United States Office of
Environmental Protection Emergency and
Agency Remedial Response
EPA/ROD/R08-93/071
June 1993
&ER& Superfund
Record of Decision:
Sand Creek Industrial
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50272.101
REPORT DOCUMENTATION I 1. REPORT NO. 2. 3. Recipient'. ACC88.lon No.
PAGE EPA/ROD/R08-93/071
4. Thle .nd Subthle 5. Report Date
SUPERFUND RECORD OF DECISION 06/30/93
Sand Creek Industrial (Operable Unit 2), CO 6.
Third Remedial Action
7. Author(.) S. Performing Organization Rept. No.
9. P.rformlng Organization Name and Add,.. 10 Project Te.kJWortl Unh No.
11. Contract(C) or Grant(G) No.
(C)
(G)
12. Sponsortng Organization Name and Addl'88. 13. Type of Raport & P.rlod eover8d
U.S. Environmental Protection Agency
401 M Street, S.W. 800/800
Washington, D.C. 20460 14.
15. Supplementary Note.
PB94-964413
16. Abstract (Umh: 200 worda)
The Sand Creek Industrial (Operable Unit 2) site is part of the SSO-acre Sand Creek
Industrial site located within the Sand Creek floodplain in Commerce City, Colorado.
The site surface is composed principally of alluvial materials and imported fill, which
covers the area so that natural features .are difficult to discern. Surficial fill
materials at the site consist of clay, silt, sand, gravel, and debris including brick,
c:oncrete, glass, metal, plastic, trash, and wood. Land use in the area is -
predominantly industrial and agricultural. An estimated 25 residents live within a
one-mile radius of the site. Municipal water is supplied to the metropolitan area
surrounding the site through ground water and surface water from alluvial and bedrock
wells and outside sources. Four suspected contaminant source areas were identified at
the Sand Creek Industrial site: the Oriental Refinery, the Colorado Organic Chemical
facility, the 48th and Holly Landfill, and the L.C. Corporation property. Each source
area was designated as an OU for remediation. from 1948 to 1958 the L.C. Corporation
operated onsite, when impoundments were constructed on the property and later enlarged.
A gravel pit and drainage ditch that discharged to Sand Creek were excavated, and large
areas were cleared and buildings were constructed. In 1968, L.C. Corporation began
disposing of spent sulfuric acid adjacent to the site, and it was to line its disposal
(See Attached Page)
17. Documant AnaIysi8 a. D88crlptora
Record of Decision - Sand Creek Industrial (Operable Unit 2), CO
Third Remedial Action
Contaminated Medium: None
Key Contaminants: None
b. Identlfie""Open-Ended Term.
c. COSATI Field/Group
1S. Availability Statement 19. Security Cia.. (ThIs Report) 21. No. of Pages
None 12
20. Security C1u8 (Thl. Page) 22. Price
None
(See ANSI-Z39.1S)
SHlnstructions on R.".18lI
OPTIONAL FORM 272 (4.77)
(Formarty NTI8-35)
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EPA/ROD/R08-93/071
Sand Creek Industrial (Operable Unit 2), CO
Third Remedial Action
Abstract (Continued)
pits with an ethylene propylene copolymer film before disposing of any acid. Some type of
liner was installed; however, its composition could not be determined because of the
disintegrated condition of the liner. The liner was breached and repaired after
approximately 7,810 tons of sulfuric acid was disposed of in the L.C. Corporation pits.
In 1974, the State investigated the property in response to a complaint involving severe
chemical burns to livestock that had strayed onto the property, and as a result, found
pools of liquid in lined pits onsite. L.C. Corporation agreed to clean up the liquid
after an analysis showed it was a sulfuric acid solution that exceeded acceptable
contamination levels. In 1975, State employees discovered a seep discharging extremely
acidic liquid to Sand Creek. As a result in 1976, the State issued an emergency cease and
desist and cleanup order against L.C. Corporation. In 1980, after several years of
investigations and negotiations, L.C. Corporation undertook cleanup at the site. A 1-acre
area was excavated to a depth of 15 to 20 feet, neutralized with lime, and covered with
soil. Due to the complex nature of the site, EPA has divided it into six operable units
in order to more effectively address specific conta~ination problems. A 1989 ROD
addressed contaminated soil, buildings, and tanks, as OU1, and a 1990 ROD addressed
contaminated soil at the Colorado Organic Chemical In 1988, site-wide RI identified
several contaminants on the L.C. Corporation property, but sources and the extent of
contamination were not defined because of the limited number of samples taken.
