Superfund Record of Decision North Penn - Area 12 Worcester Township PA


                                    EPA/ROD/R03-97/088
                                    1997
EPA Superfund
     Record of Decision:
     NORTH PENN - AREA 12
     EPA ID: PAD057152365
     OU01
     WORCESTER, PA
     09/30/1997

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NORTH PENN AREA 12 SUPERFUND SITE
RECORD OF DECISION

PART I - DECLARATION

I. SITE NAME AND LOCATION

North Perm Area 12 Superfund Site
Worcester Township, Montgomery County, Pennsylvania

II. STATEMENT OF BASIS AND PURPOSE

This Record of Decision ("ROD") presents the final remedial action selected for the
North Perm Area 12 Superfund Site ("Site"), located in Worcester Township, Montgomery
County, Pennsylvania. This remedial action was chosen in accordance with the Comprehensive
Environmental Response, Compensation, and Liability Act of 1980 ("CERCLA"), 42 U.S.C. °°
9601 et seg., as amended by the Superfund Amendments and Reauthorization Act of 1986
(SARA), and the National Oil and Hazardous Substances Pollution Contingency Plan ("NCP"),
40 C.F.R. Part 300. This decision document explains the factual and legal basis for
selecting the remedial action and is based on the Administrative Record for this Site. An
index of documents for the Administrative Record is included in Appendix A of the ROD.

The Pennsylvania Department of Environmental Protection ("PADEP") has commented
on the selected remedy and the State's comments have been incorporated to the extent
possible.

III. ASSESSMENT OF THE SITE

Pursuant to duly delegated authority, I hereby determine, pursuant to Section 106 of
CERCLA, 42 U.S.C. ° 9606, that actual or threatened releases of hazardous substances from
this Site, as discussed in Section IV (Risk Assessment) of this ROD, if not addressed by
implementing the remedial action selected in this ROD, may present an imminent and
substantial endangerment to public health, welfare, or the environment.

IV. DESCRIPTION OF THE SELECTED REMEDY

The Environmental Protection Agency ("EPA"), in consultation with PADEP, has
selected the following remedial action for the North Penn Area 12 Superfund Site. This
remedy addresses alternative drinking water and contaminated groundwater at the Site and
includes the following components:

6 A groundwater extraction and treatment system utilizing either an air stripper with
vapor phase carbon or a liguid phase carbon adsorption unit. The treated
groundwater will be reinjected into the ground by injection wells, an infiltration
bank, or spray irrigation, if it can be demonstrated that such reinjection can be
accomplished without adversely impacting the ability of the pumping system to
contain the existing contamination from migrating from the former Transicoil
property portion of the Site. A pre-design study will be completed to provide this
demonstration. If the study shows that reinjection is not
feasible, then the treated water will be discharged to a tributary to Stoney Creek.

6 A study will be conducted during the pre-design, design, or implementation of the

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            extraction system to determine what,  if any,  remedial measure(s)  (including natural
            attenuation or modification of the extraction system) may be needed or is
            technically practicable to reduce site related contaminants to MCL concentrations in
            contaminated groundwater which lies beyond the influence of the selected pump and
            treat extraction system within a reasonable time frame.

    6       The public water supply will be extended to provide drinking water to residents
            whose wells have been adversely affected or could potentially be adversely affected
            by groundwater contamination from the Site.

    6       Long term groundwater monitoring to evaluate the performance of the groundwater
            extraction and treatment system and to ensure that all affected and potentially
            affected residents are provided public water.

    6       Institutional controls that will prohibit the use of groundwater on the former
            Transicoil property, and restrict the use of Site-related contaminated groundwater
            as a drinking water supply source.

    V.      STATUTORY DETERMINATIONS

            The selected remedy is protective of human health and the environment, complies with
       Federal and State reguirements that are legally applicable or relevant and appropriate to
       the remedial action, and is cost-effective.  The remedy utilizes permanent solutions and
       alternative treatment technologies to the maximum extent practicable.   This remedy does
       employ treatment as a principal element.

            Because this remedy will result in hazardous substances  remaining on-site above
       health-based levels, a review will be conducted within five years after initiation of the
       remedial action to ensure that the remedy continues to provide adeguate protection of
       human health and the environment.

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                              NORTH PENN AREA 12 SUPERFUND SITE
                    WORCESTER TOWNSHIP, MONTGOMERY COUNTY, PENNSYLVANIA

                                       RECORD OF DECISION
                                        DECISION SUMMARY

                                       TABLE OF CONTENTS

I.      SITE NAME, LOCATION AND DESCRIPTION  	1

II.     SITE HISTORY 	1

III.   HIGHLIGHTS OF COMMUNITY PARTICIPATION	2

IV.     SCOPE AND ROLE OF THE RESPONSE ACTION 	3

V.      SUMMARY OF SITE CHARACTERISTICS EXTENT OF
       CONTAMINATION 	4

       A.   Site Characteristics  	4

       B.   Nature and Extent Contamination 	10

VI.     SUMMARY OF SITE RISKS 	13

       A.   Human Health Risk Evaluation 	13

       B.   Environmental Risk 	19

VII.   DESCRIPTION OF REMEDIAL ACTION ALTERNATIVES 	25

       A.   Groundwater Alternatives 	25

       B.   Alternate Drinking Water Alternatives 	32

VIII.   SUMMARY OF COMPARATIVE ANALYSIS OF ALTERNATIVES  	35

       1.   Protection of Human Health and the Environment 	36

       2 .   Compliance with ARARs  	38

       3.   Long Term Effectiveness and Permanence 	39

       4.   Reduction of Toxicity, Mobility, and Volume 	41

       5.   Short Term Effectiveness 	42

       6.   Implementability 	42

       7.   Cost 	44

       8 .   State Acceptance 	46

       9.   Community Acceptance  	46

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IX.    THE ELECTED REMEDY; DESCRIPTION, PERFORMANCE STANDARDS,
       AND COSTS FOR EACH COMPONENT OF THE REMEDY 	47

       A.   General Description of the Selected Remedy 	47

       B.   Description, Performance Standards, and Cost of Each Component of the
            Selected Remedy 	48

X.     STATUTORY REQUIREMENTS 	58

       A.   Protection of Human Health 	58

       B.   Compliance with and Attainment of applicable or Relevant and Appropriate
            Requirements 	58

       C.   Cost Effectiveness 	62

       D.   Utilization of Permanent Solutions and alternative treatment Technologies
            to the Extent Practicable  	63

       E.   Preference for Treatment as a Principal Element 	63

XI.    DOCUMENTATION OF CHANGES FROM THE PROPOSED PLAN 	64

XII.   RESPONSIVENESS SUMMARY

       Overview 	2

       Background 	5


       Part I:  Summary of Commentors'  Major Issues and Concerns

       A.   Preferred Ground Water Alternative 	7

       B.   Preferred Drinking Water Alternative 	13

       C.   The Potentially Responsible Parties (PRPs) 	22

       D.   The Timing of the Cleanup  	24

       E.   Residential Well Concerns  	28

       F.   EPA' s Monitoring Program	35

       G.   The Contaminants and Associated Risks 	41

       H.   Other Concerns 	46

       Part II:  Comprehensive,  Technical, and Legal Responses to Comments

       A.   Comments of O'Brien & Gere Engineers,  Inc. on behalf of Schlumberger
            Industries, Inc.,  a PRP 	48

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XIII.   FIGURES -





             Figure 1 - Site Location





             Figure 2 - Site Map





             Figure 3 - TCE Concentration in Residential Wells





             Figure 4 - Analytical Results for Surface Water Sampling





             Figure 5 - Analytical Results for Sediment Sampling





             Figure 6 - Alternative GW-2 Existing and Proposed Well Loations





             Figure 7 - Alternative GW-3 Extraction Well Alignment





             Figure 8 - Alternative DW-2 Water Main Extensions





APPENDIX A - ADMINISTRATIVE RECORD INDEX

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RECORD OF DECISION
NORTH PENN AREA 12 SUPERFUND SITE

DECISION SUMMARY

I. SITE NAME, LOCATION AND DESCRIPTION

The North Penn Area 12 Site includes the former Transicoil facility, which occupies
approximately 25 acres on Trooper Road in Worcester Township, Montgomery County,
Pennsylvania (Figure 1). The former Transicoil facility had been used for industrial and
manufacturing activities from approximately 1952 to 1991. Activities included the
manufacturing of electric motors for use by the aerospace industry. As part of the
manufacturing operations, trichloroethene (TCE), 1,1,1-trichloroethane (1,1,1-TCA) and
possibly other solvents were used to degrease parts and eguipment, and were allegedly
disposed of on the facility property.

Adjacent to the former Transicoil facility is the former Control facility for a Nike Missile
Battery installation (PH- 191) that had been operated by the U.S. Army (Figure 2). The
former Nike Control facility property was used by the Army from 1954 to 1968 and was located
on approximately 12 acres of land. Both TCE and 1,1,1-TCA allegedly were used and disposed
of at the former Nike Control facility between 1954 and 1968. In 1975, about 9 acres of the
property were donated to Worcester Township and is now maintained as a park known as Nike
Park. The remaining portion of the property was assigned to the Commonwealth of
Pennsylvania, and is currently operated by Montgomery County as a rehabilitation center for
the handicapped known as the Center Point Training Center.

II. SITE HISTORY

Sampling of soil and groundwater at the Transicoil facility in 1979, carried out by the
Pennsylvania Department of Environmental Protection (PADEP) (then the Pennsylvania
Department of Environmental Resources), indicated the presence of TCE and 1,1,1-TCA in
groundwater below both the Transicoil property and several surrounding properties' wells.
Investigation of contamination at the Transicoil facility and in the surrounding area has
been conducted on several occasions since that time. An investigation in 1980 included:
sampling near a buried waste solvent tank; sampling of the contents of the waste solvent
tank; sampling from underground septic system distribution boxes; and soil sampling in the
septic system drain field area. Groundwater in two monitoring wells was also monitored for
one year.

In January 1987, the Transicoil property was proposed for inclusion on the National
Priorities List. A soil-gas survey was completed on the Transicoil facility in 1988. A
consent agreement between EPA and two potentially responsible parties (PRPs), Transicoil,
Inc. and Eagle-Picher Industries, Inc. ("Transicoil/Eagle-Picher") was executed in 1989 and
led to the initiation of an Remedial Investigation/Feasibility Study (RI/FS) at the Site.
The RI/FS work plan was submitted to EPA Region III on May 18, 1990. EPA subseguently
approved the work plan and the field work was started.

A soil-gas survey conducted by Transicoil/Eagle-Picher in 1990 as part of the RI/FS
indicated elevated levels of volatile organic compounds (VOCs) near Building No. 2 and the
drum storage areas. Levels of TCE and 1,1,1-TCA were very low, although significant
concentrations of vinyl chloride, a TCE degradation product, was detected. A hydrogeologic
study was conducted in July and August 1988, and indicated the presence of TCE contaminated
groundwater plume that seemed to be moving from east to west and was centered beneath the
Transicoil property. Twelve monitoring wells were installed on and near the Transicoil

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property between 1988 and 1990. Residential wells near the former Transicoil facility were
sampled in 1990 and again in 1991. During the residential well sampling, 13 home wells were
found to contain TCE above the safe drinking water Maximum Contaminant Level (MCL) of 5
parts per billion (ppb). Transicoil/Eagle-Picher agreed, under an amendment to the approved
RI/FS work plan, to install and maintain carbon filtration systems on those home wells that
exceeded the 5 ppb MCL for TCE.

All ongoing RI/FS activities were halted on January 7, 1991, when Transicoil/Eagle-Picher
filed for relief under Chapter 11 of the bankruptcy code. At the time of the bankruptcy
filing, the RI/FS field investigation activities were in progress and no draft or final
documents or reports had been prepared. In accordance with the consent agreement, EPA
Region III assumed responsibility for funding, management, and completion of all remaining
RI/FS activities. The tasks to be completed included air monitoring, soil sampling, surface
water and sediment sampling, residential well sampling, monitoring well installation,
groundwater sampling, geophysical logging, packer testing, pump testing, water level
monitoring, wetlands assessment, and preparation of all associated reports and documents.

As a result of residential well sampling conducted in 1995 by EPA, additional residential
wells were found to be contaminated with TCE above the 5 ppb MCL for TCE. EPA subseguently
issued an order to four PRPs that reguired the installation and maintenance of carbon
filtration systems on residential wells found to be contaminated with TCE above the MCL.
Periodic sampling of over 100 residential wells near the Site was also reguired to ensure
that TCE levels in residential water supplies would be maintained at safe levels. Fourteen
additional home wells have been provided carbon filters in accordance with the 1995 order.

III. HIGHLIGHTS OF COMMUNITY PARTICIPATION

There have been a number of community relation activities carried out during EPA's
involvement at the Site. A fact sheet was published by EPA in November 1990 that informed
the public that a consent order was entered into with Transicoil/Eagle-Picher for the
implementation of a remedial investigation and feasibility study.

In February 1991, EPA held a public meeting to address how Transicoil/Eagle-Picher's
declaration of bankruptcy would affect cleanup activities at the site. In December 1991,
EPA issued another fact sheet that provided an update of the site status and informed the
community that the remedial investigation/feasibility study started by
Transicoil/Eagle-Picher would be completed by EPA following the declaration of bankruptcy by
Transicoil/Eagle-Picher.

A Community Relation Plan was finalized for the site on August 3, 1995. The plan
highlighted issues, concerns, and interests of the community located near the site which
were raised during interviews.

On August 22, 1995, EPA issue a fact sheet that informed residents that EPA had issued a
unilateral administrative order that reguired the responsible parties for the site to
install carbon filters on residential wells that were found to contain TCE above the safe
drinking water standard of 5 ppb, and to conduct periodic sampling of residential wells that
could potentially be impacted by contamination from the site.

Pursuant to CERCLA ° 113 (k) (2) (B) (I)-(v), the RI/FS reports and the Proposed Plan for the
North Perm Area 12 Superfund Site were released to the public for comment on July 15, 1997.
These documents were made available to the public in the Administrative Record located at
the EPA Docket Room in EPA's Philadelphia office, and the Lansdale Public Library, Lansdale,
PA. The notice of the availability of these documents was published in the Montgomery

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Observer on July 23, 1997 and the Philadelphia Inquirer Montgomery - Neighbors Section on
July 28, 1997.

A public comment period on the documents was opened from July 15, 1997 to August 15, 1997.
A timely request for a 30-day extension to the public comment was made on August 12, 1997.
As a result, the closing of the public comment period was extended until September 15, 1997.
In addition, a public meeting was held on August 6, 1997 during which EPA answered questions
about conditions at the Site and received verbal comments on the proposed remedial
alternatives.

IV.     SCOPE AND ROLE OF THE RESPONSE ACTION

The selected remedy described in this Record of Decision will comprehensively address the
threats posed by the release of hazardous substances at the site.  The principal threats
posed by the site are due to VOC contamination in the groundwater.

The concentration of contaminants in the groundwater at the site are above Maximum
Contaminant Levels  ("MCLs")  which are enforceable,  health-based drinking water standards
established under the Safe Drinking Water Act  ("SDWA"), 42 U.S.C. °° 300f to 300j - 26.

The primary objectives of the response action specified for the site are:  to prevent
exposure or potential exposure to groundwater that contains contaminants of concern at the
site at concentrations above the MCLs, which are the cleanup goals for the site; and to use
remedial technologies to reduce concentrations of site contaminants of concern to levels
that are below the MCLs.  The ROD proposes to accomplish these goals by 1) addressing
contaminated site groundwater and 2) providing a potable alternative source of drinking
water to affected and potentially affected residents.

V.      SUMMARY OF SITE CHARACTERISTICS AND EXTENT OF CONTAMINATION

        A. SITE CHARACTERISTICS

        1. Topography

          The  North Perm site is in the Triassic Lowland Section of the Piedmont Physiographic
          Province.   The topography of the area is  gently rolling,  with low-lying ridges and
          hills.  The site is approximately 480 feet (ft)  above mean sea level (msl),  along the
          crest of a broad northeast-southwest trending ridge.   Surface elevations vary from
          about 200 ft above msl to about 600 ft above msl.

        2. Surface Hydrology

        Information on the surface-water hydrology in the vicinity of the site comes from
        the United States Geological Survey  (USGS)  topographic map  (Lansdale, Pennsylvania,
        7-1/2 minute quadrangle map).  Montgomery County is on the drainage divide between
        the Delaware River and the Schuylkill River.  Perkiomen Creek, the largest tributary
        of the Schuylkill River, drains the northern half of the county.  Tributaries of the
        Delaware River drain the southern part of the county.

        The site is along the crest of a broad northeast-southwest trending ridge which acts
        as a local drainage divide.  The northern part of the site is drained by several
        unnamed tributaries of Zacharias Creek.  Zacharias Creek then drains into Skippack
        Creek, which then discharges into Perkiomen Creek; Perkiomen Creek then discharges
        into the Schuylkill River, which ultimately discharges into the Delaware River.  The

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southern part of the site is drained by unnamed tributaries of Stony Creek.  Along
several of the creeks are stock ponds used by area farmers to supply water during
the drier months.

Surface water is also fed by springs in the area. Several springs were identified
during field work southeast of the site across Trooper Road.  The spring water feeds
some unnamed tributaries of Stony Creek and provides water for stock ponds and a
spring house.  The groundwater provides an unknown amount of baseflow for local
streams.

3. Soil and Sediment

Three main soil groups are found at the site:  the Lansdale Loam, the Lansdale Silt
Loam, and the Readington Silt Loam.

The Lansdale Loam has a brown, loamy surface layer in which as much as 35 percent of
the soil material consists of pebbles and fragments of sandstone (SCS, 1967).   The
depth to bedrock ranges from 3 to 12 ft.  This soil has been severely eroded,
causing it to have a much thinner profile than the Lansdale Silt Loams.  The soil is
moderately permeable, has a high available moisture capacity, has a medium amount of
surface runoff, and has a moderate to severe hazard of erosion (SCS, 1967).

The Lansdale Silt Loam has an 8 to 10-inch surface layer and a 24 to 40-inch
subsoil.  This soil generally forms over sandstone bedrock.  Bedrock is generally 5
to 10 ft below ground surface (bgs).  The soil has moderate permeability in the
subsoil and moderate to rapid permeability in the subsoil.

The Readington Silt Loam is described as deep, moderately developed well-drained
silt loams that form on nearly level surfaces.  The surface layer varies from 2 to
24 inches and is described as a friable, dark-brown silt loam.  The depth to bedrock
is generally about 4 ft, but the depth ranges from 3 to 5 ft  (SCS,  1967) .  The
permeability is moderately rapid in the surface layer, and moderately slow in the
subsoil.   The soil is associated with a high water table.

Sediment samples were collected as part of a wetlands study conducted during the
remedial investigation.  The sediments are recent fluvial and alluvial material.

4. Regional Geology

The rocks underlying the area around the site are typically composed of the Triassic
deposits of the Newark Basin  (Longwill and Wood,  1965; Newport,  1971).

The site lies within the outcrop belt of the Lockatong and Brunswick formations.
The youngest bedrock unit is the Brunswick Formation.  This formation consists of
thin, discontinuous beds of reddish-brown shale interbedded with mudstone and
siltstone. Principal mineralogical constituents are feldspar, illite, chloride,
quartz, and calcite.  The total thickness of the Brunswick near the site is on the
order of 9,000 ft (Newport, 1971).

The Brunswick is underlain by the Lockatong Formation, but the two formations
interfinger in the vicinity of the site (USGS, June 1995).  The Lockatong consists
of massive beds of medium and dark gray argillite (a very dense shale and mudstone)
interbedded with thin beds of gray-to-black shale and siltstone.   Some dolomite,
feldspar, clay, and guartz are present.  The Lockatong is more resistant to erosion

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and forms a low ridge when outcropping at the surface.  The maximum thickness of the
Lockatong in the vicinity of the site is about 2,000 ft (Newport, 1971) .

The Stockton Formation underlies the Lockatong and consists of interbedded layers of
sandstone and shale.  The formation is typically divided into three members.  The
lower member is characterized by red-to-gray medium- to coarse-grained arkosic
sandstone (a sandstone containing appreciable feldspars) and conglomerate.  Numerous
lenses of silty and sandy red shale are interbedded with the sandstone.  The middle
member consists of brown, red, and gray fine- to medium-grained arkosic sandstone
with thick beds of red shale and siltstone.  The sandstones of this member are more
well-sorted than the sandstones of the lower member.  The upper member is comprised
of very fine-grained arkose and siltstone with an extremely hard and resistant layer
of red and gray shale at the top.  The total thickness of the Stockton in the
vicinity of the site is about 6,000 ft (Newport, 1971) .

Diabase dikes and sills occur in the subsurface and are exposed at the surface in
some parts of Montgomery County.  These features are composed of very dense
fine-grained  black diabase, containing primarily augite and labradorite.  The dikes
vary from 5 ft to 100 ft in thickness, and the sills may exceed 1,000 ft in
thickness at some locations (Newport, 1971).

The sedimentary formations typically dip to the northwest and the north at an
average angle of about 20 degrees and strike approximately northeast-southwest
(Newport, 1971).  Several broad anticlines and synclines have been identified.

Most of the rocks in the vicinity of the Site are cut by a well-developed system of
nearly vertical joints.  Three distinct joint sets have been identified in the
Brunswick (JACA,  1987).  One set strikes north-northeast while the other sets are
reportedly less well-developed and strike northwest and east-northeast.  All three
joint sets are nearly vertical in dip.  The average distance between joints is about
6 inches.  These joint sets are common in the Brunswick but are narrower and more
widely spaced in the Lockatong. Where the Brunswick and Lockatong are interfingered,
the rocks are characterized by a greater number of fractures.  Joints in all
formations generally are partly filled with either guartz or calcite cement.

5. Site Geology

Most of the study area is underlain by Lockatong rocks.   Rocks that were earlier
classified as Brunswick Formation occurring on and near the site interbedded with
Lockatong were reclassified by Lyttle and Epstein (1987) as a reddish-brown sandy
siltstone member of the Lockatong.  The presence of the Lockatong contributes to the
high topography at the site.  According to the USGS, the beds of the Lockatong
Formation strike N64IE and dip at 15! N26IW in the vicinity of the site  (USGS,
1995). Borehole video in onsite wells, along with the drilling logs for the wells,
identified alternating red and gray siltstone.  Longwill and Wood (1965)  reported
that more fracturing commonly occurs in interbedding of the Brunswick and Lockatong
formations than in the two units individually.

Fracture traces provided some evidence of the extent and orientation of fractures.

Fractures are common throughout the area.  Bionetics  (1989) reviewed aerial
photographs of the site and detected two major sets of fractures with orientations
northwest/southeast (N 105 to 305W) and east-northeast/west-southwest  (N605to 805E).
A fracture trace analysis by ERM in 1989 covered an area approximately 1.2 miles by

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0.8 miles around the site.  Seven fracture traces were located in this site
analysis.  The fractures are mainly oriented to the north-northwest.

Geophysical logging and downhole video surveying performed by the USGS in nine
wells provided information on the type, depth, and extent of fractures at the site.
Caliper logs were also run in the boreholes to locate fracture zones.  Geophysical
logging was also conducted on several wells by ERM.  Fractures were confirmed in
most wells logged by USGS using a downhole video camera.

For wells with depths greater than about 100 ft, fractures were encountered by
caliper logging most commonly within 100 ft of the ground surface.  This is
well-demonstrated in wells MW-1, MW-3, MW-9, T-3, T-5, T-6,  and the Training Center
well.  Well MW-12 is cased to a depth of 117 ft bgs and therefore provides no
information fractures above this depth.  However, neighboring well MW-11 shows
fractures occurring within 100 feet below ground surface  (bgs).   Wells MW-2 and MW-6
through MW-8 are too shallow to provide support for the assertion but at least
demonstrate the presence of fractures in the upper 100 ft of the subsurface.  The
scarcity of fractures below a depth of about 100 ft bgs may be due to the tendency
of fractures to close up at greater depths because of lithostatic pressure.

Wells MW-3, T-6, MW-7, and T-3 are along the direction of dip.  MW-11 and MW-12
are approximately along strike from MW-3 and have been projected into the plane of
the cross section from the southwest.  The location of fractures observed in each of
the wells, along with their orientation (horizontal or vertical),  where this is
known.

Bedrock formations and bedding planes dip to the northwest.   Fractures may occur at
any depth, and may be open or may be plugged with calcite deposits.  Most of the
fractures observed in boreholes on and near the site were in the upper 100 ft bgs.
Fractures may be oriented in any direction, but at this site were observed
freguently to be vertical.  Some fractures were oriented approximately horizontally
and may represent bedding plane openings.

Some bedding plane partings may be really extensive.  In other areas, bedding planes
may be discontinuous.  Fractures that may represent bedding plane partings extend
down the bedrock dip between wells T-6, MW-3, and the projection of wells MW-11 and
MW-12 into the cross section.  Some or all of these bedding plane partings may be
open continuously.  On the other hand, fractures encountered in well T-3 that may
represent bedding plane partings do not appear to extend to well T-6.  This
demonstrates the discontinuous nature of the bedding plane partings.  These bedding
plane partings do not intersect well MW-7 because it is too shallow.

The USGS  (1995) observed spikes in natural gamma logs at depth in some wells.  These
spikes likely represent thin zones of clay-rich material that appear to serve as
marker horizons in the deeper wells.  The marker horizons are discussed at greater
length in the USGS report on geophysical borehole logging.  These horizons were used
to calculate the strike and dip of bedding planes discussed above.

6. Hydrogeology/Groundwater

The geology of the study area fits the anisotropic, heterogeneous system described
above.  In an anisotropic, heterogeneous system, preferential flow paths make
determining groundwater occurrence and flow direction more complex.  In the case of
fractured bedrock, the primary porosity of the rock is very low, and most

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groundwater is found in the secondary porosity caused by fractures and bedding plane
partings.  Flow  direction is determined by the combination of hydraulic gradient
direction and the orientation of fractures and bedding planes, and groundwater flow
direction cannot be assumed to be perpendicular to the contours of hydraulic head.

Groundwater associated with the Site is found primarily in fractures and bedding
plane openings because the primary porosity of shale and Siltstone is extremely low.
Bedding planes strike at N645E and dip at N265W in the vicinity of the study area
(USGS, 1995).  Fracture traces identified by ERM (1990) and Bionetics (1989) show
fracture orientations northwest/southeast, approximately along the dip of bedding
planes, and also east-northeast/west-southwest, approximately along strike.  Much of
the groundwater below the North Penn Area 12 site is expected to be found in
secondary porosity with these orientations.

Groundwater in the Lockatong Formation may be under confined, unconfined, or under
perched conditions.  Groundwater in the upper part of the aguifer generally is under
unconfined (water-table) conditions.  Groundwater in the deeper part of the aguifer
is probably confined, resulting in local artesian conditions.

The direction of flow in the study area is determined both by the direction of
hydraulic gradient, the orientation of the fractures and bedding planes described
above, and the relationship of recharge and discharge areas.

The site is a groundwater-recharge area, located at the top of a ridge where the
topography slopes downward to the northwest and southeast.  The ridge acts as a
groundwater divide.  During sampling for the packer testing, it was discovered that
water in the upper part of the aguifer was colder and more oxygenated than water
obtained from deeper in the aguifer, suggesting that water in the upper part of the
aguifer had greater or more recent contact or exchange with the atmosphere than that
in the lower zone  (USGS, 1995).  This observation supports the designation of the
site as a groundwater-recharge area.

Water levels have been measured in onsite monitoring wells on several occasions.
The following sources of water-level data were consulted:

             ERM (May 1990; data collected in August 1988)
             CH2M HILL  (data collected in March and June 1995)
             USGS  (1995; data collected continuously beginning in late May 1995)

A piezometric-surface map based on water levels measured in August 1988 by ERM
(May 1990)  showed the gradient of hydraulic head sloping to the north to northwest.
This map indicates the potential for groundwater beneath the site generally to flow
in this direction,  parallel to the bedrock dip and down topographic slope.  The 1988
water-level measurements also indicated an area of high hydraulic head near the
septic system drainfield, which created groundwater gradients radially west, north,
and northeast from the drainfield.  The cone of depression created by the Center
Point Training Center production well is clearly indicated.

Water-level data from March and June 1995  (CH2M HILL. 1995; USGS, 1995)
confirmed that the hydraulic-head gradient slopes toward the north and northwest, so
that the direction of groundwater flow potentially is approximately in these
directions.  The area of high hydraulic head detected in 1988 near the septic system
drainfield is not evident at this time.  It is likely that the hydraulic-head
gradient on the southeast side of the ridge slopes toward the east to southeast,

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contributing to a component of groundwater flow away from the groundwater divide in
these directions.  The Center Point Training Center production well northeast of the
site modifies the natural hydraulic gradient by inducing groundwater in the eastern
part of the site to flow north and northeast rather than northwest.  Some
groundwater is drawn into the Training Center well itself.

Based on the observed water-level data, groundwater beneath the site primarily flows
toward the northwest.  Flow in this direction is due primarily to the disposition of
area topography, fracture orientation, and the dip of bedding planes.  Additionally,
most of the residential wells in the area are located north and west of the site;
pumping from these residential wells is expected to increase the local hydraulic
gradient and enhance groundwater flow northwest from the study area.  Because of the
anisotropic nature of fractured bedrock, flow will not occur consistently
perpendicular to the contours of hydraulic head.  The actual flow direction at any
given point may vary widely depending on the orientation of fractures present at
that point.  However, the net effect of the factors described above is to drive flow
generally toward the northwest.

The USGS developed a map of water levels measured in several wells within one-half
mile of the site.  This map shows the potential for groundwater to flow generally to
the north and northwest in the vicinity of the site.  Groundwater also flows to the
southeast, northeast, and southwest in a radial fashion away from the site.

