PB95-963118
EPA/ESD/R08-94/093
March 1995
EPA Superfimd
Explanation of Significant Difference
for the Record of Decision:
Denver Radium Superfund Site
(O.U. 3), Denver, CO
12/13/1993
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EXPLANAT:I:ON OP S:I:GN1:P:I:CANT D:I:PPERENCES
DENVER RADrtIK S:I:TE
OPERABLE UN:I:T :I::I::I:
1000 WEST LOUISIANA PROPERT:I:ES
nrrRODUCT:I:ON
The purpose of this document is to explain the significant
differences between the remedy selected in the Record of Decision
(ROD), signed by the U.S. Environmental Protection Agency (EPA)
on September 29, 1987, and the remedy which was implemented at
Operable Unit III (OU III) of the Denver Radium Superfund Site.
EPA is the lead agency at the OU with the support of the Colorado
Department of Health (CDH).
Operable Unit III of the Denver ~dium Site is located in
southwest Denver, west of the South Platte River and north of
Ruby Hill Park. The operable unit includes several properties
known collectively as the 1000 West Louisiana Avenue properties.
These properties are in the area of West Louisiana Avenue, South
Jason Street, and South Platte River Drive (Figure 1). The
properties cover approximately 11 acres in an area zoned for
industrial use. .
This Explanation of Significant Differences (ESD) describes
changes to the remedy that. were implemented at OU III. The ESD
explains 1) why temporary storage was not required, 2) how the
remedy was modified to address the discovery of much larger
volumes of contamination than were anticipated at the time of the
ROD, 3) why the remediation plan for the Creative Illumination
building changed from decontamination and restoration to
demolition, and 4) how contaminated soils left in place will be
managed. .
The Administrative Record, in accordance with Section
300.825(a) (2) of the National Contingency Plan, 40 CFR Part 300
(NCP), contains this ESD, the documents that form the basis for
the decision to modify the response action, and the documentation
relating to selecting a remedy for OU III. It is available for
public review at the following location: .
EPA Superfund Records Center
999 18th Street, Suite 500
Denver, Colorado 80202
Hours: M-F 8:00 AM - 4:30 PM
Telephone: (303) 293-1807
1
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Figure 1. Operable Unit Location
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This ESD is prepa~ed in fulfillment of EPA's public
participation responsibilities under Section 117(c} of the
Comprehensive Environmental Response, Compensation, and Liability
~t of 1980, 42 U.S.C. Section 9601, et seq. (CERCLA) (more
commonly referred to as Superfund), as amended by the Superfund
Amendments and Reauthorization Act of 1986, and Section
300.435 (c) (2) (1) of the NCP. .
S:ITE H:ISTORY
The Denver Radium Site is comprised of over 40 properties
located along the South Platte River Valley that were
contaminated as a .result of a radium processing industry that
flourished in Denver during the period ~rom 1915 to 1927.
Production of refined radium produced large quantities of
radioactive waste materials. Generally, these materials were
discarded or left on-site when the processing facilities were
closed.
In 1979, EPA discovered the presence of the long-forgotten
radium processing sites. Subsequent field research revealed the
presence of thirty-one radiologically-contaminated properties in
Denver. Because of the enormity and complexity of the Denver
Radium Site, EPA determined that the properties should be divided
into Operable Units based primarily upon site conditions and
proximity to other Denver Radium properties. The 1000 West
Louisiana properties, which are the subject of this ESD, comprise
Operable Unit III of the site. .
OU III consists of property owned by Creative Illumination,
Inc.; the building and vacant lot owned by Packaging Corporation
of America (PCA); the Titan Labels Building; and several.
buildings east of South Jason Street. The vacant lot owned by
PCA may have been the site of a smelter that operated in the late
19th century. This smelter may have been turned into a radium-
processing facility in the early 20th century. Chemical Products
Company occupied portions of OU III between 1918 and 1921,
separating radium and vanadium from uranium ores for the National
Radium Institute. .Most of the buildings associated with radium
processing were demolished prior to 1970. The exception was a
brick building located at 1298 Kalamath, which was purchased by
Creative Illumination, Inc., and used for light-fixture.
fabrication. .
