Superfund Proposed Plan	Diaz Chemical Corporation Superfund Site

Diaz Chemical Corporation Superfund Site

Village of Holley, Orleans County, New York

m

August 2012

PURPOSE OF THIS DOCUMENT

This document describes the remedial alternatives considered for the Diaz
Chemical Corporation Superfund site and identifies the preferred remedy with the
rationale for this preference. This Proposed Plan was developed by the U.S.
Environmental Protection Agency (EPA) in consultation with the New York State
Department of Environmental Conservation (NYSDEC). EPA is issuing this
Proposed Plan as part of its public participation responsibilities under Section
117(a) of the Comprehensive Environmental Response, Compensation, and
Liability Act (CERCLA) of 1980, as amended, and Sections 300.430(f) and
300.435(c) of the National Oil and Hazardous Substances Pollution Contingency
Plan (NCP). The nature and extent of the contamination at the site and the
remedial alternatives summarized in this Proposed Plan are described in the July
2012 remedial investigation (Rl) and feasibility study (FS) reports, respectively.
EPA and NYSDEC encourage the public to review these documents to gain a more
comprehensive understanding of the site and the Superfund activities that have
been conducted at the site.

This Proposed Plan is being provided as a supplement to the Rl and FS reports to
inform the public of EPA and NYSDEC's preferred remedy and to solicit public
comments pertaining to all of the remedial alternatives evaluated, including the
preferred soil and groundwater alternatives. The preferred remedy consists of in-
situ thermal treatment of the contaminated soil and groundwater in six source
areas, potential building demolition, monitored natural attenuation1 for the
groundwater outside the source areas, development of a site management plan,
continued operation of the existing vapor mitigation systems, and institutional
controls.

The remedy described in this Proposed Plan is the preferred remedy for the site.
Changes to the preferred remedy, or a change from the preferred remedy to
another remedy, may be made if public comments or additional data indicate that
such a change will result in a more appropriate remedial action. The final decision
regarding the selected remedy will be made after EPA has taken into consideration
all public comments. EPA is soliciting public comment on all of the alternatives
considered in the Proposed Plan and in the detailed analysis section of the Rl and
FS reports because EPA may select a remedy other than the preferred remedy.

In 2005, EPA selected the acquisition of eight properties and the permanent
relocation of the residents of those properties as an interim remedy for the site.
EPA has determined that the sale or transfer of the properties is consistent with the
final remedy proposed for the site in this Proposed Plan.

1 Natural attenuation is a variety of in-situ processes (dispersion, dilution, and degradation)
that, under favorable conditions, act without human intervention to reduce the mass, toxicity,
mobility, volume, or concentration of contaminants in groundwater.

MARK YOUR CALENDAR

August 13, 2012 - September 12, 2012:

Proposed Plan public comment period.

September 5, 2012 at 7:00 PM: Public
meeting at the American Legion, 5 Wright
Street, Holley, NY 14470.

Supporting documentation is available at
the following information repositories:

Community Free Library

86 Public Square
Holley, New York 14470
585-638-6987

and
EPA-Region II
Superfund Records Center
290 Broadway, 18th Floor
New York, NY 10007-1866
212-637-4308

EPA and NYSDEC rely on public
input to ensure that the concerns of
the community are considered in
selecting an effective remedy for each
Superfund site. To this end, the Rl
and FS reports and this Proposed
Plan have been made available to the
public for a public comment period
that begins on August 13, 2012 and
concludes on September 12, 2012.

A public meeting will be held at the
American Legion, 5 Wright Street,
Holley, NY on September 5, 2012 at
7:00 PM to present the conclusions of
the RI/FS, elaborate further on the
reasons for recommending the
preferred remedy, and receive public
comments.

Comments received at the public
meeting, as well as written comments,
will be documented in the
"Responsiveness Summary" section
of the Record of Decision (ROD), the
document that formalizes the
selection of the remedy.

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Superfund Proposed Plan

COMMUNITY ROLE IN SELECTION PROCESS

Written comments on the Proposed Plan should be
addressed to:

John DiMartino
Remedial Project Manager
Central New York Remediation Section
U.S. Environmental Protection Agency
290 Broadway, 20th Floor
New York, New York 10007-1866

Telefax: (212)637-3966
e-mail: dimartino.john@epa.gov

SCOPE AND ROLE OF ACTION

Site remedial activities are sometimes segregated into
different phases, or operable units, so that remediation of
different environmental media or areas of a site can
proceed separately in an expeditious manner. EPA has
designated two operable units for this site.

The first operable unit involved the acquisition of eight
properties and the permanent relocation of eight owner-
occupant and two tenant families who had resided in
these properties prior to being relocated to temporary
quarters in January 2002. A ROD for this operable unit
was signed on March 29, 2005.

This second operable unit, which is the focus of this
Proposed Plan, addresses contamination at the former
Diaz Chemical facility and its environs. The primary
objectives of this action are to remediate the sources of
soil and groundwater contamination, minimize the
migration of contaminants, and minimize any potential
future health and environmental impacts.

SITE BACKGROUND
Site Description

The Diaz Chemical Corporation site includes the Diaz
Chemical Corporation (Diaz Chemical) facility and parts
of the surrounding residential neighborhood. The Diaz
Chemical facility is located at 40 Jackson Street, Village
of Holley, Orleans County, New York. Figure 1 and
Figure 2 provide a site location map and site plan,
respectively.

The Diaz Chemical facility is situated on an
approximately 5-acre parcel of land. It is bounded on the
north by Jackson Street, where residential parcels and a
parcel of land owned by Diaz Chemical, which includes a
parking lot and a warehouse, are located. To the east, it
is bounded by residential parcels on South Main Street.

Diaz Chemical Corporation Superfund Site

To the south and west, it is bordered by Conrail railroad
tracks, beyond which lie undeveloped land, a former
Duffy-Mott Corporation, Inc. building now used as a
storage/shipping facility, and a small tributary to the East
Branch of Sandy Creek.

The site is located about 25 miles west of Rochester and
50 miles east of Buffalo.

The nearest municipal drinking water supply well is
located 0.66 mile south of the site2. The area
surrounding the site is provided with drinking water from
this well.

Site History

The Diaz Chemical facility was initially developed as an
industrial plant in the 1890s and was used primarily for
tomato processing and cider vinegar production before
being purchased by Diaz Chemical in 1974. Diaz
Chemical was a manufacturer of specialty organic
intermediates for the agricultural, pharmaceutical,
photographic, color and dye, and personal care products
industries. The Diaz Chemical product line varied over
the years of operation, but primarily consisted of
halogenated aromatic compounds and substituted
benzotrifluorides.

The Diaz Chemical facility had a long history of chemical
releases to the environment, extending from 1975 to
2002. Poor housekeeping practices, loss of control of
manufacturing systems, and faulty containment systems
resulted in the release of a range of chemical substances
to the air, water, and soil. Reported releases included
mineral and organic acids, caustics, bromine, chlorine,
halogenated organic compounds including
parachlorobenzotrifluoride	(PCBTF)	and

2-chloro-6-fluorophenol (CFP), organic compounds, and
petroleum-related compounds. Some releases were not
limited to the Diaz Chemical facility, but migrated to
off-property areas, including residences and the East
Branch of Sandy Creek.

Based on historic meteorological data, air emissions from
the plant would have likely dispersed toward the
residential neighborhood northeast of the plant. While
limited historical information was available, including
process schematics and descriptions, raw materials and
product lists, hazardous waste reports, spill reports,
air/water discharge permits, this information was
insufficient to accurately quantify the chemicals that were
deposited in the residential neighborhood.

From 1994 to 1999, Diaz Chemical conducted an Rl at

2 Since this supply well is not hydraulically connected to the site
groundwater, it is not impacted by groundwater contamination
from the site.

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Superfund Proposed Plan

the site under the oversight of NYSDEC. The Rl
revealed that soils and groundwater at the Diaz Chemical
facility were contaminated with volatile organic
compounds (VOCs) and semi-volatile organic
compounds (SVOCs). Contaminants detected in the soil
and groundwater included 1,2-dichloroethane (DCA),
vinyl chloride, 1,2-dibromoethane, benzene, xylene,
ethylbenzene, and a number of brominated chemical
intermediates.

In March 2002, NYSDEC selected a remedy for the Diaz
Chemical site, which required the continued operation of
a groundwater extraction and treatment system via a
trench which Diaz Chemical installed at the facility as an
interim remedial measure in 1995. This system provided
partial containment of the groundwater contaminant
plume.

An accidental air release from the Diaz Chemical facility
occurred on January 5, 2002, when a reactor vessel in a
process building overheated, causing its safety valve to
rupture and release approximately 75 gallons of a
chemical mixture through a roof stack vent. The release
consisted primarily of a mixture of steam, toluene, and
CFP, as well as related phenolic compounds. The
mixture landed on properties in the residential
neighborhood immediately adjacent to the facility and
was visible as red colored droplets on homes. Soon after
the release, residents complained of acute health effects,
such as sore throats, headaches, eye irritation,
nosebleeds, and skin rashes. As a result of the release,
several residents voluntarily relocated to area hotels with
assistance from Diaz Chemical.

In March 2002, the State of New York obtained a court
order that required Diaz Chemical to continue to fund the
relocations until an appropriate environmental and health
assessment was performed for the affected
neighborhood. At that time, NYSDEC requested that EPA
conduct an assessment of the neighborhood that was
impacted by the accidental release in order to determine
if further actions were necessary. In May 2002, when
Diaz Chemical sought to discontinue the relocations for
ability-to-pay reasons, Diaz Chemical and the New York
State Law Department requested that EPA continue the
funding of the temporary relocations. On May 16, 2002,
EPA, under its removal authority3, assumed responsibility
for the temporary relocation expenses of the residents
who remained relocated at that time.

Subsequently, the New York State Law Department and
EPA performed sampling of indoor air, soil, interior
surfaces, and household items in the affected
neighborhood. A qualitative review of the data collected

3 Removal responses at Superfund sites are performed when
contamination poses an immediate threat to human health
and/or the environment.

Diaz Chemical Corporation Superfund Site

as part of this effort, concluded that there were no
immediate or short term threats to human health.
Therefore, no further actions related to the residential
properties under EPA's removal authority were deemed
necessary.

In June 2003, Diaz Chemical filed for bankruptcy and
abandoned the facility, leaving behind large volumes of
chemicals in drums and tanks. EPA, under its removal
authority, mobilized to the site and began providing 24-
hour security at the facility to prevent public access. EPA
also began operating and maintaining the groundwater
extraction and treatment system at the facility. In addition,
EPA shipped approximately 8,600 drums and over
112,000 gallons of bulk waste from tanks and
containment areas off-site for re-use and/or disposal;
emptied, decontaminated, and disposed of 105 reactor
vessels and 34 tanks; dismantled and removed 51,280
linear feet of facility piping; recovered approximately 800
gallons of waste within the lines; removed and recycled
767 tons of structural steel, motors, and unprepared tank
and scrap steel; removed and disposed of 5,750 tons of
concrete (of which 500 tons were recycled); removed and
disposed of 9 PCB transformers; removed and disposed
of 175 cubic yards of lead-contaminated wood and 20
cubic yards of asbestos debris; decontaminated a
warehouse; and dismantled all of the production buildings
and tank containment areas, another warehouse, and a
boiler room, electrical room, laboratory, and an oil tank
storage area.

On July 22, 2004, the site was placed on the National
Priorities List.

On March 29, 2005, EPA signed a ROD which selected
the property acquisition and permanent relocation of eight
owner-occupant and two individual tenant families who
had remained in temporary quarters since January 2002.
The eight homes that were acquired by EPA are
identified on Figure 2. Under the ROD, the acquired
residences are to be maintained until the selection of a
final remedy for the site. In 2005, with the assistance of
the U.S. Army Corps of Engineers (USACE), EPA
purchased all eight homes and provided the owners with
relocation assistance. In addition, the two individual
tenants were assisted with relocating into new rental
dwellings. Since the acquisition of the eight properties,
USACE and EPA have maintained them.

EPA conducted several field investigations at the site
from 2004 through 2010. These investigations included
monitoring well installation and sampling; geological and
hydrogeological investigations; a residential vapor
intrusion investigation4; subsurface and surface soil

4 Vapor intrusion is a process by which VOCs move from a
source below the ground surface (such as contaminated
groundwater) into the indoor air of overlying or nearby

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Superfund Proposed Plan

sampling at the Diaz Chemical facility and off-property
areas; sampling of concrete chips from the former
transformer pad; sampling of surface water, sediment,
and pore water (water occupying the spaces between
sediment particles) from the East Branch of Sandy Creek
and its unnamed tributary; sampling of a seep from an
actively flowing location on the wall of the ravine; and
surface water sampling from two sumps and a catch
basin on the Diaz Chemical facility. In addition, an
ecological reconnaissance was performed at the Diaz
Chemical facility, unnamed creek, and its associated
riparian areas south of the site, Sandy Creek and
associated riparian areas, and a wooded parcel located
east of the site.

