United States
E.nvironmental Protection
Agency
Office of
Emergency and
Remedial Response
E PA/ROD/R08-86/009
September 1986
....
.EPA
Superfund
Record of Decision:
'fBt7-1 foo70
Denver Radium IROBCO,CO
--.
U.S. EnvirOJ1mental Protection Apney .
RegiQn III InfQrmation Resource
Center (3PM52)
841 Chestnut Street IY. ,",
Philadelphia, fA J91QZ.~
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Record of Decision
Remedi alA I ternati ve" Se'l e~c.tiJon
Site Name
RObinson Brick Comcany and Denver & Rio Grande Western Railroad
II ROBCO II
Operable Units IV & V
Denver Radium Site
Site Location
Denver, Colorado
--.
Documents Reviewed
I am -basing my decislon primarily on the followlng documents descrlbing
the analysis of cost-effectiveness of the remedial alternatives for the Denver
Radlum Slte OperaDle Unlts IV & V, RObinson Brick Company and Denver & Rio
Grande Western Rail road:'
- Denver Raaium Site Task 3 Focused Feasibility Study, prepared for tne
EPA ReQion VIII by CH2M Hil I, August, 1985.
- Denver Radium Site Remedlal Investigation, prepared for the EPA Region
VIII by CH2M Hill, Aprl1 30, 1986.
- Denver Radium Sites Disposal Method Study, prepared for the Coloraao
Department of Health by Dames & Moore, March, 1983.
- Englneering Assessment and Remedial Action Plan for Raaium Proces$ing
Resldues at Robinson Brick and Tile Company, unpublished report
prepared for the Colorado Department of Health by Arix, Inc., May, 1982.
- EPA StandardS for Remedial Action at Inactive Uranium Processing Sites,
40 CFR Part 192.
- j-1emor:-andum dated i~arch 3, 1986, from Philip i~Yberg to John Brlnk
pertaining to Radiation Protectl0n Standards.
- National Oil and Hazardous Waste Pollution Contingency Plan, 40 CFR
Part 300.
- Responsiveness Summary, EPA Region VIII, September 25, 1986, (attacnea).
- Revised Group IV & V Feasibility Study, prepared for the EPA Region
VIII Dy CH2I'1 Hil1, Aori 1 18, 1986.
- Summary of Remedial Alternative Selection, EPA Region VIII, SeptemDer
25, 1986, (dttachea).
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I I
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Descr1ption of Selected Rem~~r~
Tne EPA preferred altern~tJve for ROBCO 1S Full Removal and Permanent
Off-s i te Di sposa 1. Thi s al te.rnati ve attai ns or exceedS the EPA Standards for
Remed1al ActIon at Inactive Uranium Processing Sites, 40 CFR Part 192, which
have been identified as the relevant and appropriate Federal public health or
environmental requlrements for Ithe site. By attaining these standards, this
alterndt1ve effectively minim1zes the release of the radioactive substances so
that they dO not migrate to cause substant1al danger to present or future
pUblic health, welfare, or-t~e ~nvironment (40 CFR Section 300.68(a}(1 )}.
Full Removal and Permanent Offis1te Disposal entails:
- removal of approXimatJI~1 6400 cubic yards of radium-contaminated soi I
from the RODinson Brick Company property and approximately 600 cubic
yards of raaium-contaminated soil from the Denver & Rio Grande Western
Railroad rignt-of-WaYr J
- removal of approxlm-ate 1 200 cubic yards of debri s from the demo 1 i ti on
of the radioactively contaminated laboratory and office buildings on
the Robi nson Brick Compdny property; and
, )
- d1sposal of the contaminated soil and deDris at a facility suitable for
the, permanent d'sposa~1 ff lO\'-level raaioactive waste.
Until a cost-effective 'site suitable for the permanent disposal of the
. r J
ROBCO low-level raa10active waste is selected and, if necessary, acquirea and
aeve10ped, the Full Removal an~ Permanent Off-site Disposal Alternative cannot
be lmp1emented. Pursuant to~CERCLA Section I04(c}(3}(C}(i;},it is the
responsibility of the State of\Colorado to assure the availability of the
a1sposal site. Tne State pr,ed1jcts that this process caul a take up to seven
years. . In .order to prevent ~r minimize the threat to public health, welfare,
ana the environment, glven the lnaefinite amount of time until Full Removal
and Permanent Off-site Disposa can be implemented, the EPA determined that a
\ .
temporary response action should be lmplemented at the site.
Whlle both the EPA and ~h~ State of Colorado are continuing to seek a
permanent disposal slte, the EPA is actively pursuing an environmentally sate
locatlon to consolidate and ~~porarily store the Denver Radium Site waste
matenals. If a temporary q'ffrsite storage faci11ty becomes available witnin
a reasonaDle time after the 'signing of this ROD and such action does not use
storage capacity needed for 'materials from other Denver Radium Site properties
that pose a greater current ~u6liC health threat to site occupants, then the
EPA wl11 implement the Tempdra~ Off-slte Storage response action at ROBCO.