Discharge points for the groundwater moving to the north and northwest include
residential wells and possibly springs and groundwater discharge along two unnamed
tributaries of Zacharias Creek to the east and northwest.  Discharge points for
groundwater on the southeast side of the groundwater divide include residential
wells and several springs that feed an unnamed tributary of Stony Creek.  The
tributary itself may have a groundwater baseflow component.

B. NATURE AND EXTENT OF CONTAMINATION

1. Air

Volatilization of VOCs to the atmosphere is not a significant risk at the Site due
to the relatively low levels of contamination in the soil.  Air monitoring surveys
conducted in 1995 found no detections of VOCs attributable to contamination from the
Site.  Wind erosion and future construction activities have the potential of
transporting soil contamination.  Contaminants that tend to bind to the soil (e.g.,
metals)  can be released to the air with wind blown dust.  However, no Site-related
metal contamination was identified.  Risk associated with wind erosion and dust from
construction is considered to be comparable to that from other uncontaminated
locations near the Site.

Two air monitoring surveys were conducted as part of the RI field activities in
1995.  The monitoring was conducted with portable hand held volatile organic
compound detection devices.  No significant levels of volatile organic contamination
were identified during either of the monitoring events.

   2.  Soil Contamination

Soil and soil gas samples were collected between 1988 and 1994.  Soil gas samples
collected in 1990 showed evidence of VOC contamination, particularly vinyl chloride.
The maximum vinyl chloride concentration was 325 ppb and the maximum TCE

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concentration was 14 ppb.  The highest readings were found in samples taken
southeast of the parking lot and in the septic drain field.

Soil samples collected one month later, however, showed very little VOC
contamination. Soil Samples were collected from 18 locations where soil gas was
found to have elevated soil gas levels of VOCs.  Vinyl chloride was detected in only
one sample at 3 Ig/kg in the septic drain field.

Soil sampling conducted by EPA in 1994 also showed very low concentrations of VOCs.
PCE was found in two samples, one on he Nike property at 1.9 Ig/kg and one in the
septic drain field on the Transicoil property at 1.6 Ig/kg.  Comparisons of soil VOC
levels with levels that could pose a risk to human health did not show any VOCs of
potential concern in the soil.  Therefore, no soil remediation is reguired.

Soil samples collected in 1994 also showed levels of inorganic compounds (arsenic,
beryllium, and manganese) in excess of levels that could pose a potential human
health risk.  Additional off-site soil samples were collected in December,  1995,
from five locations in the vicinity of the Site to better establish background
levels of arsenic, beryllium, and manganese.  Comparison of levels of these
contaminants measured at the source area with levels measured at background
locations and with levels general found in the eastern United States documented in
literature indicates that the inorganic contaminants are not Site-related.   Also,
there is no evidence of releases of inorganic contamination from the operations at
the Site.  Therefore, the presence of arsenic, beryllium, and manganese observed in
soil are considered to be naturally occurring and are not considered to be a result
of activities at the Site.  Therefore, no remediation for inorganic contaminants in
soil will be reguired.

3. Surface Water

Five surface water samples were collected in March 1995 from ponds, a spring, and in
creeks near the Site at both upstream and downstream locations and in nearby, but
separate, watersheds.  The locations were selected to represent areas that could
potentially be affected by the Site (within the Site surface water drainage area)
and areas not affected by the Site.  No VOCs or semi-volatile organic compounds
(SVOCs) were detected in any surface water samples.  Very low levels of the
pesticides 4,4-dichlorodiphenyldichloroethane  (4,4-DDD) at 0.0044 Ig/L and
4,4-dichlorodiphenyltrichloroethane (4,4-DDT) at 0.0043 Ig/L were detected in one
surface water sample.  These pesticides are not associated with Site contaminants
and are more likely a result of local agricultural activities.  Inorganic compounds
were also found at concentrations well below published standards.

4. Surface Water Sediment

Sediment samples were collected in March 1995 from the same five locations sampled
for surface water.  Inorganic contaminants  (arsenic, beryllium, and lead) were
detected in sediment samples but, with the exception of lead, were below the lowest
toxicological screening levels for sediments.  Lead is not considered to be
Site-related and no clear path exists for surface water drainage from the Site to
the area where the highest lead levels were found.

5. On-Site Groundwater

The monitoring wells were sampled by the PRP in August 1988 and by EPA in March

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1995.  Groundwater samples were collected from production and monitoring wells
(MWs) installed on the Transicoil property, the former Nike property, and adjacent
properties.  Both TCE and tetrachloroethene (PCE)  were found at levels exceeding
drinking water standards in some samples.  In addition, 1,1,1-TCA,
1,1-dichloroethene (1,1-DCE),  Freon-113, and arsenic were detected.  The highest
levels of contamination in 1995 were found in MW-3 and MW-1 (TCE at 88 ppb, PCE at 3
ppb; and TCE at 380 ppb, PCE at 25 ppb, respectively); both are located northwest
and downgradient of the septic drain field which is one of the suspected sources of
the contamination at the site. Wells in the southeastern part of the Site had very
low levels of contamination.

Historical data show fluctuations in the level of TCE in Site groundwater,  ranging
from 75 ppb  (in 1979) to 2 ppb (in 1995) in production monitoring well T-3.  Levels
over time appear generally to be decreasing in both production monitoring wells T-3
and T-5.Samples from MW-1 through MW-5 also show a decrease in TCE concentration
between 1988 and 1995.  Although these data indicate that high concentrations near
the source on the Transicoil property are dissipating, the most recent data from
T-6, indicate that this well has a concentration of TCE which is higher now than it
has been at any point in the past (100 ppb in 1995 compared to 33 ppb in 1988) .  The
concentration of 1,1,1-TCA decreased between 1988 and 1995 in all wells sampled.

6. Groundwater in Residential Wells

Several residential wells surrounding the Transicoil property are contaminated with
TCE, 1,1,1-TCA, Freon-113, and other chlorinated organic compounds.  The
contaminated wells are primarily located to the west, northwest, and northeast of
the Transicoil property, although five wells to the southwest and southeast of the
property also showed low levels of contamination.   Most of the contaminated
residential wells are located northwest of the Transicoil property, in Blocks Number
15 and 17 on either side of Valley Forge Road (see Figure 3).   Two adjacent wells
(Lots 17-46 and 17-52, located approximately 1,500 feet west-northwest of the
Transicoil property were found to have TCE concentrations of 200 ppb and 180 ppb,
respectively in January 1995.   These two wells (Lots 17-46 and 17-52) were found to
have TCE concentrations of 130 ppb and 120 ppb,  respectively in November 1995.  One
residential well located further west of the Transicoil property site (Lot 15-10)
was found to have 40 ppb of TCE.   In addition, TCElevels in excess of MCLs also were
found north of the Transicoil property in Block 14A, with concentrations in adjacent
lots along Heebner Road ranging from 8 to 24 ppb.

Residential wells also had detectable levels of Freon-113 (for which no published
standard is available) and of 1,1,1-TCA.  Levels of 1,1,1-TCA were well below MCL
for drinking water in all residential wells sampled.  The pattern of contamination
for Freon-113 and 1,1,1-TCA generally paralleled that of TCE,  although
concentrations of these compounds were significantly lower than those of TCE.
Chloroform was detected in some residential wells containing other contaminants.
Estimated chloroform levels, which generally were below quantitative detection
limits, were slightly higher than the level that poses a potential risk to human
health  (0.15 ppb).

Contaminant levels in residential wells varied over time.  Two wells  (17-46 and
17-52), which were found to be the most contaminated during the 1995 sampling event,
had levels twice as high in 1990.  Some wells with lower contaminant levels
experienced slight increases,  while others experienced slight decreases.  The data
indicated that high levels of contamination at the Site may be gradually decreasing

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and moving down gradient.

No residential wells have been tested for inorganics. However, the North Penn Water
Authority (NPWA) regularly tests area supply wells for a variety of compounds,
including inorganics. Levels of arsenic in two NPWA monitoring wells (NP-34,
approximately 7,000 feet north-northeast of the Transicoil property, and NP-33,
approximately 4.5 miles north) were similar to levels detected onsite. NPWA
monitoring wells showed arsenic at 2 to 5 ppb, which is below the MCL for arsenic
which is 50 ppb.

VI. SUMMARY OF SITE RISKS

A. Human Health Risk Evaluation

1. Selection of Chemicals of Concern

A selection process was used to reduce the field of detected chemicals to those
considered to be the most important to the human health evaluation. Identification
of the chemicals of potential concern (COPCs) was based on methods described in Risk
Assessment Guidance for Superfund (USEPA, 1989a, 1991b), Guidance for Data Usability
in Risk Assessment (USEPA, 1992), and Selecting Exposure Routes and Contaminants of
Concern by Risk-Based Screening (USEPA, 1993b). The criteria for the selection of
COPCs were as follows:

Contaminant concentrations exceeding risk-based concentrations (RBCs) (in
accordance with Region III guidance, USEPA, 1991b, 1993b, 1994b); for soils,
saturation concentrations were calculated for organic constituents and used as
the screening value if the RBC value was greater than the saturation
concentration (USEPA, 1991b). (The RBCs are based on a target hazard index of
0.1 and target cancer risk of 1 X 10 -6.)

Maximum concentrations of inorganic constituents exceeding background
concentrations.

Human nutrient concentrations exceeding the National Research Council's (NRC)
Recommended Dietary Allowances (RDAs), Estimated Safe and Adeguate
Dietary Intakes, or Estimated Minimum Reguirements for Healthy Persons (NAS,
1989).

A total of 59 chemicals, which included VOCs, semivolatiles, pesticides, and metals
were detected in environmental media during sampling activities of the Remedial
Investigation. The complete listing of COPCs for the Site is presented in Table 1-1
of the Feasibility Study Report. The major chemicals of concern for the site were
determined to include:

6 Trichloroethene
6 1,1-dichloroethene
6 1,2-dichloroethene (total)
6 1,2-dichloroethene (cis)
6 Tetrachloroethene
6 Chloroform

2. Exposure Assessment

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The objective of the exposure assessment is to estimate the amount of each COPC at a
site that is actually taken into the body  (i.e. the intake level or dose).  There
are three primary routes through which individuals may be exposed to site related
contaminants including ingestion, inhalation, and contact with the skin.  The group
of individuals for which exposure was evaluated at the Site includes current and
future residents, and current and future workers.

The potential receptors at the site were selected on the basis of the site setting,
the nature and extent of contamination, plausible exposure pathways, and EPA
guidance.  Potential receptors for North Penn Area 12 are future site residents,
future construction workers, and current and future onsite workers  (occupational
exposures).

Exposure to contamination at the site may occur at any location or to any
contaminated  medium that is accessible to potential receptors.  Currently, the only
accessible medium at the site is surface soil.  Other media, including subsurface
soil and groundwater, on the site currently are not accessible.  The major routes of
contaminant intake include incidental ingestion of, dermal contact with, and
inhalation of surface soil fugitive dust; in surface and subsurface soil; and in
groundwater.

Exposure to chemicals in surface soil was evaluated for the occupational worker on
the site.  Because onsite workers currently do not work outdoors, inhalation of
fugitive dust is not considered a complete exposure pathway.  Dermal contact with
surface soil is considered a minor contributor to overall risk for the current
worker, and was not evaluated guantitatively.  The hypothetical future residential
land use scenario also was evaluated for exposure to surface soil, including
exposures to surface soil via incidental ingestion and dermal contact for a child
and an adult.  The site is vegetated, therefore dust inhalation is not considered a
complete pathway.

Exposure to chemicals in subsurface soil was evaluated for the hypothetical future
construction worker involved in short-term excavation activities.  The exposure
pathways evaluated are incidental ingestion, dermal contact, and inhalation of
fugitive dust.

Exposure to chemicals in the groundwater was evaluated for potential future exposure
for children and adults.  The evaluation used data from onsite monitoring well
samples.  Residential wells where contaminant levels exceeded MCLs have been
provided with groundwater treatment systems to reduce the exposure to site
contaminants.  Therefore, current exposure to groundwater was not considered a
complete pathway (the contaminant levels will be less than MCLs after treatment) and
was evaluated gualitatively.  Future exposure to groundwater was guantitatively
evaluated for residential exposure for children and adults.  The exposure routes
evaluated are ingestion, dermal contact while bathing (child), and inhalation of
volatiles while showering (adult).

3.  Toxicity Assessment

The toxicity assessment characterizes the inherent toxicity of a compound and helps
to identify the potential health hazard associated with exposure to each of the
chemicals of concern.  Toxicological values, reference doses  (RfDs) for
non-carcinogenic chemicals and the non-carcinogenic effects of carcinogens, and
cancer slope factors (CSFs)  for known, suspected, and possible human carcinogens,

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derived by USEPA were used in the Risk Assessment.

RfDs have been developed by EPA for indicating the potential for adverse health
effects from exposure chemicals exhibiting noncarcinogenic effects.  RfDs,  which are
expressed in units of mg/kg-day, are estimates of lifetime daily exposure levels for
humans, including sensitive individuals.  Estimated intakes of chemicals from
environmental media (e.g., the amount of a chemical ingested from contaminated
drinking water)  can be compared to the RfD.  RfDs are derived from human
epidemiological studies or animal studies to which uncertainty factors help ensure
that the RfDs will not underestimate the potential for adverse noncarcinogenic
effects to occur.

CSFs have been developed by EPA' s Carcinogenic Assessment Group for estimating
excess lifetime cancer risks associated with exposure to potentially carcinogoic
chemicals.  CSFs, which are expressed in units of (mg/kg-day)  -1,  are multiplied by
the estimated intake of a potential carcinogen, in mg/kg-day,  to provide an
upper-bound estimate of the excess lifetime cancer risk associated with exposure at
that intake level.

The term "upper-bound" reflects the conservative estimate of the risks calculated
from the CSF.  Use of this approach makes underestimation of the actual cancer risk
highly unlikely.  CSFs are derived from the results of human epidemiological studies
or chronic animal bioassays to which animal to human extrapolation and uncertainty
factors have been applied.

4.  Risk Characterization

The noncancer hazard indices (His) and cancer risks, and major sources of the risks
are discussed below for exposure of potential receptors to surface soil, subsurface
soil,  and groundwater.  Data from samples collected onsite were used in risk
calculations.  Table 1 presents the risk estimates for each medium and receptor and
their relative contribution to the risks at the site.  Risk calculations for
exposure to the various media are presented in Appendix 0 of the RI report.

a.    Surface Soil, Exposure Scenario

      Risk estimates were calculated for the residential receptor potentially
      exposed to surface soil via incidental ingestion and dermal contact.   The
      onsite worker and future trespasser were not evaluated because no constituents
      were selected in the COPC screening process.  The future construction worker
      was evaluated for a combined surface and subsurface soil exposure scenario and
      is discussed in paragraph b, below.

      The His for the ingestion and dermal exposure scenarios for future residents
      were below the USEPA recommended level of 1.  Aluminum,  the only CoPC
      identified in surface soil, is not considered a carcinogen and, therefore, the
      exposure estimates for carcinogens were not evaluated for the future resident.

b.    Combined Surface and Subsurface Soil, Exposure Scenario

      Risk estimates were calculated for the construction worker exposed to
      subsurface soil via incidental ingestion, dermal contact, and inhalation of
      dust during excavation activities.  The VOC inhalation scenario was eliminated
      during the COPC screening process because no VOCs were selected as COPCs.

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                  All noncancer hazards and carcinogenic risks were below or within EPA
                  threshold levels for all exposure scenarios.  The cumulative hazard was also
                  below the EPA recommended level of 1.   The cumulative cancer risk was 6.3E-06
                  which is within the EPA target risk range.



            c.     Groundwater,  Exposure Scenario

                  Reasonable Maximum Exposure Scenario

        The noncancer His for all exposure scenarios were above the recommended level of 1.   All
        of the cancer risks except ingestion of groundwater were within EPA's target risk range
        of 10 -4 to 10 -6.  Table 2 below presents a summary of human health risks from exposure
        to groundwater.

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Table 2
Human Health Risks

Cancer Risk Hazard Index
(Additional cancer
cases for every Child Adult
Group of Individuals 10,000 people)

Future on-site adult residents who inhale .66 3.5
contaminants during showering

Future on-site residents who consume 2.6 5.6 2.4
groundwater from the Site for 30 years

Future on-site child touching contaminated .19 2.2 NA
groundwater

Total Calculated Risk for Above Exposures 3.4 7.8 5.9
Children. The cumulative hazard index for ingestion of groundwater by children
is 5.6 and for dermal contact while bathing is 2.2, which are above the
threshold level of 1. TCE contributes approximately 71 percent of this hazard.
The cancer risk from dermal contact during bathing is within the EPA target risk
range.

Adults. The cumulative hazard indices for inhalation during showering and
ingestion are 3.5 and 2.4, respectively, which are greater than the EPA
threshold level. TCE contributes 93 percent of the inhalation hazard and 70
percent of the ingestion hazard. The cumulative risk from inhalation during
showering is 6.6 x 10 -5, which is within the EPA target-risk range of 10 -4 to
10 -6. The age-adjusted cancer risk from ingestion is 2.6 x 10 -4, which is
above the EPA target risk range. Arsenic contributes 44 percent of this risk,
1,1-DCE contributes 24 percent; and, TCE contribute approximately 24 percent of
the total risk. Arsenic, however, has been determined to not be site related
because it was found in soil at levels comparable to background samples
collected in the vicinity of the site.

Central Tendency Scenario

The noncancer hazard index values for all exposure scenarios were above the
recommended level of 1. All of the cancer risk estimates were within EPA's
target risk range of 10 -4 to 10 -6

Children. The cumulative HI for children for ingestion of and dermal contact
with groundwater are 2.4 and 1.7, respectively. TCE contributes approximately
71 percent of the ingestion hazard and 93 percent of the dermal hazard. The
cancer risk due to dermal contact while bathing was 1.4 x 10 -5, which is within
the EPA-recommended risk range.

Adults. The cumulative HI for ingestion is 1.7 and for inhalation during
showering is 1.9. TCE contributes 93 percent of the inhalation hazard and 70
percent of the ingestion hazard. The inhalation cancer risk while showering is
1.4 x 10 -5, which is within the recommended risk range. The age-adjusted

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ingestion cancer risk is 8.3 x 10 -5, which is within the EPA target-risk range.

In summary, the principal source of risk at the site is from exposure to groundwater.
Risks from exposure to soil are below or within EPA recommended levels. The main
contaminants contributing to the noncancer hazard from groundwater are TCE and
arsenic. The main cancer risk contaminants are TCE, arsenic, 1,1-DCE, and PCE.
Arsenic, however, has not been determined to be site-related because it was found in soil
at levels comparable to levels in background samples collected in the vicinity of the site
and also comparable to levels normally expected to be found in soils of the Eastern
United States. Arsenic in groundwater is considered to be a result of the background
concentrations in soil. Other inorganics selected as COPCs for groundwater (aluminum
and mercury) presented negligible risk at observed concentrations. Inorganics, therefore,
are not considered COPCs for the site. Site-related COPCs are the following organic
compounds: chloroform, 1,1-DCE, 1,2-DCE(total), 1,2-DCE (cis), PCE, and TCE.

B. Environmental Risk

1. Site Characterization

Potentially sensitive receptors to onsite soil-gas and soil contamination and offsite
surface water and sediment contamination include wetlands, threatened and endangered
species, and other flora and fauna on and near the site.

No threatened or endangered species were identified on or near the site. During the work
conducted under the 1990 RI, reguests for information on threatened and endangered species
near the site were sent to the regulatory authorities who have jurisdiction over matters
affecting such species and species habitat. No threatened or endangered species habitats
were identified on or near the site by those agencies. As part of the 1995 RI/FS work, CH2M
HILL recontacted each agency, reguesting updated information as to the status of threatened
and endangered species near the site. No threatened or endangered species habitats have
been identified on or near the site. Copies of letters sent to regulatory authorities, and
responses received to date, are in Appendix N of the RI Report.

On the basis of nondetection of site contaminants in surface water and sediment samples,
wetlands identified to the south of the site do not appear affected by site groundwater
contaminants. Streams, springs, wetlands, and the aguatic species they contain, may be at
some risk due to non-site-related contaminants.

Burrowing animals, animals that ingest soil, and vegetation are potentially at risk from
soil-gas contamination.

2. Environmental Assessment

The objectives of the environmental assessment were to:

Locate and characterize wetlands that might be affected by site contamination or
remediation of the site

Identify potential threatened or endangered species and their habitat within the
area potentially affected by the site

Discuss gualitatively the effect of the site contamination and potential remedial
measures on the ecology

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3. Risk Characterization

a. Soil Contamination

Few VOCs were detected in soil. PCE was detected in seven samples. Four of the
detections indicate that PCE was not found at levels substantially above the level
found in associated blanks. TCE was detected in one sample at a level below the
practical quantification limit. None of the VOC detections was above interim
draft Region III screening levels set by the biological technical assistance group
(BTAG) (BTAG, 1995).

Soil-gas data are used to screen for "hot spots" of soil and groundwater
contamination. In general, the highest concentrations of soil-gas contaminants
were found southeast of the parking area. High concentrations of vinyl chloride
and TCE also were detected in soil gas collected from the septic drainfield area.

Soil was sampled in several of the locations where soil gas was collected,
including several where soil gas was found to have elevated levels of VOCs.
Only vinyl chloride was detected and in only one soil sample, at 3 Ig/kg. High
levels of soil-gas contamination did not correspond to locations where VOCs were
detected in soils.

Selected soil samples also were analyzed on and off the site for pesticides and
SVOCs. Low levels of several pesticides were detected in samples collected both
on and off the site. The detections are consistent with the rural surroundings
because pesticides likely have been used in farming this area. Low levels of
SVOCs also were detected in several samples. SVOC contamination also may
result from pesticide or herbicide use. Several SVOCs and pesticides have
USEPA contract-reguired detection limits that are higher than the Region III
BTAG interim draft screening levels, published January 1995.

In all soils tested for inorganics, beryllium was found at levels higher than the
proposed action level of 0.2 mg/kg (Federal Register, July 27, 1990). The metal
was detected at similar levels throughout the area investigated, both in onsite
samples and in background samples. Beryllium was detected as high as 1.7
mg/kg in soils. The observed range of concentrations in the eastern United States
is <1 to 7 mg/kg, with an estimated arithmetic mean of 0.85 mg/kg (Shacklette
and Boerngen, 1984). No clear source of the beryllium was identified. There is
no indication that beryllium was used or disposed of at the Transicoil site.
Therefore, the beryllium detected in soils is not believed to be site-related.

Lead concentrations in soil were similar throughout the site, except for one
location on the Nike Park site. That sample was collected at 0.6 feet bgs and
contained 94.4 mg/kg of lead, in contrast to values ranging from 11.2 to
29.2 mg/kg in all other samples collected from the Nike and Transicoil sites. The
observed range of lead concentrations in the eastern United States is <10 to 300
mg/kg, with a mean of 17 mg/kg (Shacklette and Boerngen, 1984). Because the
contract-reguired detection limit for lead (0.6 mg/kg) is greater than the Region III
BTAG screening level for lead in soil (0.0125 mg/kg), the assumption is that all
samples exceed the BTAG screening criteria. Several other inorganics have
contract-reguired detection limits set above BTAG screening criteria. The
inorganics are antimony, beryllium, chromium, cobalt, copper, mercury, nickel,
selenium, silver, and thallium. However, no information exists that suggests th;6
metals were used or disposed of at the Transicoil site. Therefore, any possible

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detection of metal is not believed to be site-related.

Arsenic was detected at concentrations one order of magnitude lower than the
proposed federal action level of 80 mg/kg in nearly all soil samples tested, Two
soil samples collected in the area of the septic drainfield had arsenic
concentrations slightly above the 5 mg/kg Region III BTAG screening level.
Concentrations were similar throughout the site, and no clear pattern to arsenic
levels was apparent.  Arsenic is present in soils of the eastern United States at
concentrations ranging from <0.1 to 73 mg/kg,  with an estimated arithmetic mean
of 7.4 mg/kg (Shacklette and Boerngen, 1984).   Arsenic is not believed to be a
site related contaminant.

b.  Surface Water Contamination

Surface water and sediment samples were collected from ponds, a spring, and
creeks near the site.  Surface water and sediment sampling location SW-5 is a
background location, on a tributary whose drainage basin does not include the
site.   No VOCs or SVOCs were detected in surface water.  Several metals have
contract-reguired detection limits set above BTAG screening criteria.  The metals
are cadmium, chromium, cyanide, lead, mercury, and silver.  Several metals were
detected at low levels in surface water and sediment samples collected downslope
of the site.  Figure 4 presents analytical results for dissolved arsenic and
manganese found in surface water samples.

Dissolved arsenic was detected in all but one surface water sample, but the levels
detected were not significantly higher than those found in associated blank
samples.  No total arsenic was detected in surface water.  The ambient water
guality criterion (AWQC) for chronic exposure to total arsenic in surface water is
874 Ig/L.  The chronic AWQC value for arsenic in filtered samples is 190 Ig/L.
As discussed above,  arsenic is not considered a site-related contaminant.

The surface water guality criterion for manganese published by the
Commonwealth of Pennsylvania is 1.0 mg/L.  No surface water samples collected
exceeded this standard.  The highest manganese level detected in surface water at
the site was 182 Ig/L, in a sample collected from location SW-3, at the edge of a
pond on the Kitchens farm site.  A similarly high level was recorded at the outlet
of a pond that does not appear to drain from the site  (location SW-2).   The other
three samples tested had concentrations of manganese one order of magnitude
lower than SW-2 and SW-3.

A comparison of metals in surface water shows that the background sample  (SW-
5) had concentrations similar to the other samples for nearly all constituents.  As
noted above, manganese was found at higher concentrations in SW-2 and SW-3
than in SW-5.  The total lead concentration in SW-1 was higher than that in SW-
5; however, no dissolved lead was present in either sample.  Dissolved metals are
presumed to have the greatest potential to interact with aguatic organisms,
however, metals are not considered to site-related.

Surface water sample SW-3 contained very low levels of 4,4'-ODD and 4,4'-DDT.
Several of the pesticide contract detection levels are above the Region III BTAG
interim draft screening levels.  Pesticides are not considered to be site-related
contaminants.

c.  Sediment Contamination

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Figure 5 shows analytical results for arsenic, beryllium, and lead in sediment
samples.  Levels of arsenic and beryllium in sediment samples were slightly higher
than those found in soil samples.  No clear areal pattern of contamination is
evident.  Only low values of pesticides, SVOCs, and VOCs were detected.
Several of the pesticide and inorganic detection limits are above the Region III
BTAG screening levels.  The conservative assumption for compounds with
detection limits above guidance levels is that all samples exceeded the guidance
criteria.

Toxicological screening levels are available for selecting contaminants that
require further study of their effects on sediment-associated biota.  Concentrations
are reported as effects range-low (ER-L), corresponding to the lower 10th
percentile of concentrations exhibiting adverse effects, and effects range-median
(ER-M), corresponding to the 50th percentile of concentrations.

Sediment contamination detected near the Transicoil site was compared to
available guidance levels for inorganics in sediment.  The maximum
concentration detected was below the ER-L for all compounds except lead, where
all but one sample exceeded the ER-L concentration of 35 mg/kg.  The highest
concentration measured was 53.6 mg/kg, at location SD-1 in the spring southeast
of the Transicoil site.  No clear areal pattern to lead levels in sediment was
evident.  There is no clear path for surface water drainage from the site to the area
with the highest lead levels.  The background sample concentration measured
41.1 mg/kg.  Lead concentrations are probably within background range.  As
discussed above, lead is not believed to be a site-related contaminant.

d.  Groundwater Contamination

The majority of the contamination on and off the site was detected in
groundwater.  The main groundwater contaminants are TCE, 1,1,1-TCA, 1,1-
DCE, Freon-113, and arsenic.  The highest TCE concentration detected in
groundwater on the site is 380 Ig/L.

The site is on the top of a northeast trending ridge.  Depth to groundwater on the
top of the ridge is approximately 60 feet.  The majority of groundwater and
groundwater contamination is migrating off the site to the north and northwest.
Intermittent streams and ponds that may have a component of groundwater flow
exist approximately 4000 feet northwest of the site.  Some of the groundwater
from the southeast section of the site, which is on the southeast slope of the ridge,
appears to be migrating to the south.  Groundwater-fed springs, wetlands, and
streams occur south of the site.  Many of the springs, wetlands,  and streams occur
even during extended drought conditions, suggesting that they are supplied largely
by groundwater.  Some springs flow from outcropping bedrock.  Results of
sampling indicate that very little groundwater contamination is migrating to the
south and east of the site.  A few residential wells located directly adjacent to the
site have low concentrations of TCE, but TCE has not been detected in any other
residential wells south and east of the site.

No discernible decrease in flow or water level was seen in the springs, wetlands,
and streams south of the site during the aquifer-response testing.  Longer-duration
pumping, such as may be necessary with a hypothetical pump-and-treat
remediation scenario, may affect water levels in these springs, streams, and
wetlands.

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Residential well sampling north and northwest of the site suggests that the
contaminated groundwater has migrated farther north than originally anticipated.
The intermittent streams and ponds located approximately 4000 feet northwest of
the site were originally believed to be beyond the furthest extent of the
groundwater contamination.

These contaminants are not expected to pose a hazad to the environment at the
surface-water locations because concentrations of contaminants detected in the
sampled residential wells generally decline as the distance from the site increases
(which causes concentrations in residential wells sampled nearest the surface-
water bodies to be low); because of the distance from the North Perm Area 12 site
to the surface-water locations; and because the majority of the groundwater
contaminants are volatile.

e. Air Contamination

Air monitoring surveys of the site, conducted during the RI field investigation,
suggest that site-related volatile contaminants do not appear to be migrating by air
in detectable guantities.
VII. DESCRIPTION OF REMEDIAL ALTERNATIVES

A number of remedial action alternatives have been considered which would address
groundwater contamination at the Site and provide alternative residential drinking water
supplies. These alternatives are based on those presented in the Feasibility Study.