SITE HYDROLOGY/HYDROGEOLOGY
Site Hydrology

The site lies within the Western Ontario watershed. The
watershed discharges directly into Lake Ontario to the
immediate north.

The closest surface water body to the Diaz Chemical
facility is an unnamed stream that lies approximately 750
feet to the southeast. The elevation of the stream at this
location is approximately 520 feet above mean sea level
(amsl). The stream is a tributary of the East Branch of
Sandy Creek and contains approximately 4.2 miles of
wetland frontage. Off the southeast corner of the Diaz
Chemical facility, the unnamed tributary discharges into
the East Branch of Sandy Creek ravine via falls
comprised of sandstone ledges. The crest elevation of
the tributary is approximately 500 feet amsl.

The East Branch of Sandy Creek is approximately 0.5
mile east of the site and flows another 0.5 mile before it
intersects the Erie Canal. From Holley Canal Falls, the
East Branch of Sandy Creek flows under the Erie Canal
and north approximately 4 miles, where it intersects the
West Branch of Sandy Creek to form Sandy Creek.
Sandy Creek flows approximately 10 miles before it
discharges into Lake Ontario. Sandy Creek, from the
confluence of its east and west branches to Lake
Ontario, has been designated by NYSDEC as a
"Significant Coastal Fish and Wildlife Habitat." The
entire stream from the Village of Holley to Lake Ontario
has been designated as Class "C" (unprotected),
reflecting that cold water fish (salmonids) are not present
in the summer and do not successfully spawn in the
stream. The East Branch of Sandy Creek has no surface
water intakes and is not used for public water supply.

Diaz Chemical Corporation Superfund Site
Site Hydrogeology

Three major hydrogeologic zones have been defined at
the site: overburden/weathered bedrock; shallow
bedrock; and deep bedrock. These hydrogeologic zones
are described below.

Overburden/ Weathered Bedrock

The overburden/weathered bedrock groundwater zone is
comprised of unconsolidated overburden materials (fill,
swamp deposit, Pleistocene glaciolacustrine sediments,
Pleistocene lake margin sands, and glacial till) and
weathered Silurian Medina Group to Ordovician
Queenstown Formation shales and sandstones. The
weathered bedrock at the site is defined as material that
can be penetrated by an auger. Most of the mass of
VOCs and SVOCs is found in the overburden and
weathered bedrock. Because of their hydrogeologic
similarities, the overburden sediments and weathered
bedrock have been grouped into the same groundwater
zone.

The overburden/weathered bedrock groundwater zone is
unconfined and ranges in total thickness from
approximately 20 to 42 feet, thinning to the east and
southeast near the East Branch of Sandy Creek. The
depth to water in the overburden/weathered bedrock unit
ranges from 4 to 21 feet below ground surface (bgs).

Groundwater flow in the overburden/weathered rock is
through the interconnected, or permeable, pore spaces
within the glacial till and glaciolacustrine silts and sands,
in addition to fractures and pore spaces within the
weathered rock. Groundwater in this zone is continuous,
but it is restricted by localized lower permeability
deposits. The groundwater tends to follow topography
and flows to the east-southeast toward the ravine and the
East Branch of Sandy Creek. As groundwater flows
through this zone, it either moves into the shallow
bedrock or daylights to the ground surface before the
overburden pinches out at the ravine. Dense silt-clay
deposits present across the center of the Diaz Chemical
facility tend to impede groundwater flow through the
overburden under the production areas. Sand layers and
lenses within the overburden silts at the eastern end of
the site are interpreted to be preferential groundwater
flow pathways.

The connectivity between water-bearing lacustrine and
glaciolacustrine sediments in the overburden may be
limited. Consequently, the direction and velocity of
groundwater movement may be controlled by the
sedimentary facies architecture of the overburden
deposits.

buildings.

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Superfund Proposed Plan
Shallow Bedrock

The depth to water in the shallow bedrock ranges from 15
to 40 feet bgs. The water level elevations in shallow
bedrock suggest unconfined to semi-confined conditions.
Groundwater flow in the shallow bedrock zone is primarily
through bedrock joints and fractures to the
east-southeast toward the ravine and the East Branch of
Sandy Creek. As groundwater flows through the shallow
bedrock zone, it either discharges to the creek or to
seeps along the ravine. The potentiometric surface of the
shallow bedrock unit closely resembles the topography of
the top of competent bedrock.

Deep Bedrock

Water that occurs in the deep bedrock hydrogeologic
zone is largely restricted to joints and fractures.
Geophysical logging indicates the fractures in the deep
bedrock zone are relatively small and are generally low-
yield water-bearing features.

Monitoring wells screened in the deep bedrock unit are
classified as either intermediate or deep. Intermediate
wells are those in which the distance between the top of
competent bedrock and the top of the well screen is
between eight and 15 feet. These wells range in depth
from 44 to 49 feet bgs. Deep wells are those in which the
distance between the top of competent bedrock and the
top of the well screen is 15 feet or greater, or the top of
screen is set to at least 50 feet bgs. These wells range in
depth from 55 to 80 feet.

Groundwater flow through the deep bedrock is primarily
through bedrock joints and fractures. The Rl results
indicate that the presence of small, occasional fractures
with strong attenuation may be present in the deeper
bedrock that ultimately accommodates only minimal
groundwater flow, and, in turn, possibly slow solute
transport.

Groundwater generally flows east to southeast across the
site in the deep bedrock unit. There is a localized
depression in the potentiometric surface in the vicinity of
the groundwater collection trench. Just downgradient of
the collection trench, groundwater flow shifts from
southeast to more due south in the southern portion of
the site. Slow transmission of groundwater through the
deep bedrock matrix is a reasonable assumption based
on historic data and data gathered during this Rl.

RESULTS OF THE REMEDIAL INVESTIGATION

For purposes of the investigation, the site was divided
into four areas (see Figure 2):

• Diaz Chemical Facility, which includes the main

Diaz Chemical Corporation Superfund Site

Diaz Chemical facility property, bounded on the
north by Jackson Street, on the west by South
Main Street, and on the southwest by the railroad
tracks. It also includes the Diaz property referred
to as the Warehouse 9 area, located on the north
side of Jackson Street.

•	Southern Area, which is located south of the
main facility property. The area was formerly
occupied by the Diaz Chemical Corporation.

•	Residential Area, which includes residential
properties east and north of the Diaz Chemical
Facility and includes residences along Jackson
Street, South Main Street, Thomas Street, and
Batavia Street.

•	Former Transformer Pad Area, which is located
within the main facility property where electrical
transformers were previously located.

Two residential properties located upwind of the
prevailing wind direction at the site on Nelson Street and
Chippenben Drive were used as background sampling
areas.

The Rl included soil, groundwater, surface water,
sediment, pore water, rock matrix, and seep
investigations, ecological characterization of the site and
surrounding area, a topographic survey, and a cultural
resources survey.

Six source areas were identified at the facility in the
former chemical production, transfer, and storage areas-
Area C/D; Railroad Spur Area; Former Soda Ash Pit;
Area 5; Area F/Tank Farm 8; and Warehouse 2 Hot Spot
(see Figure 3).

The contaminants in the source areas are attributable to
spills and leaks during production and storage when the
Diaz Chemical facility was in operation. The
contaminants currently present in the source areas are
primarily SVOCs with lower aqueous solubility, which
allows them to persist in the unsaturated soils (above the
water table). More soluble contaminants have dissolved
into the groundwater and form the groundwater plumes
that have moved downgradient to the East Branch of
Sandy Creek.

Soils

During the Rl, one hundred surface (from the ground
surface to two feet bgs) and subsurface (deeper than two
feet) soil samples were collected from 25 locations at the
Diaz Chemical Facility. The principal contaminants in the
soils at the facility are chlorinated, fluorinated, and
brominated benzene compounds, "Tenneco Blend"

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Superfund Proposed Plan

Diaz Chemical Corporation Superfund Site

hydrocarbons (primarily, xylenes and di- and
trimethyl-benzenes), ethylene dibromide (EDB), and
1,2-DCA (see Figure 3).

NYSDEC has identified soil cleanup objectives (SCOs)
for the protection of the environment and for various
contaminants based upon the anticipated future use of
sites5. SCOs are based on the lowest concentration for
the protection of human health, ecological, or
groundwater depending upon the intended use of the
property. The most recent active use of the site is
"commercial." Table 1, below, summarizes the maximum
contaminant detections found in soils on the facility and
their SCOs. While the soil concentrations of several
contaminants do not exceed their respective SCOs, they
are listed in the table because either elevated
concentrations were detected in the groundwater or they
have been historically associated with the site.

Table 1: Maximum Soil Exceedances on Diaz Chemical Facility

Contaminant

SCO
(Mg/kg6)

Surface
Soil

(Mg'kg)

Subsurface
Soil (Mg/kg)

3-Amino-4-Chlorobenzotrifluoride

/

ND°

29.40C

Benzene

60

1C

9C

3-Bromoacetophenone

--

ND

47.60C

1 -Bromo-2-chloroethane

--

ND

967

1 -Bromo-4-ethyl benzene

--

ND

55.50C

1 -Bromo-3-fluorobenzene

--

ND

123

4-Bromofluorobenzene

--

ND

3,77C

2-Bromopyridine

--

ND

854

2-Butanone

120

27

20C

Chlorobenzene

1,100

41

4,50C

4-Chlorobenzotrifluoride

--

ND

219.00C

Cyclohexane

--

1C

2,20C

1,2-Dibromoethane

--

ND

1.10C

1,2-Dichloroethane

20

1.3

71C

1,3-Dibromobenzene

--

ND

6.19C

1,4-Dibromobenzene

--

ND

2,59C

3,4-Dichlorobenzotrifluoride

--

ND

598,00C

Ethylbenzene

1,000

26

29.00C

Fluorobenzene

--

ND

321

Isopropylbenzene

--

ND

7,70C

Methylcyclohexane

--

£

9,40C

Methylene Chloride

50

2.6

81

3-Nitro-4-Chlorobenzotrifluoride

--

ND

265,00C

Tetrachloroethene

1,300

5.7

1.60C

Toluene

700

ND

11

1,1,1-Trichloroethane

680

1C

57C

Trichloroethene

470

0.36

15

Vinyl Chloride

20

ND

0.21

m,p-Xylene

1,600

0.33

70.00C

o-Xylene

1,600

0.32

130.00C

Six concrete chip samples were collected from the
concrete pad of the former transformer area for PCB

6 NYCRR PART 375, Environmental Remediation Programs,
Subpart 375-6, New York State Department of
Environmental Conservation, December 14, 2006.
Micrograms per kilogram.

"—" denotes that this chemical does not have an SCO.
"ND" denotes that the chemical was not detected.

analysis. One PCB, Aroclor 1260, was detected in two of
the samples, ranging from 2,200 to 9,200 |jg/kg. Since
PCBs were not detected in any of the surface soil or
subsurface soil samples collected in this area, it has been
concluded that PCBs are confined to the former concrete
pad.

Twenty-nine soil samples were collected from five
locations in the Southern Area. The samples in this area
contained no site-related contaminants above SCOs.

Two hundred three surface (from the ground surface to
two feet bgs) and subsurface soil samples were collected
at 140 locations in the residential and background areas
(eleven background samples were collected from two
locations). VOCs were detected infrequently in surface
soils, with no site-specific VOCs detected above SCOs.
No VOCs or SVOCs were detected above SCOs in the
unsaturated soils in this area. Five site-specific
compounds, PCBTF, 1,3-dibromobenzene, DCBTF, 4-
bromofluorobenzene, and fluorobenzene were detected
at very low levels in the soils collected from the saturated
zone in an area located immediately adjacent to the
facility. The absence of detections from the unsaturated
soils suggests that these detections are related to the
dissolved groundwater plume, rather than migration of
source material in soils via runoff from the facility.

While CFP was detected at six residential properties in
surface soils and other outdoor media in 2002, surface
soils collected from the same properties and others in
2003 did not have detectable concentrations of CFP. In
addition, CFP was not found in any of the surface soils or
subsurface soil samples collected for the Rl in 2009. No
other site-related contaminants were detected in the
residential property soils.