Temporary O~f-site Storage ent~i Is removal of all of the radium-contaminated
s01 I from both properties ari~ ~ne raaioactively contaminated debris from the
demolition of the laboratorY and office buildings and temporarily storing the
materlal, approxlmately 72~0 ~UDiC yards, in an off-site facility. .
If a temporary off-si~e Itorage facility does not become available witnin
a reasonaDle time after the s gn1ng of this ROD or suCh actlon uses storage
capacity needed for materi~ls from other Denver Radium Site propert1es that
pose d greater current pUDllic health threat to site occupants, then the EPA
wl11 implement a cost-effedti e temporary on-s1te response action at ROBCO.
Before cnoosing WhlCh temP9rary on-Slte response action 1S most approprlate,
the EPA will complete concep~a1 des1gns of several on-s1te storage or
stab,l,zat'on opt'ons. 'j
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ThiS multi-solutlon approach allows the EPA flexibllty to choose and
lmplement a cost-effective remedlal response under changing circumstances.
Dee larations
Consistent with tne Comprehensive Environmental Response, Compehsation,
and Liability Act of 1980 (CERCLA), .and the National Contingency Plan (40 CFR
Part 300), I have aeterminea that the selected remedy at ROBCO described in
the preceding sectlon is a-cost-effective remedy that provides adequate
protection of pUbllC health, welfare, and the environment. The State of
Colorado has been consulted and agrees with the selected remedy. The remedy
may require future operatlon and maintenance actlvities by the State of
Coloraao to ensure the conti nued effectiveness of the temporary response
actlon. These activities wi1 I be considered part of the approved remedy and
will De eligible for Trust Fund monles for a period of one year after which
fundlng wll1 be provlded by the State of Colorado.
,_.
The EPA has determined that the selected remedy is appropriate when
balanced against the availability ot Trust Fund monies for use at other
sltes. In aaaitlon, the off-site transport, storage, and secure aisposition
of tne radloactlvely contam1nated mater1al 1S more cost-effective than any
other remea1al action, will create new capacity to manage hazardous waste, and
1S necessary to protect publiC healtn, welfare, or the environment. .
The EPA w1ll undert~ke aaaltional feas1bi1ity studies to evaluate
remeaidl actl0n alternatives at the otner Denver Raa1um Site Operable Units
ana will complete a Record of Decision on the Focused Feasibility Study on
permanent disposal options when a flna1 disposal option 1S selectea. If
additional remedial act10ns are determined to be necessary, a Record of
Decislon will De preparea for approval of these remedial actions.
{d-
9/30/ i'?
JOh Welles
Reg10nal Aamin1strator
EPA Reglon VIII
Date
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Summary of Remealal Alternative Selection
S ite Name
Robinson BricK Company and Denver & Rio Grande Western Railroad
II ROB CO I!
Operable Units IV & V
Denver Radium Site
Si te Hi story
When Madame Mar1e Curie discovered radium in 1898, she set in motion a
chain of events which left an unwanted legacy for fo11ow1ng generations. From
its discovery until the early 1920's, the radioactive element was touted for
its medicinal properties, especially as a treatment for cancer. As a result,
demand for radium skyroC~~ted starting the radium boom of the early 19001s.
Prior to 1914, there was no domestic production of radium. Rather,
raa1um-Dear1ng ore was shipped from the U.S. to Europe where 1t was refined.
Fear1ng that a European war might stymie U.S. importation of radium, the U.S.
Bureau of M1nes entered into a cooperat1ve agreement with a pr1vate
corporation, the Nat10nal Rad1um Institute (NRI). According to the agreement,
the Instltute was to aevelop and operate a radium processing plant in the
United States. Denver w~s the chosen location for the NRI facility due to its
proximity to the Colorado Plateau, whiCh was known to contain rich deposits of
the radlum-bear1ng ore, carnotite. Soon there were nine other radium
processing operations 1n Denver.
The Denver rad1um industry remained strong until around 1920 when
extremely rich depos1ts of radium-bear1ng ore were d1scovered in the Belgian
Congo. The Denver radium producers were not able to economically compete with
their African counterparts and were forced out" of business.
The NRI plant had closed several years earlier after hav1ng produced 8.5
grams of radium from approximately 1500 tons of ore. The legacy of the NRI
and the rest of the Denver raaium induStry is present tOday in the form of
rad10dctive tailings and unprocessed ore Wh1Ch since the early 1920's has been
spread, usea as fill and foundation material, and otherwise m1shandled.
