UNITED STATES ENVIRONMENTAL PROTECTION AGENCY REGION6

1445 ROSS AVENUE, SUITE 1200 DALLAS TX 75202-2733

APR 1 2 2016

MEMORANDUM

SUBJECT: National Remedy Review Board Revie American Creosote Works Inc. SuR rfl

FROM:

TO:

Carl E. Edlund. P.E. , Directo Superfund Division (6SF)

James E. Woolford, Director

roposed Response Action

Office of Superfund Remediation and Technology Innovation (OSRTI)

Introduction and Purpose

This memorandum provides Region 6' s rationale that the proposed response action at the American Creosote Works Inc. (ACW) Superfund site in Winnfield, Louisiana, does not warrant a National Remedy Review Board (NRRB) review. The Office of Solid Waste and Emergency Response (OSWER) Directive 9285.6-21 (National Remedy Review Board Criteria Revision and Operational Changes, September 4, 2014), call for regions to implement a regional remedy review team (RRRT) to evaluate Superfund site response actions costing between $25 million and $50 million to determine if a full NRRB is warranted or not. The preferred proposed response action at the ACW site is estimated to cost $25 million. The Region 6 RRRT reviewed the ACW proposed remedy and recommended that a full NRRB review is not warranted.

The Site Remedial Project Manager has had several conversations over the last 2 years concerning development of the proposed response action with Office of Superfund Remediation and Technology Innovation (OSRTI) staff within the Assessment and Remediation Division and the Technology Innovation and Field Services Division.

Regional Remedy Review Team Process

The Region 6 RRRT was comprised of the Remedial Branch Chief (John Meyer), two Remedial Section Chiefs (Carlos Sanchez and Blake Atkins), the State of Louisiana ACW site project manager (John Halk), four senior Remedial Project Managers (RPMs) familiar with similar proposed remedy technologies (Vincent Malott, Camille Hueni, David Abshire, and Ursula Lennox), the site risk assessor (Kenneth Shewmake), a senior risk assessor who has previous experience with the site (Jon Rauscher) , the site attorney (Jacob Piehl), the site enforcement officer (Bob Werner), and a community involvement staff member (Adam Weece).

Internet Address (URL) • http://www.epa.gov/region6 Recycled/Recyclable • Printed with Vegetable Oil Based Inks on 100% Recycled Paper, Process Chlorine Free

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On February 25, 2016, the RPM presented the following information to the Region 6 ACW RRRT:

ACW site setting and background

Overview of current remedy

Rationale for initiation of a Revised FS and alternate remedy strategy

Summary of revised risk assessment results

Areas of the ACW site that have unacceptable risks

Proposed Remedial Action Objectives

Summary of Remedial Action Alternatives

Summary of Nine Criteria Evaluation

Detailed description of the preferred response action, including IC’s and cost

Key factors for proposing the preferred response action

Timing of activities concerning the preferred response action

Potential issues that could affect implementation of the preferred response action

Summary of OSWER Directive 9285.6-21 stakeholder/site circumstances issues

After the RPM’s presentation, Mr. John Halk, the State of Louisiana ACW site project manager presented

the State’s perspective concerning the ACW site. Mr. Halk has been the State’s project manager on the

site for over 20 years and has been intimately involved in the development of the Revised RI/FS. Mr.

Halk indicated that the State does not see the benefit from continuing operations of the current remedy

and therefore, is in agreement with and supports EPA’s preferred remedy. After Mr. Halk’s comments,

the ACW RRRT engaged in questions and deliberations with the Site RPM. Comments provided by the

RRRT during the February 25, 2016, meeting are attached along with responses from the Site RPM.

Site Information and Proposed Response Action

The ACW site is located (see Figure 1) in the City of Winnfield in Winn Parish, Louisiana. Decades of

wood treating activities and improper waste disposal contaminated soil, sediment, surface water and

groundwater with polycyclic aromatic hydrocarbons (PAHs), pentachlorophenol (PCP), benzene and

dioxin. The EPA placed the Site on the National Priorities List in October 1992. Removal actions in the

late 1980s addressed immediate threats to human health and the environment. EPA selected a long-term

remedy to address remaining contamination in a 1993 Record of Decision (ROD). Cleanup began in 1993

and included on-site incineration of highly contaminated tar and sludge; capping of contaminated surface

soil; in-place biological treatment of contaminated subsurface soil; and extraction, separation and

treatment of groundwater and non-aqueous phase liquids (NAPLs).

Due to several years of declining remedy performance and growing concerns of the long-term

effectiveness of the Site’s NAPL recovery and in-place biological treatment systems, EPA initiated an

evaluation in 2010 to develop a more sustainable remedy. Incremental funding resulting from budget and

resource constraints delayed the initiation and/or completion of various activities of this evaluation. EPA

completed a new remedial investigation in April 2014. The 2014 Remedial Investigation Report verified

that the Site’s treatment systems are not effectively addressing remaining site contamination, and also

discovered the presence of site related soil contamination outside of the Site’s previously-established

boundary.

The revised risk assessment evaluated seven different areas (Figure 2), called Decision Units (DU). The

Site was divided into these seven DU’s to facilitate risk management decisions that would be incorporated

into a revised remedy. The seven DU’s that were evaluated were:

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1. Southern DU (15.6 acres). This area, also known as the south parcel in the 1992 RI/FS and 1993

ROD, was reportedly used primarily to store untreated wood. Some non-recyclable scrap metal

and other non-hazardous debris generated during the 1987-1989 removal actions was reportedly

buried here. The area is now principally owned by the Winn Parish Police Jury. EPA released this

area for use in 1998. The Police Jury leases the property to a local earthwork contractor.

2. Process Area DU (14.2 acres). This area, which is part of the north parcel described in the 1992

RI/FS and 1993 ROD, is where historical wood-treatment operations were conducted. Four

impoundments, where liquid wood-treating wastes were managed, and a waste cell containing

stabilized material from the 1987 removal action and 7,000 CY of low-level contaminated soil

excavated from the Tar Mat Disposal Area are also present. This DU, and the adjacent Non-

Process Area and Tar Mat DUs, are principally owned by Winn Parish but under the control of

EPA through an access agreement and a perimeter fence. The ongoing NAPL recovery and in situ

bioremediation remedy in this DU is addressing the subsurface source of contamination in this

DU.

3. Non-Process Area DU (10.5 acres). This area lies to the east and southeast of the Process Area DU

and contains the fire water pond. This area also contained a portion of the tarry sludge-like

material, which was excavated and incinerated between 1996 and 1998.

4. Tar Mat DU (2.4 acres). This area contained a majority of the 25,000 CY of tarry sludge-like

material, which was excavated and incinerated between 1996 and 1998. The ash generated from

the incineration of this material was placed in the Tar Mat Ash disposal area, a geotextile-lined

and clay-covered disposal cell located in this DU.

5. Northern DU (9.9 acres). Treated wood was transported by rail from the former process area to

this area for drying and staging prior to customer shipment.

6. Creek DU (4.7 acres). This area includes the far western, western, and northern branches of

Creosote Branch Creek that flows through the ACW site. Site-related contaminants were detected

in sediment samples taken from the creek during the 1992 RI/FS and in samples collected in 2008

and 2013.

7. Western DU (4.3 acres). This area contained ACW’s former administration offices. A bridge

across the western branch of Creosote Branch Creek, which has since been removed, provided

access to the former process area where wood-treating operations were conducted.

The additional site information collected post-1993 ROD was utilized to develop an updated risk

assessment. This revised risk assessment identified the following major contaminants of concern (COC):

● Volatile organic compounds – benzene, toluene, ethylbenzene, and xylene (BTEX)

● Phenols – PCP, phenol, 2,3,4,6-tetrachlorophenol, 2,3,5,6-trichlorophenol, and cresols

● PAHs – naphthalene, phenanthrene, fluorine, anthracene, and benzo(a)pyrene

● Dioxins/furans

The post-1993 site remedy investigation activities performed in 2003, 2008, 2012, and 2013 confirmed

the presence of the above COCs in all the above 7 DU’s. Based upon the evaluation performed during the

revised risk assessment, there was unacceptable risk in three of the seven DU’s. These three DU’s and

their associated unacceptable risks (Tables 1, 2, and 3) are as follows:

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1. Northern DU – surface soil. Maximum‐based intake (doses) for the deer mouse yielded No Observed Adverse Effect Level based HQ’s ranging from 3.4 to 30.4, which exceeds the

CERCLA target ecological HQ of 1.0.

2. Non‐Process Area – surface soil. The industrial worker excess lifetime cancer risk (ELCR)

of 8.3 x 10‐4 exceeded the upper bound CERCLA target risk of 1 x 10‐4.

3a. Process Area – surface and subsurface soil. The industrial worker surface soil ELCR of 2.9 x 10‐4

exceeded the upper bound CERCLA target risk of 1 x 10‐4. The industrial worker subsurface soil

ELCR of 1.4 x 10‐3 also exceeded the upper bound CERCLA target risk of 1 x 10‐4.

3b. Process Area and Non‐Process Area shallow aquifer groundwater impacted by the source area. Groundwater was carried forward into the FS based on the following considerations:

- Shallow aquifer groundwater is not a current (Class IIA) drinking water source; however, based

on EPA groundwater classification guidance (EPA, 1986a) it is considered a potential future

(Class IIB) drinking water source. Per the NCP (40 CFR 300.430(a)(1)(iii)(F)), “EPA expects to

return usable ground waters to their beneficial uses wherever practicable, within a timeframe that

is reasonable given the particular circumstances of the site. When restoration of ground water to

beneficial uses is not practicable, EPA expects to prevent further migration of the plume, prevent

exposure to the contaminated ground water, and evaluate further risk reduction.”

