United States Environmental Protection Agency 1200 Pennsylvania Avenue, N.W. Washington, D.C. 20460 September 2011 Office of Solid Waste and Emergency Response 

# Support Document for the Revised National Priorities List Final Rule – Horton Iron & Metal Co.

# Support Document for the Revised National Priorities List Final Rule Horton Iron & Metal Co. September 2011

Site Assessment and Reme dy Decisions Branch Office of Superfund Remediati on and Technology Innovation Office of Solid Waste and Emergency Response U.S. Environmental Protection Agency Washington, DC 20460Horton Iron & Metal Co. NPL Listing Support Document September 2011



### Table of Contents

Executive Summary .................................................................................................................................... ii

Introduction ............................................................................................................................................... iii
Background of the NPL .......................................................................................................................... iii Development of the NPL ........................................................................................................................ iii Hazard Ranking System .......................................................................................................................... iv Other Mechanisms for Listing ................................................................................................................. v Organization of this Document ................................................................................................................ v Glossary

............................................................................................................................... ................... vi
1. List of Commenters and Correspondence ....................................................................................... 1

2. Site Description .................................................................................................................................. 1

3. Summary of Comments ..................................................................................................................... 2

3.1 Extent of Site

............................................................................................................................... . 2
3.2 Economic Impacts of Listing ........................................................................................................ 3
3.3 Delay Listing

............................................................................................................................... . 3
3.4 Source Containment ..................................................................................................................... 4
4 Conclusion .......................................................................................................................................... 6
Attachment 1: October 2009 EPA Letter Regarding Voluntary Actions

iHorton Iron & Metal Co. NPL Listing Support Document September 2011 

## Executive Summary Section 105(a)(8)(B) of CERCLA, as amended by SARA, requires that the EPA prepare a list of national priorities among the known releases or threatened releases of hazardous substances, pollutants or contaminants throughout the United States. An original National Prio rities List (NPL) was promulgated on September 8, 1983 (48 FR 40658). CERCLA requires that the EPA update the list at least annually. This document provides responses to public comments r eceived on the Horton Iron & Metal Co. site, proposed on October 21, 2010 (75 FR 64976). This site is being added to the NPL b ased on an evaluation under the EPA’s Hazard Ranking System (HRS) in a final rule published in the Federal Register in September 2011.

iiHorton Iron & Metal Co. NPL Listing Support Document September 2011 

## Introduction This document explains the rationale for adding the Hort on Iron & Metal Co. site in Wilmington, North Carolina, to the National Priorities List (NPL) of uncontrolled hazardous waste sites and provides responses to public comments received on this site listing proposal. The EPA proposed this site to the NPL on October 21, 2010 (75 FR 64976). This site is being added to the NPL based on an evaluation under the Hazard Ranking System (HRS) in a final rule published in the Federal Register in September 2011. 

### Background of the NPL In 1980, Congress enacted the Comprehensive Enviro nmental Response, Compensation, and Liability Act (CERCLA), 42 U.S.C. Sections 9601 et seq . in response to the dangers of uncontrolled hazardous waste sites. CERCLA was amended on October 17, 1986, by the Supe rfund Amendments and Reauthorization Act (SARA), Public Law No. 99-499, stat., 1613 et seq. To implement CERCLA, the EPA promulgated the revised National Oil and Hazardous Substances Pollution Contingency Plan (NCP), 40 CFR Part 300, on July 16, 1982 (47 FR 31180), pursuant to CERCLA Section 105 and Executiv e Order 12316 (46 FR 42237, August 20, 1981). The NCP, further revised by the EPA on September 16, 1985 (50 FR 37624) and November 20, 1985 (50 FR 47912), sets forth guidelines and procedures needed to respond under CERCLA to releases and threatened releases of hazardous substances, pollutants or contaminants. On Ma rch 8, 1990 (55 FR 8666), the EPA further revised the NCP in response to SARA. Section 105(a)(8)(A) of CERCLA, as amended by SARA, requires that the NCP include criteria for determining priorities among releases or threatened releases throughout the United States for the purpose of taking remedial action and, to the extent practicable, take into account the potential urgency of such action, for the purpose of taking removal action. Removal action involves cleanup or other actions that ar e taken in response to emergency conditions or on a short-term or temporary basis (CERCLA Section 101). Re medial action is generally long-term in nature and involves response actions that are consistent with a permanent remedy for a release (CERCLA Section 101). Criteria for placing sites on the NPL, which makes them elig ible for remedial actions financed by the Trust Fund established under CERCLA, were included in the HRS. The EPA promulgated the HRS as Appendix A of the NCP (47 FR 31219, July 16, 1982). On December 14, 199 0 (56 FR 51532), the EPA promulgated revisions to the HRS in response to SARA, and established the effect ive date for the HRS revisions as March 15, 1991. Section 105(a)(8)(B) of CERCLA, as amended, requires that the statutory criteria provided by the HRS be used to prepare a list of national priorities among the known rel eases or threatened releases of hazardous substances, pollutants or contaminants throughout the United States. Th e list, which is Appendix B of the NCP, is the NPL. An original NPL of 406 sites was promulgated on Septem ber 8, 1983 (48 FR 40658). At that time, an HRS score of 28.5 was established as the cutoff for listing because it yielded an initial NPL of at least 400 sites, as suggested by CERCLA. The NPL has been expanded several times since then, most recently on March 10, 2011 (76 FR 13089). The Agency also has published a number of proposed rulemakings to add sites to the NPL. The most recent proposal was on March 10, 2011 (76 FR 13113). 