Site Location and Description
The Na,!:ional Radium Institute fac111ty was located on the site cu}'rently
occupied by RObinson Br1ck Company at 500 South Santa Fe Drive, Denver,
Colorado (Figure I). RObinson Brick Company manufactured brlCK and tile at
the slte for over forty years unt1l they movea in 1984 to a more moaern
faC1llty.
The RObinson BriCk Company property covers 17.3 acres in an area of
Denver zoned I-I for inaustrial use. The population of the City and County of
Denver is 509,000. RObinson is bounaed on the west Dy Soutn Santa Fe Dr1ve
and on the east by the Denver & R10 Granae Western Railroad (DRGWR)
r1ght-of-way. Further east of the rlght-of-way is 55 acres of property which
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Location Map
Denver Radium Site
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is undergoing full-scale redevelopment into a merchandising and shopping
center, restaurants, and an offlce complex. To the northwest of Robinson is a
Regional Transport Dlstrict bUS barn and to the south are two industrial
businesses (Figure 2). Piles of raw clay have been left at the northern end
of the property and finishelj brlck and tile are sitting on a pavement parking
lot at the southern end of the property. There are seventeen buil di ngs and
sneds on the site. Two of the Duildings, the laboratory and office, are
or191nal NRI structures. Roblnson has not used these buildings since 1979.
The DRGWR rlght-of-way immediately east of Robinson Brick Company covers
1.6 acres. ThlS property is crossed by several main rail lines and sidings.
A small building houses the remote controlled switch-relays and is the focus
of a complex network of undlerground electric lines servicing track sWltches
and lights along the railroad.
Robinson Brlck Company is located within the Platte River Val ley but is
not witnin the designate~_flood plain. The site is underlain by fill
material, alluvium, and the Denver formation. The sandy at luvlum has
permeabi lities of 10-2 cent'imeters per second and higher. The claystone,
Sil~stone, and sandstone beds of the Denver formation have permeabilities of
10- centimeters per second and lower. Depth to groundwater is
approximately 16 feet and ~epth to bedrocK is approximately 25 feet. The
topography of the site is predominantly flat although surface runoff tendS
westward toward the South Platte River. There is no surface water on the s1te.
Response Hi story
In 1979, the EPA discovered a reference to the National Radium Institute
in a 1916 U.S. Bureau of Mines report. Subsequent research revealed the
presence of thirty-one radl0active sites in the Denver metropolitan area, one
of these being RObinson Brick Company, the location of the original NRI.
Imrned1ately fo1 lowing these dlscoveries, the Colorado Department of Health,
Radiation Control Division, officially not1fi,ed the affected property owners
of the presence of contamination on thelr properties. The letters requested
that no excavation or soil movement projects be undertaken without first
contacting the Dlvis10n.
The Denver Radium Site was placed on the Interim Priorities Llst in
October, 1981, and flna1 promulgation to the National Priorities List occurred
on September 8, 1983. The Coloraao Department of Health, under a cooperative
agreement with the EPA, initiated engineering assessments of the sites in
August, 1981. The engineering assessment of RObinson Brlck Company was
comp1etea in May, 1982, by the State's contractor, ARIX, Inc.
The EPA resumed funa-1ead activities 1n June, 1983, because the Colorado
State Legislature failed to appropriate the state cost share for remedial
planning required by EPA policy at the time. In December, 1983, the EPA
directed its contractor, CH2M Hill, to conduct a Remedial Investigation and
Feaslbility Study of the Denver Radium Slte to determine the nature and extent
of the threat presented by the release and evaluate proposed remedies (40 CFR
Section 300.68(d)). During the Remedial Investigation, the extent of the
contaminatlon present at the Denver & Rio Granae Western Railroad property
adj acent to ROD1 nson Brick Company was determl ned.
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Figure 2
Site Plan
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5
Due to the enonnity and complexity of the Denver Radium Site, the EPA
determined that response actions could be conducted in groups, or operable
un1ts, that would decrease the release, threat of release, and pathways of
exposure, ana that such measures would be cost-effective and consistent with a
permanent remedy for the enti re Denver Rad; urn Site. Thus, the ori gi na 1 Denver
Radium Site properties plus several contiguous properties where contamination
was discovered subsequent to the intiaJ llsting of the site on the Interim
Prl0rltles L1st were alV1ded lnto eleven operable units.
In April, 1986, the Denver Radium Site Remedial Investlgation, which
aaaresses all eleven operable units, was released for public comment.
Operable Unit IV, Robinson Brick Company, and Operable Unit V, the Denver &
Rio Grande Western Rai I road, are addressed together in the Revised Group IV &
V Feasibility Study dated April 18, 1986, and released for pUDliC comment in
April, 1986. The Final Group IV & V Feasibility Study and Endangerment
Assessment incorporate responses to updated EPA guidance and comments received
during the public commen~_period on the Revised Group IV & V Feasibility StUdy
and will be released for informational purposes only along with this ROO and
the Responsiveness Summary.
