PROPOSED REMEDIAL ACTION PLAN (PRAP)

DRAFT SUPERFUND PROPOSEDREMEDIAL ACTION PLAN

Ordnance Products, Incorporated SiteNorth East, Cecil County, MarylandAugust 2006

I. INTRODUCTION

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The United States Environmental Protection Agency (EPA) herein identifies its PreferredAlternative for mitigating threats posed to human health and the environment at and from theOrdnance Products, Incorporated Site (OPI site or Site) located in North East, Cecil County,Maryland. In addition, this Proposed Plan includes a summary of background informationrelating to the Site, describes other cleanup alternatives evaluated for use at the Site, solicitspublic review and comment on all of the alternatives described in this Proposed Plan, andprovides information on how the public can be involved in the remedy selection process. TheProposed Plan identifies EPA's preferred remedy combining an extension of the municipal watersupply to affected residences currently on point-of-entry (POE) water treatment, containment andtreatment of contaminated ground water, removal of Munitions and Explosives of Concern(MEC) from Site soils, and excavation and offsite treatment of contaminated soil at selectedstudy areas onsite.

This Proposed Plan is issued by EPA, the lead agency for Site activities under theNational Oil and Hazardous Substances Pollution Contingency Plan (NCP), 40 C.F. R. Part 300,pursuant to the Comprehensive Environmental Response, Compensation, and Liability Act of1980, as amended (CERCLA). This Proposed Plan is based on Site-related documents containedin the Administrative Record file for the Site. The Administrative Record file can be reviewedelectronically at http://www.epa.gov/arweb or at the following locations:

Cecil County Library, Elkton Branch301 Newark AvenueElkton, MD 21921(410) 996-5600

U.S. EPA-Region III Docket RoomMs. Anna Butch1650 Arch StreetPhiladelphia, PA 19103(215)814-3157

EPA and the Maryland Department of the Environmental (MDE), the support agency,encourage the public to review and comment on the cleanup options evaluated in this ProposedPlan. The public comment period begins on August 16, 2006 and closes on September 15, 2006.On August 16, 2006 EPA will hold a public meeting to discuss this Proposed Plan at the NorthEast Branch of the Cecil County Public Library, 106 W. Cecil Avenue, North East, Marylandfrom 7:00 p.m. to 9:00 p.m. Written comments, postmarked no later than September 15, 2006,should be sent to:

Ordnance Products, Inc. Superfund Site, Cecil County, MarylandProposed Plan

Frederick N. Mac Millan (3HS23)Remedial Project ManagerU.S. EPA - Region m1650 Arch StreetPhiladelphia, PA 19103Phone: (215) 814- 3201

Comments may also be sent by September 15, 2006 via E-mail to macmillan.fred(a),epa.gov.

Interested persons are encouraged to submit their comments on this Proposed Plan toEPA during the public comment period. Although EPA has identified a preferred alternative, nofinal decision has been made. EPA may modify the preferred alternative, select another responseaction, or develop another alternative based on comments received during this period. EPA, inconsultation with MDE, will announce the selection of a remedy for the Site in a Record ofDecision.

EPA is issuing this Proposed Plan as part of its public participation responsibilities underSections 113(k)(2)(B), 117(a), and 121(f)(l)(G) of CERCLA, 42 U.S.C. §§ 9613(k)(2)(B),9617(a), and 9621(f)(l)(G), and Section 300.430(f)(2) of the NCP.

//. SITE BACKGROUND

This Proposed Plan provides an overview of the Site and is organized into the followingsections:

• Section I Introduction• Section II Site Background• Section HI Site Characteristics• Section IV Scope of the Response Action• Section V Summary of Site Risks• Section VI Remedial Action Objectives• Section VII Summary of Alternatives• Section VIII Evaluation of Alternatives• Section IX Summary of Preferred Alternative• Section X Role of the Community in the Remedy Selection Process

Location

The Ordnance Products, Inc. Site is located in the Mechanics Valley Trade Center at 1079Mechanics Valley Road in Cecil County, Maryland, approximately two miles northeast of thecity of North East, Maryland (See Figure 1).

Ordnance Products, Inc. Superfund Site, Cecil County, MarylandProbosed Plan

Site Description

The OPI Site is located on a 95-acre property consisting of wooded and open areascontaining both occupied and unoccupied buildings, trailers, junk cars and debris scatteredthroughout the Site. There are currently several active businesses at the Site, including a safetyequipment business, an automotive repair shop, and a propane storage facility. There are alsobuildings that appear to house other businesses that may or may not presently be active.

The OPI Site was originally used to assemble various munitions products, includinggrenades, grenade fuses, pyrotechnic signals, and detonators, primarily for the United Statesmilitary, from approximately 1957 to 1979 when operations at the Site ceased. In 1986, theproperty was purchased by Mechanics Valley Trade Center, Incorporated (MVTC) from KDICorporation (KDI) and then sold to the corporation's majority stockholder, William Frederick.

Site History

In 1987, investigations by the Maryland Department of the Environment (MDE) revealed severalknown or suspected disposal areas and surface impoundments, now designated Areas A throughH, comprising approximately 10 acres dispersed across the Site at various locations on theproperty (see Figure 2). Potential sources of contamination included landfills in Areas A and E,bunkers used for burning in Areas A and B, disposal trenches in Areas C and H, a disposal pit inArea D, and burn pits in Area F. In addition, abandoned bulk chemicals and a metal plating shopwith six waste discharge ponds were also present. MDE suspected that explosives materials,including those termed "Munitions and Explosives of Concern" (MEC) remained onsite. MECincludes specific categories of military munitions that may pose explosives safety risks andincludes unexploded ordnance (UXO), discarded military munitions (DMM) or munitionsconstituents (e.g. trinitrotoluene or "TNT") in high enough concentrations to pose an explosivehazard. Samples taken by MDE also showed elevated levels of volatile organic compounds(VOCs) in soil borings, surface water, and in one onsite and three offsite residential water supplywells. Area G consists of fill material adjacent to a former manufacturing building in the centralportion of the site near Area H and exhibits no significant soil or ground water contaminants.

In 1988 MDE issued orders to the Site owners to address the environmental threats.When the owners failed to comply, MDE requested EPA's assistance. EPA conducted anassessment of the Site in March 1988 and issued a unilateral administrative order (UAO) to KDIon June 27, 1988 to clean up the Site, determine the extent of groundwater contamination, andmaintain the treatment of the affected off-site drinking water wells. Later that year, the owner'scontractor sampled 52 home wells and initiated a drum and waste material removal program.Drums containing sludge, powders, acids, solvents and ordnance materials, such as fuses anddetonators, were removed.


During investigations performed by the potentially responsible parties (PRPs) andoverseen by EPA from 1989-91 under the June 1988 UAO, the presence of MEC materialsincluding portions of smoke grenades, fuses, and blasting caps, was confirmed on several areasof the Site. During 1995 and 1996 the owner's contractor designed and constructed agroundwater pump and treatment system, but that system was never operated due to lack offunds. In 1997, the Site was formally added to the National Priorities List (NPL) making iteligible for federal cleanup funds.

The Mechanics Valley Trade Center where the site is located is currently controlled by asingle stockholder. MVTC nor any of the other responsible parties are conducting any work atthe Site. EPA has undertaken enforcement actions against the responsible parties and has beencarrying out hazardous materials response actions at the Site under the Superfund program.

///. SITE CHARACTERISTICS

Sampling of residential wells in the vicinity of the Site began in 1988 by the PRPs andregular sampling by EPA continues today. Several residential wells found to be contaminated byhazardous substances from the Site were placed on individual, whole-house, point-of-entry(POE) water treatment systems in the early 1990s under EPA supervision. EPA maintains thesesystems for residential water wells in five homes just east of the OPI property and monitors theirperformance quarterly to insure that exposure to Site-related ground water contaminants aboveacceptable levels does not occur. At present, none of these residents adjacent to the Site arebeing exposed to contaminants in their domestic water wells above acceptable drinking waterstandards.

hi October 1996, EPA initiated a Remedial Investigation and Feasibility Study (RI/FS)which was completed in May 2005. The Remedial investigation (RI) identified the nature andextent of contamination, fate and transport of contaminants, and the risk posed by the Site tohuman and ecological receptors. The Feasibility Study (FS) identified options to address thecontamination found at the Site. The FS was completed in December 2005 and modified by anAddendum in May 2006.

The major findings of the RI were:

* Eight primary disposal areas, designated Areas A thru H, were confirmed in variouslocations onsite. Several appeared to have specific uses, such as landfill areas; bunkers used forstoring, burning and testing ordnance materials; disposal trenches; a disposal pit; and burn pits.Each area has the potential to release contaminants into the environment, either to ground wateror via direct contact with receptors, that is, individuals at risk of exposure, or both.

* Soil contaminants include volatile organic compounds (VOCs), metals, perchlorate andother materials associated with the manufacture of munitions, and buried remnants of munitions


and explosives of concern (MEC) such as fuses, blasting caps, etc.