The Denver Radium Site was placed on the National priorities
List in September 1983. EPA released a Remedial Investigation.
for OU III in April 1986 and a Feasibility Study in August 1987.
In September 1987, EPA issued a Record of Decision selecting a
remedy for OU III. Additional characterization of the radiologic
contamination was conducted during the design of the remedy, and
is documented in Supplemental Data Releases for OU III by UNC
Geotech dated April 1989 and May 1989.
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SUMMARY OF CONTAMINATION PROBLEMS
Radium and its associated decay products are the primary
contaminants of concern at the 1000 West Louis~ana properties.
. The radiologic contamination at the Denver Radium Site poses
a health hazard by way of three routes of exppsure: 1) inhalation
of radon gas and its decay products; 2) direct exposure to gamma
radiation from the decay of radium and its progeny; and
3) ingestion or inhalation of radium contaminated material. In
general, the greater the exposure rate and the longer the
exposure to radiation, the greater the associated health hazard.
Of these three exposure routes, the most significant risk is that
posed by radon gas accumulating in buildings. (A general
discussion of radiation and its associated units of measurement
is presented in Appendix A of the Operable Unit III Feasibility
Study. )
. The Creative Illumination and PeA buildings on the West
Louisiana properties were tested for radon. Levels exceeding the
0.02 working level (WL) standard were not detected in the PCA
building, but the Creative Illumination building was found to
contain elevated radon decay pro~uct concentrations. A maximum
radon decay concentration of 0.17 WL was detected in the basement
of this building. The average value for the building was 0.04
WL. The Creative Illumination building also contained elevated
levels of alpha radioactivity.
Gamma radiation readings in excess of background were found
over more than 200,000 square feet of the 1000 West Louisiana
properties. Average gamma" radiation measurements ranged from
background to 154 microRoentgens per hour (microR/hr) above
background. The maximum gamma radiation measurement was 2,189
microR/hr above background.
. The presence of radium in soil was verified by radiochemical
analyses of subsurface soil samples. The average radium
concentration in the contaminated soil on the 1000 West Louisiana
properties was determined to be 114 picocuries/gram (pCi/g). The
maximum radium concentration found on the properties was 2,120
pCi/g. The maximum depth of contamination was 96 inches. The
estimated total volume of radium contaminated soil and debris was
16,000 cubic yards.
SUMMARY OF THE REMEDY SELECTED IN THE 1.987 RECORD OF DECISION
. The remedial action alternative preferred by EPA for
Operable Unit III was Off-Site Permanent Disposal. Because a
permanent disposal. facility was not available at the time the
Record of Decision (ROD) was issued in September 1987, EPA
selected the On-Site Temporary Containment (capping) with the
Off-Site Permanent Disposal alternative.
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The remedy selected in the ROD included- the following:
- Cleaning up the Creative Illumination property and storing
"the approximately 200 cubic yards of contaminated material
in a temporary storage facility at Operable Unit X;
- Excavating contaminated soil on the 1000 West Louisiana
properties and consolidating and capping the material on
the vacant lot at 1000 West Louisiana Avenue;
- Maintaining the cap at 1000 West Louisiana Avenue and the
temporary storage facility at Operable Unit X until a
facility suitable for the permanent disposal of Denver
Radium wastes became available; and
- Final removal of the contaminated material from both units
to the permanent disposal facility.
SUMMARY OF AND BASIS FOR SIGNIFICANT DIFFERENCES
The significant differences from the 1987 ROD are:
1) temporary storage of contamination was not required, 2) the
area of contamination and associated volume of contaminated soils
increased, 3) the Creative Illumination building was demolished,
rather than decontaminated and restored, and 4) relatively small
volumes of radium contamination were left in place.