### Development of the NPL The primary purpose of the NPL is stated in the legi slative history of CERCLA (Report of the Committee on Environment and Public Works, Senate Repor t No. 96-848, 96th Cong., 2d Sess. 60 [1980]).

iiiHorton Iron & Metal Co. NPL Listing Support Document September 2011 The priority list serves primarily informational purposes, identifying for the States and the public those facilities and sites or other releases which app ear to warrant remedial actions. Inclusion of a facility or site on the list does not in itself reflect a judgment of the activities of its owner or operator, it does not require those persons to un dertake any action, nor does it assign liability to any person. Subsequent government actions will be necessary in order to do so, and these actions will be attended by all appropr iate procedural safeguards. The NPL, therefore, is primarily an informational and mana gement tool. The identification of a site for the NPL is intended primarily to guide the EPA in determining which sites warrant further investigation to assess the nature and extent of the human health and environmental risks associated with the site and to determine what CERCLAfinanced remedial action(s), if any, may be appropriate. The NPL also serves to notify the public of sites the EPA believes warrant further investigation. Finally, listing a site may, to the extent potentially responsible parties are identifiable at the time of listing, serve as notice to su ch parties that the Agency may initiate CERCLA-financed remedial action. CERCLA Section 105(a)(8)(B) directs the EPA to list pr iority sites among the known releases or threatened release of hazardous substances, pollutants or contaminants, and Section 105(a)(8)(A) directs the EPA to consider certain enumerated and other appropriate factors in doing so. Thus, as a matter of policy, the EPA has the discretion not to use CERCLA to respond to certain types of releases. Where other authorities exist, placing sites on the NPL for possible remedial action under CERCLA may not be appropriate. Therefore, the EPA has chosen not to place certain types of sites on the NPL even th ough CERCLA does not exclude such action. If, however, the Agency later determines that sites not listed as a matter of policy are not being properly responded to, the Agency may consider placing them on the NPL. 

### Hazard Ranking System The HRS is the principle mechanism the EPA uses to place uncontrolled waste sites on the NPL. It is a numerically based screening system that uses information from initial, limited investigations -- the preliminary assessment and site inspection -- to assess the relative potentia l of sites to pose a threat to human health or the environment. HRS scores, however, do not determine th e sequence in which the EPA funds remedial response actions, because the information collected to develop HRS sco res is not sufficient in itself to determine either the extent of contamination or the appropriate response for a particular site. Moreover, the sites with the highest scores do not necessarily come to the Agency's attention first, so that addressing sites strictly on the basis of ranking would in some cases require stopping work at s ites where it was already underway. Thus, the EPA relies on further, more detailed studies in the remedial inves tigation/feasibility study that typically follows listing. The HRS uses a structured value analysis approach to scoring sites. This approach assigns numerical values to factors that relate to or indicate risk, based on conditions at the site. The factors are grouped into three categories. Each category has a maximum value. The categories are:

• likelihood that a site has released or has the potential to release hazardous substances into the environment;

• characteristics of the waste (toxicity and waste quantity); and

• people or sensitive environments (targets) affected by the release. Under the HRS, four pathways can be scored for one or more threats as identified below:

• Ground Water Migration (S gw ) - drinking water

ivHorton Iron & Metal Co. NPL Listing Support Document September 2011

• Surface Water Migration (S sw ) The following threats are evaluated for two separate migration components, overland/flood migration and ground water to surface water. - drinking water - human food chain - sensitive environments

• Soil Exposure (S s ) - resident population - nearby population - sensitive environments

• Air Migration (S a ) - population - sensitive environments After scores are calculated for one or more pathways acco rding to prescribed guidelines, they are combined using the following root-mean-square equation to determine the overall site score (S), which ranges from 0 to 100 :



### 4 S + S + S + S = S 2 a 2 s 2 sw 2 gw

If all pathway scores are low, the HRS score is low. Howe ver, the HRS score can be relatively high even if only one pathway score is high. This is an important requirement for HRS scoring because some extremely dangerous sites pose threats through only one pathway. For exampl e, buried leaking drums of hazardous substances can contaminate drinking water wells, but -- if the drums ar e buried deep enough and the substances not very volatile -- not surface water or air. 

### Other Mechanisms for Listing There are two mechanisms other than the HRS by whic h sites can be placed on the NPL. The first of these mechanisms, authorized by the NCP at 40 CFR 300.425(c)(2 ), allows each State and Territory to designate one site as its highest priority regardless of score. Th e last mechanism, authorized by the NCP at 40 CFR 300.425(c)(3), allows listing a site if it meets the following three requirements:

• Agency for Toxic Substances and Disease Registry (ATSDR) of the U.S. Public Health Service has issued a health advisory that recommends di ssociation of individuals from the release;

• the EPA determines the site poses a signi ficant threat to public health; and

• the EPA anticipates it will be more cost-effective to u se its remedial authority than to use its emergency removal authority to respond to the site. 

### Organization of this Document The following section contains the EPA responses to site-specific public comments received on the proposal of the Horton Iron & Metal Co. site on October 21, 2010 (75 FR 64976). The site discussion begins with a list of commenters, followed by a site description, a summary of comments and Agency responses to each comment. A concluding statement indicates the effect of the comments on the HRS score for the site.

vHorton Iron & Metal Co. NPL Listing Support Document September 2011

vi 

### Glossary The following acronyms and abbreviations are used throughout the text: Agency U.S. Environmental Protection Agency ATSDR Agency for Toxic Substances and Disease Registry CERCLA Comprehensive Environmental Response, Compensation, and Liability Act of 1980, 42 U.S.C. Sections 9601 et seq ., also known as Superfund CFR Code of Federal Regulations EPA U.S. Environmental Protection Agency ESI Expanded Site Investigation FR Federal Register HRS Hazard Ranking System, Appendix A of the NCP HRS score Overall site score calculated using the Hazard Ranking System; ranges from 0 to 100 MDL Method detection limit NCDENR North Carolina Department of E nvironment and Natural Resources NCP National Oil and Hazardous Substances Pollutio n Contingency Plan, 40 C.F.R. Part 300 NPL National Priorities List, Appendix B of the NCP PAH Polycyclic aromatic hydrocarbon PCB Polychlorinated biphenyl PRP Potentially responsible party RCRA Resource Conservation and Recovery Act RI/FS Remedial investigation and feasibility study SARA Superfund Amendments and Reauthorization Act START Superfund Technical Assistance and Response Team VOC Volatile organic compoundHorton Iron & Metal Co. NPL Listing Support Document September 2011 

## 1. List of Commenters and Correspondence EPA-HQ-SFUND-2010-0641-0004 Correspondence, da ted May 26, 2010, from Dee Freeman, Secretary, North Carolina Department of Environment and Natural Resources, letter supporting placement of the Horton Iron & Metal Co. site on the National Priorities List (NPL) EPA-HQ-SFUND-2010-0641-0005 Comment, dated Dece mber 23, 2010, from Ramona Cunningham O'Bryant, Smith Moore Leatherwood LLP on behalf of Horton Iron & Metal Company, Public Commenters 