Over the last several years since the discovery of the Denver Radium
Site, Robinson Brick Company has made efforts towards the voluntary cleanup of
their property. These efforts have thus far been unsuccessful. In an attempt
to recover their costs for these actions, and based upon Robinson's premise
that tne U.S. Bureau of Mines is responsible for th& contamination, the
Robinson Brlck Companyflled a CERCLA Section 107 Cost Recovery Suit against
the United States of America on April 28, 1986, in the Federal Dlstrict Court
in Denver.
Throughout tne remalnder of this sunvnary, "ROBCO" will be used to denote
the contaminated areas on both the RObinson Brick Company and Denver & Rio
Grande Western Rai I road properties.
Community Relations
The Denver Radium S1te Convnunity Relations Phn establishes a means for
convnunicating information concernlng the site to State and local officials,
potentially interested neighborhood associations and indivlduals, and the
local media and to elicit comments from the public about actions at the site.
Per the Community Relations Plan, the EPA issued a press release announcing
the ~.1ay 5 through May 30, 1986, pUblic comment period on the Revised Group IV
& V Feasibility Study. As a result the Denver Post, the Washington Park
Profile, ana KMGH TV (Channel 7) provided media coverage.
Even though the Denver Radium Site Remedial Investigation, the Revised
Group IV & V Feasibility Stucly, and relevant fact sheets were made available
for pUDliC review at several convenient locations, no comments were received
from anyone other than governmental agencies or those who have a direct or
lndlrect interest 1n the ROBCO property. Comments were received from three
pUDlic agencies - the Colorado Department of Health, the Colorado Historical
SOClety, and the City ana County of Denver. Comments were also received from
the Denver & Rl0 Grande Western Railroad, attorneys representing Robinson
SrlCK Company, attorneys representing a prospective redeveloper of the area,
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6
and attorneys repreSentlng Shattuck Chemical Company, owner of the Operable
Un1t VIII property. The EPA's response to these comments is contalned in the
attached Responsiveness Summary.
No puolic meetings were held during the comment period because prior
pUblic meetlngs held by the Colorado Department of Health were sparsley
attenaea and current citizen interest 'remains low. The EPA has met with two
concerned parties, representatives of the prospective redeveloper, Allen S.
Reiver and Realitles, Inc.~ and representatives of RODinson Br1ck Company, and
has expressed will1ngness to hold other such meetings if the level of interest
warrants it. '
Current Site Status
Radium is the primary contaminant of concern at ROBCO. Gamma radiation
survey results were used'''to outline the extent of possible radium
contaminat10n since gamma radiation read1ngs in excess of background may
indicate the presence of radium (Figure 3). Gamma radiation readings in
excess of background were found over l2~ of the 17.3 acre site of the Robinson
Brick Company, in three of the Robinson Brick Company's buildings, and over
30~ of the 1.6 acre DRGWR right-of-way. The three bUlldings are the grlnd1ng
plant and the two remaining NRI structures, the office and laboratory. '
Surface gamma radiatlon reaaings exceed 1000 microroentgens per hour above
background in several IOcationsinclud1ng inside the laboratory (Figure 4).
(A general discussion of raaiation ana its associated units of measurement is
presentea in Appendix C of the Feasibility Stuay and in the Enaangerment
Assessment.) Tne gamma radiation reaaings insiae the laboratory exceed the
"EPA StandardS for Remedial Actlons at Inactive Uranium Processing Sites," 40
CFR Part 192, which the EPA has aetermined are the relevant and approprlate
Federal pUDlic health requirements for ROBCO. These standards are discussed
in aetai I later in this summary in the section entltled "Conslstency with
Other Environmental Laws" and the justification for selecting these standards
as the relevant and appropriate Federal public health requirements for the
site is providea in the section entitled "Alternatives Evaluation". '
The presence of radium ln the soil and underneath the buildings was
verified by radl0chemica1 analysis of subsurface soil samples (Figure 5).
Average radium concentrations ranged from 11 to 3307 picocuries per gram. The
maximum concentration, 5093 picocuries per gram, was found inside the
laboratory. Aga,n, these values exceed the relevant and appropriate EPA
standards, 40 CFR Part 192, mentioned above. Table I summarizes the data
presenteai~ Figures 3-5.
Alpha radioactivity contaminatlon, which is indicative of the raaium
contaminatlon, was found in excess of State standardS in all three buildings.