Furthermore, duplicate samples frequently did not verify the presence of contaminants. In
1990 and 1991, additional soil samples were collected, which identified contaminants
including VOCs, metals, insecticides, and herbicides. Because these chemicals occurred at
low concentrations, it was determined that the site poses no unacceptable risks to human
health and the environment; therefore, there are no contaminants of concern affecting this
site.
The selected remedial action for this site is no further action b~cause prior cleanup
activities were adequate to protect human health and the environment. There are no
present worth or O&M costs associated with this no action remedy.
PERFORMANCE STANDARDS OR GOALS:
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RECORD OF DECISION
DECLARATION STATEMENT
SITE NAME AND WCATION:
Sand Creek Industrial Site
L. C. Corporation Property
Operable Unit 2
Commerce City, Colorado
CC(Q)lr~
DECLARATIONS OF BASIS AND PURPOSE
This decision document presents the selected remedial action for Operable Unit 2, the
L. C. Corporation Property, at the Sand Creek Industrial Site in Commerce City, Colorado. This
remedial action has been developed in accordance with the Comprehensive Environmental Response,
Compensation and Liability Act of 1980 (CERCLA) as amended by the Superfund Amendments and
Reauthorization Act of 1986 (SARA), applicable state law and, to the extent practicable, with the
National Oil and Hazardous Substances Pollution Contingency Plan (the National Contingency Plan,
Title 40 Code of Federal Regulations Part 300). This decision is also based on the administrative
record for the site. The state of Colorado concurs with the selected remedy.
ASSESSMENT OF TIlE SITE AND DESCRIPTION OF SELECTED REMEDY
As a result of prior cleanup activity on the OU2 property there is no significant risk to the
public health by ingestion, inhalation, or skin absorption. The former neutralization of the acid pits
does not need augmentation or additional activity. No further action is therefore recommended for
OU2.
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STATUfORY DETERMINATIONS
I have determined that the no action alternative at the Sand Creek Industrial Site Operable
Unit 2 is a remedy that provides protection of public health, welfare, and the environment and is cost
effective. The State of Colorado has been consulted and agrees with the approved remedy. Because
this remedy will not result in hazardous substances remaining on site, above health-based levels, no
five year review will be 'necessary~..f9r OU2.
rr.3
Date
Re 19nal Administrator
U. jEnvironmental Protection Agency
Region 8
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Section
TABLE OF CONTENTS
~
DECLARATIONS
1.
II.
m.
IV.
V.
VI.
Vll.
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . i
SITE NAME, LOCATION, AND DESCRIPTION. . . . . . . . . . . . . . . . . . . . . . . .. 1
SITE HISTORY AND ENFORCEMENT ACTIVITIES. . . . . . . . . . . . . . . . . . . . .. 3
CO~NTrYRELATIONS ............. ......................... 4
SITE CHARACTERISTICS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 5
A.
SURFACE GEOLOGY. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 7
B.
SUBSURFACE GEOLOGY. . . . . . . . . . . . . . . . . . . . . . . . . . . . : . . . .. 8
HEALTH RISK ASSESSMENT. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . " 8
RECOMMENDED ALTERNATIVE. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 9
DOCUMENTATION OF SIGNIFICANT CHANGES. . . . . . . . . . . . . . . . . . . . . .. 9
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SUMMARY OF REMEDIAL ALTERNATIVE SELECTION
Sand Creek Industrial Site
L. C. Corporation Property
Operable Unit 2
Commerce City, Colorado
I.
SITE NAME, LOCATION, AND DESCRIPnON
The Sand Creek Industrial Site occupies about 550 acres in Commerce City, Adams County,
Colorado. Operations at the site, an active industrial area throughout its history, have included
trucking firms, petroleum refining operations, chemical production and supply companies,
warehouses,and small businesses. Environmental contamination at the site resulted in its inclusion on
the National Priorities List (NPL) in December 1982. Four suspected contaminant source areas have
been identified at the Sand Creek Industrial Site: Oriental Refinery, the Colorado Organic Chemical
facility, the 48th and Holly LandflII, and the L. C. Corporation property. These properties, their
ownership, and the operations on them are distinct; however, they were added to the NPL as a single
site and each source area was designated as an operable unit. A site-wide remedial investigation (RI)
was completed in 1988. This record of decision is concerned with the L. C. Corporation property
soils, operable unit (OU) 2 (see Figure 1).
The L. C. Corporation property has been part of Commerce City industry since 1948.