## 2. Site Description
The Horton Iron & Metal Co. site (hereafter referred to as the Site) is the result of the release of hazardous substances from the Horton Iron and Metal Company a nd predecessors who owned and operated facilities at the same location. The Site is located along the west bank of the Northeast Cape Fear River in Wilmington, New Hanover County, North Carolina. The Site as scored in th e HRS documentation record at proposal includes areas of contaminated soils located east of the railroad tr acks on the Horton Iron & Metal Co. property—identified as Source 1—and the associated releases from the Site into Northeast Cape Fear River sediments. The Northeast Cape Fear River has been identif ied as a human food chain fishery. The property was owned by the American Agricultural Chemical Company from 1911 until 1949 and by Naco Fertilizer Company from 1949 through 1954. Fertilizer operations carried out by American Agricultural Chemical Company began on the property by 1915. During the time of fertilizer operations at the facility, acid chambers used in the fertilizer operations were typically lined with lead. W.R. Grace owned the property from 1954 until 1959, when it sold the property to Horton Iron & Metal. In 1962, Horton Iron & Metal leased the property to Horton Indus tries. In the 1960s, the Horton Iron and Metal Company dredged out the boat slips and dredge d material was placed on the property, along the northern, western and southern edges of the slips. During the 1960s and 1970s, Horton Industries conducted ship breaking of WWII Liberty ships in the two slips located on the property. In 1988, the U.S. Coast Guard found extensive oil staining around the metal crushing equipment on the property. A Notice of Violation (NOV) was issued in 1989, orde ring a ground water investigation and soil removal. The oil-stained soils were removed and later an undergr ound storage tank (UST) removal was conducted in 1996. Based on the North Carolina Department of Environmen t and Natural Resources (NCDENR) Division of Waste Management Superfund Section recommendation, th e Site was added to CERCLIS on July 11, 2002. An expanded site investigation (ESI) conducted in 2003 found elevated levels (as compared to background levels) of metals, polycyclic aromatic hydrocarbons (PAHs), pestic ides and polychlorinated biphenyls (PCBs) in soils at the Site. Ground water, surface water and sediment samples also contained elevated levels of several metals including arsenic, cadmium, copper, lead, nickel and zinc (as well as some pesticides in one ground water sample).
The areas of contaminated soil were further delineated during a 2007 removal asse ssment conducted by Tetra Tech, the Superfund Technical Assistance & Re sponse Team (START) contractor for the EPA. A 2009 ESI detected PCBs, PAHs, volatile organic com pounds (VOCs), lead, arsenic, cadmium and mercury in surface and subsurface soil samples. Deep subsurface soil samples (8 to 12 feet below ground surface) contained

1Horton Iron & Metal Co. NPL Listing Support Document September 2011

metals, including lead and arsenic. Sediment samples coll ected from the two slips contained elevated levels of PCBs, PAHs, mercury, arsenic and lead. Ground water samples contained arsenic, cadmium and lead in the ground water beneath the property. Based on the data gathered during the ESI, including the release of contaminants to the slips along the Northeast Cape Fear River, a human food chain fishery, the Site was recommended for further evaluation and possible in clusion on the National Priorities List (NPL). 

## 3. Summary of Comments Comments were submitted in opposition to listing the Hort on Iron & Metal Co. site on the NPL by Smith Moore Leatherwood LLP on behalf of the Horton Iron & Metal Company (Horton). Horton commented on the extent of the Site and the effects that the site definition and the NPL listing may have on property values. Horton also requested that the EPA delay listing to allow potentially responsible parties (PRPs) and the EPA to explore measures to address risks posed by the Site. Horton add itionally commented that the HRS documentation record at proposal did not appropriately consider the existence of a silt fence in its evaluation of source containment at the Site. 

### 3.1 Extent of Site

Comment : Smith Moore Leatherwood LLP, on behalf of the Horton Iron & Metal Company (hereafter referred to as Horton) commented that “EPA has identified the entire facility operated by Horton as the property proposed to be placed on the NPL.” Horton continued to quote the HRS documentation record as stating that “[f]or HRS purposes, the site consists of areas of contaminated soils located east of the railroad tracks on the Horton Iron & Metal Co. property and associated releases.” Horton requested that the EPA restrict the definition of the Site to the source area identified in Figure 3 of the HRS documenta tion record at proposal. This area included the former fertilizer manufacturing operations, the boat-breaking ope rations and the areas where dredge spoil was placed on the property. Response : The HRS documentation record at proposal did not de fine the extent of the NPL site as the facility or its present property boundaries. As quoted by the comment er, HRS (Section 1.1, Definitions) defines a site as “[a]rea(s) where a hazardous substance has been deposited, stored, disposed, or placed, or has otherwise come to be located. Such areas may include multiple sour ces and may include the area between sources.” Thus, the Site was appropriately delineated in the HRS evaluation as the contaminated soil source and associated releases of contamination. Additionally, placing a site on the NPL is based on an ev aluation, in accordance with the HRS, of a release or threatened release of hazardous substances, pollutants or contaminants. However, the fact that the EPA initially identifies and lists the release based on a review of c ontamination at a certain parcel of property does not necessarily mean that the site bounda ries are limited to that parcel. CERCLA Section 105(a)(8)(A) requires the EPA to list national priorities among the known “releases or threatened releases” of hazardous substances; thus, the fo cus is on the release, not precisely delineated boundaries. Further, CERCLA Section 101(a) defines a “facility” as the “site” where a hazardous substance has been “deposited, stored, placed, or otherwise come to be located.” The “come to be located” language gives the EPA broad authority to clean up contamination when it has spread from the original source. On March 31, 1989 (54 FR 13298), the EPA stated: HRS scoring and the subsequent listing of a release merely represent the initial [emphasis added] determination that a certain area may need to be addressed under CERCLA. Accordingly, EPA contemplates that the preliminary description of facility boundaries at the time of scoring will