Because the bUllalngs are not being used, alpha raaioactivity contamlnation is
not a concern at present. Radon daughter contamlnation, which is also
ind1cative of the raaium contamination, is also not a present concern in the
buildings because of their poor cona1tion and their dlsuse. A 1979
investigation by the Colorado Department of Health measured low raaon daughter
concentrations in the laboratory ana office, probably due to the ventilation
tnrough the poorly closea bUlla1ngs. Since that time, further dilapldation of
the bU11dings has lncreased ventilation s1gnificantly.
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Figure 3
Extent of
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Figure 4
Surface Contamination
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Figure 5
Subsurface Contamination
-------
Table 1
SURFACE AND SUBSURFACE CON'fAMINATION
OPERABLE UNIT IV/V
Hadium
. volulje Ar2a Gamma hJR/hr) Depth Concentration (pCi/g)
Location (yd ) (ft) Average Maximum ( in . ) Average Maximum
Area A 5,587 78,700 67 1,059 23 486 1,260
Area B-1 604 16,300 3 17 12 11 25
Area B-2 199 4,300 13 121 15 17 31
Area C 175 2,025 179 387 28 NA NA
Area D 67 1,800 12 12 NA NA NA
Area E 46 1,250 11 12 NA NA NA
Area P 33 900 7 8 NA NA NA
Area G 39 575 11 11 22 NA NA
Area II 34 425 11 11 26 NA NA
Area I 122 900 17 17 44 NA NA
Area J 99 1,775 16 23 18 NA NA I-'
a
Lab (debris) 147 358 2,547 NA 3,307 5,093
Office (debris) 52 92 202 NA 20 55
'l'O'l'AL 7,204
(108,950 soilf:>, 199 debris)
Notes:
~R/hr = microroentgens per hour.
pC~/g = picocuries per gram.
yd2 = cubic yards.
ft = square feet.
in. = inch.
NA = Data not available or not recorded for this area. .
Maximum gamma radiation exposure rate is maximum grid scan gamma radiation
rate. Gamma radiation readings are corrected readings above background.
exposure
DE/IVANDV/043
-------
11
Low levels of non-radiological contamination, mainly polyaromatlc
hyarocaroons, have been aetected at ROBCO. There is nothing to suggest that
either dispersion or mlgration of these substances has occurred and no known
sou rces of these compounas are present on the property at thi s ti me. Thus,
there is no reason to suspect any additional release. The non-radiologlcal
contamination represents a mlnlmal concern relative to the radiological
contamination present at the site and any remedy that reduces or eliminates
the raaloiog1cdl hazara wlll ellminate the other as well.
The elevated concentration of radium at ROBCO poses a health hazard due
to three pr1ncipal potentlal exposure routes. In order of decreasing
significance, they are: (1) inhalat10n of radon gas, the immediate decay
product of radium, and radon's own short-lived decay products, (2) direct
gamma radiation exposure from the decay of radium and its progeny, and (3)
ingestion or lnhalation of radlum-contaminated materlals. Since radium is 1n
a fonn that is relatively insoluble, ingestion or contact with contaminated
surface water or groundw~~ter is not one of the principal potential exposure
pathways. There is no surface water on site and migration of contaminants
into the groundwater or off-s1te toward surface water has not been noted.
However, since radium has a half-life of 1600 years, its great persistence in
the environment dictates that the long-term potential for airborne or
waterborne migration be carefully considered in analyzing all routes of
exposure.' Each of the three principal exposure routes wi 1 I be examined
briefly 1n order to describe the potential health risks.
Innalation of Radon Decay Products:
Radon gas and its decay products, called daughters, present the greatest
health risk from long-tenn exposure. Radon gas in the air decays to a series
of short-liVed partlculates which are typically electrostatically charged at
thelr formation and often attach themselves to airborne particles. If these
contam1nated particles are inhaled, tnen the lungs and other internal organs
are exposed to the highly ionizlng sub-atomlC particles which the radon
daughters emit. Prolonged inhalatl0n of air which has a high concentration of
radon decay products has been conclusively shown to cause lung cancer1n
urdnlum mi ners.
Disperslon quiCkly dilutes radon emanating from radlum-contamlnated
ground. This mechanism will minimize the radon concentration in the air above
the open areas of the ROBCO property to such an extent that no potential
receptors are presently at rlsk. Radon decay products can concentrate to
unacceptacle levels 1n confined spaces such as Duildings built over
contaminated ground. Th1S 1S not the case for the three bUll dings on the
contamlnated portions of ROBCO because the buildings are unoccupiea and nave
enough venilation to keep the radon daughter concentration at low levels.
The analysls summarized above shows that there is no serious puoliC
health rlsk at present from the radon gas exposure pathway at ROBCO. However,
the EPA is concerned about the significant increase in public health risk if
any of the contaminated material at the ROBCO site is ever unwittingly spread
closer to potent1a1 receptors, especlally if it is usad as fill or
construction material, or if the site is ever redeveloped for any use that
involves occupancy in enclosed structures. For these reasons, the
Enaangennent Assessm~nt presents projected cancer risks if the EPA were to
take no action at the slte and tne ROBCO property were redeveloped.