A. Groundwater Remedial Alternatives:

1. Alternative GW-1: No Action

Capital Cost: $0
Annual Operation & Maintenance (O&M) Cost: $0
Total Present Worth: $0

The no action alternative is reguired by the National Contingency Plan (NCP) and it serves as a
baseline alternative. All other alternatives are judged against the no action alternative.
Under this alternative, no controls or remedial technologies would be implemented.

2. Alternative GW-2: Groundwater Extraction at Source, Air Stripping or Carbon
Treatment, and Surface Water Discharge

Capital Cost: $378,000
Annual O&M Cost: $29,000
Total Present Worth: $830,000 1

This alternative reguires installing extraction wells on the former Transicoil property.
Extraction wells are the most freguently used method for collecting groundwater. Seven new
extraction wells would be installed. Three existing monitoring wells would also be converted
into extraction wells for a total of 10 wells in the extraction system. The water table is
approximately 65 feet below ground surface (bgs). The majority of fractures in the bedrock are
generally within the upper 100 feet of bedrock. The wells would be installed to a depth of 80

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to 100 feet bgs. Extraction well modeling was conducted as part of the Remedial Investigation
activities and the results were used to determine well locations and pumping rates. The model
indicates that the contaminated groundwater could be pumped at a total flow rate of 35 gallons
per minute (gpm). Figure 6 shows approximate locations of the proposed extraction and monitoring
wells. The exact number, location, and depth of the wells would have to be determined during
the remedial design.
The present worth for all alternatives is calculated using a five percent interest rate
over 30 years. For Alternatives GW-2 through GW-5, costs have been calculated assuming
an average cost for the two treatment options.
The extracted groundwater would be treated using air stripping or carbon adsorption. These
treatment options are considered comparable with respect to cost, implementability, and
effectiveness. This alternative, therefore, does not specify which treatment option would be
selected; selection would be a part of the remedial design effort.

Air Stripping. The air stripping system would use a packed tower or series of baffles and
forced airflow to provide an interface between contaminated groundwater and air. VOCs in the
groundwater are transferred to the air. Vapor-phase carbon would then be used to remove the
VOCs from the of-gas from the air stripping unit.

Carbon Adsorption. Carbon effectively removes chlorinated organic compounds. The
contaminants accumulate on the carbon and eventually, the carbon has to be replaced. When the
carbon is replaced, the spent carbon is regenerated offsite. Regeneration is a process that
incinerates the contaminants off of the carbon to open up the surface of the carbon and allow
the carbon to be reused. The carbon would be regenerated offsite, destroying the adsorbed
contaminants.

The system would discharge the treated water to surface water. The treated water would be
piped to a culvert on Trooper Road, south of the Transicoil property, where the flow eventually
goes to an unnamed tributary of Stony Creek and then to Stony Creek approximately five miles
southeast of the property.

A preliminary evaluation was conducted to determine if a metal precipitation treatment system
would be reguired to prevent fouling of a volatile organic treatment system and to ensure
compliance with any discharge limit for metal constituents. It was concluded that a metal
treatment system would not be reguired. This determination was based on the review of existing
inorganic sampling data for wells on the Transicoil property.

Groundwater contamination beyond the Transicoil property would be managed by relying on
natural attenuation. Many of the impacted properties have low levels of TCE present in their
supply well. The residents' direct use of water is being addressed under the components for
drinking water alternatives. The natural attenuation relies on degradation, volatilization,
adsorption, and dilution which reduce contaminant concentration levels. The concentration
levels would eventually attain their MCLs. Natural attenuation would be monitored by sampling
residential wells on a regular basis to evaluate the extent of and concentrations in the
groundwater plume.

In addition, the alternative includes administrative restrictions and groundwater monitoring.
Administrative restrictions would reguire the regulation of the installation of any new supply
wells in and around the Site to assure that no further exposure to contaminated groundwater
occurs. A deed restriction would also be imposed on the Transicoil property that would prohibit

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the installation and use of supply wells on the property, and the pumping of groundwater under
the property that could adversely affect the containment affects of the extraction system.

Groundwater monitoring would continue at the Site. Several additional monitoring wells would
be installed, as indicated on Figure 6. Monitoring would monitor the extent and concentration
of the groundwater plume, and evaluate the affects of the extraction and treatment system in
removing the existing groundwater contamination. The influent and effluent of the treatment
system would be monitored routinely to ensure the effectiveness of the system and that
groundwater cleanup/treatment levels are being met.

3. Alternative GW-3: Groundwater Extraction at Source, Air Stripping or Carbon
Treatment, and Discharge, Additional Groundwater
Extraction to Reduce Contaminant Migration

Capital Cost: $1,797,000
Annual O&M Cost: $63,000
Total Present Worth: $2,760,000

This alternative adds additional groundwater extraction to Alternative GW-2 to remediate
groundwater that already has migrated off of the Transicoil property and would not be captured
by extraction wells proposed in Alternative GW-2. This alternative acts to reduce the risks
associated with residential wells that are contaminated.

Preliminary groundwater modeling and extraction system configuration indicates that one line of
extraction wells arcing around the Site would be reguired to contain the plume. The wells would
arc around the Site from the West to the North at a distance of approximately 5,000 feet from
the Transicoil property. An estimated 115 wells spaced approximately 75 feet apart would be
installed. Figure 7 shows the approximate location of the line of extraction wells. The wells
would be located downgradient from the Transicoil property and residential wells where TCE
has been detected. The flow rate from each well would be two to three gpm for a total flow rate
of roughly 300 gpm. Recent residential well data indicate the presence of contamination beyond
the modeled capture zone in the Crest Terrace Area. The final well alignment would be selected
using additional hydrogeologic and contaminant level data to ensure the appropriate capture
zone. The total number of wells and extraction flow rate would be comparable to the modeled
values. Alternate well locations could be developed during remedial design that would be able
to produce eguivalent results to the configuration specified.

Due to the positioning of the wells and combining effluent of wells prior to discharge, the
extracted groundwater would not reguire treatment because average concentrations are
anticipated to meet surface water standards. The water would be discharged directly to surface
water. This discharge would be monitored periodically to ensure that all discharge reguirements
are met. The extraction, treatment, and discharge system components on the Transicoil property
would remain the same as Alternative GW-2.

Administrative restrictions would regulate installation of any new supply wells in and around
the Site to assure that no further exposure to contaminated groundwater occurs. A deed
restriction would also be imposed on the Transicoil property that would prohibit the
installation and use of supply wells on the property and the pumping of groundwater under the
property that could adversely affect the containment affects of the extraction system.

Groundwater monitoring would continue at the Site. Several additional monitoring wells would
be installed, as indicated on Figure 6. Monitoring would measure the extent and concentration
of the groundwater plume, and evaluate the affects of the extraction and treatment system in
removing the existing groundwater contamination. The influent and effluent of the system

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would be monitored routinely to ensure the effectiveness of the treatment system and that
cleanup/treatment levels are being met.

4. Alternative GW-4: Groundwater Extraction at Source, Air Stripping or Carbon
Treatment, and Reinjection

Capital Cost: $489,000
Annual O&M Cost: $35,000
Total Present Worth: $1,040,000

This alternative is similar to GW-2, except that the disposal option for the treated groundwater
is reinjection. Ten extraction wells (see GW-2) would discharge water to the air stripping
carbon
treatment system. The effluent would be reinjected downgradient of the extraction wells.
Reinjection would be performed using injection wells, an infiltration bank, or spray irrigation.
Reinjection would be performed at a location that would avoid enhancing contaminant migration
or short-circuiting the extraction system. The injection well locations would be developed
during a pre-remedial design study. As with Alternative 2, groundwater monitoring would be
reguired and natural attenuation would be relied upon to address contamination beyond the
Transicoil property.

5. Alternative GW-5: Groundwater Extraction at Source, Air Stripping or Carbon
Treatment, and Reuse as Water Supply

Capital Cost: $774,000
Annual O&M Cost: $43,000
Total Present Worth: $1,440,000

This alternative is similar to Alternative GW-2, except that the treated water would be reused
as a water supply for the local residents by feeding it into the NPWA supply system. This
alternative would be combined with drinking water Alternative DW-2, connecting residents to the
NPWA supply system.

Ten extraction wells (see Alternative GW-2) would be used to provide extracted water to an air
stripping or carbon adsorption system. The water would be treated to meet all local, county,
state, and federal drinking water guality reguirements. In addition to the filtration and
carbon treatment components of Alternative GW-2, inorganic chemical removal (manganese, iron),
and disinfection have to be included in the system. The treatment system would be housed in a
permanent building. The system also would have fail-safe controls and other emergency
provisions to ensure that untreated water does not enter the NPWA system.

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Groundwater contamination beyond the Transicoil property would be managed by relying on
natural attenuation. Natural attenuation relies on degradation, volatilization, adsorption, and
dilution which reduce contaminant concentration levels.

In addition, the alternative includes administrative restrictions and groundwater monitoring.
Administrative restrictions would regulate installation of any new supply wells in and around
the Site to assure that no further exposure to contaminated groundwater occurs. A deed
restriction would also be imposed on the Transicoil property that would prohibit the
installation and use of supply wells on the property and the pumping of groundwater under the
property that could adversely affect the containment affects of the extraction system.

6. Alternative GW-6: Groundwater Extraction at Source, UV/Oxidation, and
Discharge

Capital Cost: $444,000
Annual O&M Cost: $44,000
Total Present Worth: $1,130,000

This alternative utilizes 10 extraction wells (see Alternative GW-2) to pump contaminated water
on the Transicoil property to the treatment system. The treatment system for this alternative
is chemical oxidation, also known as UV/oxidation. uV/oxidation is a destructive technology
with no air emissions and generates minimal waste requiring offsite disposal.

UV/oxidation uses ultraviolet light in conjunction with standard oxidants such as hydrogen
peroxide and ozone to greatly increase treatment performance over that obtained with either
hydrogen peroxide or ozone alone. A treatability study may have to be performed to optimize
operating conditions for the system.

Groundwater contamination beyond the Transicoil property would be managed by natural
attenuation. Many of the residential wells have low levels of TCE. The residents' direct use
of water is being addressed under the components for drinking water. Natural attenuation relies
on degradation, volatilization, adsorption, and/or dilution which reduce contaminant
concentration levels.

In addition, the alternative includes administrative restrictions and groundwater monitoring.
Administrative restrictions would regulate installation of any new supply wells in and around
the Site to assure that no further exposure to contaminated groundwater occurs. A deed
restrictions would also be imposed on the Transicoil property that would prohibit the
installation and use of supply wells on the property and the pumping of groundwater under the
property that could adversely affect the containment affects of the extraction system.

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7. Alternative GW-7: Groundwater Extraction at Source, Metal-Enhanced Abiotic
Degradation, and Discharge

Capital Cost: $1,380,000
Annual O&M Cost: $51,000
Total Present Worth: $2,160,000
This alternative utilizes 10 extraction wells (see Alternative GW-2) to pump contaminated water
on the Transicoil property to the treatment system. The treatment system for this alternative
is metal-enhanced abiotic degradation. Metal-enhanced abiotic degradation is an innovative
technology designed to treat halogenated VOCs in water. The technology has been evaluated
under EPA's SITE program.

The process uses a reactive granular iron medium that causes breakdown of VOCs to simple
hydrocarbons (such as methane and ethane) and halogen salts as byproducts. The influent would
reguire filtering to remove suspended solids that may inhibit flow through the medium.

The benefits to the process are the destruction of contaminants, no air emissions, no media
transfer of contaminants, low energy consumption, and low O&M costs. Disadvantages of the
technology are the amount of iron reguired for the reaction, formation of precipitates onto the
iron media, and that full-scale aboveground systems have not yet been implemented (only pilot-
scale systems have been implemented).

Treatability testing of the technology would be performed to measure the degradation rate of the
groundwater contaminants and the rate of precipitates forming on the iron media. The results of
the testing would be incorporated into a remedial design.

The remaining portions of the alternative are consistent with Alternative GW-2. The system
discharge would be piped to a culvert on Trooper Road. The treatment unit would reguire a
building, shed, or other structure for shelter from the weather. Groundwater contamination
beyond the Transicoil property would be managed by relying on natural attenuation. The
residents' direct use of water is being addressed under the components for drinking water. In
addition, the alternative includes administrative restrictions and groundwater monitoring.
Administrative restrictions would regulate installation of any new supply wells in and around
the Site to assure that no further exposure to contaminated groundwater occurs. A deed
restrictions would also be imposed on the Transicoil property that would prohibit the
installation and use of supply wells on the property, and the pumping of groundwater under the
property that could adversely affect the containment affects of the extraction system.

8. Alternative GW-8: Natural Attenuation, Institutional Controls, Groundwater,
Monitoring

Capital Cost: $88,000
Annual O&M Cost: $16,400
Total Present Worth: $350,000

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This alternative would rely only on natural attenuation to decrease contaminant levels; no
active remediation efforts would be employed.  Institutional control actions such as local
ordinances and deed restrictions would be used to prevent access to and use of contaminated
groundwater. Groundwater monitoring would be used to track the migration and attenuation of the
contaminant plume and identify locations where access to groundwater would be limited.

Natural attenuation relies on naturally occurring processes such as dilution, volatilization,
adsorption, and/or biodegradation to reduce contaminant levels.  Dilution, volatilization, and
adsorption occur in some degree at all sites, but typically are not adeguate in themselves in
achieving remedial goals throughout the plume.  Assuming site-specific conditions are
supportive of biodegradation, the biodegradation component, in conjunction with the other
naturally occurring processes, can effectively reduce concentrations.

The biodegradation process for TCE can occur as a result of reductive dehalogenation and
aerobic cometabolism.  Conditions at the Transicoil property are not believed to be supportive
of biodegradation because of the lack of other organic material needed for the microorganisms to
perform the biological degradation. Natural attenuation at the Transicoil property would rely
primarily on less effective processes such as dilution, volatilization, and adsorption.
Long-term monitoring would be reguired in any event to document the progress of the plume.

B.    Alternate Drinking Water Alternatives

1.    Alternative DW-1:   No Action

Capital Cost:             $0
Annual O&M Cost:          $0
Total Present Worth:      $0

Under this alternative no further effort or resources would be expended to provide residents
within the vicinity of the North Penn Area 12 Site with an uncontaminated drinking water
supply.  The existing drinking water sampling program would be discontinued.  The current
program of providing operation and maintenance of the carbon systems currently installed would
be discontinued, and would become the responsibility of the residents.  Current and future
residents would have unlimited access to contaminated drinking water.  Drinking water treatment
and/or connection to an alternative drinking water supply would be at the individual owners'
discretion and expense.  Because contaminated media would be left on Site, a review of Site 6
conditions would be reguired every five years, as specified in the NCP.  Alternative DW-1 serves
as the baseline against which the effectiveness of other alternatives are judged, and is
reguired under the NCP.

2.     Alternative DW-2:   Connect Residents to Public Water Supply

Capital Cost:              $2,340,000
Annual O&M Cost:                   $02
Total Present Worth:       $2,340,000.

Alternative DW-2 involves expanding the existing NPWA public water distribution system and
supplying public water to the homes and businesses that have been affected and potentially may
be affected.  New water mains would be installed in the affected areas, and all residents along
the pipeline route would be offered the option of being connected to the public water system at
no cost.  Existing private wells would be abandoned unless the owner reguests continued use of
the well for non-consumption purposes, and the current program of operating and maintaining
carbon systems already installed would be discontinued.

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Abandonment of existing residential wells would have unknown, although probably minimal,
effects on the hydraulic gradient.  Although such effects cannot be quantified at this time,
they are not anticipated to adversely effect a groundwater remedial alternative.  Services
offered to residents at no charge would include installing the water main, installing a lateral
between the main and the home, installing a water meter, connecting residences to the water
main, installing required plumbing from the water main to the plumbing system of the house, and
abandoning existing private wells.  A public water supplier, such as the NPWA, then would bill
residents for water usage.  Public water connections under this remedy would not be offered to
lots that are not yet developed.

The affected area currently is served by one NPWA 16-inch diameter main on Valley Forge
Road.  NPWA's ownership of this main terminates at the intersection of Valley Forge Road and
Township Line Road.  The Pennsylvania-American Water Company (PAWCO) owns this main
south of Township Line Road.  The expansion of the system would tie into the Valley Forge
Road NPWA main to provide water to areas where sampling and analysis indicates groundwater
contamination have affected or could affect residential drinking water supplies.  Affected and
potentially affected residences along the extension route would be offered the option of being
connected to the public water supply.  At this time public water is expected to be offered to
approximately 120 locations.  This plan could be expanded if updated residential groundwater
sampling data indicates that the site-related groundwater contamination has migrated beyond its
current extent.

The design of the public water supply extension and the construction could be performed directly
by the NPWA or by outside contractors.  After the system is completed, it is anticipated that it
will be turned over to a public water supplier, such as the NPWA, to operate and maintain.
      2   The water line would be turned over to a private water supplier, such as the NPWA, for
          O&M. Therefore, this alternative will not include an O&M cost.

Figure 8 illustrates the current water supply system and proposed extension.

In addition to providing a connection to the public water supply system, Alternative DW-2 would
require other components to reduce potential use of and exposure to contaminated groundwater.
Institutional controls, such as local ordinances or deed restrictions that regulate the
installation of new wells, would have to be implemented.  A groundwater monitoring program still
would be required to monitor the migration of groundwater contamination and confirm that all
affected and potentially affected residences are provided with clean water.  It is assumed that
the monitoring component would be accomplished as part of the selected groundwater alternative,
and therefore is not included in Alternative DW-2.

3.     Alternative DW-3:   Carbon Adsorption at Residence Wellhead

Capital Cost:                $227,000
Annual O&M Cost:              $62,000
Total Present Worth:       $1,180,000

Alternative DW-3 involves continuing the current residential well monitoring program and
providing carbon treatment systems to residents whose wells are contaminated at or above the
TCE MCL of 5 ppb.  This alternative is currently being performed by the PRPs under the
Response Action Plan dated October 1995.  Residences are categorized into three "Tiers" based
on the results of samples taken from their wells:

Tier I - Residences with TCE concentrations at or above the MCL.  Carbon treatment systems are

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required and have been provided to these residences. Drinking water samples are collected
before, in, and after the carbon systems are installed. A total of 27 carbon systems has been
(or will soon be) installed for Tier I residences. Fourteen systems are maintained by
Schlumberger Limited, Inc. and 13 systems are maintained by Eagle Picher, Inc.

Tier II - Residences with TCE concentrations below the Analytical Detection Limit. Drinking
water samples are collected and analyzed annually. These home wells have been sampled and
TCE was not detected. Approximately 100 residences are currently sampled under the Tier II
sampling program. If TCE is detected in the future, their classification would be changed to
either Tier I or Tier III.

Tier III - Residences with TCE concentrations above the analytical detection limit and below the
MCL. Drinking water samples are collected and analyzed semi-annually. If TCE is found to be
at or above the MCL, carbon systems are offered to the residences. Approximately 30 residences
are currently sampled under the Tier III sampling program.

The carbon systems consist of two vessels (primary and secondary) containing activated carbon,
which are connected in series, onto which VOCs adsorbed. The current systems are anticipated
to last three years before requiring replacement depending the level of water use and the
concentration of the contaminants.

This alternative includes continuation of the existing Tier I and Tier II sampling and analysis
programs. The need for carbon systems and associated sampling and analysis would be reduced
over time as contaminant levels decrease due to natural attenuation and implementation of the
groundwater remedial alternative.

VIII. SUMMARY OF COMPARATIVE ANALYSIS OF ALTERNATIVES

Each of the remedial alternatives summarized in this plan has been evaluated with respect to the
nine (9) evaluation criteria set forth in the NCP, 40 C.F.R. Section 300.430(e) (9). These nine
criteria can be categorized into three groups: threshold criteria, primary balancing criteria,
and modifying criteria. A description of the evaluation criteria is presented below:

Threshold Criteria:

1. Overall Protection of Human Health and the Environment addresses whether a remedy
provides adequate protection and describes how risks are eliminated, reduced, or
controlled.

2. Compliance with Applicable or Relevant and Appropriate Requirements (ARARs)
addresses whether a remedy will meet all of the applicable, or relevant and appropriate
requirements of federal, State, and local environmental statutes and regulations.

Primary Balancing Criteria:

3. Long-term Effectiveness refers to the ability of a remedy to maintain reliable
protection of human health and the environment over time once cleanup goals are
achieved.

4. Reduction of Toxicity, Mobility, or Volume through Treatment addresses the degree to
which alternatives employ recycling or treatment that reduces toxicity, mobility, or
volume of contaminants.

5. Short-term Effectiveness addresses the period of time needed to achieve protection and

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any adverse impacts on human health and environment that may be posed during the
construction and implementation period until cleanup goals are achieved.

6. Implementability addresses the technical and administrative feasibility of a remedy,
including the availability of materials and services needed to implement a particular
option.

7. Cost includes estimated capital, operation and maintenance costs, and present worth.

Modifying Criteria:

8. State Acceptance indicates whether, based on its review of backup documents and the
Proposed Plan, the State concurs with, opposes, or has no comment on the preferred
alternative.

9. Community Acceptance will be assessed in the Record of Decision following a review of
public comments received on the Proposed Plan and supporting documents included in
the Administrative Record.

1. Protection of Human Health and Environment

The primary reguirement of CERCLA is that the selected remedial action be protective of human
health and environment. A remedy is protective if it eliminates, reduces or controls current
and potential risks posed through each exposure/pathway to acceptable levels through treatment,
engineering controls, or institutional controls.

Groundwater Remedial Alternatives: Alternative GW-1 (No Action) protects neither human
health nor the environment. Human cancer risk and HI will not be reduced from the current
levels of 2.7 x 10 -4 (cancer) and 8.6 (HI), both of which exceed levels suggested by regulatory
guidance. Contaminant levels will exceed MCLs indefinitely over an increasing area as the
contaminant plume migrates away from the site. Because this alternative does not meet this
threshold criteria, it will not be considered further in this analysis.

Alternative GW-8 (Natural Attenuation and Groundwater Monitoring) would protect human
health primarily through institutional controls that limit access to contaminated groundwater.
Assuming that the institutional controls are implemented effectively, cancer and toxic risk
would be 1.0 x 10 -4 (cancer) and 0.4 (HI), both of which are within the acceptable range.
Natural attenuation would result in long-term reductions in contaminant concentrations.
However, the area and concentrations of offsite contamination may increase due to the continuing
migration of highly contaminated groundwater away from the site. The environment may not be
protected, because contamination would be allowed to continue to migrate away from the former
Transicoil property and additional areas could be affected by the contamination. Effects of
contaminant migration to surface waters would likely be minimal, due to the volatilization of
VOCs from the surface water to ambient air. Remedial technologies would not be used to reduce
contaminant concentrations.

Alternatives GW-2, GW-4, GW-5, GW-6, and GW-7 that propose using a pump and treat system
to contain and remediate contamination while relying on institutional controls and natural
attenuation to address contamination beyond the property, protect human health and provide
limited protection of the environment. All of these alternatives eventually would achieve MCLs
in groundwater beneath the Transicoil property and prevent further migration of contaminant
levels above MCLs beyond the property boundaries. Carcinogenic and non carcinogenic risks
would be 1.0x10 -4 (cancer) and 0.4 (HI), both of which are within the acceptable range.
Contaminant levels beyond the Transicoil property will be reduce through dilution and

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adsorption, but may remain above MCLs for a period of time due to the lack of an active offsite
remediation component. However, a groundwater travel time analysis conducted by EPA
indicates that the implementation of extraction wells on the Transicoil property could reduce
the time required to achieve cleanup goals beyond the property boundary locations by 15 percent
to 37 percent when compared to Alternatives GW-1 and GW-8. It should be noted that the actual
time reduction that would be achieved has not been quantified. The environment beyond the
Transicoil property boundaries, therefore, would be monitored to determine the actual future
effectiveness of the onsite pumping. Effects of contaminant migration to surface waters would
likely be minimal, due to the volatilization of VOCs from the surface water to ambient air.
Institutional controls would be used to prevent access to contaminated groundwater during the
remedial action. Alternative GW-4, however, may be somewhat less protective because the
capture zone for the extraction wells would be reduce if the reinjection area is located
downgradient of the extraction wells. This could result in the system being less effective in
preventing contaminants in groundwater beneath the Transicoil property from migrating offisite
unless it can be accomplished without adversely affecting the pumping influence of the
extraction system. However, this option provides a benefit by allowing the water table to be
replenished by replacing the extracted contaminated water with clean treated water.

Alternative GW-3 provides the maximum level of protection to human health and the
environment. The extraction component beyond the Transicoil property would remediate
contamination that already has migrated away from the property. Groundwater beneath the
Transicoil property and beyond the property would be remediated to MCLs under this
alternative. Cancer and toxic risk levels would be reduced to acceptable levels, 1.0 x 10 -4
(cancer) and 0.4 (HI) respectively, in a shorter period of time when compared to the
alternatives that provide only pumping on the Transicoil property.

Drinking Water Remedial Alternatives: Alternative DW-1 (No Action) does not protect human
health. Human carcinogenic and non-carcinogenic risks will not be reduced from the current
levels of 2.71 x 10 -4 (cancer) and 8.6 (HI), both of which exceed levels suggested by
regulatory guidance. Because this alternative does not meet this threshold criteria, it will
not be considered further in this analysis.

Alternative DW-2 (Connection to Public Water Supply) provides maximum protection of human
health, because it effectively eliminates human exposure to contaminated drinking water.
Alternative DW-3 (Carbon Treatment at Residence Wellheads) provides acceptable protection of
human health. Carcinogenic and non-carcinogenic risks associated with drinking water which
contains contamination below MCLs would be 1.0x10 -4 (cancer) and 0.4 (HI), both of which are
within the acceptable range. However, there still would be some risk of exposure at higher
levels due to analytical or treatment system error.

2. Compliance with ARARs

Section 121(d) of CERCLA requires that remedial actions at CERCLA sites at least attain legally
applicable or relevant and appropriate Federal and State standards, requirements, criteria and
limitations which are collectively referred to as "ARARs", unless such ARARs are waived under
CERCLA Section 121(d)(4). Applicable requirements are those substantive environmental
requirements, criteria, or limitations promulgated under Federal or State laws that specifically
address hazardous substances found at the site, the remedial action to be implemented at the
site, the location of the site, or other circumstances present at the Site.

Relevant and appropriate requirements are those substantive environmental protection
requirements, criteria, or limitations promulgated under Federal or State law which, while not
applicable to the hazardous materials found at the site, the remedial action itself, the site
location or other circumstances at the site, nevertheless address problems or situations

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sufficiently similar to those encountered at the site that their use is well suited to the site.
ARARs may relate to the substances addressed by the remedial action (chemical-specific), to the
location of the site (location specific), or the manner in which the remedial action is
implemented (action-specific).

In addition to applicable or relevant and appropriate requirements, the lead agencies may, as
appropriate, identify other advisories, criteria, or guidance to be considered for a particular
release. The "to be considered" ("TBC") category consists of advisories, criteria, or guidance
that were developed by EPA, other federal agencies or states that may be useful in developing
CERCLA remedies. A detailed listing of ARARs for the Selected Remedy is in Section X.B. of
this Record of Decision.

Groundwater Remedial Alternatives: Except for ARARs setting forth MCLs, all alternative
remedies would complied with all identified ARARs. The concentrations of VOCs currently in
the ground water exceed MCLs as specified in the Safe Drinking Water Act. Alternative GW-8
may not be able to achieve compliance with the ARAR requirements within an acceptable period
of time. If GW-8 is eventually able to achieve MCLs, it would take considerable longer period
of time than the other alternatives would be able to achieve ARARs. It is anticipated that all
pump and treat alternatives, GW-2, GW-3, GW-4, GW-5, GW-6, and GW-7, will be able to
achieve ARARs requirements. GW-4 would be the alternative that would achieve the ARAR
requirements in the most expeditious time period.

Drinking Water Remedial Alternatives: Both Alternatives DW-2 and DW-3 are anticipated to
be able to be implemented in a manner which comply with all ARARs by adhering to established
practices and standards. Alternative DW-2 can more readily achieve safe drinking water
standards because the water supply will be permanent. Alternative DW-3 will have to rely on
monitoring and proper maintenance to ensure that safe drinking water standards are met.

3. Long Term Effectiveness and Permanence

The alternatives will achieve long-term effectiveness and permanence in varying degrees, as
discussed below long-term effectiveness is assessed by analyzing two factors: the magnitude of
the residual risk, and the adequacy and reliability of the controls.

a. Magnitude of Residual Risk

Groundwater Remedial Alternatives: All of the alternatives employing pump and treat (GW-2
through GW-7) probably will require long-term implementation to achieve the cleanup
objectives. Alternative GW-8, the natural attenuation alternative, will rely on institutional
controls indefinitely, because contaminant levels would be reduced over a significant longer
period of time. Precise estimates of the time required to achieve the cleanup objectives would
be difficult to derive from the available information. Therefore, for the purposes of
estimating the costs of the remedial alternatives, a period of 30 years has been used.

The residual risk from Alternative GW-8 (Natural Attenuation and Groundwater Monitoring)
is acceptable, but highly dependent upon institutional controls. Alternative GW-8 relies
primarily on institutional controls, such as local ordinances to prevent exposure to
contaminated groundwater. Natural attenuation is not anticipated to significantly reduce
contaminant levels in an acceptable timeframe because conditions on the Transicoil property
are unlikely to support biological degradation of contaminants. Assuming that the institutional
controls are implemented indefinitely, carcinogenic and non-carcinogenic risks of 1.0 x 10 -4
(cancer) and 0.4 (HI) will be achieved, both of which are in the acceptable range.