* MEC materials were confirmed in Areas C, F, and H. Other likely disposal areas includeAreas A, B and D, but these were not confirmed at the time due to safety considerations.

* Two aquifers or subsurface water-bearing layers underlie the Site, a shallow (overburden)aquifer and a deep aquifer. Within these aquifers, two separate contaminated ground waterplumes containing primarily VOCs, are associated with the Site; Plume 1 in the shallow and deepaquifers generally underlying Area H and the stream valley in the northeastern portion of the Site(Figures 3 and 4), and Plume 2 in the shallow aquifer beneath Area D in the southwestern portionof the site (Figure 5). Trichloroethene (TCE) and tetrachloroethene (a.k.a. perchloroethene orPCE) are the major groundwater contaminants.

* Plume 1 shows TCE concentrations up to 3,800 ug/L (i.e. micrograms per Liter,equivalent to parts per billion) and PCE concentrations up to 5,600 ug/L. Plume 2 showedsignificant VOC contamination by Area D including PCE at 5,500 ug/L and TCE at 1,300 ug/L.Plume 1 is contaminating the aquifer used by several nearby residences for their drinking water.The shallow aquifer in Plume 2 also contains perchlorate, a very mobile and persistentcompound, in the ground water at levels as high as 3,850 ug/L. The five residences where EPAmaintains POE treatment systems on the domestic wells draw their source water from the aquiferbeneath Area H, affected by Plume 1. At present, Plume 2 is not affecting any nearby residentialwells.

* MECs pose an immediate threat due to their potential instability and possibility ofdetonation via direct contact or nearby disturbance. They must be cleared from all disposal areasbefore any environmental cleanup can commence in those areas.

* Soils contaminated with VOCs remain as a source of contamination that impacts groundwater by continuing to leach into the underlying aquifers that are used for drinking water. Thepotential risk via direct contact with ground water contaminated with PCE, TCE and vinylchloride for the most likely exposure scenario (industrial/construction worker) is beyond EPA'sacceptable risk range for exposure to potential carcinogens of 1 x 10"4 (i.e. a risk of 1 in 10,000 ofan additional case of cancer attributable to exposure to these site contaminants).

Though several residential wells are currently contaminated with VOCs from the Site,(Figure 6) treatment systems maintained by EPA are continuing to prevent exposure to Site-related ground water contaminants at levels above EPA's acceptable risk range in these homes.

IV. SCOPE OF THE RESPONSE ACTION

The response action, as currently planned, is expected to be handled as one operable unit(OU) with different phases to protect area residents, employees and the public from the hazards


associated with the Site. The first phase of the response action will be to address the physicalsafety issues associated with MEC in soils. This will be followed by removing hazardoussubstances from soil to mitigate further migration of contaminants to ground water asappropriate. Contaminated ground water at the Site will be isolated, captured and treated toremove hazardous substances and restore ground water to its beneficial use. Finally, anextension of the public water supply will be provided to affected residents currently on (POE)water treatment systems.

V. SUMMARY OF SITE RISKS

Human Health and Ecological Risks

As part of the RI/FS, EPA conducted a baseline risk assessment to determine the currentand future effects of Site contaminants on human health and the environment. The generalobjectives of the risk assessment for the Ordnance Products, Inc. Site were to estimate the actualor potential risks to human health resulting from the presence of contamination in ground water,surface soil, disturbed soil (i.e. surface and subsurface soils that have been mixed), sediment, andsurface water, and to provide the basis for determining appropriate remedial measures (ifnecessary) for these media as part of the feasibility study. This effort consisted of a baselinehuman health risk assessment (BLRA) and a screening level ecological risk assessment(SLERA).

The NCP has established acceptable levels of carcinogenic (i.e. cancer-causing) risk forSuperfund sites ranging from one excess cancer case per 10,000 people exposed to one excesscancer case per one million people exposed. This translates to a risk range of between one in10,000 and one in 1 million additional cancer cases. Expressed as scientific notation, this riskrange is between 1 x 10"4 (one in 10,000) and 1 x 10~6 (one in 1 million). A remedial action isparticularly warranted at a site when the calculated cancer risk level exceeds 1x10^.

The NCP further states that sites should not pose a health threat due to non-carcinogeniceffects. EPA quantifies a non-carcinogenic threat by the ratio of the contaminant dose at the sitethat a person may encounter to the established safe concentration. The Hazard Quotient (HQ) isthe ratio of estimated site-specific exposure to a single chemical from a site over a specifiedperiod to the estimated daily exposure level at which no adverse health effects are likely to occur.The Hazard Index (HI) is the sum of all the HQs for a particular exposure pathway, e.g.inhalation. If the HI exceeds one (1), there may be a potential for non-carcinogenic health effectsassociated with exposure to contaminants via that exposure pathway. The HI identifies thepotential for the most sensitive individuals to be adversely affected by the noncarcinogeniceffects of chemicals. As a rule, the greater the value of the HI above 1, the greater the level ofconcern.


The Ordnance Products, Inc. Site property is zoned for heavy industrial use (Zoning CodeM2) by the Cecil County, Maryland zoning board. Therefore, the reasonably anticipated currentand future land uses for the OPI property will continue to involve industrial, rather thanresidential use. Properties adjacent to the site are zoned for residential use and are, in fact,occupied by a number of private homes. Most of these properties rely on area ground water fordomestic use (drinking, bathing, and cooking). Some of these domestic-use water wells arecurrently contaminated by hazardous substances in ground water that have migrated off of theOPI property.

Human Health Risk Assessment

The BLRA assesses the toxicity, or degree of hazard, posed by contaminants found at theSite, and describes the routes by which humans could come into contact with these substances.Separate calculations are made for those substances that can cause cancer (carcinogens) and forthose that can cause non-cancer, but adverse, health effects, hi addition, exposure potentialvaries by contaminant, by environmental media (e.g. soil, ground water), by exposure route(ingestion, inhalation, dermal contact, etc.), by Site-specific source (At OPI, primary disposalareas A through H, contaminated ground water plumes 1 and 2) and by exposure scenario(residential setting versus industrial land uses).

Since the Site property itself is limited to industrial use, the risk assessment focused onprotection of human health under the most likely exposure scenarios. Those scenarios wereonsite exposure of industrial and/or construction workers, and exposure of current and futureoffsite residents to contaminated domestic well water from the Site. Based on the findings of theBLRA, the most likely exposure scenarios at the OPI Site are for the industrial worker or theconstruction worker exposed to contaminated soils and/or ground water on the Site property, andfor nearby lifetime residents exposed to contaminated ground water. The most significant humanhealth risks under these scenarios are described below.

For the future industrial worker and the future construction worker at the Site, Plume 2ground water contact was the most significant contributor to both carcinogenic and non-carcinogenic risk. Exposure to Plume 2 groundwater via inhalation of ground water vapors forthe construction worker and via dermal contact during tap water hand-washing or rinsingactivities for both the construction worker and the industrial worker represent the mostsignificant onsite risk. The carcinogenic risks exceeded 1x10^ from exposure to PCE fromPlume 2 groundwater. Exposures to PCE, and to a lesser extent, TCE, by the same route wereassociated with target organ-specific His greater than 1.

In Area F (Inside Burn Pit), contact with a surface soil or with combination of surface andsubsurface soil that may be mixed during future construction also exceeded the non-cancer HQ of1 for chromium for the onsite industrial worker and construction worker, respectively.

Ordnance Products, Inc. Supetfund Site, Cecil County, MarylandProposed Plan

Human health risks for offsite lifetime current residents most closely define the everydayrisks faced by residents in homes just east of the Site whose domestic water wells arecontaminated by hazardous materials from OPI. The reasonable maximum risk for offsitelifetime current and/or future residents is reflected by exposure to contaminated raw (i.e.untreated) groundwater from Plume 1 at the levels found in one of these contaminated residentialwells (RW46). Contact from a combination of tap water ingestion, inhalation of VOCs duringshowering, and from inhalation of vapors from ground water vapor intrusion into basementsyielded carcinogenic risks well in excess of EPA's target risk range of 1 x 10"4 to 1 x 10~6, drivenby exposures to TCE. Maximum risks for an adult offsite future lifetime resident are due tofuture exposures to Plume 2 ground water and produce similar risk results, hi addition to TCE,exposure to PCE and to the explosives manufacturing compound hexachloroethane, also drivescarcinogenic risk beyond EPA's acceptable risk range. The maximum non-cancer risks for the

offsite future lifetime resident exceeded a target organ-specific HI of 1, also driven by futureground water exposures to PCE and TCE in Plume 2.

Possible vapor intrusion into basements from VOC-contaminated ground water, thoughcontributing to cancer risks, were less than EPA's target risk range of 1 x 10"4 to 1 x 10"6. It isimportant to note that at present, no residences on or near the Site are exposed to contaminatedground water from Plume 2. Other types of ground water exposure risks (ingestion, etc.) weregenerally higher. Cancer and non-cancer risks are summarized in Tables 7-1 through 7-10 in theBLRA in the RI.