-------
12
If a hypothetical building were constructed over Area A, the largest and
most contaminated area of the ROBCO property. and several conservative
assumptions are made, the estimated radon daughter concentrat10n in the
hypothetical Duilding woula average 0.88 working levels (WL) with an estimated
maximum concentration of 2.3 WL. The radon daughter concentration in a
tYP1cal U.S. home is 0.005 WL and the relevant and appropriate EPA standard,
40 CFR Part 192, is 0.02 WL. The projected cancer risk (excluding background)
to receptors work1ng in the hypothetical bui Id1ng ranges from 9.3 to 30 cancer
deaths per 100 persons exposed with a maximum projected cancer r1sk of 21 to
55 cancer deaths per 100 persons exposed. The projected cancer risk to
receptors 1iv1ng in the hypothetical bui1dlng ranges from 34 to 74 cancer
deaths per 100 persons exposed with a maximum projectea cancer risk of 55 to
81 cancer deaths per 100 persons exposed.
These risk values can be compared to the projected cancer risk if the
radon daughter concentration in the hypothetical building was 0.02 WL. the EPA
standard. In th1S case,t-he projected cancer risk to receptors working in the
hypothetical building ranges from 2.3 to 9.1 cancer deaths per 1000 persons
exposed. The projected cancer rlSI< to receptors living in the hypothetical
build1ng ranges from 13 to 50 cancer deaths per 1000 persons exposed. If the
radon daughter concentration in the hypothetical bui Iding was that of a
typical U.$. home. 0.005 WL, then the projected cancer risk to receptors
living in the building would range from 3 to 13 cancer deaths per 1000 persons
exposed.
Gamma Raaiation Exposure:
The radioactlve decay of radium and its daughter products results in the
emission of highly penetrating gamma rays. Siml1ar to x-rays, gamma rays are
of concern Decause they can easily penetrate a few centimeters of soil to give
anyone present on the contamlnated area a reasonably uniform irradiation over
the whole DOdy. The greater the duration or intenslty of this exposure, the
larger the dose, and hence the greater the risk of adverse health effects.
The gamma radiation emmission 1S limited to the area immediately above the
contami nation.
As mentl0ned previously, the EPA is concerned about the significant
increase in pUDlic health risk if any of the contaminated material was
d1sturbed or if the area was redeveloped. If a hypothetical building were
constructed over the area with the highest gamma radiation readings, where the
laDoratory now stanas, the estlmatea annual dose to a person working in the
hypothetical building wou1a average 720 millirem per year with an estimated
maXlmum annual dose of 4600 mll lirem per year. These doses are in addition to
the Dackground dose of 130 ml11irem per year incurred by those living in the
Denver area and resulting from cosmlc, terrestrial, and internal sources. The
maXlmum allowable whole-body gamma rad1ation dose derived from the relevant
and approprlate EPA stanaard, 40 CFR Part 192, and the NCRP and ICRP recommen-
dations for a person in the workplace are 40 and 100 ml11irem per year,
respectlvely, in addltion to natural background and medical exposure. The
estimated annual dose to a person living in the hypothetical building would
average 2400 millirem per year with an estimated maXlmum annual dose of 15,000
mi11irem per year. The whole-body gamma radiation dose derived from the
relevant and appropriate EPA stanoard, 40 CFR Part 192, and the NCRP and ICRP
recommendations for a residentlal occupant are 130 and 100 mi11irem per year,
respectlvely, in aaaition to natural background and medical exposure.
-------
13
The projected cancer risk (including background) to receptors working in
tne hypothetical building would average 110 cancer deaths per 100,000 persons
exposed. The projected cancer risk to receptors living in the hypothetical
bui laing would average 500 cancer deaths per 100,000 persons exposed.
If the receptors in the hypothetical building received a lifet1me dose
equivalent to tnat of the relevant ~nd appropriate EPA standara, then the
projected cancer r1sk to receptors working in the hypothetical build1ng would
average 310 cancer deaths ~er 100,000 persons exposed and tne projected cancer
risk to receptors living in the hypothetical building would average 530 cancer
deaths per 100,000 persons exposea. The projectea cancer risk to receptors
receiving a lifetime dose of 9.5 rem resulting from the Denver area background
woula be 270 cancer deaths per 100,000 persons exposed. It should be noted
that cancer riSKS resulting from gamma radiation exposure are in addition to
those resulting from lnhalation of radon decay proaucts.