Between 1948 and 1958, impoundments were constructed on the property and later enlarged. A
gravel pit and drainage ditch that discharged to Sand Creek were excavated. Large areas were
cleared and buildings were constructed. L. C. Corporation itself was formed in 1955.
The L. C. Corporation site lies within the Sand Creek Uood plain, which is in turn part of the
South Piatte River system. Topography in the area rises gently to the south. The site surface is
composed principally of alluvial materials and imported flIl. Imported fill material covers the area
sufficiently that natural features are difficult to discern. Surficial fill materials at the site generally
consist of clay, silt, sand, gravel, and debris including concrete, brick, wood, metal, plastic, glass,
and trash. Approximately 10 feet of imported fill is present on the L. C. Corporation property at
OU2. Fill material is generally poorly compacted and highly permeable.
The site is located in Commerce City, Adams County, Colorado. U. S. Interstate 270 (1-270)
is directly north of OU2. Properties to the north of OU2 are zoned for light and heavy industrial,
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'-- :h:'~ =. .OU2 SITE. ..-- _'n_.
.BOUNDARY
,f
MORELLI
SERVICES
, -'
143 +
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S!i-~
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LEGEND
...............
PREVIOUS PITS
AI'ID LAGOONS
. .
PREVIOUS OITCHES
.. I.IONITORING WELL, WESTON 1986-1987
. DEEP .SOIL BORING (>5 FEET DEPTH)
- .. 200-SERIES DRILLED BY WESTON 1986-1987
0-1- AND OS DRILLED BY PRC 1990
01, 02. D3,DRILLED BY PRC \99\
~ SHALLOW SOIL SAMPLE (<5 FEET DEPTH),
100-SERIES COLLECTED BY W<:STON 1986-1987
S-SERIES COLLECTED BY PRC \990 .
'0
SCALE: I
'00
200
300
400 f"[ ET
I
Figure. 1
2
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industrial park, industrial park storage and agricultural uses. About 15 residences with about 25
people are located within a mile of the site. South'of OU2 are OUI and OU5, where pesticides were
manufactured during the 1960's and 1970's, and the Oriental Refinery operated prior to being
destroyed by fire in 1955.
Commerce City's Comprehensive Plan 1985 to 2010 indicates that future land use of this area
will be primarily industrial, with a recreation/open space designation for the Sand Creek floodplain.
ll.
SITE mSTORY AND ENFORCEMENI' ACTIVITIES
Shell Chemical Company contracted with L. C. Corporation in 1968 for the disposal of spent
sulfuric acid from Shell's chemical plant at the Rocky Mountain Arsenal, which is adjacent tc?
Commerce City. L. C. Corporation was to line its disposal pits with an ethylene propylene
copolymer f11m before disposing of any acid. Some type of liner was installed, however, its
composition could not be determined because of the disintegrated condition of the liner. The liner
was breached and repaired after acid was poured in the pits. Approximately 7,810 tons of sulfuric
acid were disposed of in the L. C. Corporation pits.
In November 1974, the Tri-County Health Department investigated a complaint involving
severe chemical burns to livestock that had strayed onto L. C. Corporation property. The department
found pools of liquid in lined pits on the property. L. C. Corporation agreed to clean up the liquid
after analysis showed it was a 30 percent sulfuric acid solution with a pH of 0.75, which is strongly
acidic. In July 1975, employees of the Tri-County Health Department discovered a seep discharging
extremely acidic liquid to Sand Creek. Subsequent analysis in 1976 of a sample of the seep liquid
and of water from Sand Creek indicated that both contained sulfone, an intermediate byproduct from
Shell's manufactur~ of the herbicide Planavin. Sulfone can be any number of compounds containing
the sulfur atom and is used as an indicator for an acid source. Thus far, no significance has been
ascribed to the sulfones except for their use as an indicator that sulfur compounds are present, some
'of which may be toxic. See the section in this ROD, entitled "Site Characteristics, It for more
information on the contamination at the site.
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The Colorado Department of Health (CDH) issued an emergency cease and desist and cleanup
order against L. C. Corporation, its principals, and other parties on October 25, 1976. After several
years of investigations, discussions, negotiations, and legal action, L. C. Corporation undertook
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cleanup of the site in 1980. L. C. Corporation excavated a I-acre area to a depth of 15 to 20 feet,
mixed the soil with lime, and replaced the neutralized soil in the excavation. Samples collected for
. the U.S. Environmental Protection Agency (EPA) since 1980 have contained sulfones but the soils
have not been acidic.