Groundwater

The groundwater investigation included two rounds of
monitoring well sampling both on and off the Diaz
Chemical Facility property. Round 1 (September 2009)
gathered data on the distribution of groundwater
contamination from 47 locations, including 38 existing
monitoring wells, seven piezometers, one recovery well,
and one dug well. Round 2 (January 2010) included
sampling at 56 locations including 6 newly installed and
38 existing monitoring wells, eight piezometers, one
recovery well, two production wells and one dug well.

The results of the Rl field investigation indicate that
groundwater contamination extends from the center of
the facility east approximately 400 feet to the west side of
Sandy Creek and south approximately 100 feet to the
railroad tracks (see Figure 4). Concentrations of site-
related groundwater contaminants exceeding
groundwater standards are present in many monitoring
wells on the facility. A variety of VOCs and SVOCs were

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Diaz Chemical Corporation Superfund Site

detected in groundwater samples collected at the site
including benzene, xylene, toluene, cis-1,2-DCE, vinyl
chloride, PCBTF, and other chlorobenzotrifluoride
(CBTFs) compounds, bromopyridine, EDB, and
fluorobenzene. Based upon historical information, many
of these chemicals were used at the facility or were the
constituents of releases that occurred at the site in the
past.

Contaminant concentrations are highest in the
overburden and weathered bedrock compared to the
shallow bedrock, while the shallow bedrock shows
higher concentrations compared to the deep bedrock
zone. Denser than water substances would be expected
to migrate downward into the water table toward the
bedrock, dissolve in groundwater, and then move in the
direction of groundwater flow. However, the highest
concentrations of organic compounds detected in
monitoring wells occur in the overburden/weathered
bedrock zone. This condition is consistent with downhole
geophysical logging results that indicate that the most
productive water bearing zones occur in the weathered
bedrock. Contaminants associated with soils in the
source areas (primarily SVOCs) are expected to
continue to migrate downward into groundwater in the
overburden/weathered bedrock zone.

EPA and the New York State Department of Health
(NYSDOH) have promulgated health-based protective
Maximum Contaminant Levels (MCLs) (40 CFR Part
141, and 10 NYCRR, Chapter 1), which are enforceable
standards for various drinking water contaminants.
Although the groundwater at the site is not presently
being utilized as a potable water source, achieving
MCLs in the groundwater is an applicable standard,
because area groundwater is a source of drinking water.
Table 2, below, summarizes the maximum detections of
contaminants in the groundwater and identifies their
respective groundwater standards.

Micrograms per liter.

Table 2: Maximum Groundwater Exceedances continued

Contaminant

Standard

Highest Concentration



(Hg/L)

(Hg/L)

cis-1,3-Dichloropropene

5

31

trans-1,3-Dichloropropene

0.4

10

1,2-Dibromo-3-chloropropane

0.04

21

1,2-Dibromoethane

5

25,000

1,2-Dichloroethane

5

130,000

1,3-Dibromobenzene

5

2,710

1,4-Dibromobenzene

5

1,760

Ethyl benzene

5

2,000

Fluorobenzene

5

5,260

Isopropyl benzene

5

440

Methylene Chloride

5

2,500

3-Nitro-4-chlorobenzotrifluoride

5

2,520

Styrene

5

520

Tetrachloroethene

5

57

Toluene

5

13,000

1,1,1-Trichloroethane

5

2,500

Trichloroethene

5

9.5

Vinyl Chloride

2

100

m,p-Xylene

5

4,400

o-Xylene

5

16,000

A study was undertaken to assess the extent of
contamination within the pore spaces of the rock itself - a
term referred to as matrix diffusion. The objectives of this
analysis were to estimate the contaminant mass in the
rock matrix and to estimate a cleanup timeframe if
treatment were not implemented at the site.

The results of the matrix diffusion study are consistent
with groundwater monitoring results, in that the majority
(99%) of contamination diffused into the rock matrix is
found in the overburden and weathered bedrock. Based
on these results, it is estimated that the total mass of
PCBTF within the source areas is 2,400 kg. The
estimated mass distribution for PCBTF is 77% within the
vadose zone soil and 21% in the saturated overburden
soil. Overburden groundwater accounts for 2% of the
mass of PCBTF. Of the remaining 1% of PCBTF mass a
total of 0.7% is in the weathered bedrock soil and
groundwater; only 0.1% is in the rock matrix and 0.1% is
in the fractures.

In general, contaminants in the shallow bedrock zone are
present at lower concentrations, (often an order of
magnitude lower) and tend to be less widely distributed
than in the overburden/weathered bedrock zone.
Groundwater flow in this zone occurs in limited fractures
and joints in the rock. The observed contaminant
concentrations in the shallow bedrock are consistent with
the results of the matrix diffusion study, which indicates a
rapid drop off in VOC and SVOC mass within the first 10
feet below the top of competent rock. Overall,
contaminant migration within this zone is expected to be
limited.

The deep bedrock has few water bearing features and
those that are present are poor water producers. The
deep bedrock is poorly connected to the more productive

Table 2: Maximum Groundwater Exceedances

Contaminant

Standard

Highest Concentration



(ua/L9)

(ua/L)

3-Amino-4-chlorobenzotrifluoride

5

4,930

Benzene

1

5,100

3-Bromoacetophenone

5

12,900

1 -Bromo-2-chloroethane

5

57,900

1 -Bromo-4-ethyl benzene

5

434

4-Bromofluorobenzene

5

9,200

1 -Bromo-3-fluorobenzene

5

50.2

2-Bromopyridine

5

6,040

Chlorobenzene

5

46

4-Chlorobenzotrifluoride

5

20,700

Cyclohexane

5

260

3,4-Dichlorobenzotrifluoride

5

2,250

1,1-Dichloroethane

5

12

1,1-Dichloroethene

7

6.8

trans-1,2-Dichloroethene

5

5.3

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Superfund Proposed Plan

weathered bedrock zone. Groundwater flow in this zone
is slow, depending largely on the primary porosity of the
bedrock. It is likely that the limited contamination in the
deep bedrock is the result of the dispersion and diffusion
of contaminants into groundwater over time or transport
through a few fractures, possibly created during the
blasting of the groundwater collection trench. It is
expected that contaminant concentrations in the deep
bedrock zone will not increase substantially overtime and
contaminant migration within this zone is expected to be
slow.

As was noted previously, groundwater flow in all three
stratigraphic zones is toward the east southeast, toward
the ravine, and the East Branch of Sandy Creek.
Contaminants in the overburden/weathered bedrock zone
have migrated slightly east relative to the locations of the
source areas. While the groundwater collection trench
may be influencing the eastward migration, the
groundwater plume extends eastward, beyond the trench,
and is present in the shallow bedrock zone below some
of the residential properties east of the site.

Given the time period since releases have occurred at
the facility, the current location and geometry of the
contaminant plume, and the relatively poor flow
characteristics of the bedrock, the plume is expected to
continue to migrate slowly eastward toward the ravine
and the East Branch of Sandy Creek. Contaminants in
soil source areas will continue to contribute
contaminants to groundwater. The three stratigraphic
units outcrop in the ravine where groundwater is
expected to discharge via seeps or discharge into the
creek (see "Surface Water, Sediment, Pore Water and
Seep Investigation" section, below).

The majority of the groundwater contamination is in the
overburden/weathered bedrock zone, just above the
interface with competent bedrock. Overall, contaminant
distribution in groundwater reflects the contaminant
distribution in soil. The highest groundwater
concentrations were identified in the vicinity of Area 5,
the Former Soda Ash Pit, the Rail Spur Area, and Area
F. Groundwater sampling data and pore water
concentrations derived from the matrix diffusion study

10

suggest that dense non-aqueous phase liquid may be
present in the overburden/weathered bedrock zone in
the vicinity of the bedrock collection trench in Area 5.

Contaminant concentrations rapidly decrease in the first
10 feet of competent bedrock (i.e., the shallow bedrock
groundwater zone). In the shallow bedrock zone,
concentrations typically were highest at the bedrock
collection trench, although elevated levels were
observed in the Railroad Spur Area. Additionally,

10 A liquid that is both denser than water and is immiscible in
or does not dissolve in water.

Diaz Chemical Corporation Superfund Site

elevated concentrations extend eastward, toward wells
in the Residential Area.

While no data exist for shallow bedrock groundwater in
the western portion of the facility, based on the results of
the matrix diffusion study, it is not anticipated that
groundwater contamination deviates from the trends
observed with depth elsewhere across the site.

Contaminant concentrations in the deep bedrock
groundwater zone are often orders of magnitude lower
than in the shallow bedrock. The results of the matrix
diffusion study indicate that this condition is expected, as
contaminant mass transfer to the rock matrix is in the
deep bedrock zone. In the deep bedrock, contaminant
mass migrates slightly to the north, rather than to the
east and southeast as in the overlying groundwater
zones. This suggests that contaminant mass may be
migrating along a north-south striking fracture or set of
fractures. No data exist for deep bedrock groundwater in
the western portion of the facility. It is assumed that the
results of the matrix diffusion study apply broadly to the
deep bedrock zone and, therefore, contamination in the
deep bedrock zone is not expected in the western
portion of the site.

Deep bedrock groundwater exceeded the screening
criteria by almost two orders of magnitude in the vicinity
of the bedrock collection trench in Area 5 and the
Residential Area. Fracturing of the rock (by blasting) to
construct the bedrock collection trench could have
created fractures that joined existing fractures, creating
pathways for Area 5 contamination to migrate
downgradient in the deep bedrock zone.

An assessment of the natural attenuation potential of site
groundwater was performed.

The assessment consisted of evaluating the historically
detected concentrations of benzene, 1,2-DCA, EDB, and
PCE and their degradation products in conjunction with
natural attenuation indicator parameter data (pH, specific
conductivity, dissolved oxygen, temperature,
oxidation-reduction potential11, ferrous ion, total
dissolved solids, total suspended solids, Total Kjeldahl
Nitrogen, ammonia, nitrate/nitrite, chloride, sulfate, total
organic carbon, methane, ethane, and ethane) for
evidence indicating the potential occurrence of
biodegradation processes.

The presence of PCE, 1,2-DCA, and benzene
biodegradation intermediate and final compounds, such
as cis-1,2-DCE, vinyl chloride, methane, ethane, ethene,
and nitrogen, in combination with the generally favorable
geochemical characteristics of the groundwater (i.e.,

11 Chemical reactions in which atoms have their oxidation state
changed.

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Superfund Proposed Plan

strong anaerobic condition, low oxidation/reduction
potential and the presence of a reducing zone, and
sufficient carbon source) indicate that the subsurface
conditions are likely to be conducive to natural
attenuation, especially at the perimeter of the
groundwater plume, in an area to the north of Tank Farm
9/Drum Storage Area 3/Area 5 and in the vicinity of the
bedrock trench. These areas are characterized with low
to modest contaminant concentrations, along with
elevated concentrations of iron, methane, ethane,
ethene, and chloride. It appears that 1,2-DCA, EDB,
benzene, toluene, ethylbenzene, and xylene compounds
are being degraded under methanogenic conditions at
these locations.

Although natural attenuation of site-specific compounds
is an important removal process for groundwater,
significant concentrations of site-related contaminants
continue to persist at the source areas. Therefore, it is
apparent that natural attenuation alone is not sufficient to
significantly reduce elevated concentrations of ranges of
organic contaminants at the site. It is likely that microbial
activities in the source areas have been inhibited by the
excessive chemical toxicity exhibited by the
concentrated hazardous substances.

Surface Water, Sediment, Pore Water and Seep
Investigation

Nine co-located surface water and sediment samples
were collected from the unnamed tributary of Sandy
Creek and the East Branch of Sandy Creek. One sample
was collected upstream in Sandy Creek to provide data
on background conditions. Screening levels for wetland
sediments are outlined in the NYSDEC's Division of Fish,
Wildlife, and Marine Resource's 1999 Technical
Guidance for Screening Contaminated Sediments.

No site-related compounds were detected above the
screening criteria in surface water samples.

No VOCs were detected above the screening criteria in
the sediment samples. The polycyclic aromatic
hydrocarbon (PAH) benzo(a)pyrene was detected above
screening criteria (maximum concentration of 2,670
jjg/kg; criteria of 1.3 mg/kg). PCBTF was detected at 1.89
jjg/kg, perylene at 458 |jg/kg, and 11H-benzo(b)fluorene
at 132 jjg/kg; there are no sediment criteria for these
compounds.