Alternatives GW-2, GW-4, GW-5, GW-6, and GW-7 (groundwater extraction and treatment

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on the Transicoil property) have acceptable residual risk and are less dependent upon
institutional controls. These alternatives are anticipated to achieve contaminant levels below
MCLs by extracting and treating groundwater and natural attenuation. Carcinogenic and non-
carcinogenic risks of 1.0 x 10 -4 (cancer) and 0.4 (HI) will be achieved after MCLs are
reached, both of which are in the acceptable range. Groundwater travel time analysis indicates
that the implementation of an extraction system on the Transicoil property could reduce the
time reguired to achieve cleanup goals at locations beyond the property boundary by 15
percent to 37 percent. Institutional controls would be used to prevent exposure to
contamination during the remedial action.

GW-3 will use groundwater extraction both on and beyond the Transicoil property to reduce
contaminant levels below MCLs. Carcinogenic and non-carcinogenic risks after MCLs are
achieved would be 1.0 x 10 -4 (cancer) and 0.4 (HI), both of which are in the acceptable range.
Institutional controls still would be used to prevent exposure to contamination during the
remedial action.

Drinking Water Remedial Alternatives: Alternative DW-3 (Carbon Treatment at Residence
Wellhead) will achieve acceptable residual risk. This alternative will achieve carcinogenic and
non-carcinogenic risks of 1.0 x 10 -4 (cancer) and 0.4 (HI), both of which are in the acceptable
range. However, these risk levels are contingent on the carbon vessels being replaced prior to
contaminant breakthrough.

Alternative DW-2 (Connection to Public Water) will have minimal residual risk. This alternative
will effectively eliminate the risk from Site-related contaminants. Residents would be supplied
with treated public water.

b. Adeguacy and Reliability of Controls

Groundwater Remedial Alternatives: Alternative GW-8 (Natural Attenuation and Groundwater
Monitoring) has guestionable adeguacy and reliability. This alternative relies almost
exclusively on institutional controls, such as local ordinances and groundwater monitoring.
There is uncertainty both that all of the potentially affected areas can be addressed by these
controls and that the public will comply with the controls indefinitely. While Alternatives
GW-2 through GW-7 also rely on institutional controls, these alternatives prevent the further
release of contamination beyond the Transicoil property and lower the potential risks if the
institutional controls fail.

Alternative GW-7 (Metal-Enhanced Abiotic Degradation) could be adeguate and reliable, but
technical issues must be addressed. This alternative employs an innovative, unproven
technology that has not been implemented at many sites. The ability of the technology to
adeguately treat all Site contaminants would have to be confirmed through a treatability study.
If adeguate treatability is confirmed, the alternative would be comparable to other treatment
technologies considered (see below). This alternative would rely on the implementation of
institutional controls.

The remaining alternatives (GW-2 through GW-6) are adeguate and reliable because they employ
air stripping, carbon adsorption, or UV/oxidation. These technologies have been employed at
sites with comparable contamination and are anticipated to be able to reduce Site contaminants
to the reguired levels. The technologies are well established and available from a variety of
vendors. These alternatives would also rely on the implementation of institutional controls.

Drinking Water Remedial Alternatives: Alternative DW-3 (Carbon Treatment at Residence
Wellhead) has moderate adeguacy and reliability because it depends on continuing sampling
and analysis to identify when carbon vessels should be changed out. The possibility of

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exposure to contaminant levels above MCLs also exists if analytical error occurs or if
exceedences occur between sampling events.

Alternative DW-2 (Connection to Public Water) has high adeguacy and reliability. This
alternative would effectively eliminate the possibility of exposure to contaminated drinking
water. The supply of public water is highly regulated and there is a high degree of confidence
that a continuing supply of clean water would be supplied.

4. Reduction of Toxicity, Mobility, and Volume

Groundwater Remedial Alternatives: None of the alternatives will be able to collect all
contaminated groundwater because of technology limitations and geologic conditions (fractured
bedrock). The extent to which each alternative is able to reduce contaminant toxicity,
mobility, and volume is as follows.

Alternative GW-8 (Natural Attenuation and Groundwater Monitoring) provides very limited
reductions in toxicity, mobility, and volume. This alternative relies solely on natural
attenuation to reduce contaminant levels. Because conditions at the Transicoil property
probably will not support the biodegradation component of natural attenuation, toxicity
reductions would be achieved through dilution and adsorption over a long time frame. The
mobility of the contaminants would not be reduced and a larger area would be affected. The
volume of contaminated groundwater above the MCL could increase.

The alternatives employing a pump and treat system to address contamination on the Transicoil
property (GW-2, GW-4, GW-5, GW-6, and GW-7) will significantly reduce the toxicity,
mobility, and volume of contamination. Toxicity would eventually be reduced to the
acceptable risks associated with MCLs. The mobility of contamination originating on the
Transicoil property would be hydraulically contained by the extraction system. Reductions in
contamination beyond the Transicoil property would rely on natural attenuation. However,
some additional reduction would be achieved by removing the Transicoil property as a source
of continuing contamination. UV/oxidation and metal-enhanced abiotic degradation would
destroy contaminants onsite. Contaminants collected by carbon eventually would be destroyed
when the carbon is regenerated offsite.

Alternative GW-3 (groundwater extraction on and beyond the Transicoil property) would also
significantly reduce the toxicity, mobility, and volume of contamination. The extraction
system would address all known areas of contamination and reduce contaminant concentrations
both on the former Transicoil property and away from the property to below MCLs.
Contaminants collected on the Transicoil property would be removed and destroyed through
treatment. Contaminants collected beyond the property boundary at lower concentrations
would be transferred to surface waters without treatment at levels that meet surface-water
standards.

Drinking Water Remedial Alternatives: None of the alternatives are intended to provide a
reduction of toxicity, mobility, and volume. The alternatives focus only on providing a supply
of drinking water to residents potentially affected by Site contaminants. Reduction of
toxicity, mobility, and volume is addressed through the groundwater remedial alternatives
discussed above.

5. Short-Term Effectiveness

Short-term effectiveness addresses the period of time needed to achieve protection of human
health and the environment and any adverse impacts that may be posed during the construction
and operation period until performance standards are achieved.

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Groundwater Remedial Alternatives: Alternative GW-8 (Natural Attenuation and Groundwater
Monitoring) will not result in any potential short-term risks to the community and workers with
the exception of readily mitigated risks to workers performing groundwater monitoring.
However, the components of this alternative will have to be performed indefinitely.

Alternatives reguiring pump and treat only on the Transicoil property (Alternatives GW-2, GW-
4, GW-5, GW-6, and GW-7) will result in similar risks to workers and the community. Risks to
the community during construction may arise due to fugitive dust that may be generated during
drilling and construction activities. Monitoring of fugitive dust may be reguired to ensure
that the community is protected. Standard methods to reduce the amount of dust generated can be
implemented easily during drilling. Dust is not anticipated to contain contaminants because
soil contamination has not been observed. Worker exposure during construction and operation of
the treatment systems will be mitigated through the use of engineering controls and personal
protective eguipment. Alternative GW-2 may result in emissions of contaminants to the
atmosphere if an air stripper is used and air pollution control eguipment is not employed,
however, these emissions will be reguired to meet any applicable air emission limitations.
Other treatment technologies will not result in air pollutant emissions.

Alternative GW-3 (groundwater extraction on and beyond the Transicoil property) will have
similar risks to the workers and communities as the other pump and treat alternatives. The
added number of extraction wells to be installed beyond the Transicoil property will present an
additional risk from fugitive dust that may need to be mitigated.

Drinking Water Remedial Alternatives: Alternative DW-3 (Carbon Treatment at Residence
Wellheads) has the least amount of risk to workers, provided that safe work practices are
employed.

Alternative DW-2 (Connection to Public Water Supply) worker risk is associated with
construction activities, rather than exposure to contamination. This alternative will have to
be managed to minimize the environmental impact associated with controlling erosion and reguired
stream crossings. Measures to monitor and control fugitive dust may be reguired as part of
construction activities.

6. Implementability

Implementability refers to the technical and administrative feasibility of a remedy, from design
through construction, operation and maintenance. It also includes coordination of federal,
State, and local governments to clean up the Site. The technical feasibility, administrative
feasibility, and availability of services and material for each alternative are described below.

a. Technical Feasibility

Groundwater Remedial Alternatives: Alternative GW-7 (metal-enhanced abiotic degradation)
employs an Innovative, unproven technology. The ability of this technology to achieve the
cleanup objectives is uncertain. This uncertainty would be reduced through satisfactory
completion of a treatability study.

The pump and treat alternatives (GW-2 through GW-6) employ either very simple technologies
(groundwater monitoring) or technologies that are well-established (extraction wells, air
stripping, carbon adsorption, UV/oxidation). These alternatives are considered to be
technically feasible. However, the component of GW-3 reguiring groundwater extraction beyond
the Transicoil property will be difficult to implement because of the amount of work that would
be reguired. Installation of an extraction system and piping will be difficult in the
residential area. Alternative GW-8 (natural attenuation) would be the easiest alternative to

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implement from a technical perspective.

Drinking Water Remedial Alternatives: Alternative DW-2 (Connection to Public Water Supply)
has the highest technical feasibility because it is an established practice, with minimal
possibility of system failure. Alternative DW-3 (Carbon Treatment at Residence Wellhead) has
high technical feasibility; unlikely system failures could be identified through a monitoring
program and adeguate capacity.

b. Administrative Feasibility

Groundwater Remedial Alternatives: The alternatives are generally similar to each other in
terms of administrative feasibility and are considered to be feasible. All pump and treat
alternatives will reguire compliance with eguivalent reinjection permit reguirements and/or
compliance eguivalent NPDES permit limitations for discharging either treated or untreated
groundwater. Five-year Site reviews are reguired for each alternative because contaminated
groundwater exceeding MCLs will remain on the Site during the remedial action. The
alternatives with specific administrative feasibility issues that may make implementation
difficult are discussed below.

Implementation of Alternative GW-8 (Natural Attenuation and Groundwater Monitoring) may be
hampered by possible public perception that it is not protective enough because no active
remediation efforts would be implemented. The long-term reliance on institutional controls to
prevent exposure to contaminated groundwater over a large area may also be difficult,
particularly if previously unaffected areas lose the use of existing water supplies.

Alternative GW-3 (groundwater extraction on and beyond the Transicoil property) will be
difficult to implement because of the need to obtain access or easements from approximately 20
or more private landowners for installation of extraction wells.

Drinking Water Remedial Alternatives: Alternative DW-3 has high administrative feasibility;
permits and interaction with other agencies are not reguired. Alternative DW-2 has moderate
administrative feasibility; construction activities will reguire a significant amount of
approvals from and interactions with local authorities and the NPWA.

c. Availability of Services and Materials

Groundwater Remedial Alternatives: With the exception of Alternative GW-7 (metal-enhanced
abiotic degradation), all alternatives use technologies and eguipment that are readily available
from a number of vendors. Alternative GW-7 will reguire a treatability test to confirm that the
relatively unproven technology of metal-enhanced abiotic degradation can treat Site
contaminants effectively. Although a treatability test also will be reguired for UV/oxidation
to determine the appropfiate size and power of the treatment unit, there is considerably less
uncertainty associated with the ability of UV/oxidation to treat Site contaminants.

Drinking Water Remedial Alternatives: Services and materials are readily available for both
Alternatives DW-2 and DW-3.

7. Cost

This criterion examines the estimated costs for each remedial alternative evaluated in the
Feasibility Study Report. A summary comparison of capital, O&M, and Present Worth costs
for each alternative are presented in Tables 3 and 4, below. Detailed alternative cost
estimates can be found in Appendix C of the Feasibility Study.

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Groundwater Remedial Alternatives:  Alternative GW-8 is obviously the least expensive
option, however, no active treatment of the existing groundwater contamination will be
provided.  Alternatives GW-2, GW-4, and GW-6 are the least expensive options that provide
treatment and removal of the existing groundwater contamination.  Alternative GW-6 is mid-
range treatment option that has a higher capital cost than GW-2, GW-4, and GW-6.
Alternative GW-7 is the most expensive option than only provides for pumping of the
Transicoil property groundwater because of significantly higher capital cost.

The most expensive option is alternative GW-3, however, this option provides additional
pumping of the contaminated groundwater beyond the Transicoil property.

Table 3 below presents a comparative cost summary of the groundwater alternatives.

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                                                Table 3
                                    Groundwater Remedial Alternatives
                                             Cost Summary
   Alternative

      GW-2
      GW-3
      GW-4
      GW-5
      GW-6
      GW-7
      GW-8
Capital Cost

    $378,000
  $1,797,000
    $489,000
    $774,000
    $444,000
  $1,380,000
     $88,000
 Annual
O&M Cost

   $29,204
   $62,620
   $35,000
   $43,000
   $44,364
   $50,664
   $16,416
Total O&M
   Cost

  $448,937
  $962,623
  $551,000
  $666,000
  $681,983
  $778,830
  $252,354
                                                                        Present Worth
  $830,000
$2,760,000
$1,040,000
$1,440,000
$1,130,000
$2,160,000
  $350,000
Note:  Total O&M Cost is based on a five percent discount rate over 30 years.
       worth is capital cost plus total O&M costs.
                                                            Present
Drinking Water Remedial Alternatives:  DW-2 is significantly more expensive than DW-3 due
primarily to the capital cost.   However,  there is no annual O&M cost projected for DW-2
because it is assumed that the local water authority will accept the responsibility for
ownership and all future O&M cost for this remedial alternative.
                                            Table 4
                        Drinking Water Remedial Alternatives - Cost Summary
    Alternative
                        Capital Cost
                           Annual
                          O&M Cost
                      Total O&M
                         Cost       Present Worth
       DW-2
       DW-3
      $2,340,000
        $227,000
          $0
       $62,000
       $0
    $950,000
 $2,340,000
 $1,180,000
Note:  Total O&M Cost is based on 5 percent discount rate over 30 years.   Present worth is
capital cost plus total O&M cost.

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8 .   State Acceptance

The Commonwealth of Pennsylvania Department of Environmental Protection (PADEP)  has
assisted EPA in the review of reports and site evaluations. The PADEP agrees with the
approach of EPA's selected Remedy as described in the Declaration above.

9.   Community Acceptance

A public meeting on the Proposed Plan was held on August 6, 1997 at the Fairview Village
Assembly Hall in Worcester Township, Montgomery County,  Pennsylvania.  Comments
received orally at the public meeting and in writing during the comment period are referenced
and addressed in the attached Responsiveness Summary.

Most of the comments received during the public meeting focused on three issues.  One of the
issues involved EPA' s proposal to discharge treated water to a surface water discharge near
the site as described in alternative GW-2.   Several people expressed concerns about the
pumping system affecting the water capacity of private wells near the site that will still
remain in use after public water is provided.  EPA has addressed that comment in this Record of
Decision by allowing the possibility of reinjection of the treated water as described in
alternative GW-4 if it can be shown that such reinjection will not adversely affect the
containment effects of the pumping system.   The reason that EPA did not consider reinjection
initially was because that some preliminary modeling completed during the RI/FS indicated
that reinjection at some specific locations could adversely impact the containment capability of
the pumping system.  This issue will be further studied during a pre-design study to determine
if the reinjection system could be located appropriately not to adversely impact the
containment capability of the pumping system.  If this determination can be substantiated, then
alternative GW-4 will be implemented.  If this determination cannot be made, then alternative
GW-2 will be implemented.

A number of people were concerned that EPA had determined their home wells were not
potentially affected by the Site and were,  therefore, not going to be offered a no-cost
connection to the proposed public water supply extension.  They expressed concern about the
potential effects that plans to deepen a nearby guarry might have on their water supply both
from a contamination and water capacity standpoint.  It was explained that the EPA Superfund
could not address, under CERCLA authorities, affects that the guarry might have on the water
capacity.  However, it was explained that if operations at the guarry were found to adversely
affect contamination migration from the North Penn Area 12 Superfund Site, then EPA could
identify the guarry's owner/operator as a potential responsible party.  If EPA further
determines that their wells could be potentially affected by Site contamination, EPA could
specify that the public water system be further extended.

Several people also guestioned whether or not they would be able to maintain their well for
non-consumption purposes after their homes are connected to the supply system.  EPA
informed them that there are no regulations or local reguirements that would prevent them
from maintaining their wells for such use.   However, each well would have to be disconnected
from the home distribution system to prevent any possibility of cross-contamination of the
public supply system.  EPA will also continue to specify the abandonment of the wells as part
of the remedial action.  Individual home owners could reguest that their wells be left opened at
the time they are contacted regarding being connected to the public supply system.

In summary, the Selected Remedy is believed to provide the best balance of trade-offs among the
alternatives evaluated with respect to the nine criteria.  Based on the information available at
this time, EPA believes the Selected Remedy will protect human health and the environment, will
comply with ARARs and be cost-effective.  In addition, permanent treatment options would be

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utilized to the maximum extent practicable.

IX. THE SELECTED REMEDY; DESCRIPTION, PERFORMANCE STANDARDS AND
COSTS FOR EACH COMPONENT OF THE REMEDY

A. General Description of the Selected Remedy

EPA has carefully considered State and community acceptance of the remedy prior to reaching
the final decision regarding the remedy. The Agency's preferred remedy is set forth below.
Based on current information, this alternative provides the best balance among the alternatives
with respect to the nine criteria that EPA uses to evaluate each alternative. The selected
remedy consists of the following components:

1. A groundwater extraction and treatment system utilizing either an air stripper with
vapor phase carbon or a liguid phase carbon adsorption unit. The treated groundwater
will be reinjected into the ground by injection wells, an infiltration bank, or spray
irrigation, as specified in alternative GW-4, if it can be demonstrated that such
reinjection can be accomplished without adversely impacting the ability of the pumping
system to contain the existing contamination from migrating from the former Transicoil
property portion of the Site. A pre-design study will be completed to provide this
demonstration. If the study shows that reinjection is not feasible, then the treated
water will be discharged to a tributary to Stoney Creek as specified in alternative
GW-2.

2. Based on several comments by one responsible party and a review of recently developed
draft EPA guidance regarding natural attenuation, EPA has not selected natural
attenuation as the preferred remedy for contaminated groundwater which lies beyond the
influence of the selected pump and treat extraction system. The PRP comments noted,
that not enough technical information may be available to adeguately evaluate natural
attenuation at this site, while the EPA guidance re-emphasizes the need for adeguate
natural attenuation data to be available to determine that a cleanup goal can be
achieved within a reasonable time frame before selection of natural attenuation as a
remedy. Since there is some indication, however, that natural attenuation may be a
viable remedy for the extended plume, EPA is reguiring a study be conducted during the
pre-design, design, or implementation of the extraction system to determine what, if
any, remedial measure(s)(including natural attenuation or modification of the
extraction system) may be needed or is technically practicable to reduce site related
contaminants to MCL concentrations within a reasonable time frame. Implementation of
any selected measure(s) may reguire an Explanation of Significant Differences
determination or an Amendment to this Record of Decision.

3. An alternative water supply as specified in alternative DW-2. The public water supply
will be extended to provide public water to residents whose wells have been adversely
affected or could potentially be adversely affected by groundwater contamination from
the Site.

4. Long term groundwater monitoring to evaluate the performance of the groundwater
extraction and treatment system and to ensure that all affected and potentially
affected residents are provided public water.

5. Institutional controls that will prohibit the use of groundwater on the former
Transicoil property, and restrict the use of Site-related contaminated groundwater as a
drinking water supply source.

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Each component of the selected remedy, its performance standards, and costs are listed below.

B. Description, Performance Standards, and Cost of each Component of the Selected
Remedy

1. Groundwater Remediation - An extraction and treatment system utilizing either an air
stripper with vapor phase carbon or a liquid phase carbon adsorption unit will be
implemented. The treated groundwater will be reinjected into the ground by injection
wells, an infiltration bank, or spray irrigation, if such reinjection it can be
accomplished without adversely impacting the ability of the pumping system to contain
the existing contamination from migrating from the former Transicoil property. A
pre-design study will be completed to demonstrate the feasibility of a reinjection
system. If the study shows that reinjection is not feasible, then the treated water
will be discharged to a tributary to Stoney Creek.

l.a. Description

The contaminated groundwater beneath the former Transicoil property shall be remedied through
extraction and treatment utilizing either an air stripper with vapor phase carbon adsorption or
a liquid phase carbon adsorption unit. A pre-design study will be conducted to determine
whether it would be feasible to reinject the treated groundwater by injection wells, an
infiltration bank, or spray irrigation and not adversely affect the ability of the pumping
system to contain the contaminated groundwater from leaving the Transicoil property. If
reinjection is found not to be feasible, then the treated water will be discharged to a nearby
tributary to Stoney Creek. Spent carbon will be periodically shipped to an appropriate off-site
facility to be regenerated. Groundwater beyond the Former Transicoil property will be evaluate
during a study conducted during pre-design, design, construction, or the implementation of the
extraction system to determine if any other remedial measure (i.e. natural attenuation) is
required and/or technically practicable to reduce site-related contaminants to MCL
concentrations within a reasonable timeframe in areas outside the pumping influence of the
selected extraction system.

l.b. Performance Standards

l.b.l. Extraction wells shall create a groundwater capture zone that hydraulically contains
the most contaminated groundwater that lies beneath the former Transicoil property from
migrating beyond the property. The scheme, location, and pumping rates described in Section
VII. A. 2 and illustrated in Figure 6 must be used as the pumping system. Other schemes that are
able to provide equivalent performance to the designated pumping system could be identified
during the remedial design stage with the actual number of wells and location of extraction
wells determined at that time. Any proposed equivalent pumping system will be subject to
approval by EPA, after consultation with the Commonwealth of Pennsylvania.

l.b.2. During the pre-design phase, at least one round of samples shall be collected and
analyzed for volatile organic compounds, from existing monitoring wells and the additional site
monitoring wells, in order to determine the extent of the groundwater contaminant plume at that
time. Pre-design activities shall also be conducted to determine the feasibility of reinjecting
the treated groundwater.

l.b.3. Groundwater shall be treated using an either an air stripping treatment system with a
vapor phase carbon adsorption, or a liquid phase carbon adsorption system. The treatment
system shall be capable of removing the site-related contaminants from the extracted
groundwater, unattended, on a continuous, 24-hour-per-day performance basis.

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l.b.4. A Performance Monitoring Plan shall be developed. This plan shall be developed to
evaluate the performance of the extraction and treatment system and shall require that the
system be fully monitored. Several additional monitoring wells will be installed as specified
in Section VII. A. 2 and Figure 6 of this ROD, and the need to install any additional monitoring
wells to adequately determine the extent of contamination or to adequately evaluate the
performance of the groundwater remediation system will be determined or approved by EPA, in
consultation with the Commonwealth of Pennsylvania. If new public or private supply wells are
placed into service in the vicinity of the Site, then consideration shall be given to include
these wells in the monitoring program. This would monitor any potential change in contaminant
migration that could occur due to pumping influences of these new supply wells.

l.b.5. An Operation and Maintenance Plan shall be developed for the groundwater extraction
system during the remedial design phase. The operation and maintenance plan must specify
system operation procedures and maintenance requirements to ensure that system performs
within design criteria and the requirements of the performance standards. At a minimum, the
influent and effluent from the treatment facility shall be sampled twice per month for volatile
organic compounds (VOCs). Operation and maintenance of the groundwater extraction system
shall continue for an estimated 30 years or such other time period as EPA, in consultation with
the Commonwealth of Pennsylvania, determines to be necessary, based on the statutory reviews
of the remedial action which shall be conducted no less often than every five years from the
initiation of the remedial action in accordance with the EPA guidance document, Structure and
Components of Five-Year Reviews (OSWER Directive 9355.7-02, May 23, 1991). 5-year
statutory reviews under Section 121 of CERCLA will be required, as long as hazardous
substances remain onsite and prevent unlimited use and unrestricted access to the Site. The
performance of the groundwater extraction and treatment system shall be carefully monitored on
a regular basis, as described in the long-term ground water monitoring component of this
Selected Remedy. The system may be modified, as warranted by the performance data collected
during operation to achieve performance standards. These modifications may include, for
example, alternate pumping of the extraction wells and the addition or elimination of certain
extraction wells.

l.b.6. The Operation and Maintenance Plan shall be revised after construction of the extraction
and treatment system has been completed if it is determined to be necessary by EPA, in
consultation with PADEP.

l.b.7. Existing pumping and monitoring wells which serve no useful purpose shall be properly
abandoned in accordance with PADEP's Public Water Supply Manual, Part II, Section 3.3.5.11
and Montgomery County Health Department Rules and Regulations Section XVII, in order to
eliminate the possibility of these wells acting as a conduit for future groundwater
contamination. Wells which EPA determines are necessary for use during the long term groundwater
monitoring program will be properly maintained.

l.b.8. The ground water plume shall be pumped and treated until the MCL or the non-zero
MCLG [40 C.F.R. °° 141.12, 141.50, and 141.60] for the contaminants of concern, whichever is
more stringent, as listed below, is achieved.

The performance standard for major contaminants of concern in the groundwater are listed
below:
Contaminant
MCL(ug/l) MCLG (ug/1)
Trichloroethene
1,1-Dichloroethene
cis-1,2-Dichloroethene
5
7
70
0
7
70

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1,2-Dichloroethene (total) 0 70
Tetrachloroethene 5 100
Chloroform (as trichloromethanes) 100 0

l.b.9 If reinjection is demonstrated to be the appropriate method to dispose of the treated
groundwater, then the requirements of an equivalent Water Quality Management Part 2 permit,
25 PA Code Section 91, must be met.

l.b.10. If the option to discharge the treated groundwater to the tributary of Stoney Creek is
implemented, such discharge shall comply with the appropriate substantive requirements of the
NPDES discharge regulations set forth in the Pennsylvania NPDES Regulations 25 Pa. Code
°92.31, and the Pennsylvania Water Quality Standards (25 Pa. Code °°93.1-93.9). Pursuant to
the PADEP's determination monitoring for all the other contaminants of concern shall be
conducted.

l.b.ll. Air emissions from the air stripping unit, if it is utilized as the groundwater
treatment technology, shall meet the requirements of the Resource, Conservation & Recovery Act
("RCRA") regulations set forth at 40 C.F.R. Part 264, Subpart AA - (Air Emission Standards for
Process Vents). 40 C.F.R. °264.1032 (a) requires total organic emissions from all affected
process vents at the Site to be below 1.4 kg/hr and 2800 kg/yr (3.1 tons/year) under this
regulation or reduce, by use of a control device, total organic emissions by 95% by weight. The
air emissions may also be required to comply with the Commonwealth of Pennsylvania
regulations set forth at 25 Pa. Code, Chapter 127, Subchapter A. Those regulations require that
emissions be reduced to the minimum obtainable levels through the use of Best Available
Technology ("BAT"), as defined in 25 Pa. Code °121.1. Specific BAT requirements will be
determined during the design phase of the remedy. At that time, it will be further determined
which of the two regulations mentioned above will place the more stringent requirements on the
remedy and that requirement will have to be complied with. It is anticipated that the
installation of a vapor phase carbon adsorption system would satisfy the requirements of this
performance standard.

l.b.12. Any off-site shipment of spent carbon shall comply with all applicable federal, State,
and local laws, regulations, and requirements. With respect to the operations at the Site
generally, with the substantive requirements of 25 Pa. Code °264.18 (location requirements for
hazardous waste treatment facilities), °°264.170 - 178 (in the event that hazardous waste
generated as part of the remedy is managed in containers), °°264.191 - 197 (in the event that
hazardous waste generated as part of the remedy is managed in tanks), and 25 Pa. Code Chapter
264, Subpart J (in the event that hazardous waste is managed, treated or stored in tanks).

l.b.13. Monitoring of the existing wetland areas shall be conducted during the implementatory
of the remedial action to determine if any dewatering effects are occurring. Figure 3-8 of the
Remedial Investigation Report shows the location of the wetlands areas near the Site that have
been identified. If dewatering is found to occur and it is found to adversely affect any
endangered species or their habitat, a consultation will be made with the Commonwealth of
Pennsylvania and the U.S. Fish & Wildlife Service to determine what mitigation activities may
need to be implemented.

l.b.14. The extraction and treatment system shall avoid, minimize or mitigate impacts on
floodplains and wetlands. The operation of the extraction and treatment system shall comply
with the requirements of Executive Order No. 11988 and 40 CFR Part 6, Appendix A (regarding
avoidance, minimization and mitigation of impacts on floodplains), and Executive Order No.
11990 and 40 CFR Part 6, Appendix A (regarding avoidance, minimization and mitigation of
impacts on wetlands).

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l.b.15  A study shall be conducted during the pre-design, design, or implementation of the
extraction system to determine what, if any, remedial measure(s)  (including natural attenuation
or modification of the extraction system)  may be needed or technically practicable to reduce
site related contaminants to MCL concentrations within a reasonable time frame.  Implementation
of any selected measure(s)  may reguire an Explanation of Significant Differences determination
or an Amendment to this Record of Decision.

  I.e.    Groundwater Remedy Implementation

It may become apparent after completion of the study reguired by the performance standard
specified in paragraph l.b.15, above or during implementation or operation of the ground water
extraction and treatment system, that contaminant levels in the extracted and treated
groundwater ceased to decline and remain constant at levels higher than Performance Standards
over a portion of the contaminant plume.  If EPA, in consultation with the PADEP, determines
that implementation of the selected remedy demonstrates, in corroboration with hydrogeological
and chemical evidence, that it will be technically impracticable to achieve and maintain the
Performance Standards throughout the entire area or any portion of the contaminant plume; EPA,
in consultation with the Commonwealth, may reguire that any or all of the following measures be
taken, for an indefinite period of time, as modification(s) to the existing system:

a) A technical impracticability waiver demonstration for that portion of the plume that it may
be technically impracticable to achieve and maintain the Performance Standards.

b) An alternative performance standard or alternative remedial strategy which can include but be
limited to:

  1)     long-term gradient control provided by low level pumping, as a containment measure;

  2)     institutional controls may be established/maintained to restrict or regulate access to
         those portions of the aguifer where contaminants remain above performance standards;
         and

  3)     remedial technologies for ground water restoration may be reevaluated.