- The concentration of several site‐related contaminants present in groundwater around the source area exceeds MCLs, which define chemical‐specific ARARs for groundwater that is a current or future drinking water source. For example, the BAP TEQ exposure point concentration of 351

μg/L exceeds the 0.2 μg/L MCL. Exceedance of one or more chemical-specific ARARs is the

primary basis for carrying shallow aquifer groundwater into the FS.

- Shallow aquifer groundwater is in hydraulic communication with Creosote Branch Creek. Under

the baseline (no action) condition, it is assumed that contaminated groundwater discharge to the

creek would result in surface water contaminant concentrations exceeding federal or state ambient

water quality criteria (AWQC).

Revised Remedial Action Objectives (RAO) were developed as part of the revised Remedial

Investigation/Feasibility Study (RI/FS).

The 1993 ROD listed the following RAO’s:

1. For shallow groundwater, prevent the exposure of potential receptors to on-site contaminated

groundwater in amounts above human health-based standards and to restore groundwater quality.

2. Remove the threat of potential exposure to future residents via direct contact with contaminated

surface soils, tar mat materials, and non-aqueous phase liquids (NAPL’s).

3. Reduce the potential for site contaminants to migrate into surface waters or groundwater.

Based on the findings of the human health and ecological revised risk assessment, remedial action at the

Site must address the following receptors and exposure pathways:

● Terrestrial ecological receptor direct-contact risk associated with PAH’s present in the Northern

DU surface soil.

● Industrial worker/Construction worker direct-contact risk associated with BAP TEQ, dioxin TEQ,

PCP, naphthalene, and other COC’s present in the Process Area DU surface/subsurface soil.

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● Industrial worker direct-contact risk associated with dioxin TEQ present in surface soil in the Non-

Process Area DU. Remedial actions that address dioxin TEQ are also expected to reduce BAP

TEQ direct-contact risk.

Under the current remedy, there is no unacceptable risk associated with human or ecological exposure to

COC's present in Creosote Branch Creek surface water or sediment. In the absence of remedial action,

shallow aquifer groundwater discharge to Creosote Branch Creek would likely result in surface water

COC concentrations exceeding ARAR’s or to-be-considered (TBC) guidelines. Therefore, remedial

action must also address:

● Ecological and secondary-contact recreational exposure to COC’s present in Creosote Branch

Creek surface water attributed to Process Area shallow aquifer groundwater discharge.

Based on the above human health and ecological risks that need to be addressed as determined by the

revised risk assessment (included in the Revised RI/FS), RAO’s (i.e., new, retained from 1993 ROD,

revised from the 1993 ROD, or eliminated from the 1993 ROD) for the Site are:

RAO #1 - Prevent industrial worker/construction worker exposure to surface/subsurface soil

contaminants of concern exceeding health based cleanup levels in the Process Area and

Non Process Area Decision Units. (New RAO based upon Revised RI/FS)

RAO #2 - Prevent terrestrial ecological receptor communities exposure to soil contaminants of

concern (Polycyclic Aromatic Hydrocarbons) above ecological risk based cleanup levels in

the Northern Decision Unit. (New RAO based upon Revised RI/FS)

RAO #3 - Minimize aquatic and secondary contact recreational receptors from exposure to the

contaminants of concern present in groundwater discharging to Creosote Branch at

concentrations exceeding health based and ecological based cleanup levels. (Revised 1993

ROD RAO based on Revised RI/FS)

RAO #4 - Minimize further migration of contaminants of concern from source materials to

groundwater. (Retained RAO from 1993 ROD)

RAO #5 - For shallow ground water, prevent the exposure of potential receptors to on-site

contaminated ground water in amounts above human health-based standards and to restore

ground water quality. (Retained from 1993 ROD)

With the anticipated future land use being commercial/industrial based on the Revised RI/FS, the RAO

from the 1993 ROD – Remove the threat of potential exposure to future residents via direct contact with

contaminated surface soils, tar mat materials, and non-aqueous phase liquids (NAPL’s) – is replaced with

the new RAO #1 above.

Based upon the above risks, the Revised RI/FS developed preliminary remediation goals (PRG’s)(see

Table 4). PRG’s define the allowable concentration of COC’s in environmental media that must be

achieved at the completion of the remedial action based on expectations for current and future land,

groundwater, and surface water beneficial use. PRG’s are also helpful in defining the area and volume of

environmental media to be addressed by a remedial action and to assist in the screening of various

technologies. Because there are no Federal or State cleanup standards for soil contamination, the PRG’s

for soil are based upon the revised risk assessment. PRG’s for surface water are a combination of federal

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and state ambient water quality criteria (AWQC) and other to-be-considered guidelines for the protection

of aquatic receptors and secondary-contact recreation human exposure.

EPA Region 6 evaluated seven detailed alternatives (see Table 5) in the Revised FS, which include (1) No

Action, (2) Institutional Controls with Long-Term Monitoring and Targeted Hot-Spot Excavation, (3)

Upgrade NAPL Recovery and Treatment System and Targeted Hot-Spot Excavation, (4) Slurry Wall and

Multi-Layer Cap and Targeted Hot-Spot Excavation, (5a) Partial-Depth Excavation with Thermal

Desorption and Thermal-Enhanced NAPL Recovery, (5b) Full-Depth Excavation with Thermal

Desorption, and (6) In Situ Solidification/Stabilization and Targeted Hot-Spot Excavation. While

presented for transparency, Alternative 2 was eliminated since it does not meet Threshold Criteria and

Alternative 5b was eliminated in the FS screening process due to implementability and cost. The above

alternatives are described below.

Common Elements

Common elements for the alternatives except for Alternative 1 – No Further Action are described below.

Preconstruction Activities – These activities associated with most of the alternatives include subcontractor

submittals, preparation of community involvement plan and periodic meetings to inform the community,

subcontractor mobilization and demobilization, installation of temporary facilities, underground utility

location survey, and construction surveying.

Institutional Controls – Per NCP requirements [40 CFR 300.430 (e)(3)(ii)], it is expected that IC’s, either

as a standalone alternative or as a component of alternatives employing more aggressive technologies,

would be included as appropriate to prevent or limit exposure to hazardous substances. The individual

IC’s include restrictions that limit land use to industrial/commercial, prevent deep excavation to protect

construction workers, and groundwater use restrictions in the Process Area, Non-Process Area, and Tar

Mat DU’s. Land use IC’s will be implemented through restrictive covenants written into property deeds

and would vary based on the alternative.

Northern DU Soil Excavation and Offsite Disposal – The revised risk assessment identified ecological

risk to invertebrates and terrestrial receptors through direct and indirect exposure to PAH’s in surface soil.

To achieve an acceptable level of risk, a remediation strategy will be used that is the least invasive to the

existing and functioning habitat while still facilitating DU-wide risk reduction. Sampling will be

performed to provide data in order to minimize that volume of surface soil that needs to be addressed.

These volumes of contaminated surface soil will be excavated, transported, and disposed of off-site.

Clean fill will be imported and hydroseeded to re-establish vegetation.

Creosote Branch Creek Bank and Western Fence Soil Excavation – Contaminated areas along the

northern and western fence line near Creosote Branch Creek lie outside the portion of the source area that

can be addressed by the primary technologies included in each alternative. If not addressed, these areas

will act as continuing sources of contamination. Of the technologies evaluated to address soils,

excavation is the only one capable of effectively removing soil contamination is these areas. As in the

Northern DU Soil Excavation common element above, sampling will be performed in these areas near the

creek to minimize the volume of soil that needs to be addressed. Once excavated, the contaminated soils

will be disposed of off-site. The creek excavation areas will replaced with clean fill and constructed to

maintain creek bank integrity.

Five Year Reviews - The NCP, under 40 CFR 300.430(f)(4)(ii), requires that periodic reviews be

conducted if a remedial action is selected that results in hazardous substances, pollutants, or contaminants

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remaining at the site above levels that allow for unlimited use and unrestricted exposure. These reviews

are conducted no less often than every 5 years after the selected remedial action is initiated. Four five‐year reviews (5YR) have been performed to date, with the last 5YR conducted in 2015. The 5YR would

continue in perpetuity until such a time that the industrial land use IC can be lifted (e.g., DUs released for

unrestricted use/unrestricted exposure).

Current Remedy - The on-site incineration of highly contaminated tars and sludges has been completed.

The pumping, separation, and treatment of liquid contaminants and the in-situ bioremediation components

of the 1993 ROD which were designed to address the subsurface source of shallow ground water

contamination are being replaced by the proposed remedy. A new soil cover to protect the in-situ

solidification/stabilization area will replace the capped surface soils completed under the current remedy.

The goal of restoring ground water to its potential beneficial use is retained from the 1993 ROD and

applies to the shallow ground water impacted by the source area.

The capital cost for the Common Elements is $1.6 million.