An EP A field investigation team (FIT) evaluated the Sand Creek Industrial Site for potential
inclusion on the NPL in 1982. Again, soil and water samples on OU2 contained sulfones but were
not acidic. The entire site, including OU2, was added to the NPL on December 30, 1982 because of
the history of past activities which resulted in contamination. In addition, a remedial investigation
was performed on the OU2 property in 1992.
m.
COMMUNITY RELATIONS
In general, community interest in OU2 and the Sand Creek Superfund Site has been low.
EP A has undertaken several community relations activities as part of the recent' site history. In the
fall of 1991 community interviews were conducted to update the site community relations plan. The
plan was updated and released in December of 1991. Tbe plan outlines the community concerns and
the strategies for implementing the plan.
The project manager and community relations coordinator have met with the Tri-County
Health staff, South Adams County Water and Sanitation District, Rocky Mountain Arsenal personnel,
Commerce City/Adams County officials, Metro Waste Water officials and Representative Pat
Schroeder's staff to update them on site activities.
The Proposed Plan for OU2 was issued to the public on September 9, 1992. The Proposed
Plan and RI reports were made available to the public through the Administrative Record maintained
at the EP A Region VIII Superfund Records Center in Denver and at the information repository at the
Adams County Library. A notice of availability of these documents and notification of the public
meeting were published in The Denver Post on September 11, 1992 and in Commerce City Beacon on
September 9, 1992.
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RE: OI2-
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The public comment period was open from September 11, 1992 to October 11, 1992. The
, .
public meeting was held on September 23, 1992 at the Commerce City Recreation Center and had
two attendees. EPA and the CDH explained the basis for the no further action alternative and
responded to questions. 'A transcript of the public meeting has been entered into the Administrative
Record. A Responsiveness Summary, prepared by EP A to address public comments is included in
the Administrative Record.
IV.
SITE CHARACTERISTICS
The Sand Creek Industrial Site is located in an urban environment that has been extensively
modified from its original condition over the past 50 years. The site lies in an area of low relief
within the Sand Creek flood plain, which is part of the South Platte River system. Sand Creek is a
braided, bedload stream generally wider than deep; maximum channel widths range from '22 to 28
feet within the area of the site. Sand bars are evident at numerous locations along the stream and
stream banks are vegetated. Active erosion is noticeable on the southern side of the creek
downstream from the Holly Street Dam, one of a number of artificial structures impeding stream
flow. Others include two bridges and a sheet pile dam near the downstream end of the study area
(the Vasquez Dam). The L. C. Corporat.ion property lies within the lower portion of the Sand Creek
watershed. The on-site drainage area represents less than one-half of one percent of the total drainage
to Sand Creek. As a result, the change in flow as Sand Creek passes the site is minimal. Runoff
from much of the area is carried in swales to low-lying areas, where it evaporates or infiltrates into
the underlying ground water. There are no pennanent surface water bodies at OU2.
A site-wide RI completed in 1988 identified several contaminants on the L. C. Corporation
property but sources and extent of contamination were not defined, because of the limited number of
samples taken. Furthennore, duplicate samples frequently did not verify the presence of
contaminants. Therefore, additional soil samples were collected in October and November 1990 and
in November 1991 to verify or better define contamination identified in the site-wide RI.
To detennine the health risks on the L. C. Corporation property a baseline risk assessment
" . '
was completed. The ri.)k assessment assumed there would be unrestricted use of the property. For
5
RE: 012-COl102:Z\aD:lcrek\0u2-rod\M-29-93\aJc
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example, there could be urban development on and around the site for both commercial and industrial
use.
The 131 soil samples collected during the various investigations at OU2, contained
contaminants including metals, insecticides, herbicides, volatile organic compounds (VOCs), and
semi volatile organic compounds (SVOCs). Maximum concentrations were evaluated for all
contaminants of concern (COCs). The maximum concentration was calculated for a residential area,
which is the most conservative scenario. Based upon the evaluation of the OU2 data there is no need
for further clean up of the property. Following is a detailed summary of the COCS and their
distribution.
Metals. Six metals (arsenic, chromium, lead, mercury, nickel, and zinc) were identified as
potential contaminants of concern based on observed concentrations and relative toxicity.