The decision to invoke any or all of these measures may be made during implementation or
operation of the remedy or during the 5-year reviews of the remedial action.  If such a decision
is made, EPA shall amend the ROD or issue an Explanation of Significant Differences.

  l.d.    Estimated Costs

A detailed cost estimate of the groundwater remediation is portion of the Selected Remedy can
be found in Appendix C of the Feasibility Study.  [Cost shown below are cost of the groundwater
remedy if reinjection is found to be appropriate and is implemented; cost shown within
parenthesis ( )  are cost of the remedy if the surface water discharge option is found to be more
appropriate and effective than the reinjection option and is implemented]

                                                               Surface Water
                                                Reinjection    Discharge

Estimated Capital Costs:                          $ 489,000      ($378,000)
Estimated Total O&M Costs:                        $  35,000      ($ 29,000)
Estimated 30 Year Total Present Worth Costs:    $1,040,000      ($830,000)

2.       Extension of Public Water Supply Line to Affected and Potentially Affected Residents

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         and Businesses

2.a.     Description

This component of the remedy will provide a permanent source of potable water to the affected
or potentially affected residents and businesses in the vicinity of the Site by extending the
public water system.  The North Penn Water Authority (NPWA)  currently supplies public
water to residents in Worcester Township and the Pennsylvania-American Water Company
(PAWCO)  supplies public water to residents in E. Norriton Township.  The current public
water supply systems have sufficient capacity to provide public water to the residents along the
specified water line extension route.

2.b.     Performance Standards

2.b.l    The water supply system shall be designed and constructed in compliance with the
reguirements of the NPWA and/or the PAWCO, and local and State reguirements, as 4
appropriate and authorized under CERCLA.

2.b.2.   Connections shall be offered and provided to all the residences and businesses along
the water extension route as designated in Figure 8 or as determined by EPA, in consultation
with PADEP, during the remedial design to be affected or potentially affected by contamination
from the Site.  Potentially affected wells include those that are within or near the boundaries
of the contaminated groundwater plume and those that are hydraulically impacted by the remedial
action.

2.b.3.   The water line will be installed in a trench below the freeze line along the route
indicated in the Figure 8 so that all businesses and residents that EPA determines are affected
and potentially affected by the ground water contaminant plume can be provided hook-ups.

2.b.4.   Independent connections will then be brought from the main into each of the businesses
and residences affected or potentially affected by the contaminated groundwater plume from
the Site.

2.b.5.   Following hook-up,  costs of public water usage shall be the responsibility of the
appropriate residence or business.

2.b.6.   Fire hydrants will be installed along the water line route in accordance with local
reguirements.

2.b.7.   All areas impacted by the construction activities during remedy implementation shall be
graded,  restored and revegetated, to their original condition to the extent feasible.

2.b.8.   The existing residential wells shall be abandoned unless selected by EPA for long term
monitoring or reguested to be used for non-consumption purposes by the resident.  Well
abandonment shall be completed in accordance with the reguirements of the Pennsylvania Safe
Drinking Water Act 25 PA Code 109.602 and consistent with PADEP's Public Water Supply
Manual,  Part 11, Section 3.3.5.11.  and Montgomery County Health Department Regulations,
Chapter XVII Any former private supply well not abandoned and intended for non-
consumption purposes will be completely disconnected from the home distribution system so
that there is no possibility for cross contamination of the public supply system.

2.b.9.  The installation of the water line shall avoid, minimize and mitigate impacts on
floodplains and wetlands (e.g., installation of the municipal water line).  The performance
standard will be compliance with Executive Order No. 11988 and 40 CFR Part 6, Appendix A

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(regarding avoidance, minimization and mitigation of impacts on floodplains), and Executive
Order No. 11990 and 40 CFR Part 6, Appendix A (regarding avoidance, minimization and
mitigation of impacts on wetlands).

2.c. Estimated Costs

Estimated Capital Costs: $ 2,340,000
Estimated Total O&M Costs: $ 0

Estimated 30 Year Total Present Worth Costs: $2,340,000

A detailed cost estimate for Alternative DW-2 - Connection to Public Water Supply can be
found in Appendix C of the Feasibility Study Report. EPA assumes that there will no O&M
cost associated with this portion of the remedy because it is assumed that an established public
water company will assume ownership and all O&M responsibilities after construction is
completed and the system becomes operational.

3. Institutional Controls

3.a. Description

Institutional controls will be implemented to prohibit the use of groundwater on the former
Transicoil property portion of the Site to prevent any adverse impacts on the pump and treat
system as required by the groundwater portion of the remedy specified by this ROD.
Institutional controls will also be implemented to prevent any future exposure to contaminated
groundwater that could result in potential adverse impacts on human health from the
installation and use of new residential wells near the Site.

3.b. Performance Standards

S.b.l. A deed restriction, or other appropriate and equivalent mechanism, shall be
implemented to prohibit the use of groundwater beneath the former Transicoil property to
prevent any adverse impacts on the pumping and treating of contaminated groundwater on the
property as required by this ROD. Such deed restriction shall be appropriately recorded with
the Montgomery County Recorder of Deeds.

3.b.2. The implementation of the existing Montgomery County Health Department Regulations at
Section VII will be implemented and relied upon to limit any future exposure to site related
contaminated groundwater that could result in potential adverse impacts on human health from
the installation and use of new individual supply wells near the Site. This regulation requires
a permit prior to construction and approval prior to use of any new or modified supply well. As
part of the permit procedures, sampling of the well is required. The purpose of the sampling is
verify that water from the well will meet MCLs prior to use. The regulation also provides for
revocation of the permit or approval of the well if a new condition is identified which affects
the quality of the well.

3.c. Estimated Cost

Estimated Capital Cost: $10,000
Estimated Total Cost: $ 0

Estimated 30 Year Present Worth Cost: $10,000

This cost estimate has been included and is broken out of the estimated cost of the groundwater

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remedy presented in Section l.c above and as detailed in Appendix C of the Feasibility Study
Report.

4. Groundwater Monitoring

4.a. Description

This portion of the remedy requires long term monitoring of selected wells to evaluate the
effectiveness of the groundwater remediation system, and to ensure that groundwater
contamination from the Site is not adversely affecting supply wells that are located beyond the
extent of the proposed water line extension.

4.b. Performance Standards

4.b.l. A long term monitoring program will be implemented to evaluate the effectiveness of
the groundwater remediation system, and to ensure that groundwater contamination from the
Site is not adversely affecting supply wells that are located beyond the extent of the proposed
water line extension.

4.b.2. A plan for the ground water monitoring program shall be included in the operation and
maintenance plan for the groundwater pump and treat system. The plan shall include the
sampling of a sufficient number of wells to adequately monitor the effectiveness of the
groundwater remediation system, and to ensure that the groundwater contamination is not
extending to residents who are using private wells and are located beyond the extent of the
proposed water line extension. EPA, in consultation with PADEP, will approve/determine the
number, location and appropriate construction details of the monitoring wells necessary to
satisfy the objective of this performance standard.

4.b.3. The installation of additional monitoring wells may be required. The number, locations
and construction details of these monitoring wells shall be approved/determined by EPA during
the remedial design, in consultation with the PADEP.

4.b.4. The wells shall be sampled quarterly for the first three years. Based on the findings
of the first three years of sampling, the appropriate sampling frequency for subsequent years
will be approved/determined by EPA in consultation with the PADEP.

4.b.5. Sampling activities and operation and maintenance activities shall continue until such
time as EPA, in consultation with the Commonwealth of Pennsylvania, approves/determines
that the performance standard for each contaminant of concern has been achieved throughout
the entire area of ground water contamination or a technical impractibility demonstration has
been approved by EPA in consultation with PADEP.

4.b.6. If EPA and the Commonwealth makes a determination that the performance standard for
each contaminant of concern has been achieved throughout the entire area of ground water
contamination; the wells shall be sampled for twelve consecutive quarters throughout the entire
plume and if contaminants remain at or below the performance standards, the operation of the
extraction system shall be shut down.

4.b.7. Annual monitoring of the groundwater shall continue for five years after the system is
shutdown.

4.b.8. If subsequent to an extraction system shutdown, annual monitoring shows that
groundwater concentrations of any contaminant of concern are above the Performance Standard
set forth in l.b.9. above, the system shall be restarted and continued until the performance

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standards have once more been attained for twelve consecutive quarters. Semi-annual
monitoring shall continue until EPA determines, in consultation with the Commonwealth of
Pennsylvania, that the Performance Standards in l.b.9. for each contaminant of concern has
been achieved on a continuing basis.

4.c. Estimated Costs

The estimated costs for long term ground water monitoring are included in the cost estimate for
the ground water remediation listed in I.e. above.

5. Worker Safety

5.a. All Site remedial work shall be completed in accordance with Occupational Safety and
Health Administration ("OSHA") standards set forth at 29 C.F.R. Parts 1910, 1926 and 1904
governing worker safety during hazardous waste operations.

6. Five-Year Reviews

6.a. Five-year reviews shall be conducted after the remedy is implemented to assure that the
remedy continues to protect human health and the environment. A 5-year Review Work Plan
shall be required and shall be approved by EPA in consultation with the PADER.
X. STATUTORY DETERMINATIONS

EPA's primary responsibility at Superfund sites is to select remedial actions that are
protective of
human health and the environment. Section 121 of CERCLA also requires that the selected
remedial action comply with ARARs, be cost effective, and utilize permanent treatment
technologies to the maximum extent practicable. The following sections discuss how the
selected remedy for the North Penn Area 12 Superfund Site meets these statutory requirements.

A. Protection of Human Health and the Environment

Based on the baseline Human Health Risk Assessment for the Site, measures should be
considered to reduce potential risk from several VOCs in the groundwater. Groundwater and the
several VOC contaminants were selected because potential health hazards for some exposure
scenarios exceeded the EPA target range of 1.0 x 10 -4 (or 1 in 10,000), and 1.0 x 10 -6 (or 1
in 1,000,000) for lifetime cancer risk or a non-cancer Hazard Index of one (1).

The extension of a public water supply component of the selected remedy will provide a
permanent alternative water supply to affected and potentially affected residences and
businesses which will prevent current human exposure to groundwater contaminants., however, it
will not actively reduce the contaminants in the soil or ground water, or prevent migration of
contaminated groundwater. The groundwater pump and treat system will reduce the
contamination in the groundwater.

The selected remedy protects human health and the environment by reducing levels of
contaminants in the groundwater to those levels required by ARARs through extraction and
treatment. The groundwater extraction and treatment system shall reduce the levels of
contaminants of concern in the groundwater to achieve MCLs and/or non-zero MCLG as
required by the Safe Drinking Water Act, 42 U.S.C. °° 300(f) - 300 (j), and 40 C.F.R. °° 141.12,
141.50, and 141.61. Reinjection or Discharge of the treated water through any of the discharge
point options will not adversely affect human health or the environment, provided that all

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Performance Standards and ARARs are met.

Implementation of the selected remedy will not pose any unacceptable short term risks or cross
media impacts to the Site, or the community.

B. Compliance with and Attainment of Applicable or Relevant and Appropriate Requirements
("ARARs")

The selected remedy will comply with all applicable or relevant and appropriate chemical-
specific, location-specific and action-specific ARARs. Those ARARs are:

1. Chemical Specific ARARs

a. MCLs - The selected remedy will be designed to achieve compliance with chemical-specific
ARARs related to groundwater at the site. The MCLs and non-zero MCLG, for the
contaminants of concern from the North Penn Area 12, which are listed under the performance
standards for Groundwater Remediation portion (see section XI.B.l.b.8 above) of the selected
remedy, are applicable for this action. The groundwater extraction and treatment system shall
reduce the levels of contaminants of concern in the groundwater to achieve MCLs as required
by the Safe Drinking Water Act, 42 U.S.C. °° 300 (f) - 300 (j), and 40 C.F.R. °° 141.12, 141.50,
and 141.61. If a non-zero Maximum Contaminant Level Goal ("MCLG") has been established
and is more stringent than the MCL, the MCLG shall be attained.

2. Location Specific ARARs

a. Erosion Control - The Pennsylvania Erosion Control Regulations, 25 PA Code °° 102.4 -
102.5, 102.11 - 102.13, and 102-22 -102.24, regulate erosion and sedimentation control. These
regulation are applicable to the excavation and grading activities associated with the selected
remedy.

b. Wetlands - Under 25 PA, Code ° 269.23, the siting of a hazardous waste treatment unit is
prohibited in a wetland area. The onsite treatment system will have to be located such that it
is not in wetland areas onsite.

c. Groundwater Extraction Within the Delaware River Basin - Delaware River Basin
Commission (DRBC) regulations require DRBC approval of all projects with groundwater
extraction of 10,000 gallons per day (gpd) in a groundwater protected area (GWPA). All of
Montgomery County is designated as a GWPA, DRBC Resolution No. 80-18. The estimated
extraction rate of 35 gallons per minute (gpm) equates to approximately 50,000 gpd. Per
agreement between the DRBC and EPA, a formal permit is not required for EPA-lead projects
and EPA will acknowledge the following requirements as ARARs:

1.) DRBC Groundwater Protected Area Regulations, No. (6),(f); Water Code of the
Basin, Section 2.50.2 - Proposed water withdrawal well(s) shall be equipped with
readily accessible capped port(s) and drop pipe(s) so that water levels may be
measured under all conditions.

2.) DRBC Ground Water Protected Area Regulations, No. 9; Water Code of the
Basin, Section 2.50.2 - Covered Project water withdrawal well(s) and surface
water intakes shall be metered with an automatic continuous recording device that
measures to within five percent of actual flow. [a record of daily withdrawals also
shall be maintained, and monthly totals shall be reported to DRBC].

3.) DRBC Ground Water Protected Area-Regulations. No. 10 - If the construction,

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monitoring, or any other data or information demonstrates that the operation of
the water withdrawal well or surface water intake significantly affects or interferes
with any domestic or other existing wells, an alternative supply of water or other
mitigating measures shall be provided.

4.) DRBC Ground Water Protected Area Regulations. No. 4; Water Code of the
Basin. Section 2.20.4 - The operation of a water withdrawal project shall not
cause long-term progressive lowering of groundwater levels, permanent loss of
storage capacity or substantial impact on low flows of perennial streams.

3. Action Specific ARARs

a. Reinjection of Treated Groundwater - Section 3020 of RCRA specifically addresses
waste injection in the context of CERCLA and RCRA cleanup actions. Section 3020 (a) bans
hazardous waste disposal by underground injection into or above an underground source of
drinking water (within one-guarter mile of the well). However, Section 3020 (b) exempts from
the ban all reinjection of treated contaminated groundwater undertaken as part of a remedial
action conducted under Section 104 or 106 of CERCLA. To gualify for the exemption, the
following three conditions must be met: (1) The injection is a CERCLA response action; (2)
the contaminated groundwater must be treated to substantially reduce hazardous constituents
prior to such injection; and, (3) the response action or corrective action must be sufficient to
protect human health and the environment. If reinjection is demonstrated to be feasible for the
groundwater portion of the selected remedy, then this exemption would apply. All three
conditions are met: (1) the reinjection is part of a CERCLA response action, (2) contaminated
is reguired to be treated to substantially reduce hazardous constituents in accordance with the
performance standard specified in section l.b.9 above, and (3) the response action will protect
human health and the environment as discussed in Sections VILA and X.A above.

b. Reinjection of Treated Groundwater - If reinjection is demonstrated to be the appropriate
method to dispose of the treated groundwater, then the reguirements of an eguivalent Water
Quality Management Part 2 permit, 25 PA Code Section 91, must be met.

c. Surface Water Discharge - National Pollutant Discharge Elimination System ("NPDES")
discharge regulations set forth at 25 PA Code °92.31, the Pennsylvania NPDES regulations
and 25 PA Code °°95.1 - 95.3, the Pennsylvania Wastewater Treatment Regulations, with
consideration of 25 PA Code °°93.1 - 93.9, the Pennsylvania Water Quality Standards, as a "to
be considered", would be an ARAR if reinjection is found not to be appropriate and a surface
water discharge is the appropriate method used for disposal of the treated groundwater.
Ground water collected under the selected remedy shall be treated to comply with these
applicable substantive reguirements prior to discharge.

d. Air Emission for the Groundwater Treatment Unit - Air emissions from the air stripping
unit, if it is utilized as the groundwater treatment technology, shall meet the reguirements of
the Resource, Conservation & Recovery Act ("RCRA") regulations set forth at 40 C.F.R. Part
264, Subpart AA - (Air Emission Standards for Process Vents). 40 C.F.R. °264.1032 (a)
reguires total organic emissions from all affected process vents at the Site to be below 1.4
kg/hr and 2800 kg/yr (3.1 tons/year) under this regulation or reduce, by use of a control
device, total organic emissions by 95% by weight. The air emissions may also be reguired to
comply with the Commonwealth of Pennsylvania regulations set forth at 25 Pa. Code, Chapter 127,
Subchapter A. Those regulations reguire that emissions be reduced to the minimum obtainable
levels through the use of Best Available Technology ("BAT"), as defined in 25 Pa. Code
°121.1. Specific BAT reguirements will be determined during the design phase of the remedy.
At that time, it will be further determined which of the two regulations mentioned above will
place the more stringent reguirements on the remedy and that reguirement will have to be

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complied with. It is anticipated that the installation of a vapor phase carbon adsorption
system would satisfy the requirements of this performance standard.

Fugitive dust emissions generated during remedial activities will be controlled in order to
comply with fugitive dust regulations in the federally-approved State Implementation Plan
("SIP") for the Commonwealth of Pennsylvania, 25 PA Code °° 123.1 - 123.2.

25 PA Code °° 123-31 and 123.41 which prohibits malodors detectable beyond the former
Transicoil facility property line is applicable to the selected remedial alternative.

e. Contaminated Groundwater, Treatment Residuals, and Other Contaminated Site
Derived Waste - The contaminated groundwater must be handled as a RCRA hazardous waste
pursuant to the "Contained-In Policy" under RCRA. Since the TCE in the contaminated
groundwater at the Site is believed to be the result of inappropriate disposal of spent
degreasing solvent that contained TCE, the contaminated groundwater handled as a "F001" RCRA
listed waste. Therefore, contaminated groundwater, drill cuttings, well purge water, spent
carbon and any other treatment residuals (other than treated groundwater) must be handled
consistent with the following substantive requirements, which are applicable to on-site
activities. With respect to the operations at the Site generally must comply, with the
substantive requirements of 25 Pa. Code °264.18 (location requirements for hazardous waste
treatment facilities), °°264.170 - 178 (in the event that hazardous waste generated as part of
the remedy is managed in containers), °°264.191 - 197 (in the event that hazardous waste
generated as part of the remedy is managed in tanks), and 25 Pa. Code Chapter 264, Subpart J (in
the event that hazardous waste is managed, treated or stored in tanks).

f. Well Drilling - The substantive requirements of 25 Pa. Code Chapter 107 is applicable to
the drilling of any new wells at the Site. These regulations are established pursuant to the
Water Well Drillers License Act, 32 P.S. ° 645.1 et seq.

4. To Be Considered Requirements

a. Executive Order 11990 (Protection of Wetlands) - CWA Section 404. Mitigation
measures, such as seasonal adjustment of pumping rates or possible relocation of the discharge
point, may be required to address effects on wetlands. While the Executive Order is not an
ARAR, EPA includes this requirement as a "To Be Considered" standard.

b. Well Abandonment - The substantive requirements of the PADEP's Public Water
Supply Manual, Part 11, Section 3.3.5.11 and Montgomery County Health Department
Regulations Section XVII, regarding the proper plugging and abandonment of wells, are
applicable to residential and other water supply wells, and are relevant and appropriate to
monitoring wells in order to eliminate the possibility of these wells acting as a conduit for
future groundwater contamination.

c. Surface Water Discharge - Consideration will be 25 PA Code °°93.1 - 93.9, the
Pennsylvania Water Quality Standards, as a "To Be Considered" if reinjection is found not to be
appropriate and a surface water discharge is the appropriate method used for disposal of the
treated groundwater.

C. Cost Effectiveness

The selected remedy is cost-effective in providing overall protection in proportion to cost,
and meets all other requirements of CERCLA. Section 300.430 (f) (ii) (D) of the NCP requires EPA
to evaluate cost-effectiveness by comparing all the alternatives which meet the threshold
criteria - protection of human health and the environment and compliance with ARARs - against

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three additional balancing criteria: long-term effectiveness and permanence; reduction of
toxicity, mobility or volume through treatment; and short-term effectiveness. The selected
remedy meets these criteria and provides for overall effectiveness in proportion to its cost.
The combined estimated present worth cost for the selected remedy presented in this Record of
Decision is $3,380,000. The Proposed Plan estimated that the preferred alternative would costs
$3,170,000. The difference in estimated costs between the proposed plan and this Record of
Decision is primarily due to EPA's decision to allow the reinjection of the treated groundwater
rather than discharge to surface water. A pre-design study will be conducted to determine the
feasibility of reinjection, specified in alternative GW-4, and if it can be shown that
reinjection will not adversely impact the affects of the pumping system containment
characteristics, then reinjection can be implemented. If the pre-design study concludes that
reinjection cannot be implemented without adversely impacting the containment characteristics of
the pumping system, then the treated groundwater will be discharged to surface water as
specified in alternative GW-2. If a surface water discharge option is implemented, substantive
reguirement of the NPDES regulations would have to met. This change in the preferred remedy was
made in response to comments receive from members of the public sector and from one of the
responsible parties during the public comment period. EPA estimates that a reinjection system
would be only slightly more costly than a surface water discharge. However, EPA believes that
the implementation of either method, if found to be technically feasible and appropriate, would
be cost effective. Detailed capital and O&M cost estimates for the alternatives included in the
selected remedy are contained in Appendix C of the Feasibility Study.

D. Utilization of Permanent Solutions and Alternative
Treatment Technologies-to the Maximum Extent-Practicable

EPA has determined that the selected remedy represents the maximum extent to which
permanent solutions and treatment technologies can be utilized while providing the best balance
among the other evaluation criteria. Of those alternatives evaluated that are protective of
human health and the environment and meet ARARs, the selected remedy provides the best balance
of tradeoffs in terms of long-term and short-term effectiveness and permanence, cost,
implementability, reduction in toxicity, mobility, or volume through treatment, State and
community acceptance, and preference for treatment as a principal element.

Under the selected remedy, groundwater extraction utilizing a pumping system that both treats
contaminated groundwater using either an air stripper unit or a carbon adsorption unit, and also
restricts further migration of contaminated groundwater, is more cost-effective than the other
alternatives evaluated. The selected remedy will reduce contaminant levels in the Class IIA
aguifer, a known source of drinking water, and reduce the risks associated with ingestion and
inhalation of the groundwater to the maximum extent practicable, as well as provide long-term
effectiveness.

The selection of extending the public water supply system to provide an alternative drinking
water source to affected and potentially affected residents, provides the best balance of
trade-offs among the nine NCP selection criteria for the alternative drinking water portion of
the remedy. The remedy is more costly than the carbon filter alternative, however, it also
provides the highest degree of long-term effectiveness and permanence, and provides an increased
level of protection to human health and the environment.

E. Preference for Treatment as a Principal Element

The selected remedy satisfies, in part, the statutory preference for treatment as a principal
element. The contaminated groundwater alternative addresses the primary threat of future
ingestion and inhalation of contaminated groundwater through treatment using either an air
stripping unit or a carbon adsorption unit. EPA has determined that both technologies are

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equally effective in removing site related contaminants from the contaminated groundwater and
the cost of the two treatments systems are comparable. The actual treatment system to be used
will be determined during the design of the remedial action.
XI. DOCUMENTATION OF CHANGES FROM PROPOSED PLAN

A. Treated Ground Water Discharge Options

The treated groundwater effluent will be discharged by either reinjecting the treated
groundwater or by discharging the treated groundwater through a surface discharge. One of the
responsible parties for the Site and members of the public sector commented on EPA decision to
discharge treated groundwater through a surface water discharge. The commentors encouraged EPA
to consider reinjecting the treated groundwater to replace the groundwater that would be remove
from the aguifer. Some commentors indicated concern about future groundwater capacity
because a nearby guarry had recently requested permission to deepen the quarry operation and
that could have adverse impacts on local water quantity. EPA had originally rejected the
reinjection option because modeling had indicated that reinjection would adversely impact the
containment affects of the pumping system. EPA recognizes that there may be reinjection
scenarios that were not evaluated, and has decided to allow for the re-evaluation of additional
reinjection scenarios as a pre-design study activity. If the study can show that reinjection
can be accomplished without adversely affecting the containment affects of the pumping system
and is technically feasible, then EPA will allow reinjection for the disposal of treated
groundwater. If it cannot be shown that reinjection is technically feasible and appropriate,
then the treated groundwater will be discharge to a surface water as was originally decided.

B. Groundwater-Remediation Beyond the Influence of the Extraction System

Based on several comments by one responsible party and a review of recently developed draft
EPA guidance regarding natural attenuation, EPA has not selected natural attenuation as the
preferred remedy for contaminated groundwater which lies beyond the influence of the selected
pump and treat extraction system. The PRP comments noted that not enough technical
information may be available to adequately evaluate natural attenuation at this site, while the
EPA guidance re-emphasizes the need for adequate natural attenuation data to be available to
determine that a cleanup goal can be achieved within a reasonable time frame before selection of
natural attenuation as a remedy. Since there is some indication, however, that natural
attenuation may be a viable remedy for the extended plume, EPA is requiring a study be
conducted during the pre-design, design, or implementation of the extraction system to determine
what, if any, remedial measure(s) (including natural attenuation or modification of the
extraction system) may be needed or is technically practicable to reduce site related
contaminants to MCL concentrations within a reasonable time frame. Implementation of any
selected measure(s) may require an Explanation of Significant Differences determination or an
Amendment to this Record of Decision.

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                                 SECTION XI

                           RESPONSIVENESS SUMMARY
                                  FOR THE
                       PROPOSED REMEDIAL ACTION PLAN
                                  FOR THE
                NORTH PENN AREA 12/TRANSICOIL SUPERFUND SITE
                   WORCESTER TOWNSHIP, MONTGOMERY COUNTY,
                                PENNSYLVANIA

                           Public Comment Period
                 July 15, 1997, through September 15, 1997

              North Penn Area 12/Transicoil Superfund Site

                          Responsiveness Summary
                                 for the
                       Proposed Remedial Action Plan

                            TABLE OF CONTENTS

Overview	2

Background	5

Part I:  Summary of Commentors' Major Issues and Concerns
       A.   Preferred Ground Water Alternative 	7
       B.   Preferred Drinking Water Alternative 	13
       C.   The Potentially Responsible Parties (PRPs)	22
       D.   The Timing of the Cleanup	24
       E.   Residential Well Concerns	28
       F.   EPA's Monitoring Program	35
       G.   The Contaminants and Associated Risks	41
       H.   Other Concerns	46

Part II: Comprehensive, Technical, and Legal Responses to Comments
       A.   Comments of O'Brien & Gere Engineers,  Inc. on behalf of Schlumberger
           Industries, Inc., a PRP	48

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                         Responsiveness Summary
              North Penn Area 12/Transicoil Superfund Site
          Worcester Township, Montgomery County, Pennsylvania

This Responsiveness Summary is divided into the following sections:

Overview:     This section discusses the U.S. Environmental Protection Agency's  (EPA)
              preferred alternatives for remedial action at the North Penn Area
              12/Transicoil Superfund Site (North Penn 12 Site; the site).
Background:   This section provides a brief history of community relations activities
              during remedial planning at the site.
Part I:       This section provides a summary of commentors'  major issues and
              concerns, and EPA's responses to those issues and concerns.
              "Commentors" may include local homeowners, businesses, the
              municipality, and potentially responsible parties (PRPs).
Part II:      This section provides a comprehensive response to all significant
              comments and is comprised primarily of the specific legal and technical
              guestions raised during the public comment period.  If necessary, this
              section will provide technical detail to answers from Part I.
Any points of conflict or ambiguity between information provided in Parts I and II of this
Responsiveness Summary will be resolved in favor of the detailed technical and legal
presentation contained in Part II.

Overview

     On July 15, 1997, EPA announced the opening of the public comment period and
published the Proposed Remedial Action Plan (Proposed Plan) for the North Penn 12 Superfund
Site, located in Worcester Township, Montgomery County, Pennsylvania.  The Proposed Plan
details EPA's preferred clean-up alternatives to clean up the site contamination, giving
consideration to the following nine evaluation criteria:

     Threshold Criteria

     6    Overall protection of human health and the environment
     6    Compliance with Federal, state, and local environmental and health laws

     Balancing Criteria

     6    Long-term effectiveness and permanence
     6    Reduction of mobility, toxicity, or volume of contaminants
     6    Short-term effectiveness
     6    Ability to implement
     6    Cost
     Modifying Criteria

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6 State acceptance
6 Community acceptance

EPA carefully considered state and community acceptance of the clean-up alternatives
before reaching the final decision regarding the clean-up plan. The Record of Decision
(ROD) details EPA's final clean-up decision.
EPA's selected remedy is outlined below. Based on current information, this remedy
provide the best balance among the alternatives with respect to the nine evaluation criteria
EPA used to evaluate each alternative. To speed and simplify cleanup, EPA proposed an
alternative to address the contaminated ground water and drinking water. The remedy to
address the ground water contamination is noted with the letters GW and the remedy to
address the drinking water contamination is noted with the letters DW. As a result of
comments received during the public comment period of the Proposed Plan, EPA has modified
its preferred remedy. EPA will now allow reinjection (Alternative GW-4) of the treated
ground water if a pre-design study can demonstrate that reinjection can be accomplished
without adversely impacting the containment characteristics of the pumping system. If this
demonstration cannot be made then the treated ground water will be discharged to surface
water (Alternative GW-2). The two alternatives are identical except for the treated water
disposal method.
Alternative GW-4: Ground Water Extraction at Source, Air Stripping or Carbon Treatment, and
Reinjection or, Alternative GW-2: Ground Water Extraction at the Source, Air Stripping or
Carbon Treatment, and Discharge
6 Install seven new extraction wells and convert three existing monitoring wells into
extraction wells at the site.