Alternative 1 – No Further Action

Estimated Capital Cost: $540,000

Estimated Annual O&M Cost: $0

Estimated Periodic Cost: $100,000

Estimated Present Worth Cost: $640,000

Estimated Construction Timeframe: 1 year

Estimated Time to Achieve RAOs: N/A

Section 300.430 (e)(6) of the NCP requires the inclusion of a no action alternative in the RI/FS, or a no

further action alternative if an interim or final action is already underway, for use as a baseline to compare

against other alternatives. Under this alternative, no further action would be taken in Northern and Non-

Process Area DUs, while in the Process Area DU all recovery wells, injection wells, monitor wells,

piezometers, and horizontal recovery trenches (extraction, injection, and infiltration) would be plugged

and abandoned, operation of the PLTS would cease with all process equipment being decontaminated and

decommissioned, and all underground and aboveground conveyance piping removed, decontaminated,

and decommissioned.

Alternative 1 requires the abandonment of all groundwater monitor wells, extraction wells, and injection

wells as well as the decontamination and decommissioning of the PLTS and associated equipment. The

general duration of Alternative 1 is estimated at 9 months. The present worth cost for this alternative is

estimated at $640,000 with a ‐30/+50 percent cost range of $448,000 to $960,000. Per the NCP (40 CFR 300.430), the no action alternative was carried through the detailed evaluation but was not retained since

it would not provide any protection to human health and the environment.

Alternative 2 – Institutional Controls with Long-Term Monitoring and Targeted Hot Spot Excavation

Estimated Capital Cost: $7.6 million

Estimated Annual O&M Cost: $73,000

Estimated Periodic Cost (every 5 years): $295,000

Estimated Present Worth Cost: $8.5 million

Estimated Construction Timeframe: 1 year

Estimated Time to Achieve RAOs: Greater than 100 years

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Alternative 2 utilizes an array of overlapping access controls to prevent exposure to contaminated soil and

groundwater. This alternative satisfies the NCP requirement to develop an alternative that involves little

or no treatment and protects human health and the environment by preventing or controlling exposure to

contaminants through engineering controls and, as necessary, ICs. This alternative includes the common

elements listed above, extension of perimeter fencing, the abandonment of all groundwater monitor wells,

extraction wells, and injection wells as well as the decontamination and decommissioning of the PLTS

and associated equipment, installation of a multi-layer soil cover (approximately 11 acres) in the Process

Area DU to provide a direct-contact barrier and prevent rainfall-induced leaching of contaminants present

in soil, long-term monitoring of groundwater and surface water to assess potential impacts to Creosote

Branch Creek, and long-term maintenance of the multi-layer cap.

Key components of Alternative 2 include the following:

The common elements listed above.

Extension of the perimeter fencing to the east to enclose the Non-Process Area DU, requiring an

additional 1,000 ft of 6-foot cyclone fencing to be installed.

Plugging and abandonment of all recovery wells, trenches, monitor wells, and piezometers, and

decontamination and decommissioning of the PLTS and conveyance piping as described for

Alternative 1.

Installation of a multi-layer soil cap (11 acres) in the Process Area DU to provide a direct-contact barrier

and to prevent rainfall-induced leaching of contaminants present in soil and their transport to the

shallow aquifer.

Long-term monitoring (LTM) of groundwater and surface water on a semi-annual basis with progress

reports prepared annually to assess potential impacts to Creosote Branch Creek. The scope of LTM

would be similar to that conducted currently.

LTM and O&M of the Process Area DU multi-layer cap would be conducted for at least 100 years.

Documentation of remedy performance and protectiveness in annual operation summary reports and

5YRs.

The total present worth for Alternative 2 is $8.5 million with a -30/+50 percent cost range of $6.0 million

to $12.8 million. Alternative 2 was carried through the detailed evaluation but was not retained since it

would not provide any protection to human health and the environment.

Alternative 3 – Upgrade NAPL Recovery and Treatment System, and Targeted Hot-Spot Soil Excavation

Estimated Capital Cost: $18.8 million

Estimated Annual O&M Cost: $644,000

Estimated Periodic Cost (every 5 years): $126,000, Additional periodic cost of $3.68 million for PLTS

replacement (year 30 & 60) and extraction well and trench replacement (year 50)

Estimated Present Worth Cost: $28.5 million

Estimated Construction Timeframe: 2 years

Estimated Time to Achieve RAOs: Greater than 100 years

Alternative 3 is a continuation of the current fluids recovery and in situ bioremediation remedy

component implemented under the 1993 ROD. In addition to the common elements, this alternative

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would include excavation and off-site disposal of dioxin contaminated soil in the Non-Process DU,

replacement and expansion of the soil cover in the Process Area DU, and upgrade/replacement of the

PLTS and the extraction/injection wellfield components to increase NAPL recovery and provide for

improved groundwater treatment.

Key components of Alternative 3 include the following:

The common elements listed above.

A remedial design investigation in the Non-Process Area DU to refine the surface soil excavation

footprint with excavation and offsite disposal of dioxin TEQ-contaminated soil at a RCRA treatment,

storage, and disposal facility (TSD).

Replacement of the north recovery trench and deep injection trench using one-pass technology.

Rehabilitation of all existing extraction wells through chemical addition and mechanical swabbing.

Conversion to a two-pump extraction system for groundwater and NAPL recovery.

Decontamination and decommissioning of the current system.

Upgrade of the PLTS building and treatment train.

Upgrade of the PLTS electrical and instrumentation and control (I&C) systems to provide greater

remote/offsite operations and improved reliability.

Replacement and expansion of the soil cover in the Process Area DU using a multi-layer cap to prevent

rainfall infiltration and limit vertical migration of COCs and NAPL in the vadose zone.

100 years of O&M. It is assumed the recovery wells and PLTS mechanical equipment will require

replacement approximately every 30 years.

Periodic sampling, analysis, and reporting to: 1) confirm PLTS treatment effectiveness, 2) assess the need

for treatment media change-out, and compliance with potential discharge criteria, 3) assess COC

concentration changes, and 4) verify hydraulic containment of the dissolved-phase plume.

Documentation of remedy performance and protectiveness in annual operation summary reports and

5YRs.

The total present worth cost for Alternative 3 is $28.5 million with a -30/+50 percent cost range of $19.9

million to $42.3 million.

Alternative 4 – Containment with Slurry Wall and Surface Multi-Layer Cap, and Targeted Hot-Spot Soil

Excavation

Estimated Capital Cost: $17.6 million

Estimated Annual O&M Cost: $117,000

Estimated Periodic Cost (every 5 years): $295,000

Estimated Present Worth Cost: $18.5 million

Estimated Construction Timeframe: 2 years

Estimated Time to Achieve RAOs: N/A

Alternative 4 satisfies the NCP requirement to develop an alternative that involves little or no treatment

and protects human health and the environment by preventing or controlling exposure to contaminants

through engineering controls and, as necessary, ICs. In addition to the common elements, this alternative

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would include excavation and off-site disposal of dioxin contaminated soil in the Non-Process DU, an

approximate 2,600 foot long subsurface containment slurry wall would be installed with a multi-layer

impermeable surface cap constructed to prevent infiltration into the area enclosed by the slurry wall, and a

deep aquifer dewatering system which would prevent upward groundwater migration which could result

in contaminants being pushed out of the containment area or failure of the slurry wall.

Key components of Alternative 4 include the following:

The applicable common elements listed above.

Remedial design investigation and excavation of surface soil in the Non-Process DU as described under

Alternative 3.

Remedial design investigation to determine the extent of NAPL underlying the Tar Mat Ash DU, a deep

aquifer pump test to determine the appropriate pumping rate needed to maintain a neutral vertical

gradient between the shallow and deep aquifers to prevent flooding inside the containment area, and

testing pits in the northwest corner of the Process Area DU (as necessary) to confirm that there is no

subsurface debris present that would interfere with construction of the slurry wall.

Abandonment and decommissioning of the existing groundwater extraction and injection wellfield as

described under Alternative 1.

Abandonment of 30 shallow/deep monitor wells in the Process Area DU. Ten wells located within the

slurry wall footprint and four outside the footprint would be retained as long-term monitoring

locations.

Installation of a 2,600-ft-long slurry wall encompassing the soil, NAPL, and dissolved-phase COC plume

where concentrations exceed PRGs within the Process Area DU.

Install deep aquifer dewatering wells, number of wells determined based on the results from the pump

test, it is assumed that pumping would be required for 100 years.

Installation of a GAC treatment system to treat deep aquifer groundwater if necessary.

Installation of a multi-layer cap over the area enclosed by the slurry wall.

LTM to verify remedy effectiveness.

The total present worth cost for Alternative 4 is $18.5 million with a -30/+50 percent cost range of $12.9

million to $27.7 million.

Alternative 5a – Partial-Depth Excavation with Thermal Desorption, and Thermal-Enhanced NAPL

Recovery

Estimated Capital Cost: $47.2 million

Estimated Annual O&M Cost (years 4-14): $1.3 million

Estimated Annual O&M Cost (years 15-100): $73,000

Estimated Periodic Cost (every 5 years): $295,000

Estimated Present Worth Cost: $45.7 million

Estimated Construction Timeframe: 5 years

Estimated Time to Achieve RAOs: 100 years

Alternative 5a addresses the NCP requirement to develop an alternative which at a minimum treats the

principal threats posed by the site but varies in the degree of treatment employed and quantities and

characteristics of the treatment residuals. In addition to common elements, this alternative would include

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excavation and treatment of soils down to 5 feet below ground surface, installation and operation of an

enhanced NAPL recovery system that would utilize heated water to enhance NAPL recovery, and an in-

situ barrier that would treat remaining ground water contamination as it discharges to Creosote Branch

creek.

Key elements of Alternative 5a include the following:

The applicable common elements listed above.

Remedial design investigation to determine the extent of NAPL underlying the Tar Mat Ash DU.