Difference 1. On-site temporary storage of excavated
contaminated material was not required since a permanent disposal
facility became available before excavation began. The material
was shipped by rail to the Envirocare of Utah, Inc. disposal
facility in Tooele County, Utah.
Difference 2. Additional investigations were conducted during
the remedial design which further characterized the extent of
contamination at the 1000 West Louisiana Avenue properties.
Contamination was found to extend-east of Jason Street, while at
the time of the ROD, contamination was assumed to extend no
further than Jason Street. (Figures 2 and 3 show the actual
extent of contamination.) The volume of contamination at OU III
estimated during the Remedial Investigation was 15,738 yd3. The
actual volume removed during remediation was 52,836 yd3.
Difference 3. An engineering evaluation of the brick Creative
Illumination building showed that it did not possess the -
structural integrity to withstand the stresses of the required
decontamination efforts. Consequently, the safest and most cost-
effective remedy involved the demolition-of the building. The
radium-contaminated remnants of the brick building and the
contaminated soil surrounding and beneath the demolished building
were shipped to the permanent disposal facility.
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Difference 4. Radium-contaminated soil was left in place in the
following locations: a} below the groundwater level, b) near an
underground water line at the southern boundary of the PCA
property, c} under areas of South Jason Street and South Platte
River .Drive, and d} under the PCA building. It was not known at
the time of the ROD that contamination existed near the water
line or beneath the streets. The reasons that radiologic
contamination was not excavated from these locations are
summarized below.
a} BPA decided not to excavate radium contamination below
ground water. The primary' health risk posed by radium
contamination is from the accumulation of radon gas in overlying
structures, and radon gas in ground water will tend to stay in
solution and not migrate upward to the surface.
b) Hand excavation was conducted near the water line at the
southern boundary of the PCA property to remove as much
contamination as possible. Any additional earth work around this
line could have caused a break in the line. There is no threat
of contamination to the water. The remaining contamination is
overlain by five to twenty feet of clean fill material and does
not pose a risk to human health or the environment.
c} A risk assessment prepared by UNC Geotech for EPA in March
1991, shows that the contamination remaining under Jason Street
does not pose a threat to human health or the environment as long
as it remains buried. At au VII, EPA determined that any
contamination that might be excavated during maintenance, repair,
or other construction activities will be retained and re-buried
on-site, provided that the area to be excavated is not greater
than 20% of the total area of the street. The State of Colorado
and the City and County of Denver are responsible for ensuring
that contaminated soil under the streets is managed
appropriately. The City has developed a Management Plan for the
Operable Unit VII streets. This Management Plan should be
amended to include South Jason Street and South Platte River
Drive.. The radium contaminated materials under South Jason
Street and South Platte River Drive, however, may be reburied on
site without regard to the amount of area excavated.
d} Contamination was not excavated from under the PCA building
. since EPA determined that it was not necessary for the remedy to
be protective and to meet the interior cleanup standards set
forth in 40 CPR $ection 192.12(b). That section states that in
any occupied or habitable building:
i}
The objective of remedial action shall be, and
reasonable effort shall be made to achieve, annual
radon decay product concentration not to exceed'
0.02 WL. In any case, the radon decay product
concentration shall not exceed 0.03 WL, and
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ii)
The 'level of gamma radiation shall not exceed the
background level by more than 20 microroentgens per
hour. '
The radon concentration and gamma radiation levels in the
PCA building meet these standards. '
40 CPR Part 192 provides that under certain circumstances
the agency performing the cleanup may choose a remedial action
that does not achieve complete removal of radium contamination to
the levels described in 40 CPR Section 192.12(a) ~ Under 40 CPR
. Section 192.21(c), "supplemental standards" can be applied when:
"The estimated cost of remedial action to satisfy 40
CPR Section 192.12(a) at a...site...is unreasonably
high relative to the long-term benefits, and the
residual radioactive materials do not pose a clear
present or future hazard. The likelihood that
buildings will be erected or that people will spend
long periods of time at such a vicinity site should be
considered in evaluating this hazard. Remedial action
will generally not be necessary where residual
radioactive materials have been placed semi-permanently
in a location where site-specific factors limit their
hazard and from which they are costly or difficult to
remove, or where only minor quantities of residual
radioactive materials are involved. Examples are
residual radioactive materials under hard surface
public roads and sidewalks, around public sewer lines,
or in fence post foundations."