During the RI in late 2004, significant levels of perchlorate were discovered in groundwater onsite, primarily in Plume 2. No residential wells have been affected at this time. OnJanuary 26, 2006, EPA issued new protective guidance for cleaning up perchloratecontamination, recommending a preliminary clean-up goal for perchlorate of 24.5 parts perbillion in water. EPA's new guidance was derived from the agency's reference dose forperchlorate which was based on the 2005 recommendations of the National Academy ofSciences. As yet, no Federal drinking water standard has yet been established for perchlorate.EPA will use this guidance as a preliminary clean-up level for perchlorate in ground water at theSite.

Ecological Risk Assessment

A Screening-Level Ecological Risk Assessment (SLERA) is a qualitative and/orquantitative appraisal of the actual or potential impacts of contaminants from a hazardous wastesite on plants and animals other than humans and domesticated species. The SLERA wascompleted for the OPI Site in May 2002 and accepted by EPA in September 2002. The findingsof the SLERA indicated that the potential for significant ecological impacts to occur at the Sitewas limited.


The SLERA identified several metals and VOCs as ecological Contaminants of Concern(COCs) posing potential risk to ecological receptors exposed to the soil, sediment, and surfacewater at the OPI Site. However the SLERA found that the ecological COCs are overwhelminglymetals, and that any ecological risk is due to direct toxicity. Among the ecological COCs forsoils, sediments and surface water are: aluminum, barium, cadmium, chromium, cobalt, copper,cyanide, iron, lead, manganese, mercury, nickel, vanadium, and zinc. One organic compound insediments, dirnethylphthalate, was found in the onsite tributary to the Little North East Creek.

The ecological COCs for soil are of concern only in Areas A and G, with the primary riskbeing associated with metals in Area A soils. The ecological COCs for sediment and surface waterare of concern only in the small streams on the Site, not in Little North East Creek to the east of theSite. Ecological risks to sediment and aquatic organisms are limited to the intermittent/ephemeralstream system on the Site; no constituents detected in Little North East Creek exceed the screeninglevels or the threshold affects benchmark (i.e. contaminant levels known to have demonstrableaffects on aquatic life) ecological risks.

All site source areas are subject to screening to identify and remove MEC materials. If MECmaterials are discovered, they will be cleared to depth, at whatever depth they are found. Anyexcavation associated with remediating MECs will result in the replacement of contaminated soilswith clean soils as necessary, followed by reseeding/revegetation, thereby mitigating ecological risks.In Area A, most of the soil-related ecological risk (primarily to plants and invertebrates) is expected

to reside episodically in surface soils, as defined in the RI.

Where soils may pose ecological risk, EPA will follow the MEC screening/remediationprocess with sampling of potential "hot spots," i.e. sampling of soil areas previously sampled duringthe RI which showed ecological COCs (chiefly metals) at levels of significant risk. This will befollowed by limited excavation and replacement with clean soil as necessary. This is expected to bea closely-defined operation and will be detailed during the Remedial Design (RD) phase.

VI. REMEDIAL ACTION OBJECTIVES

The Remedial Action Objectives (RAOs) for the Site are to:

• Protect employees and the public from physical hazards associated with MEC.• Protect current and future industrial receptors from adverse health effects that may result

from dermal contact and incidental ingestion of contaminated surface and subsurfacesoils, and contaminated ground water.

• Reduce potential contaminant migration from Site-related soils into groundwater.• Provide hydraulic containment of ground water within the source areas of contamination

at the Site.• Restore Site-related contaminant levels in groundwater to its beneficial use.


10

These RAOs will be met using a combination of treatment technologies that will addressthe safety issues associated with MEC and permanently reduce the toxicity, mobility and volumeof contaminants in environmental media at the Site. This proposed action will reducecontamination in ground water to accepted levels and reduce the risk of potential non-carcinogenic health effects (Hazard Index) associated with exposure to contaminated groundwater and site soils below EPA's level of concern. The proposed action will also address the riskof injury associated with the presence of MEC onsite.

Because there are no Federal or State cleanup standards for the hazardous substancesidentified by EPA as COCs in soil, EPA established target cleanup levels, or PreliminaryRemediation Goals (PRGs) relying on the baseline risk assessment. VOCs in surface andsubsurface soils present the greatest collective risk as a continuing source of contamination toground water at the Site. The attached tables list the various soil PRGs (target soil cleanuplevels) for the COCs in those disposal areas (or portions thereof) which may cause continuedsoil-to-ground water contamination into Plumes 1 and 2:

SOIL-TO-GROUND WATER PRGsSOILS IN VICINITY OF GROUND WATER PLUME 1

ORDNANCE PRODUCTS, INC. SITE

Soil Contaminants of ConcernPlume 1

1,1,2,2-Tetrachloroethane1

1,1,2-Trichloroethane1

1,2-Dichloroethene (Total) l

1,2-Dichloroethene (cis) 1

1,2-Dichloroethene (trans) *Benzene1

Tetrachloroethene1

Trichloroethene1

Vinyl Chloride1

Area ABunkerGroup 1

392

AreaB AreaCBerms

461

AreaCDisposal

461

AreaG AreaH

68793853858161854625117

l.ug/kg


11

SOIL-TO-GROUND WATER PRGsSOILS IN VICINITY OF GROUND WATER PLUME 2

ORDNANCE PRODUCTS, INC. SITE

Soil Contaminants of Concern -Plume 2

1,2-DichIoroethene (Total)1

Tetrachloroethene1

Trichloroethene1

l.ug/kg

AreaD

47637641

AreaFInside

Burn Pit

50

AreaFOutsideBurn Pit

46150

Based upon the results of the RI, the only areas with soils that have contaminant concentrationsexceeding soil-to-ground water PRGs as defined in the RI and the FS are in Areas D and H.

Contaminants in the ground water itself will be reduced to their respective Federalprimary drinking water standards, known as maximum contaminant levels (MCLs), establishedunder the Safe Drinking water Act [42 USC Section 300g-l(b)(3)(C)] or to acceptable risk-basedlevels for contaminants where MCLs have not been established. The concentrations of TCE andPCE in Plume 1 and of PCE, TCE and perchlorate in Plume 2 serve as markers for the physicalextent of ground water contamination by these and other contaminants onsite. Using thisinformation, EPA will hydraulically contain the ground water plumes to insure thatcontamination does not spread further into the aquifers. EPA will also extract and treat theground water to remove COCs (primarily VOCs and perchlorate) to levels at or below theirrespective MCLs/risk levels, and in the case of perchlorate, to levels at or below EPA's January26, 2006 preliminary clean-up goal for perchlorate of 24.5 parts per billion in water.

VII. SUMMARY OF REMEDIAL ALTERNA TIVES

Remedial alternatives for the Ordnance Products, Incorporated Site are presented below:

Common Elements

Many of these alternatives have common components. For each soil alternative (exceptthe "no action" alternative), soils in all disposal areas will be screened on a site-specific basis forthe possible presence of MEC. All potential MEC at the Ordnance Products, Inc. Site will thenbe "cleared-to-depth." This means that any potential MEC detected, regardless of depth, will beeither removed (i.e. catalogued, identified as possible MEC items, excavated to the depth wherethey are detected, removed and properly disposed of, depending on safety considerations) orresolved (i.e. catalogued, identified as not being MEC items by the contractor and disposed ofappropriately). This work is done by contractors expert in explosives disposal with equipment •

Ordnance Products, Inc. Superfund Site, Cecil County, Maryland J2Proposed Plan

(i.e. subsurface metal detectors) designed to detect "magnetic anomalies" below ground.

Clearance depths for MEC are addressed by United States Department of Defense (DOD)and EPA guidance. Since the Ordnance Products, Inc. Site property is zoned for heavy industrialuse (Zoning Code M2) by the Cecil County, MD zoning board, the reasonably anticipated currentand future land uses for the OPI property will continue to involve industrial, rather thanresidential land uses. A clearance-to-depth approach takes site-specific conditions into accountto reduce the risk associated with MEC wherever and however it came to be located on the site.

Past munitions manufacturing activities were associated with specific onsite locations.These past manufacturing areas are the "source areas" (A thru H) associated with MEC andhazardous substances disposed of at the Site. Based on Agency and DOD experience withmunitions sites, MEC associated with manufacturing facilities for munitions of the typesproduced at the Site (primarily different types of grenades and grenade fuses) is usually not foundmuch deeper than two to three feet bgs, since most of the munitions were being produced for saleand shipment to the United States Department of Defense and not for actual onsite use (e.g.training, etc.). At the Ordinance Products, Inc. Site, EPA used the four-foot depth described inpart of the current guidance for purposes of estimating cost and schedule only, but will addresspotential MEC at the site utilizing the site-specific, "clearance-to-depth" approach describedabove.