2Horton Iron & Metal Co. NPL Listing Support Document September 2011

need to be refined and improved as more informa tion is developed as to where the contamination has come to be located; this refining step generally comes during the RI/FS stage. The revised HRS (55 FR 51587, December 14, 1990) ela borates on the “come to be located” language, defining “site” as “area(s) where a hazardous substance has been de posited, stored, disposed, or placed, or has otherwise come to be located. Such areas may include multiple sources and may include the area between the sources.” Until the site investigation process has been completed and a remedial action (if any) selected, the EPA can neither estimate the extent of contamination at the site, nor describe the ultimate dimensions of the NPL site. Even during a remedial action (e.g., the removal of buried waste) the EPA may find that the contamination has spread further than previously estimated and the site definition may be correspondingly expanded. In addition, if another, unrelated area of contamination is discovered elsewhere on the property, the EPA may decide to evaluate that release for the NPL. This comment results in no change to the HRS score and no change in the decision to place the Site on the NPL. 

### 3.2 Economic Impacts of Listing

Comment : Horton commented that “placing a property on th e NPL has enormously negative consequences for the owner and operator,” and that “[s]uch a listing destroys property values and makes future use of any portion of the property, even the unaffected portions, more cu mbersome and subject to regulatory review.” Response : Any negative impacts noted by Horton would be engendered by the contamination in the area, not by placing the site on the NPL. To the contrary, listing wi ll result in positive economic impacts when the site contamination has been addressed. While NPL listing certain ly provides additional public information on the site contamination, it also provides opportunity for residents, business owners and potential investors to gain detailed knowledge and express their concerns and ideas for final so lutions in the public forums offered during other phases of the Superfund process. Both costs and benefits can be associated with listing a site on the NPL. Among the benefits associated with NPL listing are increased health and environmental protecti on as a result of increased public awareness of potential hazards. Listing sites as national priority targets also may give States increased support for funding responses at particular sites. As a result of the additional CERCLA remedies, there will be lower human exposure to high-risk chemicals and higher quality surface water, ground water, so il and air. Therefore, it is possible that any perceived or actual negative fluctuations in property values or development opportunities that may result from contamination may be countered by positive fluctu ations when a CERCLA investigation and any necessary cleanup are completed.
Furthermore, the EPA has discovered a nd is publicizing by NPL listing, c ontamination at this site, and may require owners, operators a nd other PRPs to conduct or pay for cleanup. Costs may be imposed on the PRPs based on those remedial actions. However, that does not mitigate against placing eligible sites on the NPL, and is not a factor specified by CERCLA to be considered in the decision to list a site on the NPL [see CERCLA § 105(a)(8)(A)]. This comment results in no change to the HRS score and no change in the decision to place the Site on the NPL. 

### 3.3 Delay Listing

Comment : Horton stated that, upon inquiry by the EPA, it expressed interest in removal action negotiations. Horton commented that after the EPA agreed to meet w ith PRPs, the EPA “went forward with the scoring without informing the companies or giving them an opportunity to address the factors that have caused the Site to receive