6 Reinject the treated ground water or discharge the treated water to a drain south of the
site on Trooper Road where the water eventually will flow into Stony Creek.

6 Evaluate during the pre-design, design, or implementation of the extraction/treatment
system on the former Transicoil property to determine if any other remedial measure(s)
(including natural attenuation or modification of the extaction system) may be needed or
is technically practicable to reduce site related contaminants to MCL concentrations
within a reasonable timeframe.

6 Monitor residential wells to evaluate the effectiveness of the groundwater remedy.

6 Prohibit the use and/or pumping of ground water on the former Transicoil property.
Alternative D W-2: Connect Affected and Potentially affected Residents to Public Water
Supply

6 Install new water mains in areas affected or potentially affected by site related
contaminated ground water.

6 Offer affected or potentially affected residents the option to be connected to a public
water supply system.

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6  Install the necessary plumbing, including all related eguipment, to connect each affected
   or potentially affected resident that accepts a connection to the public supply system.

6  Properly abandon existing residential wells.

6  Implement institutional controls to restrict the use of, or exposure to, contaminated
   ground water.

6  Monitor the movement of contaminants to ensure that all affected or potentially affected
   residents are offered and provided connections to the public supply system.

Background

     Some members of the community are knowledgeable about the North Penn 12 Site and
its past operations.  Many residents became interested in the site when preliminary

investigations at the site indicated contamination in ground water.
     EPA first initiated community relations activities in November 1990, with the
 publication of a fact sheet notifying residents of the status of activities at the site.
 Approximately 70 people attended a February 1991,  public meeting during which EPA discussed
 the bankruptcy claim filed by Eagle-Picher Industries, the owner of the Transicoil
 property.  At the meeting many residents wanted to know the results of a recent round of
 sampling EPA had conducted as well as who would pay for the cleanup.

    In December 1991, EPA issued a second fact sheet to update residents on activities at
 the site.  On January 24 and 25, 1994, EPA conducted community interviews with area r
 residents. These interviews allowed EPA to speak with residents one-on-one about their
 concerns and guestions regarding the site.
     EPA issued the community relations plan (CRP)  for the North Penn 12 Site in August
1995.  The CRP highlighted issues, concerns, and interests of the community located near the
site and provided background information about the Superfund process and the site.  In
addition, the CRP listed EPA's community relations objectives and activities to encourage
public participation in site activities.

     To announce the availability of and to obtain public input on the Proposed Plan,  EPA
held a public comment period from July 15,  1997, through September 15, 1997.  During the
public comment period, EPA issued a fact sheet and held a public meeting at the Fairview
Village Assembly Hall on August 6, 1997.  The purpose of the public meeting was to provide
residents with information about the site and the proposed clean-up alternatives and to
allow residents to ask guestions about or comment on the site and EPA's proposed clean-up
alternatives.  EPA announced the public meeting, the opening of the public comment period,
and the availability of the Proposed Plan in a public notice placed in the Philadelphia
Inguirer on July 28, 1997, and in the Montgomery County Observer on July 23, 1997.

     The August 1997 fact sheet highlighted EPA' s preferred alternatives to clean up the
contamination at the North Penn 12 Site, announced the availability of the Proposed Plan in
the information repository, provided a brief history of the site, invited the public to
comment on the Proposed Plan, and announced the public meeting.

     To announce the extension of the public comment period to September 15, 1997, EPA

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    placed a public notice in the Montgomery County Neighbors section of the Philadelphia
    Inguirer on August 26, 1997.
    Part I:  Summary of Commentors'  Major Issues and Concerns

         This section provides a summary of commentors'  major issues and concerns and EPA's
    responses to those issues and concerns.  "Commentors" may include local homeowners,
    businesses,  the municipality, and PRPs.  The major issues and concerns about the proposed
    clean-up alternatives for the North Penn 12 Site received during the public meeting on
    Wednesday,  August 6,  1997, and during the public comment period are grouped into the
    following categories:

         A.    Preferred Ground Water Alternative
         B.    Preferred Drinking Water Alternative
         C.    The PRPs
         D.    The Timing of the Cleanup
         E.    Residential Well Concerns
         F.    EPA's Monitoring Program
         G.    The Contaminants and Associated Risks
         H.    Other Concerns
    A.    Preferred Ground Water Alternative

    1.    Why would EPA have to discharge the ground water if it was safe?
         EPA Response:  The treated groundwater has to be disposed in some manner.   EPA
         examined many disposal options and after evaluating all the options it was concluded
         that a surface water discharge was the best option for the remedy selected However,
         after taking into account public comments that reguested EPA to allow reinjection of
         the treated groundwater,  EPA has decided that if it can be demonstrated that
         reinjection of the treated groundwater will not adversely impact the containment c
         characteristics of the extraction system, then reinjection will be the disposal method
         used.

2.        Why is EPA proposing to discharge contaminants that come out of the monitoring or
         filtering wells into the creek?  Will residents be able to drink the water after it  is
         discharged?
         EPA Response:   EPA proposed to discharge treated water,  not contaminants,  into the
         creek.   The treatment system,  either air stripping or carbon adsorption,  will be
         designed to remove the volatile organic contaminants in the contaminated groundwater
         and the levels of contaminants will be reduce to Water Quality Standards for surface
         water discharge,  Maximum Contaminant Levels (MCLs)  will be the goal established for
         groundwater cleanup.
 3.       If EPA pumps 35 gallons of water per minute out of the 11 extraction wells,  could the
         aguifer be depleted causing residents to lose the water in their wells?
         How can EPA be sure that residents'  wells will not run dry even though EPA proposes to
         extract water?

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     EPA Response:  The yield of each well will vary.   EPA used computer models to
     determine how much water would need to be pumped in order to meet EPA' s goal of
     containing the contamination.   Based on the modeling results EPA does not expect the
     aguifer to be depleted In addition,  EPA will install additional monitoring wells and
     monitor the domestic wells in the area to ensure that the water level does not
     fluctuate too drastically.  Also, most home wells within the immediate area of the site
     will no longer be pumped because they will be connected to public water.   The reduction
     in the pumping of the home wells should off-set  the pumping from the pump and treat
     system. Also,  the public water used by the residents will be recharged to the
     groundwater when placed into the septic systems  currently used by most residents in the
4.    Did EPA considered using reinjection to return the water to the ground?
     EPA Response:   EPA did consider reinjection wells to return the water to the
     environment.   However,  the modeling that was conducted indicted that reinjecting the
     treated groundwater could hinder effectiveness of the pumping system in preventing
     contaminants  from moving off the site.   Also,  the cost for installing the reinjection
     wells was approximately $200,000 greater than the discharge option.   However,  EPA only
     considered one reinjection well configuration during its modeling effort and
     acknowledges  that there could be other feasible configurations that  could be
     implemented.   Therefore,  EPA has included in its selected remedy a provision to study
     other reinjection well configuration options,  and EPA is now proposing in this ROD to
     allow reinjection to be implemented as part of the selected remedy,  if reinjection can
     be determined not to adversely impact the containment characteristics of the extraction
     system.
5.    Instead of discharging the water,  could EPA give it to the North Perm Water Authority?
     EPA Response:   EPA also evaluated this option.   However,  if EPA had chosen that
     option,  implementation would become an issue.   Permits would have to be obtained for
     the water supply well and treatment system These factors  would also add to the overall
     cost of the selected remedy.
6.    Given the geology of the area,  could reinjection affect the decontamination?
     EPA Response:   The possibility of reinjection impacting the contamination would depend
     on the location of the reinjection wells.   As discussed above,  modeling that EPA
     conducted indicated that reinjection would adversely affect the ability of the pumping
     system to prevent contamination from migrating away from the former Transicoil
     property.  However,  there may be other reinjection well configurations that may be
     implemented that will not cause this adverse effect.
7.    Why did EPA determine that reinjection was not an appropriate technology for this site?

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EPA Response: EPA did consider reinjection wells to return the water to the
environment. However, the modeling that was conducted indicted that reinjecting the
treated groundwater could hinder effectiveness of the pumping system in preventing
contaminants from moving off-site. Also, the cost for installing the reinjection wells
was approximately $200,000 greater than the discharge option. However, EPA only
considered one reinjection well configuration during its modeling effort and
acknowledges that there could be other feasible configuration that could be
implemented. Therefore, EPA has included in its selected remedy a provision to study
other reinjection well configuration options, and if a reinjection configuration can be
identified that does not adversely impact the containment characteristics of the
pumping system, EPA will allow reinjection to be implemented as part of the selected
remedy.
Even though EPA proposes to discharge treated water into a pond, the pond runs into a
seasonal stream. EPA should consider the ecological implications of discharge.
EPA Response: EPA has considered the ecological impacts of the preferred alternatives
and has researched the regulatory reguirements for discharging the water. By law, EPA
is reguired to meet all applicable or relevant and appropriate reguirements (ARARs)
with respect to hazardous substances remaining on the Site and has factored these
elements into the remedial alternatives.
9. A resident expressed his formal opposition to EPA's preferred ground water alternative.
He suggested that EPA choose Alternative GW-4 (Ground Water Extraction at Source,
Air Stripping or Carbon Treatment, and Reinjection).
EPA Response: As discussed above, EPA has taken this recurring comment into
consideration and will allow reinjection if its determined to be feasible as studied
during the pre-design stage. If reinjection is found not to be feasible, then the
treated groundwater will be discharged to surface water as was originally proposed.
10. Why is EPA proposing to extract ground water from around the perimeter of the site even
though the well showing the increase of contaminants is in the center of the site?

EPA Response: EPA is proposing to extract groundwater from the area that has the
highest degree of contamination and EPA believes to be the remaining source of the
contamination. The well that is referenced has shown an increase in contamination,
however, it is not the highest degree of contamination on the site. The contaminant
concentrations in the referenced well were lower in concentration than in the area that
is being proposed for pumping. One purpose of the pumping system is to contain the
existing contamination at the source, pumping a well further from the source could
enhance migration of the contamination plume to areas that had not been previously
significantly impacted.
Preferred Drinking Water Alternative
1. The water that residents would receive in the water lines, will it come from

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     Worcester's aquifers? Does Worcester lease those aquifers?
     EPA Response:   The water supply will be provided by the North Penn Water Authoriry.
     The North Penn Water Authority's uses a number of sources includinq surface water
     from their treatment facility,  qroundwater from their supply wells,  and drinkinq water
     from neiqhborinq supply systems.  The water that will be provided to the system that is
     required by this remedy will most likely be from a combination of these sources.
2.    Why is EPA proposinq to clean up the qround water if EPA also proposes to connect
     residents to the public water supply?  Why not allow the contaminants to attenuate
     naturally?

     EPA Response:   EPA's remediation policy requires that EPA attempt to replenish and
     clean tip contaminated qroundwater.   Althouqh residents closest to the site will be
     connected to public water,  there is  a possibility that the contamination could move
     further off-site.  Therefore,  EPA has decided to clean up the hiqhest deqree of
     qroundwater contamination and prevent it from miqratinq further.   EPA is concerned
     about the contamination continuinq to miqrate to residential wells that are located
     beyond the planned water line extension area.  EPA is requirinq that the most
     contaminated qroundwater beneath the former Transicoil property be extracted and
     treated The qroundwater away from the former Transicoil property will be evaluated to
     determine if other measures (i.e.  natural attenuation)  are feasible and/or appropriate
     to insure a timely remediation of the qroundwater in the areas where the qroundwater is
     less contaminated
3.    Either EPA or the PRPs should extend the water main to all residences potentially
     affected.   If trichloroethene (TCE)  is found in residential wells,  other than those
     found to be contaminated,  all residents would have the option to connect if necessary.
     EPA Response:   EPA's proposal for a water line extension does include all wells in
     which TCE has  been found and also includes many non-contaminated wells that EPA
     believes could potentially be affected Areas which EPA believes have little or no
     potential for  future contamination,  based on the residential samplinq results,  have not
     been included  in plans to be connect to the public water extension.   If future
     monitorinq results would indicate there is a problem or potential problem with
     residences not planned to be connected to public water,  then EPA could determine at t
     that time to have additional homes connected to the public supply system.
4.    A resident expressed her opinion that water lines should be installed for all residents
     in the area because her understandinq was that EPA is unsure if the contaminants will

     miqrate once the extraction process starts.
     EPA Response:   As mentioned above,  EPA does plan to connect homes that it has
     determined to be potentially affected by contamination ftom the site.   However,  EPA is
     limited by its statutory authority from advancinq the water line beyond those area that
     it believes could potentially be affected by the Site.   However,  there are areas that
     EPA believes are now not impacted or could potentially be impacted by the Site.   If

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     conditions change in the future,  then EPA could provide additional connections to the
     public water or require other appropriate action to remedy the problem.
5.    A resident expressed his formal approval of EPA's drinking water alternative.
     EPA Response:   EPA acknowledges the comment.
6.    If there is the potential for something in the future to interfere with residential
     wells not connected to public water,  why not extend the water main to all those
     residences?

     EPA Response:   EPA is only authorized to respond where there is a release or threatened
     release of hazardous substances or pollutants and contaminants.  There is no
     established  risk at residences not scheduled to be connected to public water.   If
     non-site related activities impacts contamination migration from the site,  then
     whomever is responsible for the that activity can become a responsible party for the S
     Site.  When such an activity occurs,  EPA has the authority to appropriately address the
     situation.
7.    Since the residences along North Trooper Road are within the contaminated area,  why is
     EPA not proposing to connect them to public water?
     EPA Response:   Residents along North Trooper Road are not within the area of
     contamination.   Further, based on past sampling and current site conditions,  EPA
     believes that  there is no future threat of contamination from the site to affect wells
     in this area Residents did express concern about a nearby guarry expanding its
     operations.   If in the future,  it is found that such an activity causes a change in
     site conditions and contamination is a threat to home wells on North Trooper Road,  then
     EPA can take appropriate action as discussed above.
     One resident commented that,  from a mechanical standpoint,  it is illogical not to run
     the water main along North Trooper Road.
     EPA Response:   EPA is only authorized to respond where there is a release or threatened
     release of hazardous substances or pollutants and contaminants.  There is no
     established risk at residences not scheduled to be connected to public water.   In
     addition,  the  extension on Township Line Road between Valley Forge and Trooper Roads
     serves closes  the loop between the water main on Valley Forge Road and the extension
     proposed for Potshop and Trooper Roads.   This will allow water to be provided to
     residents  during periods of maintenance  of the water line.
9.    In the future,  if the contamination migrated to residences not connected to public
     water or if something else happened, would those residences be able to connect to
     public water?

     EPA Response:  As discussed above,  EPA could reguire additional action if conditions

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      change and/or additional areas are found to be potentially impacted by the site.   EPA
      could require additional public water connections,  if that is  found to be the
      appropriate action.
10.    Will EPA give residents the choice between connecting to public water and maintaining
      their wells?
      EPA Response:   All residents along the water line route will be offered a connection.
      EPA is not aware of any regulation or requirement that would mandate connection to the
      water line in Worcester Township.   If after an offer is made to provide a connection to
      public water is made and if it is  refused,  any future desire to connect to the  water
      line would be at the home owners'expense.   East Norriton Township requires that any
      resident within 150 feet of a public water supply must connect.   If a resident  refuses
      connection to the public water supply system and is later required to connect to the
      system by East Norriton Township,  then that connection will be at the home owner's
      expense.
11.    Will EPA hold any additional meetings to advise residents scheduled to be connected to
      public water concerning water pressure,  gallons per minute,  and what sort of service to
      expect?
      EPA response:  EPA plans to conduct an availability session with the community after
      the remedial design is completed to discuss with residents the design of the system and
      the schedule of follow up construction activities.   EPA also will  contact residents on
      an individual  basis to formally offer to the individual home owners a connection to
      public water supply system.   This will allow for one-on-one contact between EPA and
      homeowners.   EPA will contact residents once the water lines are ready to be installed
      to the homes because residents will need to sign access agreements granting access  to
      their property for the purpose of installing the connection to the water main.
12.    Will residents scheduled to be connected to public water be required to sign any kind
      of waiver to never connect back to their wells?
      EPA Response:   These details will be determined during the design and construction
      stage of the remedy and will also depend who is conducting the remedy,  EPA or the
      responsible parties for the Site.  If EPA is performing the remedy,  then EPA will  not  a
      require that a waiver be signed but will require that a right of entry agreement be
      signed that would allow the water connection to be installed.   At the time of the
      connection to public water,  there would have to be a total disconnect from the well.
      This is a requirement that is enforced by the local water supply companies to prevent
      possible cross-contamination of the public water supply.
13.    A resident expressed concern that EPA was giving an unfair financial advantage  to
      residents scheduled to be connected to the public water supply.   She believed that home
      buyers are more likely to purchase a home that is connected to public water than a home
      with a well because of the danger this Superfund site poses.   She also stated that all
      residents who wish to be connected to public water should be given the opportunity

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      since risks posed by the Superfund site is public knowledge.
      EPA Response:   As discussed above,  EPA is not authorized to extend the water line to
      any area that  is not affected or potentially affected by a release or threatened
      release of a hazardous substance or pollutant or contaminant from the site.   EPA cannot

      take action based merely on perceptions or potential property value issues.
14.    Should residents who do not have contamination above the acceptable risk level  be
      required to pay to a connection to the public water supply?
      EPA Response:   Any residential well that has been affected or could potentially be
      affected will  be offered a connection to the public water supply system at no cost to
      the resident.   However,  if EPA has determined that a resident is not potentially
      affected and the water line is not planned to be extended to that particular area,  then
      any connection to public water will at the home owners expense.   As discussed above,
      EPA is only authorized to provide public water to affected or potentially affected
      residents.
15.    A resident identified an East Norriton Township ordinance requiring residences  within
      150 feet of a water main to connect to that water main.   The resident indicated a
      residence on EPA' s map that was not scheduled to be connected to public water but was
      within 150 feet of the main.
      EPA Response:   EPA has verified that E.  Norriton Township does have an ordinance that
      mandate any structure within 150 feet of public water to connect to the public water.
      Therefore,  any resident in E.  Norriton Township that is within 150 feet of the water
      line will be offered a connection to the public water supply.
16.    A resident inquired whether his property,  located at 1648  Landis Road,  was included in
      EPA's plans to connect residents to the public water supply?
      EPA Response:   Yes,  EPA does expect that a connection to public water will be offered
      to the resident at 1648 Landis Road.
17.    A resident commented that,  of the people he spoke with regarding EPA's  proposed clean-
      up alternatives,  many would prefer a clean-up plan allowing them to continue to use
      their wells.
      EPA Response:   EPA has not receive many comments opposing the plan to extend the
      water line.   In fact,  some residents that are located outside the proposed water line
      extension have requested that they also be offered connections.

 18.    A resident  felt he should not have to pay for the public water  supply connection or
       other associated costs.

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EPA Response: Affected residents will not have to pay for the connection to public
water. Whoever conducts the cleanup will pay for all associated costs. However, the
residents will have to pay water usage bills once they are connected to the public
water system.
19. A resident expressed his formal opposition to EPA's preferred drinking water
alternative. He suggested that EPA choose Alternative DW-3(Carbon Adsorption at
Residence Well Head).
EPA Response: EPA noted the comment and considered it when selecting the final clean-

up plan. However, the public water supply provides a more permanent solution to the
contaminated drinking water problem. Also, since public supplies are reguired to meet
drinking water standards, there is a better assurance that the supply will be safe to
drink.
C. The PRPs
1. Are there any PRPs who are not bankrupt?
EPA Response: Yes, the only responsible party that filed for bankruptcy was Eagle
Picher, Inc. which was the last owner of Transicoil, Inc. There are several other
former owner/operators that EPA is currently investigating as potential responsible
parties.
2. Who will pay for the cleanup? Will EPA pay for the cleanup?
EPA Response: EPA will first offer the responsible parties the opportunity to conduct
the design and clean up activities at the site. If an agreement can be reached, it
will be documented in a Consent Decree between EPA and the responsible party(ies). If
the responsible parties fail to agree to complete the necessary clean up activities,
then the EPA may order the responsible parties to conduct the cleanup or EPA, itself,
may conduct the clean up utilizing the Superfund. EPA then will follow up with
enforcement action to recover the cost incurred from the non-participating responsible
parties.
3. Is Nike Park contaminated and, if so, is the government a PRP?
EPA Response: Based on soil sampling results, EPA found similar levels of
contamination in the soil at the Nike facility as was found on the Transicoil facility
property. Those levels where found not to pose a environmental or health threat. EPA
has information suggesting that the Nike facility used TCE during its operations and
may have disposed of spent solvent which contained TCE on the Nike facility property.

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     This activity could have contributed to the groundwater contamination problem.   EPA is
     further investigating this possibility.  EPA did notified the U.S.  Army that it could
     be a PRP in a general notice letter dated June 7,  1988.
4.    Will someone other than the property owner pay for the public water supply connection
     into the houses,  particularly at residences that are set back several hundred feet from
     the road?
     EPA Response:   Yes.   Whoever conducts the cleanup,  either the responsible party(ies)  or
     EPA, will pay for all costs associated with the public water supply connection.   The
     home owner will be responsible for payment of the guarterly water usage bills.


5.    Who was responsible for monitoring Transicoil during the years the company was
     operating?
     EPA Response:   Reportedly,  the Transicoil facility began its operations in 1952.
     Federal regulations regarding hazardous waste handling and disposal activities did not
     become effective until 1980.   Therefore,  during the first 28 years of the facility's

     operations,  there was very little regulation or monitoring of the disposal activities
     at the site.
D.    The Timing and Cost of the Cleanup
1.    What is the total cost of the proposed clean-up alternatives?

     EPA Response:   Based on comments received during the public meeting and the public
     comment period,  EPA has revised the selected remedy from the preferred remedy
     presented in the proposed plan.  EPA will allow the reinjection of the treated
     groundwater if it can be demonstrated during a pre-design study that reinjection can be
     implemented without adversely affecting the containment characteristics of the
     extraction system.   If this demonstration cannot be made then a surface water discharge
     will be used.
         The total present worth of Aternative GW-4 which includes reinjection is estimated
     to be $1,040,000.   The total present worth of Alternative DW-2 is estimated to be
     $2,340, 000.  Therefore,  the total present worth of both alternatives if reinjection is
     implemented as part of the remedy is approximately $3,380,000.
         The total present worth of the alternative GW-2 which includes a surface water
     discharge is estimated to be $830,000.   The total present worth of Alternative DW-2 is
     estimated to be $2,340,000.  Therefore,  the total present worth of the proposed
     alternatives if a surface water discharge is implemented as part of the remedy is
     approximately $3,170,000.

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2. Will EPA install the water lines before the extraction system is started? Will water
be brought down the streets first so that if something goes wrong with the extraction
wells residents will have fresh water?
EPA Response: EPA anticipates that the water extension construction will most likely
occur before to the pump and treat system is implemented because the design for the
water line extension is more straight forward and less complicated that the design for
the pump and treat system. The design of the pump and treat system will also take a
longer period time to complete because of the pre-design study necessary to evaluate
the feasibility of reinjection. However, details of the remedial action will not be
known until the design of the two components of the remedial action are completed.

3. What is the time period EPA proposes for the cleanup?

EPA Response: After the ROD is issued that specifies the appropriate remedial action
for the Site, EPA will notify the responsible parties for the Site to determine if they
are willing to complete the design and implement the remedial action. If the
responsible parties are willing to implement the remedial action, then negotiations
will be conducted to document their commitment to complete the design and implement the
remedial action. The design process is estimated to take nine months to one year to
complete (an additional six months may be reguired for the pre-design study for the
groundwater remedy) and construction is estimated to take about one year to complete.
Based on the above, it could take approximately 30 months to complete the water line
extension and approximately 36 months to complete the pump and treat system. Actual
cleanup of the contaminated groundwater to the MCLs is estimated to take approximately
30 years.

4. What will be done between now and when the cleanup is started if the contaminants are
still present?
EPA Response: EPA will continue to enforce the existing removal order that reguires
either guarterly or semi-annual sampling of residential wells in the area. The order
also reguires the installation and maintenance of carbon filter systems if the MCL for
TCE is exceeded.
5. Will residents have to wait until all problems are worked out with the water lines
before EPA begins treating the ground water?
EPA Response: EPA does not anticipate any problems with the design and construction
of the water line. So as discussed above, the water line will most likely be
constructed and placed into service before the pump and treat system is constructed and
able to be operated.
6. EPA mentioned that installing reinjection wells would cost an additional $200,000 over
the discharge option. What percentage is that of the total clean-up cost?

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EPA Response: The total present worth of the cost for the groundwater remedy which
includes reinjection is $1,040,000. Therefore, the additional $200,000 for reinjection
wells is approximately twenty percent of the estimated cost for the groundwater remedy.
7. Who will pay for the water line if it is installed?
EPA Response: All the costs associated with the water line construction and
connections would be paid by whoever conducts the cleanup. Either the PRPs will
conduct the cleanup under an agreement with an EPA order, or EPA will conduct the
cleanup using money from the Superfund. If EPA uses money from the Superfund, EPA
would recover the costs later through litigation. The only costs residents would have
would be guarterly water usage bills.
Since the North Penn Water Authority sells water, will residents be reguired to pay for
the installation of the water line to their homes? Will the North Penn Water Authority
pay for the water lines to be installed on the roads, or will EPA take on that
responsibility?
EPA Response: Either the responsible party(ies) or EPA will assume the cost of the
water line installation. Neither the residents nor the North Penn Water Authority will
be responsible for such the costs. Residents will only be responsible for guarterly
water usage bills. Once construction of the water lines are complete, the North Penn
Water Authority will assume responsibility for operating and maintaining the lines.
E. Residential Well Concerns
1. If the nearby guarry drills an additional 120 feet deeper, could residents lose the
water in their wells?
EPA Response: EPA does not know exactly what affects could result from the deepening

of the guarry. The pumping activities planned for the site should not have any
significant adverse affect on the guantity of water available for off-site wells. The
pumping system has been designed to contain the most contaminated groundwater from
migrating further to residential locations. It should also be pointed out that the
affects of pumping groundwater from the Site should be offset some what from the
closing of the over 100 residential wells that will be connected to the public water
system. Any adverse affects from deepening of the guarry will be the responsibility of
the guarry owner and should be considered when and if the guarry is granted permission
to deepen their operation.

2. When EPA sampled wells on the eastern side of the facility, did EPA consider the depth
of the residential drinking wells?
EPA Response: It was assumed that residential wells were in the 60 to 100 foot depth
range. EPA did not make detailed comparisons of the depths because there are many

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fractures in the bedrock in the area so the depth of the wells may not make a
difference. The assumed depths were taken into consideration when developing the s
selected the remedial measures for the site.
3. What should residents do if their shallow wells run dry because of EPA's clean-up
activities but they are not allowed to dig a new well and are not connected to the
water main.
EPA Response: The area of influence that the pumping wells will affect should not be
large enough to impact surrounding shallow residential wells from a water guantity
stand-point. In addition, the resident who asked the guestion is on the opposite side
of the groundwater divide and should not be impacted by the extraction system.
However, if a residential well should go dry, there is no reason why a replacement well
couldn't be drilled. There will not a prohibition on drilling of additional
residential wells; however, there is an existing Montgomery County Health Department
regulation that reguires a supply be sampled and shown to be safe to drink before it
can be placed into use. There are standards contained in the Montgomery County Health
Department regulations that are consistent with the federal drinking water standards
that have to be met. If a newly drilled will is found to be contaminated then
treatment can be provided to meet the standards.
4. Will residents be prohibited from using water from any wells in the area?
EPA Response: No, if residents wish to maintain a well for a purpose other than
drinking water, such as agricultural use, EPA has found no regulations prohibiting such
use. However, those wells will have to be disconnected completely from the home
distribution systems to ensure that there is no possibility of cross-contaminating the
public water supply.
5. If Montgomery County decides to prohibit the use of area wells in the future, how will
residents find out about the prohibition?
EPA Response: If Montgomery County makes the decision to prohibit residents from
using their wells for purposes other than drinking water, EPA believes that the County
would notify residents in the same way it notifies residents of other regulations.
6. Can EPA guarantee that current and future activities at the site will not affect the

guantity or guality of the well water residents currently receive?
EPA Response: EPA cannot guarantee the results that are expected from the proposed
remedial action. However, studies that have been conducted indicate that water guality
beneath site and beneath residential areas near the site should improve as the remedial
action is implemented The studies also show that the affects of the proposed pumping
system should only influence the water beneath the site and should not affect water

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quantity in any off-site wells. The connection of residential wells to the public
water supply should also have a positive impact on groundwater quantity in the vicinity
of the Site.
7. What will happen if EPA's clean-up activities cause problems with residential wells?
EPA Response: EPA doesn't anticipate any problems with residential wells after the
pump and treat system is installed and becomes operational. Pumping will be adjusted
to only drawdown the water levels directly beneath the former Transicoil property.
Also, residents located nearest to the property will be provided with public water. If
for any reason there are still impacts to remaining residential supply wells, then EPA
could require the provision of public water or carbon filtration systems. EPA may
conduct a removal action at any point as it's deemed necessary. EPA will continue to
require that wells be monitored during the remedial design. During the design process,
if EPA finds, for example, that the ground waterflow has changed or any other condition
arises that was not previously known or present, EPA may undertake a appropriate
corrective action. EPA has the flexibility to respond to new situations and new
conditions as they arise.
Will residents be able to dig new wells in the area in the future?
EPA Response: Residents will be able to drill new wells in the future; however, they
must comply with Montgomery County Health Department regulations. Residents would
have to sample the water to ensure that it is safe to drink and follow any other
relevant installation requirements in accordance with the Montgomery County Health
Department Regulations before a permit for installation and use can be issued.
9. If something should happen to the wells at those residences not connected to public
water, will EPA's first reaction be to install a carbon filtration system to treat the
water?
EPA Response: Most homes near the site will be offered connection to the Public water
system, however, if residential wells that are still used were found to contain site
related contamination, EPA could consider taking action to remediate the problem. EPA
has found that installing a carbon filtration system is a quick and easy method for
treating the contaminated wells on a short term basis. However, should something
happen to these wells during the remedial action, EPA would evaluate the situation at
the time to determine the appropriate response action.
10. What is involved in abandoning or decommissioning a well?
EPA Response: Usually the mechanical parts, i.e. the pump, are dismantled and
removed. The well is filled with grout or a similar substance, and the well is provided
with a permanent cover. The Montgomery County Heath Department Regulations at
Section 17-8 specify the standards that must be followed during well abandonment

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activities.
11. If residents choose to maintain their wells, what would the homeowner's responsibility be
for present and future costs?
EPA Response: If a resident chooses not to connect to public water supply after being
offered a free connection, then the resident will become responsible for any future
contamination problem with the well. If the well is determined to be unsafe for
consumption purpose in the future, the resident would be responsible for the cost of
abandoning the well and for the cost of establishing an alternative drinking water supply.
12. EPA proposes to ban the future drilling of new wells. However, if the quarry's blasting
dries up the wells of residents not connected to public water, what will happen to these
residents' ability to obtain water?
EPA Response: As discussed above, EPA does not propose to ban the future drilling of
wells. Future well drilling would be regulated by Montgomery County Health
Department Regulations. Sampling of the well is required to verify that the well water is
safe for use as a potable source of drinking water supply. If contamination is found in
the well, treatment can be provided to provided to reduce the contaminants to acceptable
levels.
13. If the source of the water in each well is different, could the long-term results of the
cleanup be different in each well?
EPA Response: Yes, monitoring will be required during the course of the remediation to
evaluate the effectiveness of the ground water remediation system.
14. From a hydrogeologic perspective, under fractured subsurface conditions, where does
most of the water in residential wells come from? Does it come from old aquifers or is it
from long-term rainfall infiltration?
EPA Response: The source of the water in the wells is determined by the depth of the
wells. The recharge area is at the top of the hill where the former Transicoil facility is
located, so much of the water comes from rain water and infiltration. Further
downgradient, more regional flow provides the water.
F. EPA's Monitoring Program
1. Is there a chart that shows the location of those wells EPA has monitored or currently
monitors, and the levels of contaminants in those wells?
EPA Response: EPA included a map in Figure 2 of the Proposed Plan detailing the

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locations and TCE concentrations of the residential wells surrounding the site that have
been monitored in the past.
2. A resident expressed concern for residents whose wells EPA had not been monitoring.
He felt that EPA should inform all area residents of the levels of contaminants in their
wells.