Based on currently known soil contaminant concentrations it is not anticipated thattreatment of any excavated materials, whether associated with MEC clearance or not, would berequired. Soils and ground water are not expected to contain hazardous wastes as defined by theResource Conservation and Recovery Act ("RCRA," i.e. "RCRA hazardous wastes") and assuch, land disposal requirements (LDRs) set forth in RCRA are not expected to apply. Shouldany soils require treatment, they would be excavated and treated offsite to remove VOCs.Alternatively, any such soils could be disposed of at a RCRA Subtitle C landfill in lieu oftreatment.

Each of the remedial alternatives (except for the "no action" alternatives) alsoincorporates institutional controls ("ICs," e.g. deed notices such as easements or covenants) tolimit certain land uses on portions of the Site property. These types of controls may be necessaryto protect the integrity of the remedial alternative and to prevent exposure to contaminatedground water by the use of wells. The type of restriction and its enforceability will need to bedetermined for the selected remedy in the Record of Decision (ROD). Consistent withexpectations set forth in Superfund regulations, none of these remedial alternatives dependexclusively on institutional controls to achieve protectiveness. Monitoring to ensureeffectiveness of the prospective remedy, including deed notices, is likewise a commoncomponent of each alternative (except the "no action" alternatives).


NO ACTION ALTERNATIVES

Alternatives D-l, G-l, S-l: NO ACTION

Estimated Capital Cost: $0Estimated Annual O&M Cost: $0Estimated Present Worth Cost: $49,600 (for Five-Year Reviews only)

The "no-action" alternative was developed as a baseline to which other alternatives maybe compared, as required by the NCP. Under this alternative, EPA would take no action at theSite to prevent possible exposure to MEC and/or to contaminated soil, ground water or drinkingwater. The only activities to be conducted under the "no-action" alternative would be review ofSite conditions and risks every five years. The average annual O&M cost for five-year reviews is$23,000 per event. Over a 30-year period, the net present-worth cost is $49,600 (at an annual 7percent discount rate). No capital costs are associated with the no-action alternative.

DRINKING WATER ALTERNATIVES

Alternative D-2A: Community Water System - Contaminated Area Source

Estimated Capital Cost: $210,000Estimated Annual O&M Cost: $15,700Estimated Present Worth Cost: $395,000Estimated Time: Approximately 1-2 Years

The existing residential wells would be abandoned and water would be supplied via acommunity water system (CWS), a common water supply well installed within the plume area inthe vicinity of the houses to be served. Water from the well would be pumped through granularactivated carbon (GAC), a UV disinfection system, an auxiliary disinfection system (due topossible microbial buildup in the GAC), a water softener, into a storage tank and then pumpedfrom the storage tank to the houses. The system would be operated and maintained by EPAand/or MDE. Samples would be collected quarterly from the well and from the discharge of eachcarbon tank and analyzed for VOCs and perchlorate. Institutional controls, such as deed notices,would be implemented to prohibit the use of groundwater as a drinking water supply. Five-yearreviews would be performed to assess the progress of the alternative. The average annual O&Mcost for five-year reviews is $23,000 per event. Over a 30-year period, the net present-worth costis $395,000 (at an annual 7 percent discount rate).

Ordnance Products, Inc. Superfund Site, Cecil County, Maryland 24Proposed Plan

Alternative D-2B: CWS - Uncontaminated Area Source

Estimated Capital Cost: $234,000Estimated Annual O&M Cost: $4,500Estimated Present Worth Cost: $339,000Estimated Time: Approximately 1-2 Years

The existing residential wells would likewise be abandoned and water would be suppliedthrough a CWS water supply well that would be installed to the west, away from and upgradientof the contaminated groundwater plumes. Water from this well would be pumped through a sandfilter and a water softener, into a storage tank, then pumped from the storage tank to the houses.Since well water quality in the general area historically has been good, no disinfection isproposed. Water samples would be collected routinely (e.g. quarterly) from the well and analyzedfor VOCs and perchlorate. The system would be operated and maintained by the EPA and/orMDE. Institutional controls would be implemented to prohibit the use of groundwater in thevicinity of the houses as a drinking water supply. Five-year reviews would be performed toassess the progress of the alternative.

Alternative D-3: Point-of-Entry (POE) Treatment

Estimated Capital Cost: $8,800Estimated Annual O&M Cost: $5,500Estimated Present Worth Cost: $22 7,000Estimated Time: Already in Place

Under this alternative, the existing "point-of-entry" (POE) units at the five residenceswould continue to be maintained. Water from each residential well would be pumped throughwater softeners, granulated activated carbon (GAC) and a UV system. The carbon tanks wouldbe replaced annually. Water samples would continue to be collected routinely (quarterly) fromeach well and POE treatment system and analyzed for VOCs and perchlorate. The systemswould be operated and maintained by EPA and/or MDE. Institutional controls would beimplemented to prohibit the use of untreated groundwater as a drinking water supply. Five-yearreviews would be performed to assess the progress of the alternative and to insure that thesesystems remained protective.

Alternative D-4: Extend Municipal Water Supply Line

Estimated Capital Cost: $346,000Estimated Annual O&M Cost: $1,500Estimated Present Worth Cost: $415,000Estimated Time: Approximately 1 year (contingent on availability of Municipal Water Line)


Under Alternative D-4, all residents who are currently exposed to contaminatedgroundwater would be protected through the provision of a new water line. A 4-inch distributionline would be extended about 0.8 miles from the distribution water main from the Town of NorthEast slated for a new housing development. This connection would provide service lines to allresidences whose water supply contaminant levels exceed applicable MCLs or risk-based actionlevels (for those contaminants for which MCLs have not yet been established). Coordinationamong EPA, MDE, and local government would be required for the installation of the water line,connection to affected residences and to the municipal water system. Once the installations werecomplete, the Town of North East (MD) would maintain the water line and bill property ownersfor water service. The existing residential wells would be abandoned for'drinking water use.Institutional controls would be implemented to prohibit the use of groundwater in the vicinity ofthe homes as a drinking water supply. No further exposure to the contaminated groundwaterwould occur. Five-year reviews would still be conducted, but primarily due to the ground watercontamination remaining onsite. The former residential wells would be monitored for VOCs andperchlorate to assess the migration and extent of the contaminant plume.

GROUND WATER ALTERNATIVES

Alternative G-2: Groundwater Containment, Treatment, and Off-Site Discharge

Estimated Capital Cost: $1,750,000Estimated Annual O&M Cost: $342,000 > $120,000 (NB: Costs decrease over time

as contaminant levels decrease)Estimated Present Worth Cost: $4,200,000Estimated Time: Approximately 2 Years ,

Under this alternative, contaminated groundwater would be contained and extracted bypumping, treated to remove site contaminants, and then discharged to surface water.Groundwater would be pumped from extraction wells located to intercept and restrict bothPlumes 1 and 2 to a treatment plant. A new groundwater treatment plant would be constructedfor this purpose. EPA would utilize usable components (e.g. the GAC units) from the existing,though undersized ground water treatment system originally constructed by O'Brien & Gere in1997 in the new treatment plant to reduce costs. Treatment would include particulate filtrationand ion exchange to remove perchlorate (primarily for Plume 2, but also for Plume 1 ifnecessary), and GAC adsorption to remove VOCs. Treated groundwater would then bedischarged to a nearby stream. Monitoring wells would be routinely sampled (e.g. quarterly) andanalyzed to evaluate the progress of groundwater remediation. Institutional controls would beimplemented to prohibit the use of groundwater as a drinking water supply. Five-year reviewswould be conducted to assess the remaining extent of groundwater contamination, the progress ofground water treatment and any changes in potential risk posed by site contaminants.


SOIL ALTERNATIVES

Alternative S-2: Clearance-to-Depth of MEC; Containment of Contaminated Soils throughCapping, Areas H and D; Land Use Controls

Estimated Capital Cost: $1,112,900Estimated Annual O&M Cost: $3,500Estimated Present Worth Cost: $1,205,900Estimated Time: Approximately 1 Year

Under this alternative, all identified source areas that were characterized as having a highprobability of buried MEC (i.e., Areas A, B, C, D, E, F, and H) would be cleared of vegetation,screened for the presence of MEC items, and then cleared of MEC to depth. Any soils excavatedin concert with MEC clearance would likewise be screened for MEC items. Once excavatedsoils were screened for MECs, they would be replaced, regraded and revegetated. The only areaswith soils exceeding soil-to-ground water PRGs as defined in the RI and the FS are in Areas Dand H. Soils in Areas D and H would be capped to prevent any contaminants present in soilsabove the soil-to-ground water PRGs from migrating further to ground water, then these areaswould likewise be regraded and revegetated.

Because Area D showed signs of being inundated with MEC during the RI, theinvestigation had to be curtailed in that area due to safety considerations and was not completed.Available soil results from the curtailed RI show the highest levels of VOC contamination onsite.It is assumed Area D is contaminated to the soil/groundwater interface. The RI results for soilsin some portions of Area H also show exceedences of PRGs. Some contaminants are in surfacesoils but most are in subsurface soils at or below four feet, with some as deep as 14 feet belowground surface (bgs).