Excavation of surface soil in the Non-Process Area DU as described in Alternative 3.

Abandonment and decommissioning of the existing groundwater extraction and injection wellfield (as

described under Alternative 1) with the exception of the north recovery trench and extraction wells R-

19, -20, and -21. These would be operated to maintain hydraulic capture until the enhanced NAPL

recovery system is operational.

Excavation of soil from 0 to 5 ft bgs in the Process Area DU with COC concentrations greater than PRGs.

Treatment of excavated soil onsite using medium-temperature thermal desorption (MTTD).

Enhanced NAPL recovery using an array of alternating horizontal extraction and injection wells, installed

east-west perpendicular to the groundwater flow direction, using one-pass technology. A total of 12

wells is assumed.

Inject hot water (125 degrees Fahrenheit [°F]) to induce hydraulic, thermal, and viscosity gradients to

increase NAPL recovery. The effectiveness of this element and the design temperature are based on

bench-scale pilot tests conducted in 2003.

Upgrade of the PLTS (as described under Alternative 3). A heat exchanger would be installed at the head

of the PLTS to recover heat from extracted groundwater.

Installation of a multi-layer soil cap over the Process Area DU at the completion of enhanced NAPL

recovery efforts.

Installation of a funnel and gate permeable reactive barrier (PRB) as a polishing step for dissolved-phase

groundwater treatment at the completion of enhanced NAPL recovery efforts, which are presumed to

conclude after 10 years of operation.

The total present worth cost for Alternative 5a is $45.7 million with a -30/+50 percent cost range of $32.0

million to $68.6 million.

Alternative 5b – Full-Depth Excavation with Thermal Desorption

Estimated Capital Cost (nondiscounted): $101,000,000

Estimated Annual O&M Cost (nondiscounted): $73,000

Estimated 5 Year Periodic Cost (nondiscounted): $36,000

Estimated Present Worth Cost: $91,000,000

Estimated Construction Timeframe: 3 years

Estimated Time to Achieve RAOs: 5 years

Alternative 5b addresses the NCP requirement to develop an alternative that removes contaminants to the

maximum extent practicable minimizing the need for long-term management. Alternative 5b is similar to

022105

Alternative 5a but extends the excavation depth to the base of the contamination, removing all COCs

exceeding the PRG.

Key components of Alternative 5b include the following:

The applicable common elements listed above.

Remedial design investigation and excavation of surface soil in the Non-Process Area DU (detailed in

Alternative 3)

Abandonment and decommissioning of the existing groundwater extraction wellfield (detailed in

Alternative 1).

Excavation of soil from 0 to 30 ft bgs with contaminant concentrations greater than the PRGs. Excavation

would be completed in 75-ft by 75-ft cells. To reach the excavation depth and minimize dewatering,

the cells would have temporary sheet piling installed around the perimeter.

Large-scale dewatering would be required for each of the excavation cells.

Excavated soil would be treated onsite using MTTD. Treated soil would be used as backfill.

Even though this alternative was eliminated in the screening step, a detailed cost estimate was prepared,

and the total present worth cost for Alternative 5a is $88.4 million with -30/+50 percent cost range of

$62.1 million to $133.2 million.

Alternative 6 – In-Situ Solidification/Stabilization, and Targeted Hot-Spot Soil Excavation

Estimated Capital Cost: $26.1 million

Estimated Annual O&M Cost: $73,000

Estimated Periodic Cost (every 5 years): $295,000

Estimated Present Worth Cost: $25.0 million

Estimated Construction Timeframe: 6 years

Estimated Time to Achieve RAOs: 6 years

Alternative 6 addresses the NCP requirement to develop an alternative that treats the principal threats but

varies in the degree of treatment employed and the quantities and characteristics of the treatment

residuals. Although contaminants are not removed using in situ solidification/stabilization (ISS), they are

immobilized. Under Alternative 6, all mobile and immobile NAPL present within the Process Area and

Tar Mat DUs would be stabilized in situ using a mix of 1.5 percent Portland cement amended with 3.5

percent cement slag, 1 percent organo-clay, 1 percent bentonite, 2 percent tar mat ash. The mix design is

based on the results of the ISS Treatability Study presented in the Revised RI/FS. In addition, the mix

design concentrations will be doubled for the perimeter of the treatment area than used to treat the interior

portion to create a hardened shell that would have lower leachability and higher durability.

Key components of Alternative 6 include the following:

Each of the common elements listed above.

Remedial design investigation and excavation of surface soil in the Non-Process Area DU (detailed in

Alternative 3).

Remedial design investigation on the western side of the Tar Mat area to determine how much of the Tar

Mat area needs to be included in the ISS treatment area.

022106

Abandonment and decommissioning of the existing groundwater extraction and injection wellfield

(detailed in Alternative 1) with the exception of the north recovery trench and extraction wells R-19,

R-20, and R-21. These would be operated to maintain hydraulic capture until the ISS installation

reaches the downgradient portion of the Site.

ISS of mobile and immobile NAPL source materials using backhoe mixing or auger mixing.

Perimeter ISS columns extending to the bottom of the source area which would have lower leachability

and higher durability than the interior ISS columns in order to prevent any unidentified source

materials not treated by interior columns from migrating from the source area.

Air monitoring during ISS to ensure workers and residents are not exposed to site contaminants.

An approximately 3-ft-thick soil cover to protect the ISS treatment area and to prevent direct contact with

treatment residuals.

The total present worth cost for Alternative 6 is $25 million with a -30/+50 percent cost range of $17.5

million to $37.4 million.

The ACW team proposed that: (6) In Situ Solidification/Stabilization and Targeted Hot-Spot Excavation

be implemented to meet the anticipated future land use of commercial/industrial (see Figure 3 and

attached Final Draft Proposed Plan). Under Alternative 6, EPA would excavate and dispose of PAH

contaminated surface soils in the Northern Decision Unit to address unacceptable ecological risks;

investigate, excavate, and dispose of dioxin/PAH contaminated surface soils in the Non-Process Area

Decision Unit to address unacceptable human health and ecological risks; excavate a small portion and

primarily perform in situ solidification/stabilization within the source area located in the Process Area

Decision Unit to address unacceptable human health and ecological risks; and execute institutional

controls to limit land use to commercial/industrial, prevent deep excavation to protect the

solidified/stabilized source materials, and restrict the use of groundwater.

The proposed response action has an estimated capital cost of $26.1M, an annual O&M cost of $73,000,

and a periodic cost of $295,000, for a total present worth cost of $25M. EPA Region 6 estimates that the

remedy can be completed within 6 years at which time Remedial Action Objectives would be met except

for groundwater. As prescribed in the original 1993 ROD which would be amended by the proposed

response action, after the source control technologies are implemented, monitoring would be performed to

evaluate performance of the source control measures and their effect on the groundwater at the site.

The preferred alternative is protective of human health and the environment because PAH and dioxin

contaminated soil is removed and disposed off-site and source materials (principal threat wastes) are

solidified/stabilized to prevent migration of Contaminants of Concern to Creosote Branch Creek and to

surrounding groundwater. As indicated in the 1993 ROD which is being amended by the proposed

response action, groundwater at the site is expected to restore to its potential future beneficial use shortly

after completion of the solidification/stabilization of the source materials.

The proposed response action would comply with all federal and State ARARs.

The proposed response action was the highest rated alternative for the combination of Long-Term

Effectiveness, Reduction of Toxicity, Mobility, and Volume, Short-Term Effectiveness, and

Implementability compared to all the other potential alternatives. The proposed response action would

eliminate the migration of contaminants from the source materials to Creosote Branch Creek and the

022107

surrounding groundwater, would eliminate long term operation of a recovery system as being currently

implemented in the original remedy, and will make the site ready for commercial/industrial use.

All actions in the proposed response action are readily implementable and the Louisiana Department of

Environmental Quality has indicated that it supports the proposed response action.

NRRB Review Not Warranted

The ACW RRRT concluded that a review of the proposed response action by the NRRB would not be

necessary because excavation and in situ solidification/stabilization has routinely been used at other

creosote contaminated sites.

In addition, the proposed response action is less expensive than the alternative which upgrades the current

remedy at site and provides significantly more certainty concerning potential migration of contaminants

from the source area. It will also enable the site to be available for commercial/industrial use whereas the

alternative which upgrades the current remedy at the site would not.

Lastly, in consideration of pertinent stakeholder concerns and other site circumstances – (1) the Louisiana

Department of Environmental Quality supports the proposed response action at the ACW site and

understands that it would be responsible for a 10 percent cost match at the site, (2) there has been no

Congressional or community interest in the site since the implementation of the original remedy in the

mid-1990’s, specifically, no citizens attended the last public meeting held in December 2015. The City of

Winnfield is only interested in the site being addressed so that the site can be developed for

commercial/industrial purposes, (3) there are no tribal interests associated with the site, and (4)

technologies in the proposed response action are common to other sites and therefore, are consistent with

previous EPA response actions.

Please signify your concurrence below:

__________________ I concur that review of the proposed response action by the NRRB is not

warranted.

__________________ I do not concur.

Attachments (9)

022108

Regional Remedy Review Team

American Creosote Superfund Site

February 25, 2016

INTRODUCTION

The use of In-Situ Stabilization/Solidification (ISS) for treatment of shallow source material at former

wood treater and oily waste sites is considered to be a regional presumptive remedy approach in Region 6.