The three stratigraphic units outcrop in the ravine where
groundwater is expected to discharge via seeps or
discharge into the creek. While pore water samples were
proposed at each surface water and sediment sampling
location, only five pore water samples were collected.
Despite repeated attempts to collect samples, many of
the pore water locations did not produce an adequate
volume of water. PCBTF was the only site-related

Diaz Chemical Corporation Superfund Site

compound detected in two pore water samples
(maximum concentration of 9.36 |jg/L). This detection
suggests that groundwater is discharging to the creek.

No site-related compounds were detected above the
screening criteria in the seep sample collected from the
west face of the ravine or in surface water samples
collected from the East Branch of Sandy Creek or the
unnamed tributary.

Surface water samples were also collected from two
sumps and one catch basin on the facility. Only one
SVOC, benzo(b)fluoranthene (0.091 |jg/L), exceeded the
water quality standard in one sump. In one sump
sample, eight PAHs, fluorobenzene (3,670 |jg/L), PCBTF
(195 jjg/L), 3-amino-PCBTF (110 jjg/L), DCBTF (26.4
jjg/L), 3-nitro-PCBTF (24 |jg/L), 4-bromofluorobenzene
(20.2 |jg/L), 2-bromopyridine (19.4 jjg/L) and 1-bromo-3-
fluorobenzene (9.98 |jg/L), exceeded their water quality
standards. While inorganics were detected in two sump
samples, they are not believed to be related to on-site
activities.

Vapor Intrusion Investigation

Beginning in 2004, EPA performed soil vapor intrusion
sampling at 14 homes that were deemed to be potentially
impacted by the underlying plume of contaminated
groundwater. Although no indoor air impacts were found
after 4 years of annual monitoring, in 2007, as a
conservative measure, EPA installed a vapor mitigation
system in a home where VOCs were found to be
collecting under the foundation so as to ensure that
indoor air quality is not impacted in the future. In
addition, in 2009, carbon filter systems were installed in
the basement of two other homes to remove low-levels of
VOCs. The three homes with mitigation systems are
located in the general vicinity of the intersection of South
Main and Batavia Streets.

EPA continues to monitor these three homes on an
annual basis.

SITE RISKS

Based upon the results of the Rl, a baseline risk
assessment was conducted to estimate the risks
associated with current and future property conditions.
A baseline risk assessment is an analysis of the
potential adverse human health effects caused by
hazardous-substance exposure in the absence of any
actions to control or mitigate these under current and
reasonably anticipated future land uses.

The human health risk assessment was based on
current reasonable maximum exposure scenarios and
was developed by taking into account various

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Diaz Chemical Corporation Superfund Site

conservative estimates about the frequency and duration
of an individual's exposure to the contaminants of
potential concern (COPCs), as well as the toxicity of
these contaminants.

A screening level ecological risk assessment (SLERA)
was conducted to evaluate the potential for ecological
risks from site-related contaminants to terrestrial and
aquatic environments present within the study area.

Human Health Risk Assessment

As was noted above, the facility is currently vacant and is
surrounded by a locked, chain link fence to restrict site
access. The site's historical usage has been
commercial/industrial. It is anticipated that the land use
in the future will stay the same. However, the possibility
that the site could be redeveloped for residential use was
also considered.

A four-step human health risk assessment process was
used for assessing Site-related cancer risks and
noncancer health hazards. The four-step process is
comprised of: Hazard Identification of Chemicals of
Potential Concern, Exposure Assessment, Toxicity
Assessment, and Risk Characterization (see the box on
the right, "What is Risk and How is it Calculated," for
more details on the risk assessment process).

The baseline human health risk assessment identified the
current and potential future receptors that may be
affected by contamination at the site, the pathways by
which these receptors may be exposed to site
contaminants in various environmental media, and the
parameters by which these exposures and risks were
quantified.

Current land use in the vicinity of the Diaz Chemical
Facility is primarily residential and commercial. To ensure
overall completeness of the baseline human health risk
assessment, a future recreational land use scenario was
also considered. Potential receptors were based on
current and potential future land uses of the site.
Potential receptors evaluated under the current land use
scenario included trespassers at the Diaz Chemical
Facility, residents within the Residential Area, and
recreational users of the East Branch of Sandy Creek.
Potential receptors evaluated under the future land use
scenario included residents and utility workers within the
Residential Area, recreational users of the East Branch of
Sandy Creek, and receptors associated with three
different potential future land uses at the Diaz Chemical
facility: industrial/commercial use involving site workers,
trespassers, and construction/utility workers; residential
use accounting for residents and construction/utility
workers; and park use including park users and
construction/utility workers.

WHAT IS RISK AND HOW IS IT CALCULATED?

A Superfund baseline human health risk assessment is an
analysis of the potential adverse health effects caused by
hazardous substance releases from a site in the absence of any
actions to control or mitigate these under current- and future-land
uses. A four-step process is utilized for assessing site-related
human health risks for reasonable maximum exposure scenarios.

Hazard Identification: In this step, the COPCs at the site in various
media (i.e., soil, groundwater, surface water, and air) are identified
based on such factors as toxicity, frequency of occurrence, and
fate and transport of the contaminants in the environment,
concentrations of the contaminants in specific media, mobility,
persistence, and bioaccumulation.

Exposure Assessment: In this step, the different exposure
pathways through which people might be exposed to the
contaminants in air, water, soil, etc. identified in the previous step
are evaluated. Examples of exposure pathways include incidental
ingestion of and dermal contact with contaminated soil and
ingestion of and dermal contact with contaminated groundwater.
Factors relating to the exposure assessment include, but are not
limited to, the concentrations in specific media that people might
be exposed to and the frequency and duration of that exposure.
Using these factors, a "reasonable maximum exposure" scenario,
which portrays the highest level of human exposure that could
reasonably be expected to occur, is calculated.

Toxicity Assessment: In this step, the types of adverse health
effects associated with chemical exposures and the relationship
between magnitude of exposure and severity of adverse effects
are determined. Potential health effects are chemical-specific and
may include the risk of developing cancer over a lifetime or other
non-cancer health hazards, such as changes in the normal
functions of organs within the body (e.g., changes in the
effectiveness of the immune system). Some chemicals are
capable of causing both cancer and non-cancer health hazards.

Risk Characterization: This step summarizes and combines
outputs of the exposure and toxicity assessments to provide a
quantitative assessment of site risks for all COPCs. Exposures
are evaluated based on the potential risk of developing cancer
and the potential for non-cancer health hazards. The likelihood of
an individual developing cancer is expressed as a probability. For
example, a 10"4 cancer risk means a "one-in-ten-thousand excess
cancer risk"; or one additional cancer may be seen in a population
of 10,000 people as a result of exposure to site contaminants
under the conditions identified in the Exposure Assessment.
Current Superfund regulations for exposures identify the range for
determining whether remedial action is necessary as an individual
excess lifetime cancer risk of 10"4 to 10"6, corresponding to a
one-in-ten-thousand to a one-in-a-million excess cancer risk. For
non-cancer health effects, a "hazard index" (HI) is calculated. The
key concept for a non-cancer HI is that a threshold (measured as
an HI of less than or equal to 1) exists below which non-cancer
health hazards are not expected to occur. The goal of protection
is 10"6 for cancer risk and an HI of 1 for a non-cancer health
hazard. Chemicals that exceed a 10"4 cancer risk or an HI of 1
are typically those that will require remedial action at the site.

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Superfund Proposed Plan

Exposure pathways evaluated for soil included incidental
ingestion, dermal contact, and inhalation of fugitive dust
and vapor by trespassers, residents, site workers, park
users, and construction/utility workers. Exposure
pathways evaluated for groundwater included ingestion
for future site workers, and ingestion, dermal contact, and
inhalation (vapor released during showering and bathing)
by future residents. Exposure pathways evaluated for
surface water and sediment included incidental ingestion
and dermal contact by recreational users.

As part of the baseline human health risk assessment, a
qualitative screening assessment to evaluate the
potential for vapor intrusion into indoor air was
investigated. Because many factors affect the potential
for vapor intrusion into indoor air, EPA conducts vapor
intrusion studies on a building-by-building basis. Several
vapor intrusion studies at the Diaz facility and in the
residential area have been conducted. As was noted
above, as a conservative measure, EPA installed vapor
mitigation systems in three homes to ensure that indoor
air quality is not impacted in the future.

Two types of toxic effects were evaluated for each
receptor in the risk assessment: carcinogenic effects and
non-carcinogenic effects. Calculated risk estimates for
each receptor were compared to EPA's acceptable range
of carcinogenic risk of 1 x 10~6 (one-in-one million) to 1 x
10~4 (one-in-ten thousand) and calculated hazard index
(HI) to a target value of 1.

For current receptors (trespassers at the Diaz Chemical
Facility, recreational users visiting East Branch of Sandy
Creek, and residents in the Residential Area), the
estimated cancer risks and noncancer hazards are below
or within EPA's target threshold values (cancer risk of
1 xio 6 to 1 xio 4 and noncancer HI of 1).

Although groundwater is not currently utilized for drinking
water at the Diaz Chemical Facility and in off-property
areas and future potable use of groundwater is highly
unlikely because a municipal water supply is readily
available and serves the area, a hypothetical future use
of contaminated groundwater as a potable water supply
was assessed. The estimated cancer risks for future site
workers (4^10"2), residents (1), and child park users
(2x10"4) at the Diaz Chemical Facility exceed EPA's
target thresholds. Additionally, estimated noncancer HI
for future site workers (40) and residents (3,644) at the
Diaz Chemical Facility exceed EPA's target threshold of
1. These future site workers and residential risks are
almost entirely due to the hypothetical future use of
contaminated groundwater as a potable water supply.
The utilization of groundwater by off-property residents in
the future scenario presents an increased cancer risk of
9x10"1 and a noncancer HI of 3,645. The major risk
drivers identified in groundwater were BCE, 1,2-DCA,
EDB, DBCP, PCBTF, benzene, ethylbenzene,

Diaz Chemical Corporation Superfund Site

dibenz(a,h)anthracene, TCE, vinyl chloride, and o-xylene
in groundwater.

For future child park users at a theoretical future park at
the Diaz Chemical Facility, the increased cancer risk is
almost entirely due to the incidental ingestion of
carcinogenic PAHs (cPAHs) in soil, with the major risk
driver identified as the cPAH benzo(a)pyrene.

The results of the 2003 dust, interior surface, and
household item sampling were discussed with NYSDOH;
no concerns related to human health were identified.

Ecological Risk Assessment

The SLERA is intended to conservatively screen data in
order to evaluate the potential for ecological risks
associated with terrestrial and aquatic environments
present within the study area. Conservative assumptions
are used to identify exposure pathways and, where
possible, quantify potential ecological risks.

An ecological reconnaissance was performed for the
site. Areas included in the ecological reconnaissance
consisted of the former facility, an unnamed creek and
associated riparian areas south of the site, and Sandy
Creek and its associated riparian areas, and a wooded
parcel located east of the site.

Information was collected regarding threatened and
endangered species and ecologically sensitive
environments that may exist at or in the vicinity of the
site.. A review of the United States Fish and Wildlife
Service records indicated that the bog turtle (Clemmys
muhlenbergii) and Eastern prairie fringed orchid
(Platanthera leucophea) are listed as being found within
Orleans County. Further review of wetland maps, the
New York State Herpetological Atlas, and historical
records indicate that both species are unlikely to occur
within the site or immediate surrounding areas. NYSDEC
reported that a review of their records for the site and
surrounding area indicated no known occurrences of
rare or state-listed species, or significant natural
communities and habitats.

For the purposes of the SLERA, the sources of
contamination were surface and subsurface soil, and
groundwater contamination associated with historic site
activities, spills, and releases. Contamination from these
sources may have migrated, or may continue to migrate
to surrounding areas via erosion, overland flow,
groundwater migration, and wind dispersion. An
exposure pathway is the means by which contaminants
are transported from a source to ecological receptors.

Observations made during the ecological
reconnaissance indicate the study area provides habitat
for a number of terrestrial and aquatic species, including

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Superfund Proposed Plan

invertebrates, fish, reptiles, amphibians, birds, and
mammals. Ecological receptors utilizing these areas
may be exposed to contaminated media via direct
contact or ingestion of contaminated media and/or prey.
Although several potential exposure scenarios can be
identified for ecological receptors, it is most appropriate
to focus the assessment on critical exposure scenarios
or those most likely to contribute to risk. Thus, the
SLERA focused on the direct contact exposure scenario.