Migration of contaminants would be contained by largely impervious, multi-layered capsthat would prevent infiltration of surface water via precipitation (rainfall, snowfall, etc.) to soilscontaminated above PRGs. This would prevent precipitation from leaching further contaminantsinto ground water from the soils in the subsurface where they are currently bound. Cappingcontaminated soils in Area D, which are known to be highly contaminated at the surface andbelieved to be so in the subsurface, would be very effective at preventing further soil-to-groundwater contamination. Capping at Area H is expected to have more limited effectiveness, sincethe levels of soil contamination are lower and since the contamination has largely reached thesubsurface near to the water table (the level of ground water in the aquifer). Essentially, much ofthe migration of contamination through the soils towards ground water in portions of Area H hasalready happened, hi addition, contaminant levels in Area H soils do not exceed soil-to-groundwater PRGs throughout this source area. Therefore EPA is using a conservative estimate for theportion of Area H to be capped, equal to approximately three quarters of the areal extent of Area

Ordnance Products, Inc. Superfund Site, Cecil County, Maryland 2 7Proteased Plan

H. The actual area to be capped will be further evaluated during the upcoming remedial design(RD).

Capping Area D and approximately 75% of Area H, following MEC clearance-to-depth isestimated to take approximately one year and would also entail institutional controls such as deednotices to assure the continued integrity of the multi-layer soil caps. Five-year reviews wouldalso be required to assess any future risk posed by contaminants remaining at the site.

Alternative S-3: Clearance-to-Depth of MEC; Excavation and Off-Site Disposal ofContaminated Soils, Area D; Containment of Soils through Capping, Area H; Land UseControls

Estimated Capital Cost: $1,205,400Estimated Annual O&M Cost: $3,500Estimated Present Worth Cost: $1,298,400Estimated Time: Approximately 1 Year

For this alternative, the same approach to MEC clearance would be used for the Site andArea H would be capped in the same manner as described in Alternative S-2. Under AlternativeS-3, all soils in Area D contaminated above soil-to-ground water PRGs would be excavated anddisposed of offsite following MEC clearance. Area D is believed to have been a disposal pitwhen the OPI Site was in operation and is relatively small compared to the other source areasonsite, estimated to cover only about 315 square feet. Although the remedial investigation couldnot be completed, Area D surface and subsurface soils are believed to be highly contaminatedwith VOCs, perhaps to the soil-ground water interface. If Area D soils are contaminated abovePRGs in the subsurface down to bedrock, EPA estimates a contaminated soil volume of 350cubic yards. Excavating and disposal of Area D soils would remove the most highlycontaminated soil-to-ground water source onsite, and largely remove the continuingcontamination source for Plume 2, which would significantly aid in ground water cleanup.Plume 2 in the vicinity of Area D is also contaminated with significant levels of perchlorate, acompound known to interfere with iodine uptake in the human thyroid gland and a very mobileand persistent ground water contaminant. The presence of perchlorate in ground water in Plume2 may be due tq a discrete source that may be discovered and removed during excavation.

Excavating and disposing of contaminated soils in Area D and placing an impervioussynthetic clay cap atop a portion of Area H would likewise take about one year to complete.Alternative S-3 would require no soil-related institutional controls under the current industrialuse scenario, except for portions of Area H. This would be the only area onsite where a soilremedy would need to be protected, but five-year reviews would still be required to assess anyfuture risk.

Ordnance Products, Inc. Superfund Site, Cecil County, Maryland JgProposed Plan

Alternative S-4: Clearance-to-Depth of MEC; Excavation and Off-Site Disposal ofContaminated Soils, Area D; Land Use Controls

Estimated Capital Cost: $867,900Estimated Annual O&M Cost: $3,500Estimated Present Worth Cost: $960,900Estimated Time: Approximately 1 Year

Alternative S-4 would proceed much like Alternative S-3 except for the capping of AreaH. The same approach to MEC clearance would be used for the Site as described forAlternatives S-2 and S-3. Under Alternative S-4, all soils in Area D contaminated above soil-to-ground water PRGs would be excavated and disposed of offsite following MEC clearance asdescribed in Alternative S-3 but no impervious cap would be installed atop Area H soils.

Area H is situated on topography sloping downward from west-to-east, in the naturaldirection (downhill) of area ground water flow towards the valley where the Little North EastCreek and several contaminated residential wells are situated. This topography favors increasedpercolation to ground water beginning far west of Area H in the natural ground water flowdirection, thus flowing beneath Area H and any surface-mounted cap. Furthermore, Area H soilscontaminated above PRGs have been found predominantly at depths between 4 and 14 feet bgs.Soil samples indicate that contaminants are relatively dispersed at those depths, rather than in ahighly concentrated, leachable mass at or near ground surface such as is typical of many landfills,or at suspected disposal pits like Area D. These site conditions mitigate both against theeffectiveness of a surface capping approach and against the excavation and disposal of largequantities of relatively diffusely-contaminated soil at depth, already at/near the ground watertable.

In addition, current and past soil and ground water investigations indicate that previouslydisposed contaminants of concern (chiefly VOCs) have, in general, already leached to groundwater beneath Area H (Plume 1). In several areas, subsurface soil contamination levels areexceeded by ground water contamination levels, indicating that hazardous substances disposed ofat Area H have, for the most part, already leached from soil to ground water in this area.

EPA believes that the best approach to soil contamination beneath Area H may be toallow remaining subsurface soil contaminants to continue to "flush" into the alreadycontaminated ground water (Plume 1) and to capture those contaminants through ground watercleanup. Under this scenario, attempting to impede ground water flow in Area H by a cappingapproach, even with the constraints described above, would not only be ineffective, but may becounterproductive.

Under Alternative S-4, EPA would not cap or excavate soils in Area H following MECclearance. EPA would install capture wells to draw contaminated ground water away from the

Ordnance Products, Inc. Superfund Site, Cecil County, Maryland J pProposed Plan

contaminated residential wells and to capture remaining contaminants flushing from subsurfacesoils at Area H, pump these to a ground water treatment plant, remove the contaminants anddischarge the treated ground water to the nearby creek. EPA would also install monitoring wellsin this area to observe the reduction in ground water contamination levels, and would take soilsamples to monitor soil contamination reduction over time. No capping would be applied andground water flow in this area would be encouraged to promote more rapid capture and cleanupof the contaminated ground water plume (Plume 1).

Alternative S-5: Clearance-to-Depth of MEC; Excavation and Off-Site Disposal ofContaminated Soils, Areas H and D; Land Use Controls

Estimated Capital Cost: $953,600Estimated Annual O&M Cost: $3,500Estimated Present Worth Cost: $1,046,600Estimated Time: Approximately 1 Year

Alternative S-5 would be similar to Alternative S-4, but would also include excavationand disposal of contaminated soils contributing to ground water contamination beneath Area H.The same approach to MEC clearance would be used for the Site as described for Alternatives S-2, S-3 and S-4. Under Alternative S-5, all soils in both Areas D and H contaminated above soil-to-ground water PRGs would be excavated and disposed of offsite following MEC clearance asdescribed in Alternative S-3, excavated soils would be replaced by clean soil, regarded andrevegetated.

Based on a review of sampling data from the FS, VOCs found in Area H soils are not evenlydistributed spatially or by depth. Therefore, for volume calculation purposes for this alternative,each sampling location was considered an individual hot spot, hi order to estimate soilremoval/disposal volumes, a 10-foot radius around each soil location was also assumed. Thisapproach results in an assumed surface area of 315 square feet for each location. Based on theseassumptions the volume of soils with VOCs exceeding PRGs is estimated per the followingequation: 315 sq. ft. times the depth of contamination from FS data = estimated soil volume perlocation in cubic feet. Using the depth and contamination data for the Area H soil samples from theFS, the estimated aggregate contaminated soil volume to be removed is approximately 3,800 cubicfeet (approximately 140 cubic yards). This volume estimate of contaminated Area H soils ispresented in Appendix A of the May 2006 FS Addendum.

The above cost estimates are based on the calculated Area H aggregate soil volumes and theestimated excavation depths (between 4-14 feet bgs). Soil confirmation sampling upon completionof excavation) would be required to determine if residual soil contamination above soil-to-groundwater PRGs still remains and whether additional excavation would be required.


This approach would produce a reduction in the source volume of contaminated soil, andEPA would expect an accompanying drop in ground water contaminant levels. VOC-contaminated ground water flowing through the newly placed clean soil would tend tocontaminate that clean soil, thus removing some of those contaminants from ground water, butnot below PRGs. This is because ground water is already contaminated, in general abovesubsurface soils levels, beneath Area H. Contaminants migrating to clean soils fromcontaminated ground water would eventually serve as a source of contaminants to ground waterin the future.