3Horton Iron & Metal Co. NPL Listing Support Document September 2011

a high hazard ranking score.” Horton asserted that threats at the Site “can be reduced by controls on the property and by removal of materials from the boat slips and n earby sediments,” and that the EPA should delay NPL listing until it has determined PRP willingness to address the risks presented by the site. Response : Placing a site on the NPL is not delayed to allow negotiations regarding response actions to be completed. Proceeding with the listing process need not i nhibit efforts to determine response actions. If Horton or any designated PRP wishes to expedite cleanup efforts, it may continue negotiations with the EPA and undertake removal actions under supervision of the EPA and pursuant to appropriate agreements with governmental authorities (under enforcement authorities of CERCLA or those of other statutes). Placing a site on the NPL does not encumber or preclude PRPs from entering into th ese agreements. The EPA has entered into many such agreements before and after a site’s promulgation to the NPL, and such an alternative is available to others 1

. Furthermore, North Carolina has supported moving forward with NPL listing at the present time. This comment results in no change to the HRS score and no change in the decision to place the Site on the NPL. 

### 3.4 Source Containment

Comment : Horton noted that the HRS documentation record at proposal assigned a containment value of 10 to Source 1 (contaminated soil). However, Horton asserted th at “[t]he HRS Documentation Record does not reflect that, at the request of the EPA and in a manner approved by the State and the EPA, Horton installed a silt fence to restrict any migration from the former fertilizer manufacturing operations to the river and put up fencing to restrict access.” Horton concluded that the HRS documen tation record scoring should be revised to reflect this “engineered, functioning and well maintained run-off control system.” Response : The containment factor of 10 assigned to Source 1 in the HRS documentation record at proposal was consistent with the HRS. The presence of a silt fence does not alter this assessment.
HRS Section 2.2.3, Identify hazardous substan ces available to a pathway , directs the assignment of containment values in general: In evaluating each migration pathway, consider the following hazardous substances available to migrate from the sources at the site to the pathway:

. . . • Surface water migration—overland/flood component.

- Hazardous substances that meet the crit eria for an observed release to surface water in the watershed being evaluated.

- All hazardous substances associated with a source with a surface water containment factor value greater than 0 for the watershed (see sections 4.1.2.1.2.1.1 and 4.1.2.1.2.2.1).
HRS Section 4.1.2.1.2.1.1, Containment , directs the assignment of the su rface water overland/flood containment factor, stating in relevant part:
Determine the containment factor value for the watershed as follows:

1 For example see the following sites: Fort Hartford Coal Co. Stone Quarry, EPA ID KYD980844625; National Southwire Aluminum Co., EPA ID KYD049062375; Standard Auto Bumper Corp., EPA ID FLD004126520; Coleman-Evans Wood Preserving Co., EPA ID FLD991279894; CTS Of Asheville, Inc., EPA ID NCD003149556; Geigy Chemical Corp. (ABERDEEN PLANT), EPA ID NCD981927502; Interstate Lead Co. (Ilco), EPA ID ALD041906173; LCP Chemicals Georgia, EPA ID GAD099303182 ; Macalloy Corporation, EPA ID SCD003360476; Red Panthe r Chemical Company, EPA ID MSD000272385; and Woolfolk Chemical Works, Inc., EPA ID GAD003269578.

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•

. . . • If none of the sources is located in surface water in the watershed, assign a containment factor value from table 4–2 to each source at the site that can potentially release hazardous substances to the hazardous substan ce migration path for this watershed. Assign the containment factor value for the watershed as follows:

- Select the highest containment factor value assigned to those sources that meet the minimum size requirement described below. Assign this highest value as the containment factor value for the waters hed. Enter this value in table 4–1.