This technical recommendation is based on the experience of the Remedial Project Managers participating

in the RRRT and their experience and expertise gained from implementing remedial actions at a number

of sites over the last 20 years. The successful implementation of ISS has been completed at similar wood

treater and oily waste sites including North Cavalcade Street, Texarkana Wood Preserving, Mountain Pine

Pressure Treatment, and South 8th Street Landfill. At sites that did not include ISS as part of the remedy

implementation, there are long-term operational and maintenance issues with potentially significant costs.

RECOMMENDATIONS:

RPM 1 Comments

At the RRRT review, Solidification/stabilization (S/S) was presented as the preferred alternative. The

RRRT recommends that the following items be considered during the design and implementation of the

remedy:

S/S is expensive per cubic yard – by excavating soil above the S/S area, we can decrease the cubic yard stabilized. Solidification (cement) is not the major cost, stabilization (Powered Activated

Carbon - PAC) is the major cost.

1) We can expect up-to 30% swell of the solidified material, which will require offsite disposal or onsite consolidation in a cell (type cell depends on excavated soil risk). Based on soil volumes

discussed; the onsite cell appears to be more cost effective than offsite disposal.

RPM Response – The issue of how to manage swell will be evaluated in the RD.

2) For reuse – we may want to consider excavation of sufficient soil at the S/S site to allow for sufficient clean fill/soil thickness to promote tree growth, slabs, posts/pilings, etc.

RPM Response – Methods to reduce cost, such as excavation of clean soil to minimize the

amount of material that is addressed with in-situ solidification/stabilization will be evaluated

in the RD.

3) If we excavate for S/S, we should excavate a small area (e.g., 1-acre), S/S that area, and then backfill as soon as practicable, in this way we minimize contaminated stormwater

management.

RPM Response – Methods to minimize storm water management will be evaluated in the

RD.

4) A bench scale test usually tests to a UCS of 50 psi and a percent by weight carbon for concentrations below the MCL (usually 4%). I agree with the Pilot Test mentioned; we can

decrease costs by reducing the UCS based on the potential reuse (e.g., storage – 15-20

UCS). We can also reduce the cost for PAC through the Pilot.

RPM Response – The most predominant factor in the treatability study performed during

the FS was the leaching potential of contaminants. Various mixes that achieved acceptable

leaching results over achieved the requirements of unconfined compressive strength and

022109

hydraulic conductivity. The treatability study results will be re-evaluated in the RD to

determine if any changes to the treatability study mix designs.

Section Chief Comments

At the RRRT presentation, the RPM provided information to amend the soil remedy for the site. However, not enough information was provided regarding the groundwater component of the

existing remedy.

The RRRT recommends that the RPM fully discuss what is planned for the groundwater

component in the decision document.

RPM Response – The groundwater component of the existing/proposed remedy will be more

thoroughly discussed in the Proposed Plan.

At the RRRT presentation, the RPM discussed alternative 5b which was full removal of the contaminated soils. However, this alternative was not fully discussed under the nine criteria. The

RRRT recommends that alternative 5b be presented through the nine criteria and evaluation in the

decision document.

RPM Response – Alternative 5b will be incorporated into the Proposed Plan.

RPM 2 Comments

As explained at the RRRT review presentation, Solidification/Stabilization (SS), will both contain the larger NAPL source area and provide additional source “treatment” through immobilization of

mass within the SS ring itself. The SS approach is consistent with source remedies implemented at

Region 6 creosote sites over the last ~5 years, after original pump and treat remedies were shown

to be problematic. The combination of a SS ring, anchored in the Cockfield confining zone, with

a constructed cover over the interior of the ring will effectively encapsulate the primary source

area. During discussions, it was noted that the bottom confining layer is a Cockfield transitional

facies overlying the Sparta, the drinking water supply aquifer. There may be concerns that the

Cockfield may be a “leaky” confining layer, so the argument that the Cockfield has not been

impacted becomes most important. The RRRT recommends that the RPM clarify in the ground

water/site characteristics discussion that the monitoring coverage on the Cockfield is adequate to

make this argument. And you may want to consider that monitoring will continue into the future

and the network will be further evaluated during design or the Five-Year Review. You would want

to prepare a case for not needing to monitor the Sparta, if that is the case.

EPA Response – Several well pairs completed in the shallow/deep aquifers have been monitored

since before and after the remedy startup in the mid-1990’s. Historical observations from these

well pairs, including observations during non-pumping conditions, have always indicated an

upward gradient from the deep aquifer (Cockfield) to the shallow aquifer. In addition, the

Cockfield is approximately 150 feet thick and is comprised of interbedded clays, silts, and sands.

Based upon the historical upward gradient and the thickness of the Cockfield, it does not

appear that monitoring the Sparta is necessary.

RPM 3 Comments At the RRRT review, Alternative 6 was presented as the preferred alternative. The RRRT recommends

that the following items be considered during for the preferred alternative that could result in cost saving

during design and implementation of the remedy

For Alternative 6, consider dewatering of the former fire water pond and utilize the storage

capacity for excess ISS treated material within the Site boundary. The combination of the pond,

022110

and a potential excavation area within the incinerator ash waste cell, will provide capacity to

reduce the amount of mounding anticipated after ISS treatment of the contaminated soil area.

RPM Response – The use of the fire water pond for ISS swell management will be evaluated in

the RD.

For Alternative 6, consider removal and storage of the clean soil cap material for later use as the

soil cover on the ISS treated material. This material will reduce the total volume of soil requiring

ISS treatment.

RPM Response – Methods to reduce cost, such as excavation of clean soil to minimize the

amount of material that is addressed with in-situ solidification/stabilization will be evaluated in

the RD

For Alternative 6, consider adding a statement in the Proposed Plan on the need for air monitoring

during the ISS treatment to address potential exposure pathways to the community downwind of

the Site.

RPM Response – A statement concerning planned air monitoring during the ISS activities will

be inserted into the Proposed Plan.

For Alternative 6, consider incorporating the contaminated soil from the hot spots into the ISS

mixing process to eliminate the need for off-site transport and disposal. If the potential funding

plan does not allow this action, then consider adding an explanation in the Proposed Plan or other

record on why the action is a priority for risk reduction.

RPM Response – Methods to reduce costs such as combining hot spot contaminated soils into

the ISS mixing process will be evaluated in the RD.

For Alternative 6, the ISS treatment process that provides a continuous treatment perimeter as well

as treatment of the source material waste is not expected to require further treatment or monitoring

of the ground water remaining below the treated waste. Following completion of the source area

ISS treatment, the remaining ground water is considered to be within the waste management area,

and the ground water restoration objective in the ROD is not considered relevant for future action.

RPM Response – Agreed and the goal of restoration for the groundwater surrounding the

source area will be described in the Proposed Plan.

At the RRRT review, Alternative 2 was presented as one of the alternative considered. The RRRT

recommends that the RPM consider the following:

For Alternative 2, consider removing this alternative and include the remedy components as

common elements for Alternatives 3 – 6. While Alternative 2 does address RAOs 1 – 3, the

Alternative does not provide an action that will address the proposed RAO #4 for minimizing

further migration of contaminants of concern from source materials.

RPM Response – Agreed that Alternative 2 does not meet all the RAO’s, however, it will still be

presented in the Proposed Plan in order to be transparent to the public concerning all the

alternatives that EPA considered. However, the Proposed Plan will be clear that Alternative 2

cannot be considered for remedy selection since it does not meet the Threshold Criteria.

At the RRRT review, the RPM presented the RAOs for the Proposed Plan. The RRRT recommends that

the RPM consider including an explanation in the Proposed Plan that the objective to restore groundwater

quality has not been changed in the planned ROD Amendment.

022111

RPM Response – The Proposed Plan will be revised to make it clear RAO’s are either new, modified

from the original ROD, eliminated from the original ROD, or not eliminated from the original ROD

and thus still apply.

The RRRT notes that implementation of Alternative 6, or any of the other alternatives, does not trigger a

site-wide construction completion until the ground water issues are addressed in a subsequent ROD

Amendment.

RPM Response – It is acknowledged that the site-wide construction completion target is not achieved

until ground water issues are ultimately addressed.

022112

Figure 1 - American Creosote Works Inc. - Site Location Map

Disclaimer: This map and any boundary lines within the map are approximate and subject to change. The

map is not a survey. The map is for informational purposes only regarding EPA’s response actions at the

Site.

• Winnfield,

American Creosote Works, Inc. • (Winnfield Plant)

Louisiana "----~ Superfund Site

0 250 500 1,000 ••c:::=•••-Feet

0 NORTH

X -X Site Fence

American Creosote Works, Inc. (Winnfield Plant) Superfund Site Winnfield , Winn Parish, Louisiana

022113

_̂

Site Location

LEGEND

Former FireWater Pond

BoilerBuilding TankFarmRetort

Retort

Far West (FW) Branch

North (N) Branch

West (W) Branch

WasteCell 1 2

2 4

Southern Decision Unit/South Parcel(15.6 acres)

Process Area Decision Unit/North Parcel(14.2 acres)

Northern Decision Unit(9.9 acres)

Non-Process Area Decision Unit/North Parcel(10.5 acres)

Western Decision Unit(4.3 acres)

Tar Mat Decision Unit(2.4 acres)

FIGURE 2

American Creosote WorksWinnfield, Louisiana

0 225 450Feet

FenceCreek (Creosote Branch)

Pond/CreekHistorical Process Area Surface Water Drainage

! !