Based on a comparison of maximum detected
concentrations of contaminants in site soil, sediment,
surface water, and pore water to conservatively derived
ecological screening levels, there is potential that
ecological risk may occur. Specifically, the SLERA,
which utilized the most conservative assumptions,
indicated potential risk to ecological receptors from a
variety of COPCs. However, with the exception of
specific site-related compounds, the majority of these
are most likely associated with regional geology, and
typical anthropogenic sources such as motor vehicles
and residential/agricultural pesticide application. Other
than physical disturbance, observations of impacts to
local flora and fauna communities related to site
activities were not observed during the ecological
reconnaissance. Risks from exposure to the majority of
potential site related chemicals are inconclusive due to a
lack of toxicity information for these compounds.

Summary of Human Health and Ecological Risks

The results of the human health risk assessment
indicate that the future use scenario at the site presents
an unacceptable exposure risk and the ecological risk
assessment indicates potential risk to ecological
receptors from exposure to media-specific COPCs.

Based upon the results of the Rl and the risk
assessment, EPA has determined that actual or
threatened releases of hazardous substances from the
site, if not addressed by the preferred remedy or one of
the other active measures considered, may present a
current or potential threat to human health and the
environment.

REMEDIAL ACTION OBJECTIVES

Remedial action objectives are specific goals to protect
human health and the environment. These objectives are
based on available information and standards, such as
applicable or relevant and appropriate requirements
(ARARs), to-be-considered (TBC) guidance, and site-
specific risk-based levels.

The following remedial action objectives were established
for the site:

Diaz Chemical Corporation Superfund Site

•	Reduce or eliminate any direct contact, ingestion,
or inhalation threat associated with contaminated
soils;

•	Reduce or eliminate the migration of
contaminants in soils to groundwater;

•	Reduce or eliminate the uptake of contaminants
in soil by biota;

•	Protect human health by preventing exposure to
contaminated soil, groundwater, and soil vapor;
and

•	Restore groundwater to levels that meet state
and federal standards within a reasonable time
frame.

SUMMARY OF REMEDIAL ALTERNATIVES

CERCLA §121 (b)(1), 42 U.S.C. §9621 (b)(1), mandates
that remedial actions must be protective of human health
and the environment, cost-effective, comply with ARARS,
and utilize permanent solutions and alternative treatment
technologies and resource recovery alternatives to the
maximum extent practicable. Section 121(b)(1) also
establishes a preference for remedial actions which
employ, as a principal element, treatment to permanently
and significantly reduce the volume, toxicity, or mobility of
the hazardous substances, pollutants, and contaminants
at a site. CERCLA §121 (d), 42 U.S.C. §9621 (d), further
specifies that a remedial action must attain a level or
standard of control of the hazardous substances,
pollutants, and contaminants which at least attains
ARARs under federal and state laws, unless a waiver can
be justified pursuant to CERCLA §121 (d)(4), 42 U.S.C.
§9621 (d)(4).

Detailed descriptions of the remedial alternatives for
addressing the contamination associated with the site
can be found in the FS report. The FS report presents
five soil alternatives, and four groundwater alternatives.

While in-situ soil vapor extraction (ISVE) was considered
to address the VOCs in the soil, it was screened out due
to the prevailing site characteristics. ISVE requires high
conductivities in order to effectively extract the vapors
from the soil. The soils found at the site, however, have
low conductivity and permeability.

While chemical oxidation was considered to address the
contaminated groundwater, it was screened out due to
potential issues with the delivery of the chemical
oxidants. Due to the high contaminant mass in the source
zones and the tight soils, a high density of injection points
along with a large quantity of oxidant (with multiple
injection rounds) would likely be required.

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Diaz Chemical Corporation Superfund Site

To facilitate the presentation and evaluation of the
alternatives, the FS report alternatives were reorganized
in this Proposed Plan to present the remedial alternatives
discussed below.

The construction time for each alternative reflects only
the time required to construct or implement the remedy
and does not include the time required to design the
remedy, negotiate the performance of the remedy with
any potentially responsible parties, or procure contracts
for design and construction.

Each of the active groundwater alternatives includes the
continued operation and maintenance (O&M) of the
existing vapor mitigation systems that have been installed
in three residences until ongoing monitoring indicates that
mitigation is no longer required.

The remedial alternatives are:

Soil Alternatives

Alternative S-1: No Action

Capital Cost:

Annual O&M Cost:

Present-Worth Cost:
Construction Time:

$0

$0
$0

0 months

The Superfund program requires that the "no-action"
alternative be considered as a baseline for comparison
with the other alternatives. The no-action remedial
alternative for soil does not include any physical remedial
measures that address the problem of soil and sediment
contamination at the site.

Because this alternative would result in contaminants
remaining above levels that allow for unrestricted use and
unlimited exposure, CERCLA requires that the site be
reviewed at least once every five years. If justified by the
review, remedial actions may be implemented to remove,
treat, or contain the contaminated soils and sediments.

Alternative S-2: Capping

Capital Cost:

Annual O&M Cost:
Present-Worth Cost:
Construction Time:

$4,300,000
$15,000
$4,500,000
12 months

This alternative consists of the installation of a multi-layer
cap over approximately 1 acre of contaminated soil in six
source areas.

Structures which are required to be removed to
implement this alternative would be demolished.
Demolition debris would be segregated and stockpiled
on-site. Building materials would be disposed off-site in
accordance with applicable regulatory requirements.

After building demolition, the contaminated area would be
cleared and grubbed. Cleared vegetation would be
disposed of at a nonhazardous waste landfill or could be
mulched and used elsewhere on-site. In order to keep
the site as close to the current elevation as possible,
approximately three feet of soil would be excavated.
The excavated area would be graded for positive
drainage to the edge of the excavation area. The
excavated soil would be disposed off-site or consolidated
onto the contaminated area for grading purposes.

It is anticipated that the cap would include a geosynthetic
clay liner, a 40-mil low density polyethylene polymeric
liner, drain netting, a common fill layer and top soil. A
drainage collection system would be installed on top of
the impermeable barrier to collect infiltration water and
discharge this water away from the contaminated area.
Any soil hotspots outside of the capped area would be
excavated and consolidated within the area to be capped.

The capped area would be fenced to prevent vehicles
from parking on top of the cap. Any vegetation that
potentially would grow roots that would damage the
impermeable layer would be removed during the long-
term maintenance program.

Under this alternative, institutional controls (ICs) in the
form of an environmental easement would be used to
prohibit future residential development/use of the area
that would be capped and restrict intrusive activities in
the capped area in accordance with an EPA-approved
"Site Management Plan."

The Site Management Plan would provide for the proper
management of all post-construction remedy
components. Specifically, the Site Management Plan
would describe procedures to confirm that the requisite
restrictions are in place and that nothing has occurred
that would impair the ability of the ICs to protect public
health or the environment. The Site Management Plan
would also include use restrictions; the necessary
provisions for the implementation of the requirements of
the above-noted environmental easement; a provision for
the performance of the operation, maintenance, and
monitoring required for the remedy; and a provision that
the property owner or party implementing the remedy
submit periodic certifications that the institutional and
engineering controls are in place.

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Because this alternative would result in contaminants
remaining on-site above levels that allow for unrestricted
use and unlimited exposure, CERCLA requires that the
site be reviewed at least once every five years.

Alternative S-3: Excavation and Off-Site Disposal

Capital Cost:

Annual O&M Cost:
Present-Worth Cost:
Construction Time:

$9,600,000
$0

$9,600,000
12 months

ISS treatment would limit potential future impacts from
soil to groundwater by reducing the leaching/mobility of
contaminants in soil, minimizing the amount of free
liquids in the soil pore space and reducing the hydraulic
conductivity of the soil.

During the design phase, bench- and pilot-scale
treatability studies would be performed to evaluate the
effectiveness of various soil stabilization mixtures at
reducing the leachability and permeability of the impacted
soil at the site. Solidification mixtures would be evaluated
for compatibility with the contaminants of concern and
tested for density, permeability, strength, and leachability
of contaminants.

This alternative includes the excavation of an estimated
19,300 cubic yards contaminated soil exceeding the soil
cleanup objectives above the water table (maximum
depth of 16 feet bgs) with off-site disposal at an off-site
Resource Conservation and Recovery Act (RCRA)-
compliant disposal facility.

Structures which are required to be removed to
implement this alternative would be demolished.
Demolition debris would be disposed of off-site in
accordance with applicable regulatory requirements.

Cleared vegetation would be disposed of at a
nonhazardous waste landfill or could be mulched and
used elsewhere on-site.

The excavated areas would be backfilled with imported
clean fill.

Because contaminated soils in the water table would
remain under this alternative, a readily-visible and
permeable subsurface demarcation layer would be
placed at the bottom of the excavation areas to delineate
the interface between the contaminated native soils and
the clean backfill.

This alternative would also include ICs and a
Management Plan as described in Alternative S-2.

Site

Alternative S-4: In-Situ Stabilization

Capital Cost:	$8,200,000

Annual O&M Cost:	$0

Present-Worth Cost:	$8,200,000

Construction Time:	12 months

This alternative consists of in-situ stabilization (ISS) of
the contaminated soils in the six source areas.

Structures which are required to be removed to
implement this alternative would be demolished.
Demolition debris would be disposed of off-site in
accordance with applicable regulatory requirements.

Prior to initiating the ISS process, any fill or debris within
the treatment area would be excavated and properly
disposed.

For ISS in the deep contamination area, an auger mixer
would be used to drill down to the desired depth.
Chemical reagents would be added into the ground as
the auger advances. The auger would mix the soil and
the reagents as it advances and retracts. The process
would be repeated throughout the contaminated areas.
The treatment "cylinders" would be overlapping to ensure
total coverage. Soil mixing would occur in two parts;
surface soil mixing (simple rototilling to 4 feet bgs) and
deep soil mixing (5-30 feet bgs). The reagents would be
added to the soil while the soil is being tilled and mixed.
After the treatment is completed, the treated areas would
be compacted and graded. A 6-inch topsoil layer would
be placed on top of the treated soil and seeded for
erosion control.

Testing of the treated soil using a series of tests to
simulate leaching would be required to verify the
effectiveness of the treatment process.

Because the volume of the media in the treatment area
would increase due to the addition of reagents, the
treatment areas would need to be regraded.

This alternative would also include ICs and a
Management Plan as described in Alternative S-2.

Site

Because this alternative would result in contaminants
remaining on-site above levels that allow for unrestricted
use and unlimited exposure, CERCLA requires that the
site be reviewed at least once every five years.

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Diaz Chemical Corporation Superfund Site

Alternative S-5: In-Situ Thermal Treatment

Capital Cost:	$8,900,000

Annual O&M Cost:	$0

Present-Worth Cost:	$8,900,000

Construction Time:	12 months

This alternative consists of installing and operating an in-
situ thermal treatment system, such as Electrical
Resistance Heating (ERH), in the six source areas to a
maximum depth of 16 feet (to the water table).

biotic/abiotic process (probably coupled with iron) to
eliminate chlorinated VOCs.

Sampling of the treated soil would be required to verify
the effectiveness of the treatment process.

Under this alternative, ICs in the form of an
environmental easement would be used to prohibit future
residential development/use of the site.

Groundwater Alternatives

Alternative GW-1: No Action

ERH uses electrodes to direct the flow of electrical
current to raise subsurface temperatures to the boiling
point of water (100°C). The heat generated from the
resistance of the subsurface causes the contaminants
and water to evaporate, creating in-situ steam and vapor.
The electrodes are co-located with a vapor extraction
system where the evaporated VOCs, steam, and NAPL
are carried to the surface under vacuum pressure.
Standard treatment technologies, such as catalytic
oxidation and granular activated carbon (GAC) are
applied at the surface before emission (under compliance
of state air emission standards) to the atmosphere.
Research has shown that the elevated temperatures from
the application of ERH may remain for up to six months
following the completion of the application of current.
Therefore, the vapor recovery effort would have to
continue.

ERH is effective in low conductivity and low permeability
matrices (which are prevalent across the site) and within
unsaturated and saturated zones. Since electricity
preferentially travels along lower resistance pathways
and given that in-situ vapor collection is co-located at the
point of application of resistive heating, ERH is able to
overcome these limitations of low conductivity and low
permeability matrices.

This alternative would require pre-design pilot/treatability
testing to optimize the effectiveness of thermal treatment
in remediating the COPCs. Thermal treatment can
operate inside, beneath, and near buildings and
infrastructure. Therefore, it may be possible to
implement this alternative without the demolition of
structures on the site. Whether or not demolition is
necessary would be determined during the pre-design
investigation. If demolition is required, demolition debris
would be disposed of off-site in accordance with
applicable regulatory requirements.