Concentrations were generally higher in shallow soil samples than in deep samples. None of the
measured concentrations of chromium exceeded that action level of 50 milligrams per kilogram
(mg/kg); the mean concentration of all other metals except mercury was below background
concentrations established during the s.ite-wide RI. Concentrations of mercury exCeeded background
levels in three shallow soil samples. However, the maximum mercury concentration - about twice the
background level - appears anomalous because the concentrations in all other samples were below the
background level. The maximum mercury concentration is below the accepted risk level. In
addition, many of the high concentration values could be considered anomalous due to lack of
consistency with the majority of the samples obtained. Overall, contamination of OU2 soils by these
metals was judged of lesser concern than other contamination at OU2 because of the very small
number of samples with elevated metal measurements.
Insecticides. A few soil samples contained insecticide concentrations that exceeded
background levels. These samples did not indicate a distinct source of contamination. These
insecticide concentrations most likely have resulted from their application for insect control during
historical site operations.
" ,
Herbicides. Relatively high herbicize concentrations were found in a few soil samples
collected near a heavily traveled street, where application of herbicides for weed control would be
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expected. As with insecticides, the distribution of herbicides throughout the site did not indicate a
distinct source of contamination.
.f
Volatile Organic Compounds. A few VOCs were detected in the soil samples taken on the
OU2 property. Acetone and methylene chloride compounds are common laboratory-induced .
contaminants and were detected in method blanks. Acetone and methylene chloride are used in the
laboratory extraction process and may have contaminated the method blanks and the samples. The
other VOCS detected in soil samples were at concentrations below baseline risk for the site.
Semi volatile Organic Compounds. Numerous polyaromatic hydrocarbons (pAHs), detected
in soils at OU2. The high concentrations of PAHs found during the site-wide investigation (1982
Remedial Investigation) could not be verified by subsequent sampling.
Based upon an evaluation of the OU2 data, and the remediation that has been performed,
there is no need for any additional cleanup of the site.
A.
SURFACE GEOLOGY
Topography in the area rises gently to the south, with elevations ranging from 5,160 feet
above' mean sea level (MSL) in the northwestern comer of the site to 5,250 feet MSL in Ute
southeastern comer. Interpretation of natural features is complicated by the extensive amount of fill
that has been brought into the area. Natural drainage paths also have been altered by development in
much of the area. Surficial deposits consist of Pleistocene and Holocene alluvium, eolian sediments,
and loess. Alluvial deposits range in thickness from less than 30 feet to approximately 90 feet near
the Oriental Refmery property. The deposits generally consist of interbedded gravel, sand, silt, and
clay, the minor amounts of cobbles and pebbles. Because these deposits are generally unconsolidated,
permeability in the sand and gravel layers is high. In addition, paleochannels eroded in the bedrock
may influence the occurrence and movement of ground water.
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B.
SUBSURFACE GEOLOGY
The subsurface geology consists of Quaternary alluvial deposits, artificial fill, and Tertiary
bedrock. Alluvial deposits consist of sand, silt, and clay of the Piney Creek alluvium, eolian deposits
of silt and clay, and sand and gravel of the Broadway alluvium. Clay and gravel sediments of the
Slocum alluvium also underlie parts of the site.
Bedrock beneath the site is made up of claystone, shale, siltstone, and sandstone of the
Denver formation. In the northwestern and southeastern limits of the study area, the bedrock lies
within 30 feet of the ground-water surface. The Denver formation is underlain by the Arapahoe
formation, Laramie formation, and Fox Hills sandstone. Outcrops of bedrock are not visible at the
LCC property.
v.
HEALTII RISK ASSESSMENT
To determine the health risks on the L. C. Corporation property a baseline risk assessment
was completed. The risk assessment assumed there would be unrestricted industrial use of the
property. For example, there could be urban development on and around the site for both
commercial and industrial use.
The risk assessment for OU2 produced the following results:
o
Due to low concentration of contaminants, there is no significant risk
to the public health by ingestion, inhalation, or skin absorption.
Polycyclic aromatic hydrocarbon [P AH] concentrations at OU2 are
typical of those in urban environments.
o
Current off-site migration of contaminated surface soils and surface
water pose no significant human health risk to adjacent commercial
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and industrial areas. '
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VI.
RECOMMENDED ALTERNATIVE
EP A and CDH have selected a No Action alternative for OU2, because the operating unit has
already been cleaned up. No further remediation is needed. The OU 2 RI and risk evaluation found
that there is no current or potential threat to human health and the environment. No other alternatives
were evaluated, for OU2 is already in a protective state.
vn.
DOCUMENTATION OF SIGNIFICANT CHANGES
No changes in the proposed remedy have been made since the release of the OU2 RI and the
OU2 Proposoo Plan.
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