Inhalation or Ingestion of. Radium-Contaminated r~aterial:
Inhalation of tne long-lived rad10nuclides like uranium, thorium, and
radium is possible for persons living or working near the ROBCO site. Surface
material suspended by the wind may contain smal I concentrations of these
elements and the resulting airborne contaminat10n is a potential human
exposure pathway. Studies by the U.S. Department of Energy have snown,
however, that the projected radiation dose from this source are many times
smaller than those eSti~ated for either radon decay product inhalation or
direct gamma radiation exposure using even the most conservative assumptions.
Dust control measures ordinarily employed during excavation have been shown to
prov1de suffic1ent control of exposure from this source. Therefore, no
quant1 tat1 ve ri sk numbers fortn1 s exposure pathway were developed in the
Endangerment Assessment.
Direct ingestion of long-lived raaionuclides can result in significant
doses to various internal organs of the bOdy. Slnce it is unlikely that a
person woula ingest large amounts of the raaium-contaminated material on the
ROBCO site, the EPA acknowleages this human exposure pathway, but no .
quantitatlve rlsk numbers were aeveloped in the Endangerment Assessment.
The foregolng discussion demonstrates that a release or substantial
threat of release of a hazaraous substance or pollutant or contaminant into
the environment has occurred at ROBCO and that the release or threat of
release may present an 1mm1nent and substantial endangerment to public health
or welfare. It is clear from the calculated risks that remedial action at
ROBCO 1S justifiea. Since a probable remedial action 1nvolves excavating
contaminated material, it stands to reason that the remeaial action workers
coula be exposed to radioactivity. The projected risks from this type of
exposure have been developed by the EPA and are contained in the Endangerment
Assessment. Worker exposure can be significantly reduced by limiting worker
time on the site and exercising the strict safety controls which are an
essential part of any remedial action program. Studles Dy the U.S Department
of Energy of potent1al worker exposure under similar circumstances have shown
this exposure to be sma I I in relation to the applicable and relevant and
appropriate Federal health and safety requirements and projected risks of
al lowlng the contaminated materlal to remain in place for the indefinite
future.
-------
14
Enforcement
The respons1Dle party search thus far has 1aentif1ed only the U.S Bureau
of M1nes as a potent1ally responslble party. The U.S. Bureau of Mines may
nave Deen an "operator" ot the Denver processlng plant w1th1n the meaning of
CERCLA Sectlon IU7(a). RODinson Brlck Company and Denver & Rio Grande Western
Ra11roaj could De consiaere~ resDonSlb1e parties unaer CERCLA Section
107(a)( I) Dy virtue of their current ownership of the contaminated propert1es.
Tne responSible party search was a1scontinued in June 1986 when the TES I
contract exp1rea. The EPA plans to resume the search in the future. However.
the EPA aoes not feel that remedial action should be de1ayea in anticipat10n
of finding other responsible parties.
Upon finalizatlon of the responsible party search. the EPA intends to
formally notify responsible parties Wh1Ch may have been identified of the
remeay selectea in thf~ ROD and in1t1ate negot1ations for either the
1mplementation of the remedy or recovery of the EPA's response costs.
Negot1at10ns wi II not exceea Slxty days. Thereafter. 1f the responsible
part1es do not formally Comm1t to perform1ng the remedy in a timely manner.
tne EPA W1 I I proceed w1tn a tuna-financea remea1al design ana remedial act10n.
Alternat1ves Evaluat10n
Tn~ EPA's ult1m~te goal at tne ROBCO slte 1S. dur1ng the course of
remedlal alternat1ve select10n. to give pr1mary consideration to response
actlons that are etfectl~e 1n prevent1ng or. wnere prevention 1S not
practlcaDle. min1mizing the release of the raaloactive sUDstances so that they
ao not mlgrate to cause suDstant1al aanger to present or future publ1C health,
welfare. or the env1ronmeni (40 CFR Sect10n 300.68(a){1 )}. This goal can~ as
a general rule. be accompl1shed by pursu1ng remed1a1 alternatives that atta1n
or exceed the requirements of appl1cab1e or relevant and appropriate Federal
pUDl1C health or env1ronmental laws. The EPA has determinea that the IIEPA
Stanaards for Remed1al Actlon at Inactive Uranium Processing Sites." 40 CFR
Part 192. are relevant and appropriate to the ROBCO site because (l) it is the
rad1um content of the uranium m1l1 tailings which is regulated; (2) the waste
proaucts result1ng from uranium ore processing are very similar to those from
rad1um ore processing; (3) the residues from both processes enter the
enV1ronment through the same exposure pathways; and (4) the adverse health
effects resul t1 ng from exposure to the residues from both processes are the
same. Henceforth, attainlng the maximum al lowaDle exposure levels speclfied
In the "EPA Stanaards for Remedlal Actl0n at Inactive Uranium Processing
Sltes". 40 CFR Part 192. W1 I] be referred to as the remed1al action oDjectives
tor ROBCO.