EPA Response: Over 100 residential wells near the Site have been extensively monitored
in accordance with an order issued to several responsible parties to the Site. When
sampling was completed, results have been sent to the residents. If any individual has not
been receiving the results from the well sampling, they should notify EPA and the results
will be compiled and forwarded as appropriate. EPA will continue to require monitoring
beyond the extent of the proposed water line and to ensure that the residences beyond the
extent of the water line continue not to be impacted.
3. Will EPA increase the size of the monitoring area following completion of the cleanup?
Will EPA increase the size of the monitoring area regardless of the chosen clean-up plan?
Will EPA increase the size of the monitoring area prior to starting the cleanup to verify
the contaminated areas?
EPA Response: The monitoring program for the site will be developed as the remedial
activities are further designed and developed. The monitoring program will be designed
to evaluate the effectiveness of the extraction and treatment system and will also be
developed to ensure that all affected and potentially affected home wells are provided
connections to the public supply system. The cleanup activities will not be considered
complete until it is demonstrated that contamination is reduced below drinking water
standards (MCLs) in all groundwater associated with the Site. During the cleanup
activities, monitoring will be conducted to evaluate the performance of the pump and
treat system and to assure that any resident whose well that has been affected or that
could potentially be affected is provided an opportunity to connect to the public water
supply extension. The details of the monitoring system will be developed during the
remedial design stage.
4. Does EPA have data from testing upgradient of the well where the increased level of
contaminants was found? Does EPA have enough data points upgradient of the well that
showed an increase in contaminant levels to understand where the contamination is
coming from?
EPA Response: The level of TCE contamination in well T-6 which was once used as a
Transicoil supply well has increased from its 1988 level of 33 ppb to a 1995 level of 100
ppb. This well is located on the Transicoil property very near the peak of the
groundwater divide that exists at the Site. Therefore, EPA believes that there probably
are no upgradient wells to T-6. It is not know why the TCE concentration has increased
in this well. EPA will, however, require monitoring of this well when the groundwater
monitoring portion of this remedy is designed and implemented. Sampling of
downgradient wells near the Site have not shown any increase in contamination and
wells on this side of the divide will continue to be monitored.

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5.    A resident stated that her well had never been tested.   She inquired if her well would be
     tested and what the process is for selecting wells to be tested.
     EPA Response:   EPA does not test all wells in an area,  but tries to take a representative
     sample to understand the situation in that area.  EPA will determine if this well  should be
     included in the future monitoring efforts.
6.    Does EPA always test the same wells or different ones each time?  Is the selection
     process random, geographical, etc.?
     EPA Response:   The selection process is not a random one,  EPA selects a monitoring
     system that it believes is able to produce information representative of the study area.

     The wells that are designated as part of the monitoring are sampled periodically during
     the course of the study.   If information is obtained that  indicates that additional wells
     are needed to better define the extent of contamination then adjustments are made to the
     monitoring system by adding wells to be sampled.   This has happened at the North Penn
     Area 12 Site.   A set of wells were included in the initial residential well monitoring
     program based of their proximity to the Site.  As sampling information was obtained that
     showed that the extent of contamination extended beyond the monitoring system,
     additional residential wells were added to the monitoring  program.
7.    After installing the water lines,  will EPA continue to test area wells?  At what point will
     EPA stop testing?  What causes EPA to stop testing?  How long will EPA monitor the
     wells in the area?  Will EPA continue to test residential wells during the clean-up
     process?
     EPA Response:   Both monitoring wells and residential wells will continue to be monitored
     after the public water supply lines are extended.   This monitoring will be conducted to
     evaluate the performance of the groundwater treatment system and to ensure that all
     affected or potentially affected residents are provided a safe source of drinking water.
     EPA will only cease monitoring after it has been shown that contaminated groundwater
     has been cleaned up to meet the safe drinking water standards (MCLs)  for all site related
     contaminants.
8.    Will EPA continue to monitor residents on the borderline,  that is,  those residences that
     are extremely close to those to be connected to public water?
     EPA Response:   EPA will continue to monitor a set of residential wells that are outside
     the public water supply line extension to ensure that all affected or potentially affected
     residents are  provided a safe drinking water supply.
9.    How long will EPA continue to test the wells once the clean-up goals have been achieved?
     EPA Response:   EPA will require that the monitoring continue on a quarterly basis  for

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three years after the groundwater cleanup standards (MCLs) are achieved. If
contaminant levels are maintained for during that period of time, the treatment system
will be allowed to shutdown. Monitoring will then be reguired to continue for another
five years on an annual basis. If cleanup levels are maintained during the five year
period, monitoring will be allowed to cease. If the five year monitoring shows that
contamination exceeds the clean up standards, then the system must be re-started.
10. A resident believed his carbon filtration unit was working correctly and inguired if that
system would continue to be tested and analyzed during the 30-year operation and
maintenance (O&M) period.
EPA Response: All residents that currently have carbon filters installed will be offered
connection to the public water supply line. If a resident refuses to accept a connection
when offered, then the responsibility for O&M of the carbon filter system will be at
his/her own expense.
11. A resident inguired why Figure 2 of the Proposed Plan did not indicate that her well has
been sampled in the past. She also commented that her well had been sampled for the last
three or four years and she has only received letters that indicate that no contamination
over the MCLs has been found in her well. She reguested that the actual sample results

be provided.
EPA Response: There apparently was a mistake made when Figure 2 was prepared. EPA
has reguested the responsible party who is conducting the residential well sampling to
provide actual sample concentrations when sending the letters notifying residents of their
sampling results.
12. A resident stated that her well is extremely shallow. She is concerned that it could run
dry if the water table is lowered due to clean-up activities. She reguested that EPA
continue to monitor her well during the clean-up process for guality and guantity of
water.
EPA Response: EPA will take this reguest under consideration during the design of
groundwater monitoring system.
G. The Contaminants and Associated Risks
1. Has EPA summarized the medical data used to determine the acceptable risk levels of the
contaminants?
EPA Response: EPA's has set cleanup standards for site related contaminants by
establishing standards based on the Maximum Contaminant Levels (MCLs) as reguired
by the Safe Drinking water Act, 42 U.S.C. °°300(f) - 300 (j), 40 C.F.R.. °°141.12,141.50,
and 141.61 for each contaminant. The MCL is the standard set for public water supply

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systems under the Safe Drinking Water Act. This standard is based upon the risk
associated with the contaminant and the available technologies to remove the
contaminants from groundwater.
EPA has verified the use of the MCL by evaluating two types of risk. The first type is
non-cancer health effects, called the hazard index. The acceptable level for the hazard
index is less than one. The second risk is cancer risk. The acceptable risk range for
cancer risk is between one in 1,000,000 and one in 10,000.

EPA's has determined that the risks from contaminants if cleaned to the MCLs, fall
within EPA's acceptable risk range for both non-cancer and cancer risks.
2. How does the North Penn 12 Site compare to other sites in terms of the levels of TCE and
other contaminants present? What is the increased cancer risk caused by the contaminant
levels? Given the level of TCE residents find in their wells, should they be concerned?
How much increase in a person's cancer risk will be caused by the levels present?
EPA Response: It difficult to compare the health threat posed by North Penn Area 12 Site
to other contaminated sites since the type, number, and concentration of contaminants at
other sites vary to a large degree from site to site. However, the potential calculated
cancer risk from future exposure to contaminated groundwater located beneath the
former Transicoil property is approximately 3.4 additional cancer cases for every 10,000
people which is above the EPA's acceptable level of 1 additional cancer case for every
10,000 people. The non-cancer Hazard Index is 7.8 for children and 5.9 for adults, both
of which are over the acceptable level of 1.

For comparison purposes, the cancer risk of the average person living in the United
States is approximately one in three. Therefore, EPA is very conservative in estimating

the a protective risk level of exposure because EPA's unacceptable risk is one in 10,000
or greater. This risk means that if there is a chance that greater than one extra person
out of 10,000 people has the chance to contract cancer as a result of the contamination
present, EPA will clean up the contamination to below that risk level.
3. Are the risks that EPA has calculated for the site for current hypothetical situations or
situations that will not exist in the future?
EPA Response: EPA calculated hypothetical risks to future on-site residents. These risks
would become a reality if no treatment occurred at the site and a person installed a well
on the site and consumed the levels of contaminants currently present in the water at the
site.

Another way the risks could become a reality would be if EPA did not take action at the
site, the contaminants migrated to an off-site well, and residents consumed that water.
4. If EPA took no action at the site, would the contamination disappear in five or ten years?

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EPA Response: EPA has not calculated definite times that it would take for the
groundwater to remediate. It is difficult to predict how long it would take for the
contaminants to attenuate naturally.
5. Is there a way to measure the concentration of contaminants in the soil or did EPA only
test the aguifer for contamination? Did EPA find that the TCE is continuing to move
through the system?
EPA Response: EPA did sample soil at the site and in stream sediment. EPA did not find
any site related contamination in the soil that would result human health risk above EPA
acceptable levels. Risk in levels above EPA acceptable health levels were only found in
the ground water. Therefore, EPA believes that the main contamination is being
transported via the ground water. Contaminants are not in the soil, rather they are
dissolved in water.
6. What is EPA's theory on why contamination levels in monitoring well T-6 are increasing?
EPA Response: The increased reading was unusual. In most wells the contamination
decreased. EPA will continue to reguire the well be sampled to try to determine the
possible reason for the increase.
7. Is it possible that blasting at the guarry could affect the bedrock and the fractures in
it? Is it possible that the blasting could shift the area of contamination? Is it
possible that whatever is done at the guarry could affect the ground water flow on the
site? Would it change the ground water divide?
EPA Response: When EPA first examined this site, the guarry did not seem to affect the
contamination. A ground water divide runs through the former Transicoil property and
groundwater on the north and west side of the Site runs down away from the guarry and
has had a greater impact on the contamination than groundwater on the guarry side of
the site. When the pump and treat system is installed, the divide could change by
increasing the gradient toward the guarry side of the site. One purpose of the pump and
treat system is to prevent the contamination from moving away from the site. EPA also

will continue to monitor wells in the area to assure that no area that are now unaffected
by the site become affected in the future. If it is found that activities at the guarry
adversely affect the migration of contamination from the site, the guarry owner could be
named a PRP.
Is it true that the contamination is mostly north and west of the site?
EPA Response: Yes. EPA found most of the ground water contamination that exceeded
MCLs in residential wells north and west of the former Transicoil facility which is
considered to be the main source of the contamination.

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H.   Other Concerns
1.   A resident expressed his opinion that what was happening at the site was unfair.   He felt
     that no resident should have to be burdened with the problems caused by the site.   EPA
     should spend whatever amount of money is necessary to clean up the site.
     EPA Response:  EPA noted the comments and has considered them when selecting the
     final clean-up plan.
2.   Will EPA implement the preferred clean-up alternatives unless someone presents
     important information to the contrary?
     EPA Response:  EPA has considered all comments and guestions submitted by the public
     in making its remedy selection.
3.   Is information about Superfund sites accessible to the public?
     EPA Response:  When a site is placed on the National Priorities List,  it becomes public
     knowledge.  There is an information repository for each site where EPA keeps all
     relevant documents about the site for the public to view.   The information repository for
     the North Penn 12 Site is located at the Lansdale Library and at EPA's Region III
     Regional Office in Philadelphia.  In addition, EPA Region III maintains a web site that
     contains information about all the Superfund sites in Region III.
4.    How fast does the water flow through soil from the surface down to an aguifer
     approximately 100-feet deep?
     EPA Response:  The rate at which the water flows through the soil depends on the type of
     soil.  Around the North Penn 12 Site there is a lot of clay in the soil,  so the water tends
     to move slower.
5.   Will residents vote on EPA's recommendations?
     EPA Response:  No.  The public meeting and public comment period are the public's
     opportunity to express their concerns and ask guestions about EPA's proposed clean-up
     plan.  EPA will take all of the public's comments and guestions into consideration before
     deciding on the final clean-up plan.

     Part II:  Comprehensive, Technical,  and Legal Responses to Comments
        This section provides technical detail in response to comments or guestions on the North
     Penn 12 Site.  EPA received these comments or guestions by mail or e-mail during the public
     comment period.  These comments or guestions may have been covered in a more general

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fashion in Part I of this Responsiveness Summary. The following specific comments are
addressed:
A. Comments of O'Brien & Gere Engineers, Inc. on behalf of Schlumberger Industries,
Inc., a PRP.

In a three-page letter dated August 13, 1997, Schlumberger Industries, Inc.
(Schlumberger) submitted comments prepared by O'Brien & Gere Engineers, Inc., concerning
EPA's Proposed Plan to clean up the North Penn 12 Site. In addition, Schlumberger
submitted a nine-page letter dated May 27, 1997, commenting on the Final Feasibility Study.
Schlumberger requested that EPA include these comments as part of the company's comments on
the Proposed Plan. The comments contained in each letter are addressed below. The
responses are grouped as they were presented in each letter.

The comments included in Schlumberger's August 13, 1997 letter are addressed below:
1. EPA did not evaluate completely Nike Park's contribution of volatile organic compound
(VOC) contamination to the ground water. The distribution of VOCs detected in
residential water supplies suggests the potential for VOC sources other than the
Transicoil facility. Therefore, the contribution of VOCs from Nike Park and the
responsibility of other parties should be investigated further.
EPA Response: EPA believes that sufficient evaluation of the contamination from the site
has been completed. EPA did conduct rather extensive soil sampling on the former Nike
facility property and additional investigations were conducted to evaluate the
contribution that Nike activities could have had on groundwater contamination near the
Site. EPA continues to evaluate Nike and other potential responsible parties that could
have contributed to the Site related contamination.

2. As part of the selected drinking water alternative, EPA should clarify that connections to
the public water main extension, during the remedial action, only will be offered to
residences with drinking water concentrations of TCE or other site-related exceeding the
MCLs.
EPA Response: Connection to the public water supply extension will be offered to every
home along the designated water line extension route. EPA will require that offers be
made for connections to every affected and potentially affected resident. This action is
part of a long term remedial action and in order to adequately protect all potentially
affected residents from the possibility of their home wells from being contaminated in the
future and to provide permanent protection from Site related contamination,
comprehensive coverage of the alternative drinking water remedy is required.
3a. EPA should consider reinjection as a discharge option for the ground water remedy.
Reinjection returns ground water to the hydrogeologic system, thereby reducing or
eliminating significant losses of water from the local ground water basin or potential
effects to local ground water supplies. Since EPA did not identify a VOC soil or residual
contaminant source during the remedial investigation, there are no indications that
reinjection would affect VOC concentrations in ground water negatively. The absence of
a soil or residual source allows reinjection to be accomplished by various methods,

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including reinjection wells or infiltration basins.

EPA Response: EPA has included in its selected remedy for groundwater the possibility
to reinjection treated groundwater rather than discharge to surface water as was
originally proposed. However, before reinjection can be implemented, it must be
demonstrated that the reinjection will not adversely affect the containment characteristics
of the extraction system. A pre-design study will be necessary to make the demonstration.
Modeling conducted by EPA as part of the remedial investigation indicated that
reinjection could adversely affect the containment characteristics of the pumping system.
If such a demonstration cannot be made then the treated water will be discharged to
surface water as was previously proposed.
3.b. EPA's cost estimates appear under-estimated, particularly for O&M. Given the
uncertainties in the ground water pumping rates, influent guality, and treatment methods
and reguirements, it is likely that reinjection could be implemented at a lower cost than
surface water discharge. Therefore, cost concerns should not result in the elimination of
the reinjection option.
EPA Response: EPA did not eliminate reinjection solely on the basis of cost but primarily
because modeling indicated that reinjection would adversely affect the ability of the
pumping system from preventing the migration of the higher concentration contamination
from moving to residential areas at the Site. However, as discussed above, EPA will
consider the possibility of reinjection if it is demonstrated to be feasible.
4. As EPA proposes, ground water pumping may not affect ground water travel times or
VOC concentrations measurably at residential receptors, given the complex
hydrogeologic setting and the current distribution of VOC concentrations in the ground
water. The ground water model did not include a guantitative analysis of travel times or
remedial time frames. As part of the remedial design phase, EPA should evaluate further
the possible effects of pump-and-treat on ground water flow and VOC transport.
EPA Response: The time travel model was not intended to be a guantitative model.
Because of the uncertainty relating to the groundwater conditions, EPA decided to have a
gualitative model performed to indicate if pumping of the contaminated groundwater on
the former Transicoil property would produce a positive affect on the remedy regarding
the time it would take to achieve MCL at locations near the residential wells. EPA
believes that the modeling did adeguately show that beneficial results would be obtained
from the pumping on the former Transicoil property.
5. The Montgomery County Health Department implemented a new regulation effective
February 1, 1997, (Individual Water Supply System Regulations, Chapter 17, Section 17)
which reguires the abandonment of any well no longer in use. In addition, individual
water supply systems must meet current drinking water standards for VOCs, including
TCE, 1,1,1-trichloroethane, and 1,1-dichloroethene, or be treated to meet these standards.
Enforcing this regulation would prohibit water use from new or modified water supply
wells with impacted ground water above MCLs. Therefore, EPA should consider further
natural attenuation as an appropriate ground water alternative for on-site ground water.

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EPA Response: EPA is aware of the Montgomery County Health Department Regulations
and in fact has based a portion of its institutional controls for the Site on this
regulation. However, this regulation would only address potential exposure to new wells
that are drilled and used as supply wells. This regulation reguires sampling of new supply
wells before they can be used for consumption purposes. The ROD will reguire expansion of
the monitoring system to include a monitoring of areas where new supply wells are
located in the area of the Site to ensure that after new supply wells become functional,
they continue to provide safe water to drink. This reguirement does not affect EPA's
decision to reguire pumping and treating of contaminated of contaminated groundwater

beneath the former Transicoil property. The pump and treat system will provide a means
to remove and contain contamination that exists beneath the former Transicoil property.
The recognition of the Montgomery County Health Department regulation will help
prevent exposure to contaminated groundwater in future residential areas.
6. Schlumberger Limited recommends that the groundwater remedial alternative selected for
the Site be flexible enough so that the groundwater remedial objectives can be met with
an appropriate and effective remedial technology that is more specifically developed
during the Remedial Design phase. The study can be accomplished by allowing for
further evaluation within a specified time frame as part of the Remedial Design work.
Within this time frame, a demonstration through appropriate hydrogeologic and
engineering studies would be conducted with site-specific factors to support a specific
groundwater remedial alternative.
Response: EPA agrees in part with this reguest. EPA agrees that additional study
information should be developed to verify that reasonable measures are implemented (i.e.
natural attenuation) to achieve cleanup standards (MCLs) in the residential areas away
from the former Transicoil property.
The comments included in Schlumberger's May 27, 1997 letter are addressed below:
1. As stated in the FS Report, one of EPA's remedial action objectives (RAO) is to "prevent
exposure or potential exposure to ground water that contains concentrations of COCs
from the site that are above clean-up goals [MCLs]." A second RAO is to "[u]se
appropriate remedial technologies to reduce concentrations of COCs from the site in the
ground water that are above clean-up goals." There is no clear risk basis for using this
RAO. Specifically, given the response measures implemented, currently there are no
unacceptable risks associated with contaminated ground water and it is likely that future
potential risks will be within EPA's acceptable risk criteria within a reasonable amount of
time based on the reported declining ground water COG concentrations. The FS Report
did not support the establishment of the second RAO based on the ARARs. EPA should
reevaluate the need for this second RAO since the first achieves the ARARs established
for the site.
EPA Response: The RAO in guestion is based on the prevention of continued degradation
to the environment (in groundwater) outside the limits of the Transicoil property, also
future risks for exposure to offsite contamination. By pumping and treating the highest
area of contamination of the plume, the MCL cleanup times in the areas away from this
pumping influence will be reduced and further spreading of the plume will also be

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reduce. However, no substantial evidence exists to support the contention regarding the
decline of future risks. Although contaminant concentrations in some wells have declined
with time, a clear trend has not been demonstrated. Further, the agency is mandated to
restore groundwater to a state of beneficial use. For this reason, if no other, an attempt
should be made to reduce contaminant level in groundwater, thus supporting the need for
the second RAO.
2. EPA did not evaluate a current exposure pathway for ground water since residential wells
where contaminant concentrations were observed in excess of the MCLs had been
provided with treatment systems, thereby eliminating potential risks. Data presented in
the FS Report indicated that the COG concentrations in on-site and off-site ground water
are decreasing with time. This observation indicated that the potential risks associated
with ground water exposure also will decline with time. A review of more recent
sampling data may support the apparent decline of COG concentrations further. As
documented in the Remedial Investigation (RI) Report, EPA observed similar
concentration reductions in off-site wells. Further reductions in COG concentrations

would result in lower calculated risks, such that risk associated with potential ground
water exposure may be reduced to an acceptable range within a reasonable amount of
time.
EPA Response: Its agreed that the concentrations of chemicals appear to be declining
with time. This could be occurring because of the apparent lack of a defined source in
the soil or bedrock. However, maintaining this trend cannot be assumed, especially in a
fractured-rock aguifer, where contamination adsorbed on and stored in fractures can be
released at erratic rates over time (100 %g/l of TCE in well T-6 in 1995 after several
years of concentrations less than 50 %g/l). It is unreasonable to assume, for the purpose
of the risk assessment, that a given chemical will be at an estimated concentration at
some point in the future. Therefore, using either 95th% upper confidence level or the
maximum observed concentration is reasonable. Schlumberger acknowledges that the
correct current methodology, therefore the comment is unjustifiable.
3. The amount of residential well data is a limiting factor to the understanding of
groundwater flow and contaminant fate and transport and the potential effectiveness of
the remedial alternatives. In the RI and FS Reports, EPA did not investigate or discuss
regional ground water guality with respect to VOC concentrations.
EPA Response: Its agreed that it would be helpful to have better data on residential well
construction, but this type of information is difficult to obtain. It is also recognized
that there is a regional groundwater contamination problem in the North Penn area and that
the there is a potential for other source of contamination to exists. However, EPA
believes that the former Transicoil property is the likely source of the contamination
observed residential wells near the site. Although detailed data are limited regarding
residential well construction, the available data from the area indicate that most
residential wells are less than 200 feet deep, and many are less than 100 feet deep,
because they are drilled until they reach the most-shallow reliable groundwater.
Therefore, it is reasonable to assume that most of the residential wells are contaminated
by the local source, of Transicoil is the most likely.

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4. If dispersion is an important influence on the presence of TCE on and around the site,
then ground water extraction may disperse TCE within the aquifer further. The
complexity of contaminant transport should be considered carefully when EPA plans
future remedial activities.
EPA Response: Although groundwater flow at the site likely is predominantly through
fractures and bedding planes, in the absence of continuous strong pumping influences,
such as the Center Point Training Center (CPTC) production well, groundwater does not
necessarily move only along paths of preferred flow that are oriented along strike. At
North Penn 12, its believed that the topographic variation predominantly controls the
direction of flow in the absence of pumping. This is obvious from potentiometric maps of
the site and region. Transicoil's location on a topographic high and the disposition of
the terrain makes it a very-likely scenario that contaminated groundwater moves from the
site to the north and possibly to the northeast. This factor was considered in the
groundwater-extraction modeling and the remedial measures designed based on that
modeling.
5. EPA's conclusions regarding the benefits of ground water extraction based on the
modeling work cannot be supported technically. It is critical to the formulation of a
successful remedy that the remedial plan be flexible enough to allow for a more thorough
understanding of hydrogeologic and contaminant transport conditions, prior to the
selection of a final remedy. Further modeling should be conducted to decide on the
appropriate remedy to meet the MCLs.

EPA Response: Development of the groundwater flow model considered all of the
hydrogeologic information available for the Transicoil Site and the surrounding area.
Site-specific information was rather limited, but did include the results of an aguifer
response test and several sets of water level measurements. Regional data used in
developing the model included estimates of the hydraulic conductivity of the Brunswick
Formation and comparative estimates for the Lockatong, based on well yield data. The
model provides a realistic overall representation of the observed potentiometric surface
within the model domain. It incorporates the hydrologic effects of streams in the model
area and uses a reasonable recharge rate based on the average annual rainfall.
However, as noted, it is not considered to be rigorously calibrated to detailed flow
conditions in this highly heterogeneous fractured rock aguifer. Conseguently, it has only
been used to test the potential effectiveness of various extraction well scenarios and to
make rough comparative evaluations between different remedial alternatives. It has not
been used for predictive simulations.
Travel Time Analysis
The travel time analysis presented in Appendix E of the Feasibility Study emphasized
repeatedly that only a relative comparison was made between the No-Action Alternative
and the On-Site Extraction Alternative. The results were presented as a range of
potential reductions in cleanup time specifically to avoid the impression that actual
cleanup times were being predicted. This comparative use of the groundwater flow
model depends on its ability to represent the effects of an on-site groundwater extraction
system on overall flow patterns in the down-gradient area. While the model is not
calibrated to represent the details of flow in the fractured rock aguifer, it does provide
realistic representation of the large-scale flow patterns. And, it uses valid

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hydrogeologic concepts, with the best available estimates of aquifer parameters, to
estimate the effects of on-site extraction wells on those flow patterns.
Incorporation of Off-site Pumping of Residential Wells and Production Wells
It is true that the model does not explicitly include off-site residential wells and
production wells. It is unlikely that the residential wells have a clearly defined effect
on the large-scale groundwater flow, because they are widely dispersed and the individual
pumping rates are low. Furthermore, the emphasis of the travel time analysis was on
changes in groundwater flow caused by the on-site extraction alternative. No changes in
residential well pumping are foreseen as a result of this.

The production well at the CPTC is believed to divert the natural hydraulic gradients in
the eastern part of the site area from the northwest toward the north and northeast.
Some groundwater from the site may actually be drawn into the Training Center well.
However, the FS analysis does not rely on this well to maintain its capture zone in the
future, because its operation is under independent control.
Direction of Groundwater Flow
As noted in the Remedial Investigation Report, the primary direction of groundwater flow
appears to be toward the north west. This is the primary flow direction indicated in the
model. However, the hydraulic characteristics of the aquifer are believed to be
anisotropic, with the primary axis of hydraulic conductivity directed along the strike of
the bedding planes. This anisotropy, which is reflected in the groundwater model, would
tend to magnify the effects of hydraulic gradient components in the east-west direction.
Water level measurements taken in 1988 show significant mounding in the area of the
septic system drain field on the Transicoil Site, with a resulting hydraulic gradients
radiating outward to the west, north, and northeast. This mounding would likely have

caused westward migration of contaminants from the site. However, more recent water-
level data no longer show the groundwater mound at the drain field. This suggests that
the driver for westward flow has been removed and the primary flow direction is now to
the northwest, as represented in the model.
6. EPA's theoretical travel time estimates for ground water migration to the receptor wells
for the no action alternative and the on-site extraction alternative overlap considerably.
Therefore, there is not sufficient information to conclude that any difference in the
travel time would occur if EPA implemented on-site extraction. EPA's analysis did not
consider the effects of the nearby production well at the Center Point Training Center or
residential well pumping on ground water flow paths and travel times. Further, the
analysis assumes that the percent change in the travel time is linear for all parameters
such that the percent change would be valid for any condition of on-site extraction. This
assumption is not technically valid since: (1) the effect of extraction on the ground
water velocity and overall travel time is a function of the area of influence and hydraulic
gradients and is not a linear relationship for combinations of site parameters; and (2) the
portion of the ground water travel path affected by extraction, which occurs only in the
area hydraulically influenced by extraction, will vary for different aquifer parameters and
may not be significant with respect to the total travel time to the receptor well.