K

Approximate Locationof Historical Tar Mat Area

Historical ImpoundmentsHistorical Treated WoodStorage Areas

HOU \\Hollister\Groups\IS\Proj\American_Creosote\apr-mxd\2015\Figure 1-02 ACW Historic Facilities and Decision Units.mxd cg021858 4/21/2015 5:00:22 PM

Historic Facilities andDecision Unit Map

Source: ESRI World Imagery online mapping service

Decision UnitsCreek Decision UnitNon-Process Area Decision Unit/North ParcelNorthern Decision UnitProcess Area Decision Unit/North ParcelSouthern Decision Unit/South ParcelTar Mat Decision UnitWestern Decision Unit

Waste Cell

022114

TABLE 1 Process Area Decision Unit Quantitative Human Health Risk Summary American Creosote Works, Winnfield, Louisiana

Receptor Exposure

Area Medium Exposure

Route

Excess Lifetime Cancer

Risk Hazard Index Chemicals of Potential Concern

Industrial/

Commercial

Worker

Soil

(Process Area

DU)

Surface Soil

(0-1 foot bgs)

Total 2E-03 3.5 Total dioxin TEQ, 1,1-biphenyl, PCP, total BAP

TEQa

Subsurface Soil

(0-10 feet bgs)

Total 2E-03 4 2-methylnaphthalene, PCP, total BAP TEQ,

1,1-biphenyl, naphthalene

Groundwater

(Process Area

and Non-

Process DUs)

Groundwater Total 2E-01 262 Noncarcinogenic PAHsb, methylphenols, 1,1-

biphenyl, 1,1,2,2-tetrachloroethane, 1,1,2-

trichloroethane, 1,2-dibromoethane, 1,2-

dichloropropane, bromodichloromethane,

PCP, total BAP TEQ, benzene, and

ethylbenzene

Construction

Worker

Soil

(Process Area

DU)

Surface Soil

(0-1 foot bgs) Total 2E-04 6 Total dioxin TEQ, naphthalene, PCP, total BaP

TEQ

Subsurface Soil

(0-10 feet bgs) Total 2E-04 7 2-methylnaphthalene, PCP, total BAP TEQ,

naphthalene

Shallow

Aquifer

Groundwater

(Process Area

and Non-

Process DUs)

Groundwater Total 4E-03 11 Fluoranthene, PCP, naphthalene, total BAP

TEQ

Notes: a BAP TEQ includes: benzo(a)anthacene, benzo(a)pyrene, benzo(b)fluoranthene, benzo(k)fluoranthene, chrysene,

dibenz0(a,h)anthacene, and indeno(1,2,3-cd)pyrene b noncarcinogenic PAHS include: acenaphthene, acenaphthylene, anthacene, fluoranthene, fluoranthene, phenanthrene, and pyrene

% = percent BAP TEQ = benzo(a)pyrene toxicity equivalent

bgs = below ground surface

COC = chemical of concern

DNAPL = dense non-aqueous phase liquid Dioxin TEQ = 2,3,7,8 tetrachlorodibenzo-p-dioxin toxicity equivalent

DU = decision unit

NAPL = non-aqueous phase liquid

PCP = pentachlorophenol

022115

TABLE 2 Preliminary Risk Screening All Decision Units American Creosote Works, Winnfield, Louisiana

Decision Unit Medium

Dioxins (ng/kg) PAHs (mg/kg) Quantitative RA

Dioxin TEQ Exposure

Point Conc. PRE (ELCR)*

BAP TEQ Exposure

Point Conc. PRE (ECLR)*

Total PRE (ECLR)

Exceeds Upper Bound (1.0E-04) of CERCLA Risk Range

Risk-based Screening Level (Industrial)** 18 1E-06 0.21 1E-06

Northern

Surface Soil (0 to 1 feet bgs)

175.1 1.E-05 17.7 8.E-05 9.E-05 No

Subsurface Soil (1 to 10 feet bgs)

NA NA 1.96 9.E-06 9.E-06 No

Non-Process Area

Surface Soil (0 to 1 feet bgs)

14,634.00 8.E-04 4.54 2.E-05 8.E-04 Yes

Subsurface Soil (1 to 10 feet bgs)

NA NA 2.83 1.E-05 1.E-05 No

Process Area

Surface Soil (0 to 1 feet bgs)

237.4 1.E-05 59.1 3.E-04 3.E-04 Yes

Subsurface Soil (1 to 10 feet bgs)

NA NA 296 1.E-03 1.E-03 Yes

Southern

Surface Soil (0 to 1 feet bgs)

288 2.E-05 4.87 2.E-05 4.E-05 No

Subsurface Soil (1 to 10 feet bgs)

NA NA 1.12 5.E-06 5.E-06 No

Western Surface Soil (0 to 1 feet bgs)

199.8 1.E-05 3.85 2.E-05 3.E-05 No

Tar Mat Subsurface Soil (1 to 10 feet bgs)

285.4 2.E-05 0.23 1.E-06 2.E-05 No

RSLs Sediment (Industrial)** 18 0.21

Fire Water Pond Sediment 79.96 4.E-06 0.44 2.E-06 7.E-06 No

022116

TABLE 2 Preliminary Risk Screening All Decision Units American Creosote Works, Winnfield, Louisiana

Decision Unit Medium

Dioxins (ng/kg) PAHs (mg/kg) Quantitative RA

Dioxin TEQ Exposure

Point Conc. PRE (ELCR)*

BAP TEQ Exposure

Point Conc. PRE (ECLR)*

Total PRE (ECLR)

Exceeds Upper Bound (1.0E-04) of CERCLA Risk Range

North Creosote Branch Sediment

60.55 3.E-06 3.33 2.E-05 2.E-05 No

West Creosote Branch Sediment

7.66 4.E-07 0.40 1.9E-06 2.E-06 No

Background Values

Background

Surface Soil 31.81 NA 0.432 NA NA

Subsurface Soil NA NA 0.425 NA NA

Surface Water NA NA 21.134 NA NA

Sediment 10.77 NA 0.876 NA NA

Notes: Identifies Decision Units and media carried forward to feasibility study based on exceedance of upper bound CERCLA risk range. *PRE = Preliminary Risk Evaluation = (Dioxin TEQ or BAP TEQ/ Industrial RSL)*10^-6 for carcinogens ** = PRE was calculated for sediment using the soil Industrial RSL value of 18 ng/kg for dioxins and 0.21 mg/kg for PAHs. Surface water criteria were not available for industrial workers for a PRE calculation. BAP-TEQ = benzo(a)pyrene toxicity equivalent concentration bgs = below ground surface CERCLA = Comprehensive Environmental Response, Compensation, and Liability Act of 1980 Dioxin TEQ = 2,3,7,8-TCDD toxicity equivalent concentration DU = Decision Unit ECLR = Estimated Lifetime Cancer Risk kg = kilogram mg = milligram NA = not applicable ng = nanogram

022117

TABLE 3

Summary of Risks ‐‐ Terrestrial Habitats

American Creosote Works, Winnfield, Louisiana

Constituents

Decision Unit

Direct Exposure

Indirect (Food Web) Exposure

Birds Mammals

NBQ AW AK DM NBA M RF

PAHs

Northern x

(HPAH)

x (6 HPAH)

Non‐Process x

(HPAH)

x (1 HPAH)

Process x

(LPAH & HPAH)

x

(2 HPAH)

x (8 HPAH)

Southern Western

Dioxins/Furans

(TEQs)

Northern

Not Evaluated

x Non‐Process x x x x x

Process x Southern Western

Notes:

An "x" indicates risk; blank cells indicate no risk. HPAH = high molecular weight PAHs AK =

American Kestrel LPAH = low molecular weight PAHs AW =

American Woodcock PAH = polycyclic aromatic hydrocarbon DM =

Deer Mouse TEQ = toxic equivalents

M = Mink NBA = Nine‐banded

Armadillo NBQ = Northern Bobwhite

Quail RF = Red Fox

022118

TABLE 4 Preliminary Remediation Goals for Soil and Groundwater American Creosote Works - Winnfield, Louisiana Preliminary Remediation Goal