The residual radioactive material that was left in place at
the 1000 West Louisiana properties meets the criteria for the
application of supplemental standards. Detailed maps, included
in the December 1992 Operable Unit III Closeout Report, show the
location and estimated volume of the radium contamination that
remains on the OU III properties. This Closeout Report is
included in the Administrative Record so that any agencies or
individuals who conduct maintenance or excavation activities on
the property will be aware of the presence of radiologically
contaminated materials. Institutional controls will be ,placed on
these properties to assure that interested parties are aware of '
the presence of radiqlogical contamination on OU III.
Institutional controls may include deed restrictions and special
zoning.
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Qriqinal.Remedy
Summary of Significant Differences
1) Temporary on-site storage
of contaminated material and
removal to permanent disposal
facility when one becomes
available
2) Excavation of 15,738 yd3
of contaminated soil
3) Decontamination and restora-
tion of Creative Illumination
building
4) Excavation of all
. contaminated soil
SUPPORT AGENCY COMMENTS
Modified Remedy
1) No temporary storage
. prior to removal to
permanent disposal.
facility
2) Over 52,000 yd3 of .
. soil excavated, area of
contamination extended
east of Jason Street
3) Demolition of the
Creative Illumination
building
4) No excavation of cont-
aminated. soil
- below ground water
- near water ~ine
- under S. Jason Street
- under Platte River Dr.
- under PCA building
The State of Colorado concurs with the implementation of the
remedy presented in this ESD.
STATO'TORY DETERMINATIONS
Considering the new information that has been developed and
the changes.that.have been made to the selected remedy, EPA and
the Colorado Department of Health believe that the remedy remains
protective of human health and the environment, complies 'with
federal and state requirements that are applicable or relevant
and appropriate to this remedial action, and is cost-effective.
In addition, the revised remedy utilizes permanent solutions and
alternative treatment technologies to the maximum extent.
practicable for this site. Even though the remedy does not
satisfy the statutory preference for treatment which reduces the
toxicity, mobility, or volume of. hazardous substances as its
principal element, the principal threat at the properties will be
addressed. Treatment was determined to be impracticable based
upon effectiveness, technical feasibility, implementability, and
cost factors.
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. .
PUBLIC PARTICIPATION
This ESD will become part of the Administrative Record
Rqrsuant to Section 300.825(a) (2) of the NCP. The Administrative
Record is available for public review at the following location:
EPA Superfund Records Center
999 18th Street, Suite 500
Denver, Colorado 80202
(303) 293 -1807
Hours: M-F 8:00 am - 4:30 pm
8
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.
STATE OF COLORI\DO
)
COLORADO DEPARTMENT OF HEALTH
Deqic:ated to protecting and improving the health and
environment of the people of ColoradO
4300 Cherry Creek Dr. S. LaboratOry Building
Denver, Colorado 80222-1530 4210 E. 11th Avenue
Phone (303) 692-2000 Denver, Colorado 80220-3716
(303) 691-4700
November 5, 1993
Roy Romer
Ca.Iemor
Patricia A. Nolan. MO. MPH
ExeaJIive Direacr
Mr. Jack W. McGraw
Acting Regional Director
U.S. EPA, Region VIII
999 18th Street, Suite 500
Denver, CO 80202
Re: Explanation of Significant Differences, Denver Radium Site, Operable Unit ill
~JL-
Dear ~MCGraw: . .
This letter confIrms the Colorado Departtnent of Health's (CDH) support of the U.S.
Environm~ntal Protection Agency's (EP A) issuance of an Explanation of Significant
Differences (ESD) to the Denver Radium Superfund Site, Operable Unit (OU) ill.