ERH enhances bioremediation processes since
increasing temperatures can be very beneficial to most
microbes. Some microbes use a combination

Capital Cost:

Annual O&M Cost:
Present-Worth Cost:
Construction Time:

$0
$0
$0

0 months

The Superfund program requires that the "no-action"
alternative be considered as a baseline for comparison
with the other alternatives. The no-action remedial
alternative would not include any physical remedial
measures to address the groundwater contamination at
the site.

Because this alternative would result in contaminants
remaining on-site above levels that allow for unrestricted
use and unlimited exposure, CERCLA requires that the
site be reviewed at least once every five years. If justified
by the review, remedial actions may be implemented to
remove or treat the wastes.

Alternative GW-2: Groundwater Extraction and
Treatment and Monitored Natural Attenuation

Capital Cost:

Annual OM&M Cost:
Present-Worth Cost:
Construction Time:

$374,000

$382,000
$6,600,000
12 months

Under this alternative, the on-site groundwater plume
would be hydraulically controlled by extraction trenches.
The existing extraction trench would be extended to the
south and modified to increase extraction efficiency. A
second trench would be installed upgradient of the
existing trench. A vertical barrier consisting of a high
density polyethylene (HDPE) curtain or slurry wall would
be installed on the downgradient side of each trench to
prevent groundwater migration and enhance the
groundwater capture zone. The depth of the trenches

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Superfund Proposed Plan

Diaz Chemical Corporation Superfund Site

would be to the top of shallow bedrock. A perforated
HDPE header pipe would be placed in the bottom of the
trench to convey groundwater and product to two sumps.
The new trench would be approximately 3 feet wide and
would be backfilled with aggregate to approximately 3
feet below ground.

The extracted groundwater would be treated with a
skid-mounted GAC/catalytic oxidizer treatment system
housed in a prefabricated structure. The treated water,
which would meet applicable discharge requirements,
would be discharged to the unnamed tributary or the
East Branch of Sandy Creek. Treatability studies would
be required to develop and design the specific treatment
process.

The downgradient contaminants would be allowed to
attenuate naturally.

Pilot testing, including pump tests, would be required to
determine sump pumping rates and to optimize the
groundwater management system.

highly unlikely because a municipal water supply is
readily available and serves the site and vicinity, local
ordinances do not prohibit the installation of private wells
in the area. Therefore, ICs to prevent the installation of
wells in the contaminated aquifer would be required.
Specifically, an environmental easement would be
required to prevent the use of groundwater on the Diaz
Chemical Facility property and would also require that
future buildings on the property either be subject to vapor
intrusion studies or be built with vapor intrusion mitigation
systems in place until the cleanup criteria have been
achieved throughout the Diaz Chemical Facility property.
To prevent the installation of wells in the affected off-
property areas, the governmental entity that would
authorize the installation of a private well would be
notified that private wells could not be installed in these
areas.

Because this alternative would result in contaminants
remaining on-site above levels that allow for unrestricted
use and unlimited exposure, CERCLA requires that the
site be reviewed at least once every five years.

In order to evaluate the performance of this alternative,
periodic monitoring of the groundwater would be
performed. Monitoring of the treatment system
performance would also be required. The resulting data
would be used to optimize the treatment process and
evaluate the effectiveness of this remedial alternative.

Groundwater contamination was first detected at the
facility over twenty years ago. High concentrations of
contaminants persist in on-site soils and groundwater,
yet monitoring and studies have identified relatively little
mass mobility within the underlying aquifers. As a
standard engineering practice, the duration of the
remedy is assumed to be 30 years. Following pump
testing, the remediation timeframes would be revised.

While it will take a relatively long time frame for natural
processes to attain remediation goals in the groundwater,
this remediation time period is appropriate for conditions
at the site, since there is no anticipated need for site
groundwater during this period.

Once site characterization and initial performance
monitoring activities have provided these data,
monitoring frequency may be revised if trends are
established and the remedy is progressing as expected.
Increases and decreases in monitoring frequency may
occur over the life of the remedy in response to changes
in site conditions and monitoring needs.

The entire groundwater plume would not immediately
achieve cleanup levels upon implementation of this
alternative. Although groundwater is not currently used
for drinking water at the Diaz Chemical Facility and in off-
property areas and future potable use of groundwater is

Alternative GW-3: In-Situ Thermal Treatment with
Monitored Natural Attenuation

Capital Cost:

Annual O&M Cost:
Present-Worth Cost:
Construction Time:

$12,400,000
$127,000
$13,800,000
12 months

This alternative would use the same technology as
Alternative S-5, in-situ thermal treatment, but it would
only be applied below the water table to the shallow
bedrock (to depths ranging from 25-50 feet bgs).
Natural attenuation would be used to address the
downgradient areas.

This alternative would include the same institutional
controls described in Alternative GW-2.

Because this alternative would result in contaminants
remaining on-site above levels that allow for unrestricted
use and unlimited exposure, CERCLA requires that the
site be reviewed at least once every five years.

Alternative GW-4: Vertical Barrier with Monitored
Natural Attenuation

Capital Cost:

Annual OM&M Cost:
Present-Worth Cost:

$2,200,000
$489,000
$9,700,000

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Diaz Chemical Corporation Superfund Site

Construction Time:	12 months

This alternative consists of installing two 1,000 linear feet
HDPE vertical barrier walls to prevent groundwater and
surface water flow into the site and limit NAPL and
contaminant migration downgradient of the Diaz
Chemical Facility property. Natural attenuation would be
used for downgradient areas.

One vertical groundwater barrier would be installed
along the eastern perimeter of the site to prevent
contaminated groundwater from moving off of the facility
property. A vertical barrier would also be installed
upgradient of the source areas to impede groundwater
flow into and through the contaminated material.

Hydraulic control would be maintained within the
overburden/shallow bedrock on-site via extraction wells
and/or trenches installed on the upgradient side of the
eastern barrier wall. The extracted groundwater would
be treated with a skid-mounted GAC/catalytic oxidizer
treatment system housed in a prefabricated structure.
The treated water, which would meet applicable
discharge requirements, would be discharged to the
unnamed tributary or the East Branch of Sandy Creek.
Treatability studies would be required to develop and
design the specific treatment process.

This alternative would include the same ICs described in
Alternative GW-2.

Because this alternative would result in contaminants
remaining on-site above levels that allow for unrestricted
use and unlimited exposure, CERCLA requires that the
site be reviewed at least once every five years.

COMPARATIVE ANALYSIS OF ALTERNATIVES

During the detailed evaluation of remedial alternatives,
each alternative is assessed against nine evaluation
criteria, namely, overall protection of human health and
the environment, compliance with applicable or relevant
and appropriate requirements, long-term effectiveness
and permanence, reduction of toxicity, mobility, or volume
through treatment, short-term effectiveness,
implementability, cost, and state and community
acceptance.

The evaluation criteria are described below.

Overall protection of human health and the
environment addresses whether or not a remedy
provides adequate protection and describes how
risks posed through each exposure pathway
(based on a reasonable maximum exposure

scenario) are eliminated, reduced, or controlled
through treatment, engineering controls, or ICs.

Compliance with ARARs addresses whether or
not a remedy would meet all of the applicable or
relevant and appropriate requirements of other
federal and state environmental statutes and
requirements or provide grounds for invoking a
waiver.

Long-term effectiveness and permanence refers
to the ability of a remedy to maintain reliable
protection of human health and the environment
overtime, once cleanup goals have been met. It
also addresses the magnitude and effectiveness
of the measures that may be required to manage
the risk posed by treatment residuals and/or
untreated wastes.

Reduction of toxicity, mobility, or volume through
treatment is the anticipated performance of the
treatment technologies, with respect to these
parameters, a remedy may employ.

Short-term effectiveness addresses the period of
time needed to achieve protection and any ad-
verse impacts on human health and the
environment that may be posed during the
construction and implementation period until
cleanup goals are achieved.

Implementability is the technical and administra-
tive feasibility of a remedy, including the avail-
ability of materials and services needed to imple-
ment a particular option.

Cost includes estimated capital and O&M costs,
and net present-worth costs.

State acceptance indicates if, based on its review
of the RI/FS reports and Proposed Plan, the
State concurs with the preferred remedy at the
present time.

Community acceptance would be assessed in the
ROD and refers to the public's general response
to the alternatives described in the Proposed
Plan and the RI/FS reports.

A comparative analysis of these alternatives based upon
the evaluation criteria noted above follows.

Overall Protection of Human Health and the
Environment

Alternative S-1 would not protect human health and the
environment, because it would not actively address the
contaminated soil, which presents unacceptable risks of

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Superfund Proposed Plan

ecological exposure and is a source of groundwater
contamination, which poses a human health risk.
Alternatives S-2 through S-5, on the other hand, would
provide protection to human health and the environment,
since these alternatives rely upon a remedial strategy or
treatment technology capable of eliminating human and
ecological exposure and address the source of
groundwater contamination.

Because Alternative GW-1 would not actively address
the contaminated groundwater, it would not be as
protective as Alternatives GW-2, GW-3, and GW-4,
which include active treatment or containment of the
contaminated groundwater. The ICs under Alternatives
GW-2 and GW-3, and GW-4 would provide protection of
public health until groundwater standards are met.

Under Alternative GW-1, the restoration of the
groundwater would take a significantly longer time than
the estimated 30 years for all three of the active
groundwater alternatives. Therefore, the three active
groundwater alternatives would be more protective of
human health and the environment than the no action
alternative.

There are considerable hydrogeologic concerns that
would affect the performance of both the extraction
(Alternative GW-2) and vertical barrier (Alternative GW-
4) alternatives. The very low hydraulic conductivity and
permeability of the aquifer would significantly hinder the
ability to extract groundwater. Also, the presence of
fractured bedrock underlying the overburden would limit
the ability of a vertical barrier to contain contamination,
as it could likely travel under the wall and migrate
beyond the system. It would be difficult to effect
hydraulic control at the site. ERH (Alternative GW-3),
on the other hand, is effective in low conductivity and low
permeability matrices. Also, ERH enhances
bioremediation processes, since increasing
temperatures can be very beneficial to most microbes.

While it will take a relatively long time frame for natural
processes to attain remediation goals in the groundwater
under Alternatives GW-2, GW-3, and GW-4, this
remediation time period is appropriate for conditions at
the site, since there is no anticipated need for
groundwater in the area during this period.

Compliance with ARARS

There are currently no federal or state promulgated
standards for contaminant levels in sediments. There
are, however, other federal or state advisories, criteria,
or guidance (which are used as TBC criteria).
Specifically, NYSDEC's sediment screening values are
TBC criteria. Soil cleanup objectives were evaluated
against NYSDEC's 6 NYCRR Part 375, Environmental
Remediation Programs, Subpart 375-6, effective

Diaz Chemical Corporation Superfund Site
December 14, 2006.

Since the contaminated soils would not be addressed
under Alternative S-1, this alternative would not achieve
the chemical-specific ARARs.

Alternative S-2 would comply with the chemical-specific
ARARs by preventing direct contact risks and infiltration
of water if the cap is properly maintained and ICs
enforced.

Alternative S-3 would comply with chemical-specific
SCOs through the removal of the contaminated soils.
Alternative S-4 would comply with chemical-specific
SCOs by preventing direct contact risks and mobilization
of contaminants through solidification. Alternative S-5
would comply with chemical-specific SCOs through
mass removal.

Since Alternative S-3 would involve the excavation of
contaminated soils, this alternative would require
compliance with fugitive dust and volatile organic
compound emission regulations. In addition, this
alternative would be subject to New York State and
federal regulations related to the transportation and off-
site treatment/disposal of wastes. In the case of
Alternative S-5, compliance with air emission standards
would be required for the thermal treatment system.
Specifically, treatment of off-gases would have to meet
the substantive requirements of New York State
Regulations for Prevention and Control of Air
Contamination and Air Pollution (6 NYCRR Part 200, et
seq.) and comply with the substantive requirements of
other state and federal air emission standards.

EPA and NYSDOH have promulgated health-based
protective MCLs (40 CFR Part 141, and 10 NYCRR,
Chapter 1), which are enforceable standards for various
drinking water contaminants (chemical-specific ARARs).
Although the groundwater at the site is not presently
being utilized as a potable water source, achieving
MCLs in the groundwater is an applicable standard,
because area groundwater is a source of drinking water.

Alternative GW-1 would fail to be compliant with the
chemical-specific ARARs identified for the site, since no
action would be taken. Alternative GW-2 removes and
GW-4 isolates contaminated groundwater at the facility.
Accordingly, these alternatives would reduce
contaminant levels in groundwater over the long term
and are likely to meet chemical-specific ARARs.
Implementing Alternatives GW-2 and GW-4 in
conjunction with one of the soil alternatives to isolate,
immobilize or remove the contaminants in the
unsaturated soils could reduce the time needed to attain
chemical ARARs for groundwater. Alternative GW-3
would reduce contaminant levels in groundwater and
would likely meet chemical-specific ARARs.