Contaminant of Concern Units Northern DU Non-

process Area DU

Process Area DU

PRG Basis

Soil

High Molecular Weight PAHsa mg/kg 18 NA NA Ecological Receptor at HQ=1

1,1-Biphenyl mg/kg NA NA 200 Human Health at HQ = 1

2-Methylnaphthalene mg/kg NA NA 3,000 Human Health at HQ = 1

BAP TEQ mg/kg NA 3.0 3.0 Human Health at ELCR = 1 x 10-4

Dioxin TEQ mg/kg NA 0.00073 0.00073 Human Health at HQ = 1

Naphthalene mg/kg NA NA 290 Human Health at HQ = 1

Pentachlorophenol mg/kg NA NA 400 Human Health at ELCR = 1 x 10-4

Shallow Aquifer Groundwaterf

1,1-biphenyl µg/L NA 14 Ecological Screening Valuee

1-Methylnaphthalene µg/L NA 2.1 Ecological Screening Valuee

2-Methylnaphthalene µg/L NA 63 Ecological Screening Valuee

3&4-Methylphenol (m&p-Cresol) µg/L NA 272 Ecological Screening Valuee

Acenaphthene µg/L NA 23 Ecological Screening Valuee

Acenaphthylene µg/L NA 7,731 Site-specific Secondary Contact Recreationd

Anthracene µg/L NA 0.30 Ecological Screening Valuee

BAP TEQ µg/L NA 0.25 Site-specific Secondary Contact Recreationd

Benzene µg/L NA 1,125 Louisiana AWQC - Aquatic Organism Protectionb

Benzo(a)anthracene µg/L NA 35 Ecological Screening Valuee

Benzo(a)pyrene µg/L NA 0.014 Ecological Screening Valuee

Chrysene µg/L NA 7.0 Ecological Screening Valuee

Dibenz(a,h)anthracene µg/L NA 5.0 Ecological Screening Valuee

Dibenzofuran µg/L NA 94 Ecological Screening Valuee

Ethylbenzene µg/L NA 1,600 Louisiana AWQC - Aquatic Organism Protectionb

Fluoranthene µg/L NA 6.2 Ecological Screening Valuee

Naphthalene µg/L NA 250 Ecological Screening Valuee

Pentachlorophenol µg/L NA 15 Federal AWQC - Aquatic Organism Protectionc

Phenanthrene µg/L NA 30 Ecological Screening Valuee

Pyrene µg/L NA 7.0 Ecological Screening Valuee

Xylenes µg/L NA 1,340 Ecological Screening Valuee

Notes: a Ecological PRGs were not developed for individual high molecular weight PAH compounds, but they are included in the total high molecular weight PRG calculation. The individual high molecular weight PAHS include: benzo(a)anthracene, benzo(a)pyrene, benzo(b)fluoranthene, benzo(g,h,i)perylene, benzo(k)fluoranthene, chrysene, dibenz(a,h)anthracene, fluoranthene, indeno(1,2,3-c,d)pyrene, and pyrene. b Reference: Table 1, Freshwater Chronic Numerical Criteria for Specific Toxic Substances Louisiana Administrative Code Title 33, Part IX, Subpart 1 (2014b) c Reference: Environmental Protection Agency (EPA) National Recommended Water Quality Criteria (EPA, 2014) d Reference: Site-specific calculated value based on lowest value of excess lifetime cancer risk of 1 x 10-4 or hazard quotient of 1.0 e Reference: Texas Commission on Environmental Quality, http://www.tceq.state.tx.us/assets/public/remediation/eco/0106eragupdate.pdf f Non-Process Area and Process Area Decision Units lie in the same geographic portion of the shallow aquifer; therefore, the PRGs are the same. µg/L = microgram per liter AWQC = ambient water quality criteria BAP = benzo(a)pyrene DU = Decision Unit ELCR = excess lifetime cancer risk HQ = hazard quotient mg/kg = milligram per kilogram NA = not applicable PAH = polycyclic aromatic hydrocarbon PRG = preliminary remediation goal TEQ = toxicity equivalent

022119

Table 5- Comparative Evaluation of Alternatives American Creosote Works, Winnfield, Louisiana

Alternative 1: Criterion No Further

Action

Key Treatment Technologies

Northern DU Soil

Non-process Area DU (Soil) Not

Process Area DU (Soil < 5 feet) Applicable Process /\rea DU (Soil > 5 feet)

Threshold Criteria

Process Area, Non-process

Area, and Northern DUs

Protects H HE No

Complies with ARARs No

Balancing Criteria

Long-term Effectiveness and Not evaluated

Permanence

Reduction of TM V through Treatment Not evaluated

Short-term Effectiveness Not evaluated

lmplementability Not evaluated

Cost

Total Present Worth Cost $640,000

Present Worth Cost Range

-30 Percent $448,000

+50 Percent $960,000

Annual O&M Cost $0

Periodic Cost $0

Total Non-discounted Cost $640,000

Modifying Crit eria

Stat e Acceptance

Community Acceptance

Alternative 2: ICs with Alternative 3- Upgrade NAPL

LTM and Targeted Hot-Recovery and Treatment System,

spot Soil Excavation and Targeted Hot-Spot Soil

Excavation

Excavation and Disposal Excavation and Disposal

ICs and Fence

ICs and Multi-layer Cap Multi-layer Cap

Upgrade N/\PL Recovery and Treatment

Non-Process process, Process Non-process, Area DU Northern Area DU Northern DUs

DUs

No No Yes Yes

Yes' Yes Yes' Yes

Not evaluated * **** Not evaluated

·~ **** Not evaluated ** **** Not evaluated ***· ***Cl

$8,500,000 $28,500,000

$5,97,000 $19,920,000

$12,780,000 $42,690,000

$73,000 $664,000

$295,000 $4,930,000

$17,370,000 $92,450,000

****= The alternative performs superior against the CERCLA balancing criterion with no disadvantages or uncertainties

Alternative 4- Containment Alternative Sa- Partial Depth with Slurry Wall and Multi-layer Excavation- Thermal Cap with Targeted Hot-spot Soil Desorption, and Thermal

Excavation Enhanced Extraction

Excavation and Disposal Excavation and Disposal

Slurry Wall and Cap Excavation and MTID

Thermal Enhanced N/\P L Recovery

Process Non-process, Process Non-process, Area DU Northern DUs Area DU Northern DUs

Yes Yes Yes Yes

Yes' Yes Yes' Yes

** **** *** **** **ti1 **** *** **** *** **** ** **** rt-::n *** *-- ***Cl

$18,500,000 $45,700,000

$12,920,000 $32,010,000

$27,690,000 $68,605,000

$117,000 $1,300,000

$295,000 $295,000

$31,680,000 $69,040,000

Not evaluated in this FS

*** ** *

= The alternative performs well against the CERCLA balancing criterion with minimal disadvantages or uncertainties

=The alternative performs fair against the CERCLA balancing criterion but with some disadvantages or uncertainties

=The alternative performs poorly against the CE RCLA balancing criterion with more disadvantages or uncertainty

'This assessment does not include groundwater. The groundwater decision is postponed to a future decision document.

>=less than < = greaterthan ARARs =applicable or relevant and appropriate requirements CERCLA =Comprehensive Environment31 Response, Compensation, and Uability Act of 1980 (commonly known as Superfund)

DU =decision unit FS =feasibility study H HE = Human Health and the Environment I C = institutional control ISS= in situ solidification/stabilization

LTM =long-term monitoring MTID =medium temperature thermal desorption NAPL =nonaqueous phase liquid O&M =operation; and maintenance TMV =toxicity, mobility, and volume

Alternative Sb- Full Depth Excavation with Thermal Alternative 6 -ISS

Desorption

Excavation and Disposal Excavation and Disposal

Excavation and MTID ISS

Process Non-process, Process Non-process, Area DU Northern DUs Area DU Northern DUs

Yes Yes Yes Yes

Yes' Yes Yes' Yes

**** **** **** **** **** **** **** **** * " **** ** : **** _..1 ***~ ...-:~ '**'*"

$91,000,000 $25,000,000

$64,000,000 $17,4 70,000

$137,000,000 $37,430,000

$73,000 $73,000

$36,000 $295,000

$104,000,000 $31,190,000

022120

_̂

Site Location

LEGEND

PLTS SupportBldg.

PLTSBldg.Bioreactor

Pond

0 15075Feet K

T:\IS\Proj\American_Creosote\apr-mxd\Alt6_remediation_footprints.mxd 4/8/2016 gtwigg

FenceCreek (Creosote Branch)

! !

Site Utility RoadsTar Mat Ash Disposal Cell

Figure 3Alternative 6 Remediation FootprintsIn-Situ Solidification/StabilizationAmerican Creosote WorksWinnfield, Louisiana

NPDU – Non-Process Decision UnitDioxin Soil Excavation Footp rint(This Area will be Refined duringRemedial Desig n)NDU – Northern Decision Unit SoilExcavation Footp rintPDU – In Situ Solidification/Stabilization Footp rint

022121

PROPOSED PLAN Amendment to April 1993 Record of Decision

American Creosote Works Inc. Superfund Site

Winnfield, Louisiana

Xx/xx, 2016

The purpose of this Proposed Plan is to:

● Identify the proposed alternate remedy that will amend the April 1993 remedy;

● Summarize the information that prompted and supports fundamentally changing

the April 1993 remedy;

● Solicit public review and comment on the alternate cleanup strategy as well as

information contained in the Administrative Record file; and,

● Provide information on how the public can be involved in the remedy selection

process for the American Creosote Works Inc. Site.

Dates to Remember:

● Public Comment Period:

Xx/xx/xxx to xx/xx/xxxx

The EPA and LDEQ will accept written comments on the Proposed Plan during the public

comment period.

● Public Meeting: xx/xx/xxxx

The EPA will hold a public meeting to explain the Proposed Plan and all of the alternatives

presented in the Feasibility Study. Oral and written comments will also be accepted at the

meeting. The meeting will be held at the Winn Parish Library, 200 N. St. John Street,

Winnfield, LA, 71843, at x:xx pm.

● Administrative Record is available for viewing at:

EPA Region 6 LDEQ Headquarters

7th Floor Reception Area Public Records Center

1445 Ross Avenue, Suite 12D13 Galvez Building, 1st Floor – Room 127

Dallas, TX 75202-2733 602 N. Fifth Street

Toll Free (800) 533-3508 or (214) 665-6597 Baton Rouge, LA 70802

Monday – Friday 7:30 – 11:00 am/1:00 – 4:00 pm (225) 219-3181

Winn Parish Library

200 N. St. John Street

Winnfield, LA 71843

(318) 628-4478

Hours – 8:30 am-5:30 pm Monday - Friday, 10 am-2pm Saturday

022122

Introduction

In this Proposed Plan, the U.S. Environmental Protection Agency (EPA) presents summary

information for an alternate remedy for the American Creosote Works Inc. Superfund Site (Site)

located in the City of Winnfield, Winn Parish, Louisiana (Figure 1). The remedy implemented

pursuant to the April 1993 Record of Decision has been successful in reducing the amount of

contamination at the Site. However, due to several years of declining remedy performance and

growing concerns of the long-term effectiveness of the Site’s Non-Aqueous Phase Liquid

(NAPL) recovery and in-place biological treatment systems, EPA has concluded that the

previously selected remedy will not achieve existing cleanup objectives in a reasonable amount

of time.