The ESD accounts for differences between the original Record of Decision (ROD) and the
remedial action performed. The changes were necessary because 1) temporary storage was.
not required prior to removal of cont;tminated material to a permanent disposal facility; 2)
excavation of over 52,000 cy3 was performed, rather than the 15,738 yd3 estimated in the
ROD; 3) demolition of the Creative illumination building, rather than decont;tmination and
restoration, and; 4) no excavation of contaminated soils in selected areas, including below
ground water, near an existing water line, under S. Jason St., under S. Platte River Dr., and
under the PCA building. The contaminated material which remains in place will be
managed through the use of institutional controls.
CDH agrees that the revised remedy remains proteCtive of human health and the
environment, complies with federal and state requirements that are applicable or relevant
and appropriate, and is cost effective.
Sincerely,
~
Thomas P. Looby
Director
Office of Environment
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prot:ecU'N of h1lJlUlJl health aDd the 8uviroll88nt. Aaco:'4ingly, BPA.
Region VIII. has -~ 1:11. C!ODsU1~at1oD re~t of the ~ty
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',UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
REmON VIII
999 18th STREET - SUITE 500
DENVER. COL,'RADO 80202-2466
IIIIII~I
048098
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[E~ , 4 /993
ADMINISTRATIVE
. RECORD
(C(Q)[P'1
, Ref:
8HWM-SR
MEMORANDUM .
FROM:
Robert L;Duprey, D:Lrector
Hazardous Waste Ma~agement Division
Rebecca 'J. ~omas, RPM ..It'd' A J
Denver Radium pro:ect ~
TO:
Denver Radium 8.uDerfund Site
Operable Unit III -.1000 West Louisiana Properties
Explanation of Si.~ificant Differences;
Attached is the Ex?l~~ation of Significant Differences (ESD)
between the 1987 Record of Decision (ROD) and the remedy which
was implemented at Ope=abl: Unit III of the Denver Radium
Superfund Site. .
SUBJECT :
The remedy select;:d :..n the 1987 ROD for OU III called for
the excavation of radi~un-:ontaminated soils to meet cleanup
levels identified in 4) C7.R Part 192. Excavated soils were to be
temporarily maintained OL site until a permanent off-site
disposal facility becam~ available.
It became necessc.r}r to modify the selected remedy to address
the following signifi,;act differences from the 1987 ROD:
1) temporary stcrac;-e of contamination was not required,
2) the area of con~amination and associated volume of
contaminated seils increased,
3) the Creative I:lumination building was demolished, rather
than decontc~~ated and restored, and
4) relativelY'3m2,ll volumes of radium contamination were
left in place,
The State of Colorado supported implementation of the remedy
as described in this ESD.' . In addition, EPA headquarters has
reviewed this ESD i~(i has provided written concurrence to the
Region (attached). : recommend approval of the changes to the
remedy described in =his ESD.
Attachments
o Printed on Rtn:yr:ied Psp-'
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EXPLANATION OF SIGNIFICANT DIFFERENCES
RECORD OF DECISION (ROD) - OPERABLE UNIT III
DENVER RADIUM SUPERFUND SITE
DECLARATION
Considering the new information that has been developed and
the changes that have been made to the selected remedy chosen in
the September 1987 ROD, EPA has determined that the remedy
remains protective of human health and the environment, complies
with Federal and State requirements that are applicable or
relevant and appropriate to this remedial action, and is cost-
effective. The remedy utilizes.peJ:Il1aD.ent; solutions and
alternative treatment technologies to the 'maximum extent
practicable. Even though the revised remedy does not satisfy the
statutory preference for treatment which reduces the toxicity,
mobility, or volume of hazardous substances as its principal
element, the principal threat at the properties will be
addressed. Treatment was determined to be impracticable based
upon effectiveness, technical feasibility, implementability, and
cost factors.
/ij/ J/ f7J
Date.
Division
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