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The technical basis for using the travel time alone, and not concentrations for the
assessment of the clean-up time frame for wells outside the capture zone, is not clear.
The model only considers retardation and does not include the effects of dispersion or
other attenuation mechanisms that affect contaminant migration and concentration. The
assumption that a 15 to 37 percent reduction in the total travel time will result in a
concentration reduction occurring proportionally sooner is doubtful and may not be valid.
EPA Response: Overlapping of Travel Time Analysis Ranges
The ranges in Table E-2 overlap because of uncertainty in the aquifer parameters used in
the model and in the transport parameters used in the particle tracking. However, for
any given set of parameters, the analysis showed a decrease in travel times to the
receptor locations as a result of on-site extraction.

CPTC Production Well not Considered in Travel Time Analysis
It is true that the CPTC production well was not considered in the analysis.
Contaminants that are within the capture zone of this well would not reach any of the
receptor locations used in the analysis as long as the pumping rate of that production
well is maintained. However, the particle tracking was done backwards from the
receptor locations. If the production well had been included in the analysis, different
flow paths would have been generated leading to receptors 4 and 5. These particle
tracks would probably show some deflection around the capture zone of the CPTC well.
The travel times for the deflected particle tracks would also be affected by an on-site
extraction system. The differences in travel times might be greater or less than the
differences simulated without the production well.

Linearity of % Change in Travel Time across Range of Hydraulic Parameters and
Pumping Rates

The analysis does not assume that changes in aguifer parameters or pumping rates would
have a linear effect on travel times. Simulations were done for only one set of aguifer
parameters. The values used were estimates based on the available site-specific and
regional information. Uncertainty in these estimates was acknowledged by expressing
the results as ranges, but no formal attempt at analysis of the effects of uncertainty was
attempted.

Technical Basis For Using Travel Time Rather Than Concentration For Cleanup Time

Assessment
Travel time alone was used as an indicator of the potential for on-site extraction to
shorten cleanup time because it was judged that there is not sufficient information
available to support credible solute transport modeling. As explained in Appendix E of
the Feasibility Study, there are several solute transport mechanisms that would affect the
simulated concentrations at receptor locations if a solute transport model were being
used. Advection is usually one of the dominant processes. Advective transport was
rather conveniently simulated using the groundwater flow model and particle tracking,
without the necessity of making numerous additional assumptions about the other
transport processes. Historical observation of the concentrations in monitoring and

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residential wells around the Transicoil Site seem to indicate a general decline in
concentrations. This is attributed to natural attenuation. Natural attenuation is an
observed phenomenon that probably includes the processes of advection, dispersion, and
degradation, although it is not clear which of these is the strongest attenuation
mechanism. The implication of this comment is that degradation may be the dominant
process, and, if so, it would over-ride any differences in contaminant travel times. This
contention, however, has not been proven. The degradation rates of VOC contamination
are difficult to predict. As indicated in Appendix E of the Feasibility Study, experience
suggests that decay rates for VOCs are relatively slow. The observed concentration
reductions at the Transicoil Site may be mostly due to the advective processes that were
represented in the travel time analysis.
7. In the FS Report, EPA rejected the potential use of reinjection for the disposal of
extracted ground water. However, EPA did not provide a sufficient technical basis for
rejecting this option. EPA's ground water model may not be an adeguate representation
of the hydrogeologic characteristics of the site and was not calibrated correctly due to a
lack of data. The actual effect of reinjection is not known. Reinjection would only
reduce the capture zone if the resulting hydraulic influence of reinjection overlaps the
extraction areas of influence. As this is dependent on the injection rate and conductivity
which are not well-known, it is egually possible that reinjection could be conducted
without making capture more difficult.
EPA Response: The economical use of reinjection depends upon its application near the
site to limit the reguired construction of piping and associated structures.

Unfortunately, this increases the likelihood that the reinjection will affect the
groundwater conditions at the site hydraulically. Therefore, the use of reinjection under
the assumed hydrogeologic conditions does not appear to offer an advantage to remediation.
However, EPA has reconsidered as a result of this comment and others received during the
public comment period for the Proposed Plan and now is proposing to allow reinjection if it
can be demonstrated that it will not have any adverse impact on the containment
characteristics of the pumping system.
In the RI Report, EPA suggested that VOC concentrations in some residential water
supplies may increase initially before decreasing due to natural attenuation. However,
EPA did not provide data in the RI and FS Reports to support this conclusion.
EPA Response: Historical trends on contaminant concentrations in residential wells have
exhibited both increases and decreases. Between the sampling in 1990 and 1991 and the
sampling in 1995, several residential wells sampled during both periods showed
increases in TCE and/or 1,1,1 -TCA. Such increases may indicate that migration of
masses of groundwater with elevated levels of contamination through the groundwater
system.
9. EPA concluded that additional data are needed to assess more thoroughly the natural
attenuation potential at the site. Therefore, the remedial design for the site should be
flexible enough to include further consideration of the role and effectiveness of natural
attenuation on VOC concentrations in on-site and off-site areas.

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EPA Response: See response to comment # 2 above.
10. The RI/FS did not provide data regarding the organic material within the groundwater or
aguifer matrix beneath the site, or other site-specific data, with the exception of oxygen
and pH, which are now commonly used to perform detailed assessments of degradation
potential for VOCs due to naturally occurring processes. On a preliminary basis, the
VOCs detected and their concentrations indicate the possible degradation of TCE.

Evidence of detection of many of the products of biological degradation of PCE, TCE,
and 1,1,1-TCA (namely 1,1-DCE, 1,2-DCE, and 1,1-DCA). As concluded in the FS
Report, additional data are needed to more thoroughly assess the natural degradation
potential at the site. In consideration of this, the remedial plan for the Site should be
flexible enough to include further detailed consideration of the role and effectiveness of
natural attenuation on VOC concentrations in the on-site and off-site areas.
EPA Response: The conclusion that there is a lack of organic material needed for active
biodegradation was based on the fact that this generally is true in deep aguifers because
oxidation consumes most organic material soon after recharge to the aguifer, unless
there is a large source such as a spill of petroleum hydrocarbons. Preliminary
indications are that no biological degradation of TCE is presently occurring.

What one would expect to see as daughter products of TCE are primarily cis-l,2-DCE,
and vinyl chloride; neither are present in detectable concentrations in most of the wells.
While 1,1-DCE is present in some wells, it is not likely to be a result of the biological
breakdown of TCE. When TCE undergoes biological reductive dechlorination it has
been found that the first breakdown product is most commonly cis-l,2-DCE, the next-
most-common form is trans-1,2-DCE, and the least common is 1,1-DCE.

If the 1,1-DCE found in the groundwater was a result of biodegradation we would also
expect to see the cis and trans forms in greater (or at least comparable) concentrations.
It is more likely that the 1,1-DCE is either the result of some abiotic degradation or that
it was introduced into the environment in that form.

More importantly, even if the low concentration of 1,1 DCE indicated some type of
breakdown of TCE, the relative concentration of 1,1-DCE to TCE (there is typically 1
order of magnitude more TCE than 1,1-DCE in any given well), the lack of any daughter
products at the toe of the plume, and the fact that the contaminants have been present in
the ground for 20 to 40 years lead to the conclusion that it is having no significant
positive effect on the migration or remediation of the groundwater.

Because no significant concentrations of daughter products are present, and because the
aguifer matrix is deep fractured rock which is not typically considered to contain the
organic substrate necessary to support biological reductive dechlorination, we believe
the conservative assumption that degradation should not be counted on to significantly
reduce contaminant concentrations is reasonable. The availability of supportive data in
the future may necessitate revisiting this conclusion.
11. Several of the remedial alternatives rely on natural attenuation processes to reduce COG
concentrations in ground water. This is reasonable because the historic data indicate that
natural attenuation is occurring, thereby reducing VOC concentrations in on-site and off-
site ground water. However, EPA did not consider natural attenuation fully in the

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detailed evaluation of alternatives in the FS Report.

EPA Response: Its agreed that potential benefits of natural attenuation could have been
identified more consistently, particularly for Alternative GW-1 (no action), but the
conclusions of the FS are not affected by this. Alternatives GW-2, GW-6, GW-7 (onsite
extraction and treatment, offsite natural attenuation) , and GW-8 (natural attenuation
with institutional controls) note natural attenuation. Alternative GW-3 (onsite and
offsite extraction) did not need to invoke it, as the contaminants would be extracted. The
conclusions based on the FS and ROD would not be affected by the noted inconsistency.
12. EPA indicated that the overall effectiveness of pump-and-treat remedial alternatives is
substantially greater than natural attenuation. However, the limited effectiveness of
ground water extraction to affect low-level COG concentrations in ground water,
especially in fractured rock aguifers, is well documented. It may not be feasible or
possible to permanently remediate ground water to MCLs in a shorter time frame than
that for natural attenuation. Further, ground water extraction could adversely affect
ground water conditions (dewatering and reduction of residential and nearby public water
supplies).
EPA Response: Its recognized a number of pump-and-treat remedial systems have not
been very successful, and that groundwater extraction may be associated with some of
the indicated negatives. That is one of the reasons for including Alternative GW-8
(natural attenuation) in the FS report. The difficulties with pump-and-treat, potential
dewatering issues, and the uncertainty associated with predicting the time to achieve
remedial goals have been documented throughout the FS report and have been taken into
consideration in developing the remedial alternatives.
13. EPA did not include, or underestimated, several items for the pump-and-treat remedial
alternatives which should be considered. Therefore, the costs presented underestimate the
actual costs that would be associated with their implementation, possible affecting the
overall cost analysis. Some examples:

System Pretreatment: Capital and O&M costs are not considered for possible pre-
treatment reguirements for metals or other considerations that could result in the fouling
of other unit processes.

Monitoring Costs: Identified costs for ground water and treatment system
monitoring and data analysis and reporting appear low for Contract Lab Program (CLP)
level data, given the need for liguid and vapor monitoring reguirements for Alternatives
GW-2 and GW-3.

Pipe Installation/Trenching: Trenching costs appear low for Alternative GW-3
since asphalt, concrete, and other materials at the surface would increase the cost. Site
restoration costs are not provided for any of the alternatives except DW-2, which could be
substantial for off-site areas under Alternative GW-3. Costs also were not included for
installation of electrical lines and bedding materials in the trenches for Alternatives
GW-2 through GW-7.

O&M Costs: O&M costs appear low for Alternatives GW-2 through GW-7,
which could be significant since O&M costs over a 30-year period represent a significant
portion of the present worth values. It appears that costs for eguipment repair and

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replacement, which can be substantial, were not considered, especially for the number of
extraction points considered in Alternative GW-3. It also appears that costs for stripper
backwashing and disposal and sand filter replacement were not included for Alternatives
GW-2 and GW-3. Monitoring costs also appear low.
EPA Response:
System Pretreatment:
Metals pretreatment has been evaluated and is not anticipated to be reguire. It is
unknown if biofouling would be an issue at the site. Biocide vendors have indicated that
if total plate count of the extracted groundwater exceeds 100 colony forming units per
milliliter biocide application may be needed. Data for the North Penn Area 12 site are
not available to determine if a biocide would be reguired.

Estimated capital costs for a biocide system for a 35 gallons per minute extraction system
is $2,000. Annual O&M associated with providing biocide chemical is estimated at
$15,000 per year, a present worth cost (5% interest rate, 30 years) of approximately
$230,000. The present worth cost of on-site pump and treat alternatives would increase
by an estimated $232,000.

Use of a biocide may be a NPDES permitting issue for alternatives discharging to
surface waters, unless liguid-phase carbon is used. We recommend that the potential for
biofouling be addressed during the design phase of the remedial action through
evaluation of groundwater guality and treatment system design specifications.

Monitoring Costs - Contract Laboratory Program (CLP) Data:

The costs for data analysis were based on laboratory guotations for standard (non-CLP)
data deliverables. Review of the guotations indicates that the costs do not reflect CLP
deliverables. The surcharge to provide CLP-level results is estimated by the laboratory
at 1.5%. If CLP data are reguired, the increase in analytical costs would result in an
increased present worth of approximately $10,000 for Alternatives GW-4 and GW-8, and
$20,000 for Alternatives GW-2, GW-3, GW-5, GW-6, and GW-7. These increases are
less than 3% of the original estimates of the original estimated present worth, within the
FS reports targeted cost estimate accuracy range of -30 to +50 percent. These same
assumptions were used for all alternatives.

Pipe Installation/Trenching and Site Restoration:

Is agreed that possible surface conditions for Alternative GW-3 (on-site and off-site
extraction) may result in increased trenching costs. Its also agreed that costs for the
additional site restoration activities for this alternative should be considered due to the
extensive area that would be affected by the off-site alternative. Inclusion of such costs
would make this alternative, already the most costly evaluated, even more expensive than
the other alternatives. The off-site trenching costs could be increased by $25,000 (10%
of total contingency, 1% of total present worth cost) to account for these activities.
This cost increase is within the FS report's targeted cost estimate accuracy range.
Site restoration activities have not been called out as a separate cost for the on-site
treatment component of the other alternatives. Installation of electrical lines and
bedding materials have also not been called out as separate cost items. The costs for

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electrical line are included in associated cost items such as "power and
instrumentation". Costs were not included for pipe bedding materials, this may add
another $10,000 to $20,000 ($4 to $8/foot) to the cost of the onsite treatment
alternatives. The detailed costs would be the same for all alternatives incorporating an
on-site treatment component. These additional costs, if any, are anticipated to be within
the FS report's targeted cost estimate accuracy range.

O&M Costs:

We agree that estimated O&M costs do not include eguipment repair and replacement.
Assuming an annualized repair/replacement cost of 10% of original eguipment and
instrumentation costs, the total present worth would increase approximately 2% (GW-7),
6% (GW-5), 10% (GW-2 and GW-4), 14% (GW-6) and 18% (GW-3). These increased
costs are within the FS report's targeted cost estimate accuracy range.

The cost estimate assumed a low-profile air stripper which does not reguire a backwash

system. Our experience with these systems is that periodic manual cleaning, if found to
be reguired, could be accomplished for less than $1,000 per year. Periodic sand filter
media replacement, if reguired, would not result in significant increased costs. The
original cost for the sand filter is estimated at $2,000.
14. The recent residential well VOC data are not included in the FS Report. The RI Report
(CH2M Hill, January 1996) included residential well VOC data through January 1995.
Figure 1-7 of the FS Report presents a range in TCE levels for residential wells based on
data (including preliminary data) through July 1996. For consistency, it would be helpful
to include and evaluate the 1996 residential well VOC data, so that the comparison of
historical VOC concentrations presented in the RI Report (Table 4-25) from 1990-1995
could be continued with more recent data. An evaluation of historical residential ground
water data may further demonstrate the potential effects of the natural attenuation, as
discussed herein.
EPA's Response: The figure in the June, 1996 draft report illustrating TCE
concentrations in residential wells used the maximum TCE concentration observed
through January, 1996. The corresponding figure in the October, 1996 final report was
updated per EPA reguest to reflect preliminary July, 1996, data (July, 1996
Schlumberger Monthly Report) indicating that lot 18-16 (Benner) had TCE above the
MCL. These data were also used in the February, 1997 revisions to the final report. We
consider this approach to be a conservative method of identifying residences that could
potentially be affected by the groundwater contamination, particularly given the
uncertainty associated with predicting plume migration using residential well data. We
agree that a time comparison of concentrations over time may be beneficial. Preliminary
review of the available residential well data, however, indicates that there is limited
evidence of significant concentration decreases over the short time frame (January 1995 -
January 1996) covered by the residential well data. Conclusions based on the FS report
are not anticipated to change. All the residential well data generated as reguired by the
August 22, 1995 - Administrative Order for Removal Response Action, Docket No. III-
95-56-DC will be placed into the administrative record for the site.
15. On page 1-15 of the FS Report, micrograms per liter is defined as "mg/L". The correct
abbreviation, as utilized in other FS Report sections, should be "Ig/L". The

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groundwater concentration fro monitoring wells and residential wells are subseguently
reported with the mg/L units, although the reported numerical concentrations are actually
in "Ig/L".  This should be noted in the future to avoid possible confusion by reviewers of
the FS Report or prior to adaptation of this section for the ROD.

EPA's Response:  The use of the "mg/L" on pages 1-15 and 1-16 is an error; the units
should read "Ig/L".  The numerical concentration values reported are correct, however,
the wrong abbreviation was used as noted.

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                                             FIGURES

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                                        Appendix A
                             Administrative Record Index
                                   NORTH PENN AREA 12
                             ADMINISTRATIVE RECORD FILE *  **
                                  INDEX OF DOCUMENTS

III.   REMEDIAL RESPONSE PLANNING

      1.    Report:   Hydrogeologic Evaluation of the Influence of
           Production Well Pumping on Groundwater Movement,
           prepared by JACA Corporation, 2/20/87.
           P.  000001-000014.

      2.    Report:   Technical Evaluation of Zone of Contamination
           12  Transicoil Incorporated Site, Worcester,
           Pennsylvania; prepared by Versar, Inc., 7/15/88.
           P.  000015-000088.

      3.    Report:   Preliminary Health Assessment for the
           Transicoil Inc.  (Zone 12)  North Penn Area Site,
           Worchester, Pennsylvania,  prepared by the Office of
           Health Assessment Agency for Toxic Substances and
           Disease Registry  (ATSDR),  9/29/88.  P. 000089-000091.

      4.    Letter to Ms. Roseanne M.  Mistretta, U.S. EPA, from Mr.
           Marc L.  Greenberg, Eagle-Picher Industries, Inc.,  re:
           Designation of the Project Coordinator, for the
           respondents at the site, 6/9/89.  P.  000092-000092.

      5.    Administrative Order by Consent In The Matter Of:
           Transicoil Site, Docket No. III-89-14-DC, Eagle-Picher
           Industries, Inc., and Transicoil, Inc., respondents,
           6/29/89.  P.  000093-000121.

      6.    Letter to Ms. Marcia E. Mulkey, U.S. EPA, from Ms. Mary
           Letzkus, Environmental Resources Management, Inc., re:
           Notification that Ms. Letzkus has no conflict of
           interest in working at the site, 7/7/89.
           P.   000122-000122.

      7.    Letter to Mr. Paul Harper, Eagle-Picher Industries,
           from Mr. Christopher B. Pilla, U.S. EPA, re:
           Designation of the EPA Project Coordinator, for the
           site,  7/13/89.  P.  000123-000123.

      8.    Letter to Mr. Christopher B. Pilla, U.S. EPA, from Mr.
           Mark Johnson, Eagle-Picher Industries, Inc., re:
           Designation of Remedial Investigation/Feasibility Study
           (RI/FS)  contractor for the site, 7/13/89.

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     P.  000124-000124.

Administrative Record File available 5/14/96, updated
7/18/97.

The North Penn Area 12 Removal Administrative Record is
hereby included by reference.

9.   Letter to Mr. Dennis Cunningham, U.S. EPA, from Mr.
     Ronald J. Chernik, Dynamac Corporation, re:
     Transmittal of the RI/FS work plan for the site,
     8/31/89.  P.  000125-000145.  The work plan is attached.

10.  Memorandum to Mr. Jim Feeney, U.S. EPA, from Ms.
      Cynthia Kennedy, U.S. EPA, re:  Transmittal of review
      comments for the draft RI/FS work plan, 10/13/89.
      P.  000146-000164.   The comments are attached.

11.  Letter to Mr. James J. Feeney, U.S. EPA, from Mr.
     Nicholas Cianfrone,  Dynamac Corporation, re:  Review of
     the RI/FS work plan, 11/9/89.  P.  000165-000171.

12.  Memorandum to Mr. Jim Feeney, U.S. EPA, from Ms. Donna
     Abrams, U.S. EPA, re:  Review of the draft RI/FS work
     plan, 11/17/89.  P.   000172-000174.  The review is
     attached.

13.  Letter to Mr. James J. Feeney, U.S. EPA, from Mr.
      Woodrow R.  Cole, Pennsylvania Department of
      Environmental Resources (PADER), re:  Comments on the
      draft RI/FS work plan and request for information
      concerning the aguifer pumping test, 11/30/89.
      P.  000175-000176.

14.  Letter to Mr. Mark M. Johnson, U.S. EPA, from Mr. James
     J. Feeney, U.S. EPA, re:  Comments on the draft RI/FS
     work plan, 12/01/89.  P.  000177-000185.

15.  Facsimile transmittal letter to Mr. Jim Feeney, U.S.
     EPA, from Mr. Woodrow R. Cole, PADER, re:  Review of
     draft RI/FS work plan, 12/08/89.  P.  000186-000191.  A
     memo detailing PADER's hydrogeological concerns about
     the site is attached.

16.  Letter to Mr. Mark M. Johnson, Transicoil Inc., from
     Ms. Karen D. Johnson, U.S. EPA, re:  Transicoil's
     status with regard to further legal actions by the EPA,
     2/1/90.  P.   000192-000221.  The following are attached:

           a)  trip reports;
           b)  sampling data analysis;
           c)  chain of custody reports;
          d)  handwritten notes concerning trip visits.

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17.  Letter to Mr. James Feeney, U.S. EPA, from Ms. Mary
     Letzkus,  Environmental Resources Management, Inc., re:
     Response to U.S. EPA comments on the draft RI/FS work
     plan,  3/16/90.  P.  000222-000249.  The comments and
     revisions to the work plan are attached.

18.  Memorandum to Mr. James J. Feeney, U.S. EPA, from Ms.
     Dawn A. loven, U.S. EPA, re:  Comments concerning the
     draft RI/FS work plan, 5/4/90.  P.  000250-000264.  A
     memorandum reguesting a review of the work plan and a
     revised portion of the work plan are attached.

19.  Letter to Mr. James J. Feeney, U.S. EPA, from Mr. Bruce
     Beach, Dynamac Corporation, re:  Submittal of oversight
     soil sampling results, 12/10/90.  P.  000265-000411.
     The soil sampling results are attached.

20.  Letter to Mr. James M. Feeney, U.S. EPA, from Mr.
     Francis P. McCune, Eagle-Picher Industries, Inc., re:
     Confirmation of a telephone conversation between Mr.
     Feeney and Mr. Paul Harper regarding developments in
     Bankruptcy Court and the full implementation of the
     RI/FS work plan, 2/15/91.  P.  000412-000412.

21.  Letter to Mr. Scott McEwen, CH2M Hill, from Mr. Patrick
     M. McManus, U.S. EPA, re:  Comments on the draft RI/FS
     work plan for the site, 10/8/93.  P.  000413-000431.
     Comments from the U.S. EPA hydrogeologist, U.S. EPA
     toxicologist, and PADER are attached.

22.  Letter to Mr. Scott McEwen, CH2M Hill, from Mr. Patrick
      M.  McManus,  U.S. EPA, re:  Comments on the December,
      1993, draft RI/FS work plan for the site, 1/12/94.
      P.   000432-000451.  Comments from the U.S. EPA
      hydrogeologist, U.S. EPA toxicologist, and the PADER
      site manager are attached.

23.  Report:  North Perm Area 12 Draft RI/FS Work Plan,
     prepared by CH2M Hill, 3/94.  P.  000452-000658.

24.  Letter to Mr. Patrick M. McManus, U.S. EPA, from Mr.
      Stephen Brand,  CH2M Hill, re:  Transmittal of well
      construction logs for the site, 4/22/94.
      P.   000659-000677.  The construction logs are attached.

25.  Memorandum to Mr. Patrick M. McManus, U.S. EPA, from
      Ms. Dawn A.  loven, U.S. EPA, re:  Comments on the draft
      sampling and analysis plan for the site,  6/2/94.
      P.   000678-000679.

26.  Memorandum to Mr. Patrick M. McManus, U.S. EPA, from
     Ms.  Barbara Rudnick, U.S. EPA, re:  Comments on the
     draft sampling and analysis plan for the site, 6/15/94.
     P.  000680-000683.

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27.  Memorandum to Mr. Patrick M. McManus, U.S. EPA from Mr.
      Robert S.  Davis, U.S.  EPA,  re:   Comments on the draft
      sampling and analysis  plan for the site, 6/23/94.
      P.   000684-000685.

28.  Letter to Mr. Patrick M. McManus, U.S. EPA, from Ms.
     Monica D. Jones, U.S. EPA, re:  Review and comments on
     the field sampling and guality assurance plans for the
     site,  6/29/94.  P.  000686-000702.  A Quality Assurance
     Project Plan Review Checklist is attached.

29.  Report:  North Perm Area 12 Sampling and Analysis Plan,
     prepared by CH2M Hill,  7/94.  P.  000703-000997.

30.  Letter to Mr. Stephen Brand, CH2M Hill, from Mr.
     Patrick M.  McManus,  U.S. EPA, re:  Comments on the
     sampling and analysis Plan,  7/1/94.  P.  000998-000999.

31.  Letter to Mr. Stephen Brand, CH2M Hill, from Mr.
     Patrick M.  McManus,  U.S. EPA, re:  Transmittal of
     PADER's comments on the sampling and analysis plan,
     7/11/94.  P.  001000-001002.

32.  Letter to Mr. Patrick M. McManus, U.S. EPA, from Mr.
     Stephen Brand, CH2M Hill, re:  Response to comments on
     the sampling and analysis plan for the site, 7/20/94.
     P.  001003-001009.  The comments and a Federal Express
     airbill are attached.

33.  Letter to Mr. Stephen Brand, CH2M Hill, from Mr.
     Patrick M.  McManus,  U.S. EPA, re:  Approval of the
     sampling and analysis plan,  9/8/94.  P.  001010-001010.

34.  Letter to Mr. Patrick M. McManus, U.S. EPA, from Ms.
     Lanny Helms, Target Environmental Services, Inc., re:
     Transmittal of the guality assurance plan for screening
      services at the site,  11/28/94.  P.   001011-001022.  The
      guality assurance plan is attached.

35.  Memorandum to Mr. Mike Showlter and Ms. Susan
      Guicheteau, CH2M Hill,  from Mr. Stephen Brand,  CH2M
      Hill,  re:   Project sampling instructions,  2/7/95.
      P.   001023-001032.

36.  Letter to Mr. Patrick M. McManus, U.S. EPA, from Ms.
     Lisa Senior, U.S. Department of the Interior, Water
     Resources Division,  re:   Explanation and transmittal of
     water-level recorder charts from tests conducted on
     wells at the site, 7/19/95.   P.   001033-001048.   The
     charts are attached.

37.  Memorandum to Mr. Patrick M. McManus, U.S. EPA,  from
      Mr.  Robert S. Davis, U.S. EPA,  re:  Review and comments
      on the remedial investigation report, 9/26/95.

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     P.  001049-001051.

38.  Memorandum to Mr. Patrick M. McManus, U.S. EPA, from
     Ms. Dawn A. loven, U.S. EPA, re:  Review and comments
     on the draft remedial investigation report, 9/29/95.
     P.  001052-001054.

39.  Letter to Mr. Patrick M. McManus, U.S. EPA, from Mr.
     Chet Zazo, PADER, re:  Comments on the remedial
     investigation report, 10/6/95.  P.  001055-001056.

40.  Memorandum to Mr. Patrick M. McManus, U.S. EPA, from
      Ms.  Barbara Rudnick, U.S.  EPA, re:   Review and comments
      on the remedial investigation report, 10/23/95.
      P.  001057-001061.

41.  Letter to Mr. Stephen Brand, CH2M Hill, from Mr.
      Patrick McManus, U.S. EPA,  re:  Comments on the
      remedial investigation report, 10/24/95.
      P.  001062-001067.

42.  Letter to Mr. Patrick M. McManus, U.S. EPA, from Ms.
     Lisa Senior, U.S. Department of the Interior, Water
     Resources Division,  re:  Transmittal and explanation of
     water-level recorder charts from tests conducted on
     wells at the site, and final map of the water levels of
     the wells, 12/8/95.   P.  001068-001102.  The charts and
     map are attached.

43.  Report:  North Perm Area 12 Remedial Investigation
     Report, prepared by CH2M Hill, 1/96.  P.  001103-001810.

44.  Report:  North Perm Area 12 Site Trip Report and Report
     of Results, prepared by Roy F. Weston, Inc., 2/9/96.
     P.  001811-001911.  A transmittal letter is attached.

45.  Letter to Mr. Don Henne, U.S. Department of the
      Interior, from Mr.  Patrick M. McManus, U.S. EPA,  re:
      Transmittal of the  final draft of the remedial
      investigation report for the site,  2/28/96.
      P.  001912-001912.

46.  Letter to Mr. Charles Sardo, Township Manager, Township
     of Worcester, from Mr. Patrick M. McManus, U.S. EPA,
     re:  Transmittal of the remedial investigation report
     for the site, 3/19/96.  P.   001913-001913.

47.  Report:  North Perm Area 12 Remedial Investigation
     Report, Addendum 1,  prepared by CH2M Hill, 4/96.
     P.  001914-001953.

48.  Report:  Evaluation of Geophysical Logs for North Penn
     Area 12 Superfund Site, Montgomery County,
     Pennsylvania, prepared by U.S. Geological Survey,  1996.

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     P.  001954-001982.  A March 18, 1997, transmittal letter
     to Mr. Patrick M. McManus, U.S. EPA, from Mr. Dennis W.
     Risser,  U.S. Department of the Interior, is attached.

49.  Report:   North Perm Area 12 Feasibility Study Report,
     prepared by CH2M Hill, 2/97.  P.  001983-002238.

50.  Memorandum to Mr. Patrick M. McManus, U.S. EPA, from
     Mr. Thomas Nilan and Lee Davis, CH2M Hill, re:  North
     Penn Area 12 - Preliminary Review of Requirement for
     Metals Treatment, 5/6/97.  P.  002239-002243.

51.  Proposed Plan, North Penn Area 12 Site, 7/97.
     P.  002244-002278.

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