This Proposed Plan highlights key information about the progress of the current remedy, the

current extent of the remaining contamination at the site, and the revised cleanup objectives. The

EPA is issuing this Proposed Plan to recommend the following alternate remedy for the Site:

● Alternative 6 – In-Situ Solidification/Stabilization, and Targeted Hot-Spot Soil Excavation

Alternative 6 would solidify/stabilize in situ the subsurface source of ground water

contamination (i.e., mobile and immobile NAPL) present within the Process Area and Tar Mat

Decision Units.

● Current Remedy – The on-site incineration of highly contaminated tars and sludges has been

completed. The pumping, separation, and treatment of liquid contaminants and the in-situ

bioremediation components of the 1993 ROD which were designed to address the subsurface

source of shallow ground water contamination are being replaced by the proposed remedy. A

new soil cover to protect the in-situ solidification/stabilization area will replace the capped

surface soils completed under the current remedy. The goal of restoring ground water to its

potential beneficial use is retained from the 1993 ROD and applies to the shallow ground water

impacted by the source area.

The EPA has conducted its activities in connection with the Site in accordance with the

Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA or

Superfund), 42 U.S.C. §§ 9601 et seq., and the National Oil and Hazardous Substance

Contingency Plan (NCP), 40 C.F.R. Part 300. The EPA is issuing this Proposed Plan in

accordance with and as part of its public participation responsibilities under CERCLA § 117(a),

42 U.S.C. § 9617(a) and 40 C.F.R. § 300.430(f)(2). The summary information and

recommendations set forth in this Proposed Plan are based on information and documents

contained in the Administrative Record file for the Site.

The EPA Region 6 office is the lead agency for this Site and has conducted remedial activities at

the site since the 1990’s. The Louisiana Department of Environmental Quality (LDEQ) is the

support agency and provided technical review of the remedy performance through a cooperative

agreement with EPA.

022123

Community Participation

This Proposed Plan highlights information contained in the Administrative Record for the Site

which includes annual operation and maintenance reports, historical and revised investigation

reports, revised feasibility study reports, and other documents and reports used in preparing this

Proposed Plan. The EPA encourages the public to review those documents to obtain more

information about the Superfund activities that have been conducted at the Site. The EPA also

encourages the public to participate in the decision-making process for the Site. The

Administrative Record file is available at the following information repositories:

EPA Region 6 LDEQ Headquarters

7th Floor Reception Area Public Records Center

1445 Ross Avenue, Suite 12D13 Galvez Building, 1st Floor – Room 127

Dallas, TX 75202-2733 602 N. Fifth Street

Toll Free (800)533-3508 or (214)665-6597 Baton Rouge, LA 70802

Monday-Friday 7:30-11:00 am/1:00-4:00 pm (225)219-3181

Winn Parish Library

200 N. St. John Street

Winnfield, LA 71843

Monday-Friday 8:30 am-5:30 pm, Saturday 10:00 am-2:00 pm

The EPA will hold a public meeting to inform residents of the proposed alternate remedy for the

cleanup of the Site and obtain comments on the Proposed Plan for the American Creosote Works

Inc. Site in the City of Winnfield, Winn Parish, Louisiana.

The public meeting will be held on XXXXXX, MONTH DAY, YEAR, at TIME at the

Winn Parish Library, 200 N. St. John Street, Winnfield, Louisiana, 71843. The public meeting is

being held in a fully accessible facility. Should you have specific needs or questions about the

facility, please contact Michael A. Hebert, Remedial Project Manager, at (214) 665-8315 or toll-

free (800) 533-3508 or Jason McKinney, Community Involvement Coordinator, (214) 665-8132

or toll-free (800) 533-3508.

Public comments can be presented at the public meeting or can be submitted during the public

comment period from DATE, through DATE. All written comments should be addressed to:

Michael A. Hebert, Remedial Project Manager

U.S. EPA Region 6 (6SF-RL)

1445 Ross Avenue

Dallas, Texas 75202-2733

214-665-8315

hebert.michael@epa.gov

For specific information about the LDEQ’s participation in the Superfund process, please

contact:

022124

John Halk, Project Manager

Louisiana Department of Environmental Quality

Remediation Services Division

Group 3

P.O. Box 4314

Baton Rouge, LA 70821-4314

225-219-3717

john.halk@la.gov

Site Background and Characteristics

The ACW site is a former wood-treating facility, spanning about 62 acres, located at 1006 Front

Street in Winnfield, Louisiana. According to the U.S. Census Bureau, about 4,600 people lived

in Winnfield in 2013. Land uses nearby include agricultural, residential, commercial, and

recreational uses. Residences near the Site are connected to the City of Winnfield’s public water

system. Wood treatment operations at the Site began around 1901 and continued under various

ownerships until 1985, when the Louisiana Department of Environmental Quality (LDEQ)

discovered that the Site had been abandoned.

Unplanned releases of creosote and pentachlorophenol (PCP) based wood-treating oil, and waste

handling practices resulted in extensive soil, groundwater, and sediment contamination.

Contaminant sources present at the time of abandonment included two storage tanks, visibly

contaminated soil present in the former process area, waste material present in a surface

impoundment located just north of the fire water pond, and tarry-sludge material present in an

area later identified as the Tar Mat sludge disposal area. In response to these conditions, EPA

completed two removal actions to stabilize contaminant sources and reduce the potential for

further contaminant releases. The removal actions were performed between 1987 and 1989.

A Remedial Investigation/Feasibility Study (RI/FS) was performed in 1992/1993 and focused

primarily on the areas where wood treating operations were conducted. From information

reviewed during the RI, the wood treating operations were determined to have occurred in the

north-central portion of the Site. A tank farm, with no visible secondary containment, was also

located in this north-central part of the site. The earliest aerial photographs (1940 and 1947) of

the Site showed evidence (soil staining and stressed vegetation) that wood-treating oil flowed

unimpeded from the former process area towards Creosote Branch Creek. An onsite drainage

pathway that discharged to Creosote Branch Creek is also visible on a 1940 aerial photograph as

is a natural drainage that flows eastward from the former process area.

Between April 1950 and May 1952, two impoundments were constructed in the process area

which received liquid wastes from the wood-treating process. Several shallow drainage ditches

were also constructed to convey runoff from the process area. A 1959 aerial photograph shows a

pool of standing liquid northeast of the tank farm in the process area. Evidence of standing

liquid and dark-stained soil at this location appears in subsequent aerial photographs through

1973.

022125

Sometime prior to 1966, additional wood treatment facilities were built in the southern portion of

the process area and a third impoundment was constructed east of the process area.

Interpretation of aerial photographs indicates heavy wood treating activity at the Site during the

mid- to late-1960s. According to facility records, during a 7-month period in 1966, 750,000

gallons of petroleum distillate, 40,000 gallons of creosote, and 54,000 pounds (3,200 gallons) of

PCP were used to treat 7.5 million board-ft of lumber. Between 1973 and 1976, extensive

earthwork that was performed north and east of the Process Area covered up the majority of

stained soil and removed all evidence of Impoundment 1. A fourth impoundment was built

northeast of Impoundment 2. This impoundment may have received drainage or overflow from

Impoundment 2. A water storage pond was also constructed south of Impoundment 2 to collect

and store rainwater for emergency fire-fighting. Evident in a 1973 photograph is the formation

of the “Tar Mat” area, located approximately 500 feet east of the Process Area. The Tar Mat was

a large, flat, asphalt-like waste material that extended over a marshy portion of the Site. The

source of the Tar Mat material is unknown, but the 1992/1993 RI/FS Report indicates that it

might have resulted from a large, single spill event. The Tar Mat area also may have resulted

from removal and disposal of impoundment sludge. By 1983, Impoundments 2 and 4 had been

backfilled, presumably with wood chips, and the impoundment dikes had been leveled.

However, Impoundment 3 remained active.

In June 1985, the Louisiana Department of Environmental Quality (LDEQ) found the site

abandoned and referred it to EPA, which placed the site on the National Priorities List (NPL) on

October 14, 1992, based on a hazard ranking score of 50.7.

The 1992/1993 RI/FS determined that the primary threats that the Site posed to public health

were direct contact or ingestion of contaminated site soils and ingestion of contaminated site

groundwater by potential future residents. The RI determined that site soil was contaminated

with polycyclic aromatic hydrocarbons (PAHs), volatile organic compounds (VOCs), dioxins

and PCP. The most heavily contaminated surface soils were located in the former process and

impoundment areas, the tar mat area, and its related drainage area in the northeast portion of the

Site. Contaminated subsurface soil is present throughout the former process area, the

impoundment area and the tar mat area. Contaminants in shallow aquifer groundwater include

PAHs, phenols and benzene. The RI determined that groundwater contamination was present

primarily in the former process and impoundment areas and areas hydraulically downgradient of

those locations. Surface water and sediment in Creosote Branch Creek were also impacted by

site activities.

EPA concluded that a future residential use scenario was most appropriate for estimated risks

posed by the Site. Exposure to contaminated soils at the Site under a residential exposu