Furthermore, current soil contamination already deep below ground surface and at/nearthe Area H ground water table does not equal nor significantly exceed local ground watercontamination levels (Plume 1). This indicates that contaminants were likely disposed of in thesoil at Area H originally have largely migrated to the ground water beneath. EPA believes thatremoval/replacement of these contaminated soils at depth beneath Area H under Alternative S-5would do little to foster ultimate ground water cleanup in this aquifer.

VIIL EVALUATION OF ALTERNATIVES

In accordance with the NCP (40 C.F.R. Section 300.430(e) (9) (iii) (A-I)) nine criteria areused to evaluate the different remedial alternatives individually and against each other in order toselect a remedy. This section of the proposed plan profiles the relative performance of eachalternative against the nine criteria in the NCP, noting how it compares to the other criteria underconsideration.

The nine evaluation criteria are discussed below. The "Detailed Analysis of Alternatives"can be found in the FS and the FS Addendum for the Site.

• Overall Protectiveness of Human Health and the Environment determineswhether an alternative eliminates, reduces, or controls threats to public health and theenvironment through institutional controls, engineering controls, or treatment.

• Compliance with ARARs evaluates whether the alternative meets Federal and Stateenvironmental statutes, regulations, and other requirements that pertain to the site, orwhether a waiver is justified.

• Long-term Effectiveness and Permanence considers the ability of an alternative tomaintain protection of human health and the environment over time.

• Reduction of Toxicity, Mobility, or Volume of Contaminants through Treatmentevaluates an alternative's use of treatment to reduce the harmful effects of principalcontaminants, their ability to move in the environment, and the amount ofcontamination present.


• Short-term Effectiveness considers the length of time needed to implement analternative and the risks the alternative poses to workers, residents, and theenvironment during implementation.

• Implementability considers the technical and administrative feasibility ofimplementing the alternative, including factors such as the relative availability ofgoods and services.

• Cost includes estimated capital and annual operations and maintenance costs, as wellas present worth cost. Present worth cost is the total cost of an alternative over time interms of todays dollar value. Cost estimates are expected to be accurate within arange of+50 to -30 percent.

• State/Support Agency Acceptance considers whether the State agrees with theEPA's analyses and recommendations, as described in the RI/FS and Proposed Plan.

• Community Acceptance considers whether the local community agrees with EPA'sanalyses and preferred alternative. Comments received on the Proposed Plan are animportant indicator of community acceptance.

1. Overall Protection of Human Health and the Environment

Under the CWS approaches in Drinking Water Alternatives D-2A and D-2B and themunicipal water line extension from an existing CWS in Alternative D-4, all residences that arecurrently exposed to contaminated groundwater in excess of MCLs or whose use of their privatewater supply would result in carcinogenic risk greater than 1 x 10"4 or noncarcinogenic riskgreater than an HI of 1.0 would be protected. All exposures (ingestion, inhalation, and dermalcontact) that would result from the use of untreated contaminated groundwater would beeliminated. Alternative D-2A and point-of-entry treatment system Alternative D-3 wouldeliminate this exposure via treatment, Alternatives D-2B and D-4 would eliminate this exposureby providing a new, uncontaminated source of water to residences. Each alternative would alsorely on institutional controls to prevent the use of untreated, contaminated ground water.

Ground Water Alternative G-2 would be protective of human health and the environmentby eliminating ground water contamination through treatment.

Soil Alternatives S-2, S-3, S-4 and S-5 would be protective by preventing exposure toMEC and contaminated soils. These alternatives would remove or resolve MEC to depth sitewide. Alternative S-2 would cap any soils contaminated above PRGs remaining in Areas D andH following MEC remediation. Alternative S-3 would likewise cap soils in Area H above PRGsfollowing MEC remediation, but remove all soils contaminated above PRGs in Area D andbackfill this area with clean soil. Alternative S-5 would yield similar outcomes for Area D and


remove/replace contaminated soils in Area H as well. Soil removal efforts in Area D underAlternatives S-3, S-4 and S-5 also might possibly locate and remove discrete perchlorate sourcematerials causing perchlorate ground water contamination of Plume 2 in the vicinity of Area D.Alternative S-4 would likewise be protective of human health by removing contamination fromArea D but would depend on ground water flushing to transfer remaining contaminants fromsubsurface soils beneath Area H to contaminated ground water, and address them through groundwater treatment. Alternative S-5 would remove the subsurface soil contamination from Area H,but would likely result in the same scenario of continuing ground water treatment. Newly-placed,clean subsurface soils would themselves become contaminated by exposure to contaminatedPlume 1 ground water and serve as a future source of ground water contamination that would stillhave to be addressed through continued treatment, much as in Alternative S-4.

Finally, the "no action" alternatives under consideration (i.e. D-l, S-l, and G-l) are notprotective of human health and the environment. Therefore, they were eliminated fromconsideration under the remaining eight criteria.

2. Compliance with ARARs

Alternative D-2A, D-2B, D-3 and D-4 would comply with federal and state chemical-specific ARARs since these alternatives would furnish water that has been treated to meet theprimary drinking water criteria (MCLs). Alternative G-2 would eventually eliminate potentialexposure via contaminated groundwater in excess of MCLs or groundwater that would result incarcinogenic risk greater than 1x10^ and HI greater than 1.0 (for contaminants for which noMCL have yet been established). Soil Alternatives S-2, S-3, S-4 and S-5 would likewiseeliminate such potential exposure to contaminated soils to construction and industrial workers inaccordance with current land use at the Site.

Each alternative except D-3 would include measures to satisfy location-specific ARARs.Measures would be implemented to not disturb any wetlands or impair the flood storage capacityof floodplains. Reviews would be conducted to identify any endangered species or sensitivehabitats possibly labile to remediation activities. Should any historic or archeological artifacts orobjects be encountered during excavation, the appropriate federal and state agencies would benotified to coordinate measures that would preserve or mitigate any adverse effects.

Each alternative would also comply with action-specific requirements under Title 29 ofthe Code of Federal Regulations for occupational safety and health since workers performing theexcavation would conform to these requirements. The transport and disposal of any contaminatedsoil would comply with applicable portions of RCRA (40 CFR Parts 262 and 263) and theapplicable portions of the Hazardous Materials Transportation requirements (49 CFR 107,171-179), including spent activated carbon under Alternatives D-3 and G-2. In addition, AlternativesD-3 and G-2 would comply with the action-specific requirements under Title 29 of the Code ofFederal Regulations for occupational safety and health for workers who install and perform


periodic maintenance of the treatment systems and workers who sample the long-termmonitoring wells.

3. Long-Term Effectiveness and Permanence

Alternatives D-2A, D-2B and D-4 would be effective in the long term and would providepermanent solutions to the contaminated water supplies. These CWS alternatives would beeffective in protecting human health from exposures as long as the raw water is adequatelytreated. Overall carcinogenic and noncarcinogenic risks through exposures to contaminatedgroundwater would be reduced to within or below EPA's acceptable risk range (1 x 10"4 to1 x 10"6), and Hazard Quotient of 1.0, respectively), and residents would not be exposed tocontaminants in excess of drinking water criteria (MCLs). These alternatives would eliminateingestion, inhalation, and dermal contact risks resulting from contaminated water use.Alternative D-3 would be effective in the long term and could be implemented as a permanentremedy which would eliminate the contaminated water supplies problem. The proposedtreatment systems under this alternative should be capable of maintaining treatment goals(MCLs) since the individual treatment components have been demonstrated at the Site overseveral years to be effective in removing the contaminants of concern. Treatment systems wouldneed to be upgraded as necessary and maintained indefinitely until contaminant source controland remedial actions have been implemented so that the groundwater quality is restored to itsbeneficial use.

Under Alternative G-2, overall carcinogenic and noncarcinogenic risks through exposuresto contaminated groundwater will eventually be reduced to within or below the EPA's acceptablerisk range (1 x 10"4 to 1 x 10~6 and HI of 1.0, respectively). The long-term reliability of thisalternative would depend on the proper operation and maintenance (O&M) of the treatment unitsto ensure effective removal of ground water contaminants.

Under Alternatives S-2 and S-3, the potential for migration of contaminants from the soilto the groundwater would be eliminated. Under Alternative S-4, soil contaminants at Area Dwould be removed and soil contaminants beneath Area H would be transferred to contaminatedground water by flushing and then captured and treated along with contaminated ground water asdescribed in Alternative G-2. Under Alternative S-5, soil contaminants at Area D would beremoved as in Alternative S-4; soil contaminants currently present beneath Area H would beremoved altogether. Any contaminants migrating to clean subsurface soil would be bound thereuntil flushed out into Plume 1 ground water, captured and treated as in Alternative S-4.