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In the case of Alternatives GW-2, GW-3, and GW-4,
compliance with air emission standards would be
required for the treatment systems. Specifically,
treatment of off-gases would have to meet the
substantive requirements of New York State Regulations
for Prevention and Control of Air Contamination and Air
Pollution (6 NYCRR Part 200, et seq.) and comply with
the substantive requirements of other state and federal
air emission standards.

The ICs in Alternatives S-2, S-3, S-4, S-5, GW-2, GW-3,
and GW-4 would be implemented consistent with the
provisions of New York State Environmental
Conservation Law Section 27-1318, Institutional and
Engineering Controls,

Long-Term Effectiveness and Permanence

Alternative S-1 would involve no active remedial
measures and, therefore, would not be effective in
eliminating the potential exposure to contaminants in soil
and would allow the continued migration of contaminants
from the soil to the groundwater. Alternative S-2, would
achieve long-term effectiveness by containing
contaminated soils under a cap. Maintenance of the cap
would be required over the long-term to assure
permanence. Alternative S-3 would achieve long-term
effectiveness and permanence through removing the
contaminated soils and treating and disposing of them
off-site. Alternative S-4 would achieve long-term
effectiveness and permanence by stabilization of the
contaminated soils. Removal of contaminant mass
through in-situ treatment under Alternative S-5 would
achieve long-term effectiveness and permanence.

Under Alternatives S-4 and S-5, treatability studies would
be required to evaluate the effectiveness of various soil
stabilization mixtures at reducing the leachability and
permeability of the impacted soil at the site and the
effectiveness of various thermal treatment technologies,
respectively.

Under Alternative S-5, the extracted vapors would be
treated by granular activated carbon before being vented
to the atmosphere. The granular activated carbon would
have to be appropriately handled (off-site
treatment/disposal). Alternatives S-1, S-2, S-3, and S-4
would not generate such treatment residuals.

While natural attenuation of site-specific compounds Is
occurring at the perimeter of the groundwater plume, in
an area to the north of Tank Farm 9/Drum Storage Area
3/Area 5, and in the vicinity of the bedrock trench,
significant concentrations of site-related contaminants
continue to persist at the source areas and areas
immediately downgradient of the source areas. It is
apparent that natural attenuation alone is not sufficient to
significantly reduce elevated concentrations of ranges of

organic contaminants at the site. Therefore, Alternative
GW-1 would not provide long-term effectiveness and
permanence since no action would be taken since
contaminants would persist and continue to migrate into
the environment. No controls would be implemented to
prevent future exposure. Alternative GW-2 would not be
a practicable approach to address the contamination in
the groundwater due to the low hydraulic conductivities
that were measured across the site. The Rl indicated
that minimal groundwater contamination is observed in
the deep bedrock zone, where groundwater typically
occurs in fractures that are not in hydraulic
communication with the overlying groundwater zones;
but given the limitations imposed by the low
conductivities, it is possible that overburden
contamination could continue to migrate to the shallow
and deep bedrock under Alternative GW-2. The
performance of Alternative GW-2 would likely be
improved by addressing source area soils under
Alternatives S-3, S-4 or S-5, but effectively addressing
the contamination already present in the bedrock may
still prove difficult. Alternative GW-3 may be the only
remedy that can address the contaminants that are
sorbed and/or diffused into the rock matrix, including the
elevated concentrations of PCBTF in the shallow
bedrock zone in Area 5 and the railroad Spur Area and
in deep bedrock wells located along the current
collection trench. Alternative GW-4 would provide a
moderate degree of long-term effectiveness and
permanence by removing and treating contaminated
groundwater and establishing a barrier to prevent
downgradient movement of contaminated groundwater,
and could take 30 years or longer to achieve the RAOs
for groundwater. The long-term effectiveness and
permanence of Alternative GW-4 would be improved if
completed in conjunction with one of the soil alternatives
to remove, isolate or immobilize the contaminated
unsaturated subsurface soils; although as with
Alternative GW-2, it may not adequately address the
contamination already present in the shallow and deep
bedrock zones. In fact, given that contamination has
been detected in the shallow and deep bedrock
suggests contaminant transport from the
overburden/weathered bedrock zone has already
occurred.

Alternatives GW-2 and GW-4 would generate treatment
residues that would have to be appropriately handled.
Under Alternative GW-3, the extracted vapors would be
treated by granular activated carbon (or a similar
treatment technology) before being vented to the
atmosphere. The granular activated carbon would have
to be appropriately handled (off-site treatment/disposal).
Alternative GW-1 would not generate treatment residues.

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Reduction in Toxicity, Mobility, or Volume through
Treatment

Alternative S-1 would provide no reduction in toxicity,
mobility or volume. Alternative S-2 would reduce the
mobility of the contaminants, but not through treatment.
Alternative S-3 would reduce the volume of on-site
contaminant soil through removal. The toxicity, mobility
or volume of the contaminants in the soil would be
reduced if treatment is required at the off-site treatment
and disposal facility. Alternative S-4 would not reduce
the toxicity or volume of contaminants, but the mobility
would be reduced by immobilization. Under Alternative
S-5, the toxicity, mobility, and volume of contaminants
would be reduced or eliminated through on-site
treatment.

Alternative GW-1 would not effectively reduce the toxicity,
mobility, or volume of contaminants in the groundwater,
as this alternative involves no active remedial measures.
This alternative would rely on natural attenuation to
reduce the levels of contaminants; a process that has
been slowly occurring at the site. Alternatives GW-2 and
GW-4 would provide a moderate reduction of toxicity,
mobility or volume through the treatment component of
the alternative. Alternative GW-3 would provide a high
level of reduction in contaminant toxicity, mobility or
volume through treatment.

Short-Term Effectiveness

Since Alternative S-1 does not include any physical
construction measures in any areas of contamination, it
would not present any potential adverse impacts to
remediation workers or the community as a result of its
implementation. Alternatives S-2 and S-3 could present
some limited adverse impacts to remediation workers
through dermal contact and inhalation related to
excavation and grading activities.

Noise from the excavation and grading of the capping
material treatment, excavation work, and solidification
process associated with Alternatives S-2, S-3, and S-4
respectively, could present some limited adverse impacts
to remediation workers and nearby residents.
Alternatives S-2 through S-5 would generate noise and
impact traffic due to heavy construction equipment that
would need to be mitigated through site control and traffic
control measures.

For Alternatives S-2 and S-3, there is a potential for
increased storm water runoff and erosion during
construction and excavation activities that would have to
be properly managed to prevent or minimize any adverse
impacts. For these alternatives, appropriate measures
would have to be taken during grading and excavation
activities to prevent the transport of fugitive dust and
exposure of workers and downgradient receptors. Dust

Diaz Chemical Corporation Superfund Site

control would need to be implemented through the use of
dust suppression techniques (e.g., water or foam sprays)
to minimize impact to the workers and the local
community. In addition, air monitoring would be required
to reduce risks to workers and the community from
fugitive emissions during construction and remediation.
Soil sampling under Alternatives S-2, S-3, S-4, and S-5
would pose a potential exposure risk to remediation
workers through dermal contact and inhalation. The
excavation work under Alternatives S-2 and S-3, as well
as the installation of the treatment grid through
contaminated soil under Alternative S-5 would also pose
a potential dermal contact exposure risk to remediation
workers. The noted risks to remediation workers under all
of the action alternatives could, however, be mitigated by
following appropriate health and safety protocols, by
exercising sound engineering practices, and by utilizing
proper protective equipment.

Alternative S-3 would require the off-site transport of
contaminated soil (approximately 1,365 truck loads),
which would potentially adversely affect local traffic and
may pose the potential for traffic accidents, which in turn
could result in releases of hazardous substances.
Alternative S-3 would also require the transport of
approximately 1,365 truckloads of clean soil to the site.

Since no actions would be performed under Alternative
S-1, there would be no implementation time. It is
estimated that Alternatives S-2, S-3, S-4, and S-5 would
require 12 months to implement.

Alternative GW-1 would have no short-term impact to
workers or the community, and would have no adverse
environmental impacts, since no actions would be taken.
Alternatives GW-2, GW-3, and GW-4 might present
some limited risk to remediation workers through dermal
contact and inhalation related to groundwater sampling
activities. The installation of the treatment grid under
Alternative GW- 3 would also pose a potential exposure
risk to remediation workers. In addition, air monitoring
would be required to reduce risks to workers and the
community from fugitive emissions during construction.
The noted risks to remediation workers under all of the
action alternatives could, however, be mitigated by
following appropriate health and safety protocols, by
exercising sound engineering practices, and by utilizing
proper protective equipment.

Since no actions would be performed under Alternative
GW-1, there would be no implementation time. The time
for implementing Alternatives GW-2 and GW-3 is
estimated to be 12 months. For Alternative GW-4, the
total time for implementing this alternative is estimated to
be 2 years. For all of the action alternatives, the overall
duration of this remedy to achieve the cleanup criteria
throughout the entire groundwater plume is estimated to
be 30 years.

EPA Region II - August 2012

20


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Superfund Proposed Plan

Diaz Chemical Corporation Superfund Site

Implementabilitv

Alternative S-1 would be the easiest soil alternative to
implement, as there are no activities to undertake.

Alternatives S-2, S-3, and S-4 are technically
implementable and use conventional construction
equipment. Equipment, services, and materials needed
for these alternatives are readily available and the actions
under these alternatives would be administratively
feasible. Sufficient facilities are available for the
treatment/disposal of the excavated materials under
Alternative S-3. Because of the unusual chemicals that
are present in the soils, it is possible that in-situ
solidification under Alternative S-4 may prove to be
difficult.

Since the boiling point and solubility of PCBTF are within
the range that you could confidently apply ERH,
Alternative S-5 is technically implementable. Alternative
S-5 is also administratively implementable. Alternative S-
5 also would facilitate the implementability of
groundwater Alternative GW-3 by allowing direct
application of a thermal treatment grid to the saturated
subsurface soil.

Since no action would be performed under Alternative
GW-1, it would be the easiest to implement. Alternative
GW-2 would be technically and administratively
implementable but not be a practical approach for the
site due to the low hydraulic conductivities that were
measured across the site. Alternative GW-3 is
technically and administratively implementable.
Alternative GW-4 would also be technically and
administratively implementable, although the barrier
would extend only to tie in to the shallow bedrock,
meaning that contamination present in or migrating to
open fractures would not be contained by the vertical
barrier.

The implementation of ICs would be relatively easy to
implement under all of the soil and groundwater
alternatives.

Cost

The present-worth costs associated with the soil
remedies are calculated using a discount rate of seven
percent and a five-year time interval. The present-worth
costs associated with the groundwater remedies are
calculated using a discount rate of seven percent and a
thirty-year time interval.

The estimated capital, O&M, and present-worth costs for
each of the alternatives are presented in Table 3, below.

Table 3: Remedial Alternatives Costs

Alternative

Capital

Annual
O&M

Total
Present
Worth

S-1

$0

$0

$0

S-2

$4,300,000

$15,000

$4,500,000

S-3

$9,600,000

$0

$9,600,000

S-4

$8,200,000

$0

$8,200,000

S-5

$8,900,000

$0

$8,900,000

GW-1

$0

$0

$0

GW-2

$374,000

$382,000

$6,600,000

GW-3

$12,400,000

$127,000

$13,800,000

GW-4

$2,200,000

$489,000

$9,700,000

The soil and groundwater alternatives and their
corresponding costs were developed for stand-alone soil
and groundwater alternatives. If, however, thermal
treatment is used to address both the soil and
groundwater contamination (i.e., Alternatives S-5 and
GW-3), the implementation would be concurrent and
construction and operation of only one treatment system
would be required, thereby resulting in a substantial cost
savings. Therefore, the capital, annual O&M, and
present-worth costs for thermal treatment for both the
soil and groundwater would be $13.2 million, $110,000,
and $14.5 million, respectively (as compared to the
individual combined totals of $21.3 million, $110,000,
and $22.7 million, respectively).

State Acceptance

NYSDEC concurs with the proposed remedy.

Community Acceptance

Community acceptance of the preferred alternative
would be addressed in the ROD following review of the
public comments received on the Proposed Plan.

PROPOSED REMEDY

Based upon an evaluation of the various alternatives,
EPA, in consultation with NYSDEC, recommends
Alternative S-5 (in-situ thermal treatment) as the
preferred alternative to address the contaminated soil at
the site and Alternative GW-3 (in-situ thermal treatment
with monitored natural attenuation) as the preferred
alternative for the groundwater.

