .0406 of this Section.  Such report shall include, at a minimum:

(1)           a location map, based on a USGS topographic map, showing the radius of 1500 feet from the source area of a confirmed release or discharge and depicting all water supply wells and, surface waters and designated wellhead protection areas as defined in 42 U.S.C. 300h-7(e) within the 1500-foot radius.  For purposes of this Section, source area means point of release or discharge from the underground storage tank system;

(2)           a determination of whether the source area of the discharge or release is within a designated wellhead protection area as defined in 42 U.S.C. 300h-7(e);

(3)           if the discharge or release is in the Coastal Plain physiographic region as designated on a map entitled "Geology of North Carolina" published by the Department in 1985, a determination of whether the source area of the discharge or release is located in an area in which there is recharge to an unconfined or semi-confined deeper aquifer which is being used or may be used as a source of drinking water;

(4)           a determination of whether vapors from the discharge or release pose a threat of explosion due to the accumulation of vapors in a confined space or pose any other serious threat to public health, public safety or the environment;

(5)           scaled site map(s) showing the location of the following which are on or adjacent to the property where the source is located:  site boundaries, roads, buildings, basements, floor and storm drains, subsurface utilities, septic tanks and leach fields, underground storage tank systems, monitoring wells, borings and the sampling points;

(6)           the results from a limited site assessment which shall include:

(a)           the analytical results from soil samples collected during the construction of a monitoring well installed in the source area of each confirmed discharge or release from a noncommercial or commercial underground storage tank and either the analytical results of a groundwater sample collected from the well or, if free product is present in the well, the amount of free product in the well.  The soil samples shall be collected every five feet in the unsaturated zone unless a water table is encountered at or greater than a depth of 25 feet from land surface in which case soil samples shall be collected every 10 feet in the unsaturated zone.  The soil samples shall be collected from suspected worst-case locations exhibiting visible contamination or elevated levels of volatile organic compounds in the borehole;

(b)           if any constituent in the groundwater sample from the source area monitoring well installed in accordance with Sub-item (a) of this Item, for a site meeting the high risk classification in 15A NCAC 02L .0406(1), exceeds the standards or interim standards established in 15A NCAC 02L .0202 by a factor of 10 and is a discharge or release from a commercial underground storage tank, the analytical results from a groundwater sample collected from each of three additional monitoring wells or, if free product is present in any of the wells, the amount of free product in such well.  The three additional monitoring wells shall be installed as follows: as best as can be determined, one upgradient of the source of contamination and two downgradient of the source of contamination.  The monitoring wells installed upgradient and downgradient of the source of contamination must be located such that groundwater flow direction can be determined; and

(c)           potentiometric data from all required wells;

(7)           the availability of public water supplies and the identification of properties served by the public water supplies within 1500 feet of the source area of a confirmed discharge or release;

(8)           the land use, including zoning if applicable, within 1500 feet of the source area of a confirmed discharge or release;

(9)           a discussion of site specific conditions or possible actions which could result in lowering the risk classification assigned to the release.  Such discussion shall be based on information known or required to be obtained under this Paragraph; and

(10)         names and current addresses of all owners and operators of the underground storage tank systems for which a discharge or release is confirmed, the owner(s) of the land upon which such systems are located, and all potentially affected real property owners.  When considering a request from a responsible party for additional time to submit the report, the Division shall consider the extent to which the request for additional time is due to factors outside of the control of the responsible party, the previous history of the person submitting the report in complying with deadlines established under the Commission's rules, the technical complications associated with assessing the extent of contamination at the site or identifying potential receptors, and the necessity for immediate action to eliminate an imminent threat to public health or the environment.

 

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(c)(4);

Amended Eff. December 1, 2005.