The overall carcinogenic and noncarcinogenic risks for industrial and constructionworkers through exposure to contaminated soil would be permanently eliminated except forpotential noncarcinogenic risks due to exposure to soils contaminated with metals (chieflychromium) in the Inside Burn Pit portion of Area F. Depending on the concentration of MEC(suspected to be high); this area may have to be extensively excavated. Following excavation for


MEC clearance, the excavated soils will be replaced, then these soils will be covered with sixinches of clean topsoil and revegetated. The soil/vegetation cover will eliminate potential dermal,ingestion and inhalation contact with remaining metals-contaminated soils in the Inside Burn Pitin Area F. Institutional controls would be put in place to prevent industrial and/or constructionactivity in this area without proper safeguards for addressing potentially contaminated soils undercurrent and future land use scenarios.

The long-term reliability of drinking water and ground water alternatives depends on theO&M associated with each, hi addition, each alternative relies on implementing and enforcingthe institutional controls. Long-term monitoring, inspections and the five-year reviews would berequired to confirm that systems are maintained, ground water contaminants are treated, coversoil is maintained and that the property is not put to unauthorized land use.

4. Reduction of Toxicity, Mobility, and Volume through Treatment

Alternative G-2 would be expected to reduce overall carcinogenic and noncarcinogenicrisks through exposure to contaminated groundwater to within EPA's acceptable risk range viatreatment and would satisfy this criterion.

Alternatives D-2A and D-3 provide only a nominal amount of direct treatment ofcontaminated ground water. Spent GAC could be regenerated and reused, resulting in thermaldestruction of organic ground water contaminants. Overall, the statutory preference for treatmentto reduce risks posed by contaminated groundwater would not be satisfied under Alternatives D-2A or D-3. Alternatives D-2B and D-4 do not provide any direct treatment of contaminatedgroundwater associated with the site and thus do not meet this criterion.

Alternative S-2 does not meet this criterion for contaminated soil, but Alternatives S-3 andS-4 partially meet this criterion for Area D. Alternative S-5 would meet this criterion forcontaminated soil in Areas D and H. Some contaminated soil is being capped or covered onsite(Area F, Inside Burn Pit) which would provide a reduction in mobility. Soil contaminants in AreaH soils still contributing to ground water contamination in Plume 1 would be transferred to thecontaminated ground water plume via natural flushing for treatment, and other contaminated soilswould be removed offsite (Area D). However, in general, toxicity, mobility, and volume will notbe directly reduced through treatment.

5. Short-Term Effectiveness

Alternative D-3 is already in place and operating. Its continued operation is not expectedto pose any significant risks to the local community, the remedial workers, or to the environment.Implementation of Alternatives D-2A, D-2B, and D-4 are not expected to pose any significantrisks to the local community, the remedial workers, or to the environment. Alternative D-4 couldbe fully implemented approximately 1 year after the ROD has been signed and approval is issued


by EPA; Alternatives D-2A and D-2B in 1 to 2 years. The existing POE systems underAlternative D-3 would continue to operate while the CWSs or municipal water line connectionsare completed.

Alternative G-2 could likewise be implemented within 1-2 years after the ROD is signedand EPA approval is issued. Any short term risk posed to the community due to construction ofthe remedial measures or exposure to contaminated ground water would be limited andmanageable via traffic control, appropriate health and safety measures and the use of personalprotective equipment (PPE). Additional precautions for MEC clearance would be required. Thisactivity would accompany excavation, would be performed onsite, and involve limited accessand specially trained personnel for screening, destroying, and/or disposing of MEC.

Risks posed to the local community, remedial workers or the environment by AlternativesS-2, S-3, S-4 and S-5 following MEC clearance would be similar, in general, to those forAlternative G-2, though additional truck traffic for offsite soil disposal would be anticipated.

6. Implementability

Alternatives D-2A, D-2B and D-4 are technically and administratively implementable.The CWS treatment facilities for Alternatives D-2A, D-2B and the piping for all threealternatives can be installed using standard construction techniques and equipment. Potentialfuture remedial actions may be needed if additional .private residential water supplies areidentified as contaminated. Additional residences could be connected to the CWSs or to themunicipal water line extension if necessary. Coordination among EPA, MDE, and localgovernment would be required for the installation of CWS facilities/water line extensions andconnections to affected residences. Permits maybe required for construction and some form of alocal water authority would be needed to manage and administer the distribution of water.Coordination with other agencies may be required to implement ordinances to prohibit use ofuntreated contaminated groundwater for drinking and for the five-year review process.Alternative D-3 is likewise implementable and already in place at five residences. UnderAlternative D-3, one potential future remedial action might be the need to address rising levelsand/or additional contaminants (i.e. perchlorate) in ground water. The existing systems can beaugmented with additional treatment components or replaced by larger ones with greatercapacity. If needed, additional residences could also be provided with POE treatment systems iftheir wells become contaminated. Since vendors and equipment are readily available, suchadditional actions would not be difficult to implement.

Alternative G-2 would be readily implementable. A groundwater extraction andtreatment system, including an ion exchange system to remove perchlorate could readily beconstructed. Installation of new monitoring wells, new capture wells, maintenance of existingand new wells, sampling and analysis of groundwater and treated water discharge, andperformance of five-year reviews could readily be accomplished. The resources, equipment,


materials and personnel required for these activities are readily available. Construction permitsmay be required for this alternative, but the administrative aspects would be relatively simple toimplement.

Alternatives S-2, S-3, S-4 and S-5 would likewise be readily implementable. The site iseasily accessible through existing roads that are capable of handling large-scale excavators andtrucks. Excavation and disposal expertise and services for the types of contaminated soils at the siteand for MEC are available within a reasonable distance of the site. Several areas requiring deepexcavation may require sheet piling or other deep excavation precautions to complete.Construction permits may be required for this alternative but the administrative aspects ofAlternatives S-2, S-3, S-4 and S-5 would be relatively simple to implement.

7. Cost

The alternatives are grouped by environmental media; drinking water, ground water, andsoil. The no-action alternatives are the least costly in each case, but are not viable alternatives forany media. For the drinking water alternatives, the estimated present worth cost of AlternativeD-3 is the least costly alternative and is already in place. Of the CWS alternatives, AlternativeD-2B is the least costly, but less than $100,000 in present worth cost separates the three CWSAlternatives D-2, D-2B, and D-4. Alternative G-2 is the sole ground water alternative. SoilAlternative S-4 is the least costly alternative, followed in order of increasing costs byAlternatives S-5, S-2 and S-3.

8. State Support/Agency Acceptance

The State of Maryland currently supports the Preferred Alternative. State acceptance ofthe preferred alternative will be further evaluated after the public comment period ends and willbe described in the ROD for the Site.

9. Community Acceptance

Community acceptance of the preferred alternative will be evaluated after the publiccomment period ends and will be described in the ROD for the Site.

IX. SUMMARY OF THE PREFERRED ALTERNA TIVE

The Preferred Alternative for cleaning up the Ordnance Products, Incorporated Site is acombination of the Drinking Water Alternative D-4, the Ground Water Alternative G-2 and theSoil Alternative S-4.

The preferred drinking water alternative was selected over other alternatives because itwill maintain substantial immediate risk reduction and achieve long-term risk reduction byeliminating any exposure to contaminated ground water under normal domestic use (drinking,

Ordnance Products, Inc. Superfund Site, Cecil County, Maryland 2 7Proposed Plan

cooking, and bathing). The preferred ground water alternative will provide substantial long-termrisk reduction through treatment of contaminants and protect against future exposure bypreventing migration of contaminated ground water and returning it to its beneficial use. Thepreferred soil alternative substantially reduces exposure risk for site occupants by eliminatingcontact with soil contaminants and MEC. This alternative also provides additional ground waterrisk reduction by preventing further migration of soil contaminants to ground water (Plume 2) inthe case of Area D, and by augmenting ground water treatment of soil and ground watercontaminants (Plume 1) by continuing to encourage ground water flow towards a natural capturezone beneath Area H with similar effectiveness and less cost than competing alternatives.

Based on the information available at this time, EPA believes the Preferred Alternativewould be protective of human health and the environment, would comply with ARARs, would becost-effective, and would utilize permanent solutions to the maximum extent practicable.Because the preferred alternative treats source material that constitutes the principal threats (i.e.ground water), this remedy would meet the statutory preference for selection of a remedy thatinvolves treatment as a principal element. The Preferred Alternative can change in response topublic comment or to new information.

X. ROLE OF COMMUNITY IN THE SELECTION PROCESS

EPA encourages the public to gain a more comprehensive understanding of the site andthe Superfund activities that have been conducted at the Site. EPA provides informationregarding the cleanup of the OPI Site to the public through public meetings, the AdministrativeRecord file for the site, and via announcements in the Cecil Whig.

In addition, this Proposed Plan is being distributed to solicit public comment on theappropriate cleanup action for the Site. EPA relies on public input so that the remedy selectedfor each Superfund site addresses the concerns of the local community. EPA is providing a 30-day comment period beginning on August 16, 2006, and ending on September 15, 2006, toencourage public participation in the remedy selection process for the OPI Site. EPA willconduct a public meeting during the comment period in order to present the Proposed Plan andsupporting information, answer questions, and accept both oral and written comments from thepublic. The public meeting will be held on August 16, 2006 at 7:00 p.m., at the North EastBranch of the Cecil County Library, 106 W. Cecil Avenue, North East, Maryland.