- If, for this watershed, no source at the site meets the minimum size requirement, then select the highest containment factor value assigned to the sources at the site eligible to be evaluated for this waters hed and assign it as the containment factor value for the watershed. Enter this value in table 4–1. A source meets the minimum size requirement if its source hazardous waste quantity value (see section 2.4.2.1.5) is 0.5 or more. Do not include the minimum size requirement in evaluating any other factor of this surface water migration component, except potential to release by flood as specified in section 4.1.2.1.2.2.3. HRS Table 4-2 directs the assignment of a containment factor of 10 for the contaminated soil source at a site if there is: [n]o evidence of hazardous substance migration from source area and: (a) Neither of the following present: (1) maintained engineered cover, or (2) fu nctioning and maintained run-on control system and runoff management system. Thus, a containment factor value of 10 would be assigne d unless one of the two controls was documented to be present. Section 2.2, Source Identification, Containment on page 22 of the HRS documentation record at proposal states that “[t]here is no maintained engineered cover or f unctioning and maintained run-on control system and runoff management system, and contaminated soil is ava ilable for continuous and ongoing overland flow.” There is no evidence of a maintained engineer cover a nd a silt fence does not qualify as a run-on control system and runoff management system because it typically only captu res large particulate; finer particulate and dissolved contaminants may still migrate with runoff through the silt fence. Furthermore, because soil contamination existed prior to the installation of the silt fence, contaminants had already migrated to surface water via runoff. The HRS documentation record at proposal established contamina tion in Source 1 based on soil samples collected in August 2009 (see section 2.4.1, Hazardous Substances, of the HRS documentation record at proposal), and observed releases were based on sediment samples coll ected in April 2003 and August 2009 (see section 4.1.2.1.1, Observed Release, of the HRS documentation reco rd at proposal. The agreement to install the silt fence was not made until after the releases were established, as documented in a meeting on September 30, 2009 (see Attachment 1, October 2009 EPA Lette r Regarding Voluntary Actions). Add itionally, a silt fence is generally only considered a temporary measure. That is, a silt fe nce would not prevent or obstruct the migration of hazardous substances from the source to surface water. Also, the commenter has only claimed that the silt fence is a runoff control system; for the second item required by HR S table 4-2 to be satisfied, there must be a “run-on control system and runoff management system.” Theref ore, the HRS documentation record is correct in its assignment of a containment factor value of 10 for Source 1. This comment results in no change to the HRS score and no change in the decision to place the Site on the NPL.

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## 4 Conclusion
The original HRS score for this site was 48.03. Based on the above responses to public comments, the Site score remains unchanged. The final scores for the Horton Iron & Metal Co. site are:

Ground Water: NS Surface Water: 96.06 Soil Exposure: NS Air Pathway: NS HRS Score: 48.03

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7 

## Attachment 1 October 2009 EPA Letter Rega rding Volunt ary Actions^^^t o sr. , UNITE D STATE S ENVIRONMENTA L PROTECTIO N AGENC Y REGIO N 4 ATLANT A FEDERA L CENTE R 

# isi s 6 1 FORSYT H STREE T

. /

• U PnQX'i y ATLANTA , GEORGI A 30303-896 0

OC

T 2 7 

### Horto n Iro n an d Meta l c/ o Mr

. Ralp h Horton , Sr

. P.O.Bo x 128 5 Wilmington , Nort h Carolin a 2840 2

SUBJ : Horto n Iro n an d Meta l Wilmington , Ne w Hanove r County , Nort h Carolin a
Dea r Mr

. Horton :
Th e purpos e o f thi s lette r i s t o confir m EPA' s understandin g ofth e action s yo u agree d t o voluntaril y perfor m t o contro l release s o f hazardou s substance s a t th e above-reference d Site

. Th e Unite d State s Environmenta l Protectio n Agenc y (EPA ) ha s documente d th e releas e o r threatene d releas e o f hazardou s substances , pollutants , o r contaminant s a t th e Site

. O n Jul y 21 , 2009 , EP A notifie d yo u ofth e potentia l liability , a s define d b y Sectio n 107(a ) ofth e Comprehensiv e Environmenta l Response , Compensation , an d Liabilit y Ac t o f 1980 , 4 2 U.S.C. § 9607(a) , a s amende d (CERCLA) , tha t yo u ma y hav e incurre d wit h respec t t o th e Site

. O n Septembe r 30 , 2009 , yo u me t with EPA' s O n Scen e Coordinator , Kennet h Rham e t o discus s action s yo u ca n tak e immediatel y t o reduc e worke r exposur e an d preven t contaminant s from migratin g off-sit e durin g stor m events

. Yo u agree d t o instal l a gate d acces s t o th e are a consistin g ofth e fonne r lea d aci d chamber s t o preven t unauthorize d entr y int o tha t location

. Additionally , yo u agree d t o instal l a sil t fenc e betwee n th e forme r fertilize r aci d chambe r are a an d th e boa t sli p t o preven t contaminant s from migratin g int o th e Northeas t Cap e Fea r River

. You r performanc e ofth e action s note d abov e wil l no t preclud e EP A from requirin g PRP s t o perfor m respons e activitie s i n th e fiatur e pursuan t t o CERCL A o r an y othe r applicabl e law

. Unles s EP A reache s a n agreemen t unde r whic h a potentiall y responsibl e part y (PRP ) o r partie s wil l properl y perfor m o r finance suc h actions , EP A ma y perfor m thes e action s pursuan t t o Sectio n 10 4 o f CERCLA

.
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