The remedy would consist of installing and operating an
in-situ thermal treatment system, such as ERH, in the six
source areas. The ERH process can deliver varying
amounts of energy via electrodes into discrete
subsurface unsaturated and saturated intervals, resulting
in increased temperatures for rapid contaminant source
zone remediation and enhanced biodegradation. The
application of heat increases the partitioning of organic
chemicals into the vapor or gas phase, where they would

EPA Region II - August 2012

21


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Superfund Proposed Plan

be extracted by a co-located vapor recovery system. The
extracted vapors would be treated by GAC before being
vented to the atmosphere.

During the design phase, further soil sampling would be
performed to better characterize areas requiring
remediation. Also during the design phase, bench- and
pilot-scale treatability studies would be performed to
evaluate the effectiveness of the various thermal
treatment technologies.

Sampling of the treated soil and groundwater would be
required to verify the effectiveness of the treatment
process (i.e., its ability to treat to soil SCOs and MCLs,
respectively).

Performance and compliance monitoring and testing
would be performed during the treatment process to
determine residual contaminant concentrations, assess
the need for continued treatment, and monitor the
natural attenuation of the contamination at the periphery
of the groundwater plume.

If building demolition is required, demolition debris would
be disposed of off-site in accordance with applicable
regulatory requirements.

Upon completion of the remedy, a one-foot soil cover
would be placed over areas where surface soils exceed
the commercial SCOs on the site12. Before the
placement of the soil cover, a readily-visible and
permeable demarcation layer would be placed over these
areas to delineate the interface between the
contaminated native soils and the soil cover. The soil
cover would meet the requirements as set forth in 6
NYCRR Part 375-6.7(d) for commercial use. The upper
six inches of the soil cover would be of sufficient quality
to maintain a vegetation layer.

The remedy would also include the continued operation
and maintenance of the three existing residential vapor
mitigation systems until monitoring data indicates that
mitigation is no longer required.

Under this alternative, ICs in the form of an
environmental easement would be used to restrict the
property to commercial use and restrict intrusive activities
in areas where residual contamination remains unless the
activities are in accordance with an EPA-approved Site
Management Plan. Since the entire groundwater plume
would not immediately achieve cleanup levels upon
implementation of this alternative, the environmental
easement would also prevent the use of groundwater and

12 Contaminants not related to spills or disposal operations are
present outside of the six source areas. SCOs would be
attained in the six source areas through the implementation
of the remedy.

Diaz Chemical Corporation Superfund Site

would require that future buildings on the Diaz Chemical
Facility either be subject to vapor intrusion study or be
built with vapor intrusion mitigation systems in place until
the cleanup criteria have been achieved throughout the
property. To prevent the installation of wells in the
affected off-property areas, the governmental entity that
would authorize the installation of a private well would be
notified that private wells could not be installed in these
areas.

The Site Management Plan would provide for the proper
management of all post-construction remedy
components. Specifically, the Site Management Plan
would describe procedures to confirm that the requisite
restrictions are in place and that nothing has occurred
that would impair the ability of the controls to protect
public health or the environment. The Site Management
Plan would also include the necessary provisions for the
implementation of the requirements of the above-noted
environmental easement; a provision for the performance
of the operation, maintenance, and monitoring required
by the remedy; and a provision that the property owner or
party implementing the remedy submit periodic
certifications that the institutional and engineering
controls (i.e., demarcation layer) are in place.

It has been determined, in consultation with NYSDOH,
that no remedial actions are warranted at any of the
residential properties.

The environmental benefits of the preferred remedy may
be enhanced by consideration, during the design, of
technologies and practices that are sustainable in
accordance with EPA Region 2's Clean and Green
Energy Policy and NYSDEC's Green Remediation
Policy3. This would include consideration of green
remediation technologies and practices.

Because this remedy would result in contaminants
remaining on-site above levels that allow for unrestricted
use and unlimited exposure, CERCLA requires that the
site be reviewed at least once every five years after the
initiation of the action.

Basis for the Remedy Preference

While Alternatives S-2, S-3, and S-4 would effectively
achieve the soil cleanup levels, Alternative S-2, leaves
the contaminated soil in place and would limit future
reuse options of the property. It also requires significant
long-term maintenance. Although Alternative S-3 is a
more permanent solution than the capping, it is
significantly more expensive to implement due to the

13 See http://epa.gov/reaion2/superfund/areen remediation and
http://www.dec.ny.gov/docs/remediation_hudson_pdf/der31.
pdf.

EPA Region II - August 2012

22


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Superfund Proposed Plan

disposal costs. Also, there are a number of short-term
issues with the excavation remedy, i.e., community
disturbance from trucks driving into and out of the facility
property through the residential neighborhood, noise,
dust and air issues, etc. Alternative S-4 would require
treatability tests to determine the most effective
stabilization agent for the unusual contaminants that are
present at the site, identifying a suitable agent may prove
to be difficult. ERH (Alternative S-5) is effective in low
conductivity and low permeability matrices which are
prevalent across the site. Since electricity preferentially
travels along lower resistance pathways and given that
the in-situ vapor collection system is co-located with the
electrodes, ERH overcomes the limitations of low
conductivity and low permeability matrices.

With regard to the groundwater, there are considerable
hydrogeologic concerns that would affect the
performance of both the extraction (Alternative GW-2)
and vertical barrier (Alternative GW-4) alternatives. The
very low hydraulic conductivity and permeability of the
aquifer would significantly hinder the ability to extract
groundwater. Also, the presence of fractured bedrock
underlying the overburden would limit the ability of a
vertical barrier to contain contamination, as it could likely
travel under the wall and migrate beyond the system. It
would be difficult to effect hydraulic control at the site.

Considerable cost-savings would be realized if thermal
treatment is used to address both soil and groundwater
contamination because only one treatment system would
need to be constructed and operated.

EPA believes that Alternatives S-5 and GW-3 would
effectuate the soil and groundwater cleanup while
providing the best balance of tradeoffs with respect to the
evaluating criteria.

The preferred remedy is believed to provide the greatest
protection of human health and the environment, provide
the greatest long-term effectiveness, be able to achieve
the ARARs more quickly, or as quickly, as the other
alternatives, and is cost effective. Therefore, the
preferred remedy would provide the best balance of
tradeoffs among alternatives with respect to the
evaluating criteria. EPA and NYSDEC believe that the
preferred remedy would treat principal threats, be
protective of human health and the environment, comply
with ARARs, be cost-effective, and utilize permanent
solutions and alternative treatment technologies or re-
source recovery technologies to the maximum extent
practicable. The preferred remedy also would meet the
statutory preference for the use of treatment as a
principal element.

Diaz Chemical Corporation Superfund Site

RESIDENTIAL PROPERTY DISPOSITION

In the 2005 ROD for the site, EPA selected the
acquisition of eight properties and the permanent
relocation of the residents of those properties as an
interim remedy for the site. Subsequently, with the
assistance of USACE, EPA acquired the properties.
Since that time, USACE and EPA have been maintaining
the acquired properties and will continue to do so until the
disposition of the properties is determined in a
forthcoming ROD for the overall site.

The properties were acquired by the United States
pursuant to the requirements of Section 104(j) of
CERCLA. Under CERCLA Section 104(j)(1), 42 U.S.C. §
104(j)(1), EPA is authorized to acquire any real property
or interest in real property that is needed to conduct a
remedial action under CERCLA. This authority may be
used when: 1) the President, in his or her discretion,
determines that the property acquisition is "needed to
conduct a remedial action;" and 2) before the real estate
interest is acquired, "the State in which the interest to be
acquired is located assures the President, through a
contract or cooperative agreement or otherwise, that the
State will accept transfer of the interest following
completion of the remedial action." Section 104(j)(1) and
(2), 42 U.S.C. §96040)(1) and (2).

The 2005 ROD documented the justification to acquire
residential properties, and, thus, it satisfies the CERCLA
Section 104(j)(1) authorization.

In 2005, New York State entered into a Superfund State
Contract (SSC) with EPA14. The SSC provides in
Paragraph K.1. that the State agreed to acquire or
otherwise accept transfer of any interests in real property
located on-site or incident thereto which EPA deems
necessary for the performance of the remedial actions at
the site. This language in the SSC satisfies the CERCLA
Section 1040(2) requirement. In 2006, the State entered
into Amendment No. 1 to the SSC with EPA. The
amended SSC included additional language regarding
the sale of the properties in Paragraph K.1., stating that:
"[i]f and when any real property acquired under this
Contract is sold, the net proceeds will be distributed to
EPA and the State in the same proportion as provided in
this SSC." This language shows that EPA and the State
envisioned the possible future sale of the properties that
were acquired at the site.

While Section 1040 of CERCLA requires that the State
must assure EPA that it will accept transfer of the interest
following completion of the remedial action, CERCLA

14 The purpose of an SSC is to identify EPA's and the State's
roles and responsibilities associated with remedial actions
and to obtain a commitment for the State's remedial action
cost share.

EPA Region II - August 2012

23


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Superfund Proposed Plan

Diaz Chemical Corporation Superfund Site

does not require that such properties must only be
transferred to the State.

This Proposed Plan identifies a preferred remedy for the
site which does not require remedial actions on the
residential properties other than the continued operation
and maintenance of the three existing residential vapor
mitigation systems15. Therefore, EPA has determined
that the sale or transfer of the eight properties acquired
by EPA (see Figure 2) is consistent with the proposed
final remedy and it intends to dispose of such properties
in a manner consistent with the SSC.

15 The mitigation systems are in three homes located in the
general vicinity of the intersection of South Main and Batavia
Streets.

EPA Region II - August 2012

24


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C:\IMS\GIS\Diaz\MXD\RIFINAL\Fig1-1_SiteLocMap.mxd

K Miles
1

Figure 1
Site Location Map
Diaz Chemical Corporation Site
Holley, New York

Lake Ontario


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WAREHOUSE 9

Jackson St

MAINTENANCE
SHOP

3,4-Dichlorobenzotrifluoride, PCBTF,
EDB and 1,2-DCA
Down to 25-ft

WAREHOUSE

WESTERN
DSA

WAREHOUSE

AREA A

"£REAF

AREA B

TRANSFORMER
PADl f

WAREHOUSE

OFFICE

AREA C

AREA D

AREAE

AREA 5

iFORMER SODA
ASH PIT

LOADING DOCR]

BEDROCK*
TRENCH I

HILLCREST LOT

Railroad Spur Area
PCBTF, Xylene, and Tenneco
Blend hydrocarbons
Down to 16-ft (water table)

Former Soda Ash Pit
PCBTF, 3-Nitro-PCBTF and Xylene
Down to 16-ft (water table)

IMS IGIS\DIAZ\mxd\PRAP\Fig3_ProposedPlan_Summary of Soil Contamina tion. mxd

D

Warehouse 2 Hot Spot (one location)
PCE and PCBTF down to 4 ft

inr-

Diaz Facility
Southern Area
Residential Area
un Source Areas (estimated)

DSA = Drum Storage Area
TF = Tank Farm

Note: Listed contaminants exceed
cleanup goals

0 75 150

1 Feet

Figure 3

Summary of Soil Contamination
Diaz Chemical Corporation Site
Holley, New York

Area C/D

PCBTF, Xylene, Tenneco Blend hydrocarbons,
EDB and 1,2-DCA
Down to 16-ft (water table)

Area F7 Tank Farm 8

DSA" 21

PCBTF and 3-Nitro-PCBTF

Down to 8-ft (water table)


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Jackson St

SANDY CREEK
(EAST BRANCH)

SANDY CREEK
(UNNAMED TRIBUTARY)

Extent of Contaminated Groundwater
Hydrogeologic Zone

Overburden/Weathered Bedrock
Shallow Bedrock
Deep Bedrock

Contours represent the approximate extent of
groundwater exceeding cleanup goals

Hydrogeologic Framework

1.	Overburden/Weathered Bedrock: ground surface to -30-44 ft bgs

2.	Shallow Bedrock: -30-50 ft bgs (upper portion of competent bedrock)

3.	Deep Bedrock: >50 ft bgs

© Site Monitoring Well
in Source Areas (estimated)

Diaz Facility
¦¦¦ Edge of Ravine

= Bedrock Groundwater Collection Trench

Arrow Indicates General Groundwater Flow Direction
(flow in each zone is toward the East Branch of Sandy Creek)

Figure 4

Extent of Groundwater Contamination
Diaz Chemical Corporation Site
Holley, New York


-------