EPA will summarize and respond to comments received at the public meeting and to writtencomments postmarked or E-mailed by September 15,2006, in the Responsiveness Summary sectionof the Record of Decision that will document EPA's final selection of a cleanup alternative for theOPI Site. To obtain additional information regarding the Proposed Plan, please contact either of thefollowing EPA representatives:


28

William D. Hudson (3HS43)Community Involvement FacilitatorU.S. EPA - Region HI1650 Arch StreetPhiladelphia, PA 19103Phone:(215)[email protected]

Frederick N. Mac Millan (3HS23)Remedial Project ManagerU.S. EPA - Region m1650 Arch StreetPhiladelphia, PA 19103 'Phone: (215) [email protected]

GLOSSARY OF TERMS

Specialized terms used in the Proposed Plan are defined below:

Administrative Record — An official compilation of site-related documents, data, reports, and other information thatare considered important to the status of and decisionsmade relative to a Superfund site. A copy of theAdministrative Record is maintained at the Cecil CountyLibrary in Elkton, MD, and the EPA Region III DocketRoom in Philadelphia, PA

Applicable or Relevant and Appropriate Requirements(ARARs) - the regulatory requirements set forth by federaland state environmental rules, regulations, and standards,which must be reached during the implementation of theremedial action These requirements may vary among sitesand alternatives

Comment Period - A time for the public to review andcomment on various documents and actions taken, either bythe Navy, EPA, or PADEP. A minimum 30-day commentperiod is held to allow community members to review theAdministrative Record and review and comment on theProposed Plan

Community Water System (CWS) - a public water systemthat serves at least 15 service connections used by year-round residents or regularly serves at least 25 year-roundresidents (from National Primary Drinking WaterRegulations, 40 CFR Part 141).

Comprehensive Environmental Response, Compensationand Liability Act (CERCLA) - The federal law initiallypassed in 1980 and modified in 1986 by the SuperfundAmendments and Reauthortzation Act (SARA) The lawestablishes the program commonly known as Superfund, andregulated by the United States Environmental ProtectionAgency, to investigate and remediate uncontrolled orabandoned hazardous waste sites

Contaminant plume (plume) - a column of contaminationwith measurable horizontal and vertical dimensions that issuspended in and moves with ground water.

Discarded Military Munitions (DMM) — Militarymunitions that have been abandoned without properdisposal or removed from storage in a military magazine orother storage area for the purpose of disposal. The termdoes not include unexploded ordnance, military munitionsthat are being heldfor future use or planned disposal, or military munitionsthat have been properly disposed of consistent withapplicable environmental laws and regulations.

Feasibility Study (FS) - An engineering study conductedunder the scope of CERCLA designed to evaluate potentialclean-up alternatives, and determine which alternative wouldbe best suited in terms of cost and feasibility to achievecleanup criteria

Hazard Index (HI) - a measure of potential human healthhazards from noncarcmogenic substances The HI is equalto the sum of all such hazards for a specific pathway orscenario The acceptable Hazard Index standard is less thanone, if it exceeds one, the possibility exists for systemictoxic effects

Hazard Quotient (HQ) - The Hazard Quotient (HQ) is theratio of estimated site-specific exposure to a singlechemical from a site over a specified period to theestimated daily exposure level at which no adverse healtheffects are likely to occur.

Land Disposal Restrictions (LDRs) - RCRA requirementsfor certain wastes to be treated before disposal into theland.

Maximum Contaminant Levels (MCLs) - MCLs weredeveloped by the EPA, m accordance with the Safe DrinkingWater Act. MCLs are legally enforceable for drinking watersupplies and represent the allowable concentration for a givenconstituent in drinking water.


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Micrograms per Liter (ug/L) - one one-millionth of agram in one liter of fluid, usually water, equivalent to onepart in one billion

Munitions - war material, especially weapons andammunition including explosives, propellants, et al.

Munitions and Explosives of Concern (MEC) — A termthat distinguishes specific categories of military munitionsthat may pose unique explosives safety risks, including: (1)Unexploded ordnance (UXO); (2) Discarded militarymunitions (DMM), or (3) Munitions Constituents (e.g.TNT, RDX) present in high enough concentrations to posean explosive hazard. Formerly known as Ordnance andExplosives (OE)

National Oil and Hazardous Substances PollutionContingency Plan (NCP) - The NCP, more commonlycalled the National Contingency Plan, is the federalgovernment's blueprint for responding to both oil spills andreleases of hazardous substances, pollutants, or contaminantsThis national response capability plan promotes the overallcoordination among a hierarchy of responders andcontingency plans

National Priorities List (NPL) - This list, compiled byEPA pursuant to CERCLA Section 105, identifies theuncontrolled or abandoned hazardous substance releases inthe United States that are priorities for long-term remedialevaluation and response

Ordnance - military weapons as a whole, along withammunition and the equipment and supplies to maintainthem

Oral Reference Dose (RfD) - An estimate (with uncertaintyspanning perhaps an order of magnitude) of a daily oralexposure of a chemical to the human population (includingsensitive subpopulations) that is likely to be without risk ofdeleterious noncancer effects during a lifetime.

Perchlorate — a man-made and naturally occurringoxidizing compound associated with munitionsmanufacture that is highly soluble m water and verypersistent in the environment Perchlorate compounds areknown to interfere with iodine uptake in the thyroid glandAmmonium perchlorate is the mostly widely usedperchlorate compound

Point-of-Entry (POE) - a water treatment device applied tothe drinking water entering a house or building for thepurpose of reducing contaminants in the drinking waterdistributed throughout the house or building.

Pre-Remedial Goal (PRG) - In the Superfund and RCRAprograms, a risk-based concentration (of a contaminant),derived from standardized equations combining exposureinformation assumptions with EPA toxicity data. PRGs areconsidered by EPA to be protective for humans (includingsensitive groups), over a lifetime.

Present Worth Analysis - a method of evaluatingexpenditures that occur over different time periods. Bydiscounting all costs to a common base year, the costs fordifferent remedial action alternatives (including their totaloperations and maintenance costs) can be compared on thebasis of a single figure (the Present Worth Cost) for eachalternative

Proposed Plan - A document that presents a proposedcleanup alternative, rationale for the preference, and requestspublic input regarding the proposed alternative.

Pyrotechnic - Controlled exothermic chemical reactionsmanaged to create specific effects or a combination ofeffects (heat, gas, sound, light, etc ) Examples includefireworks, flares and explosives

Record of Decision (ROD) - A legal public document thatdescribes the cleanup action or remedy selected for aCERCLA site, the basis for the choice of that remedy, andpublic comments on alternative remedies. The ROD is basedon information and technical analysis generated during theRI/FS

Remedial Action Objective (RAO) - RAOs are site-specific,initial clean-up objectives that are established on the basis ofthe nature and extent of contamination, the resources that arecurrently and potentially threatened, and the potential forhuman and environmental exposure.

Remedial Investigation (RI) - An investigation conductedunder the scope of CERCLA designed to determine thenature and extent of contamination, identify potential humanhealth and ecological risks posed by the site, and identifyclean-up criteria

Resource Conservation and Recovery Act (RCRA) - theFederal act that established a regulatory system to trackhazardous wastes from the time they are generated to theirfinal disposal (i.e. "cradle-to-grave"). RCRA also providesfor safe hazardous waste management practices andimposes standards for transporting, treating, storing anddisposing of hazardous waste

Revegetate - to establish and/or reestablish plant growth ona land surface to prevent wind and water erosion.

Subsurface soil - At the OPI Site, soil 0 5 feet belowground surface or deeper


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Unexploded Ordnance (UXO) - Military munitions thathave been primed, fuzed, armed, or otherwise prepared foraction and have been fired, dropped, launched, projected,or placed in such a manner as to constitute a hazard tooperations, installation, personnel, or material and thatremain unexploded either by malfunction, design, or anyother cause

Volatile Organic Compounds (VOCs) - chemicalcompounds that have a high vapor pressure and low water

solubility The group includes a wide range of carbon-based compounds Common examples of VOCs includepaint thmners, solvents, and some constituents ofpetroleum fuels (e g gasoline). VOCs are sometimes _accidentally released into the environment, where they canbecome ground-water contaminants. Vapors of VOCsescaping into the air can also contribute to air pollution

FIGURES

1) Site Location

2) Soil Contamination Areas

3) Plume 1, Overburden (shallow) Wells

4) Plume 1 Deep Wells

5) Plume 2 Overburden Wells

6) VOCs in Residential Wells

PROPOSED REMEDIAL ACTION PLAN (PRAP)

Documents

Transcript of PROPOSED REMEDIAL ACTION PLAN (PRAP)