Durlng the remedial alternat1ve selection process, the EPA gave
consideration to the gamma raalatlon exposure llmits recommendea by the
Nat10nal Commlttee on Radlat10n Protection and Measurement (NCRP) and tne
Internat10nal Comm1ss1on on Rad1ologic Protection (ICRP) and the alpha
part1cle em1SS10n lim1ts recommended in the Coloraoo Department of Health
guldelines. A d1Scussion of these gU1ael1nes 1S provioed later in thlS
document 1 n the sect 1 on entlt lea "Cons1 stency Wah Other Envl ronmenta 1 Laws". ,
-------
]5
In ltS presently uncontrolled state, the raalum-contaminated mater1al
could be misused or 1naavertantly spreaa, POSS1bly increaslng the risk to
present or future PUblic healtn, welfare, or the environment. Any alternative
WhlCh entai Is permanent off-slte disposal is not immed1ately ;mplementable
because there is no economical or suitable disposal facility for low-level
raa;OaCt1ve waste avai laDle at this time. Pursuant to CERCLA Section
I04(c)(3)(C)(ii), it is the respo~stbillty of the State of Colorado to assure
tne ava11ability of a disposal site. Although progress is being made to this
end, the State does not ~xpect to have an avai lable aisposal facility for up
to seven years. In the meantime, the cost of final remedial action is liable
to increase due to inflatlon; the property owners face economic losses
associated with restricted use of their properties; the EPA may incur further
costs by updatlng site studies in the face of changing site conditions; and
most importantly, the EPA 1S not able to achieve its ultimate goal of
preventing or minimizing the release of radioactive contaminants so that they
do not mlgrate to cause substantlal danger to present or future puolic health,
welfare, or the environment (40 CFR Section 300.68(a)(I)).
Therefore, 1n order to insure consideration of remed1es that are
1mmediately implementable, the EPA evaluated temporary response act10ns along
w1th alternatives wnlch involve permanent off-site disposal. Given the
lndefin~te amount of t1me until a permanent disposal facility is likely to be
located ana, 1f necessary, aeveloped, the EPA determined that temporary
response actions are not only justified, but necessary in order to minimlZe
the threat to puolic health, welfare, or the environment.
The obJectives of these temporary response actions are to take actions
Wh1Ch:
- are cons1stent w1th the permanent remedy;
- prevent or minimize the release of hazardous substances or pOllutants
or COntaminants so tnat they dO not migrate to cause substantial
aanger to pUbl1C health, welfare, or the environment (40 CFR Section
300.68 (a)( I ) ). .
In select1ng the appropriate extent of remedy from among the
alternatives that would achieve adequate protection of public health,
welfare, or the environment, the EPA consiaered cost, technology,
reliability, aaministrative and other concerns, and their relevant effects on
publ1C heal tn, welfare, or the environment pursuant to 40 CFR Section
300.68(i). Tnese factors were used to develop the following corrollaries of
tne remeaial act10n ana temporary response action Objectives aescr1Dea above:
- that the temporary response action be implementable pending the
ava1 I abi 11 ty of a permanent 01 sposa I Sl te;
-that the temporary response action prevent accidental or intentional
a1sturDance or m1suse of the contam1natea material;
- that the temporary response act10n optimize the use of the property;
ana
- that tne temporary or short-term measures oe consistent wlth the final
remeay for the ROBCO slte.
-------
16
The appropr1ate factors listed 1n 40 CFR Section 300.68(e)(2) were
assessed 1n determ1n1ng whether or wnat type of remedial and/or removal
act10ns would De cons1dered in the Feasibility Stuoy. Th1S initial scoping
revealea only a 11m1ted numDer of remedial action technologies which were
suitable to abate the threat of the low-level radiological contamination
present at ROBCO.
Consistent w1th 40 CFR Part 300.68(g), remedial action technologies from
the in1tial scoping were i-nitially screened using the remedial action
object1ves and the NCP criteria of cost, acceptable eng1neering practices,
and effectiveness. The remedial action technologies and the remedial action
technology screening process are summarizea in Table 2. Remedial action
technologies which were rejected during the init1al screening and the
justifications for tne rejections are presented in Table 3. Several
technolog1es SUCh as reprocess1ng, physical barriers, and shielding with
leao, concrete, or s011 were rejected because they could not meet the
. remedial action objectiv.s. Some technologies such as dilution of the
contam1nated soil with clean soi I or the use of sealants in the buildings
were rejected because they were not effective in contriDuting to the
protect10n of publ1C health, welfare, or the environment. However, as noted
in Table 3, some technologies, while not suitaDle for permanent
impl ementat1 on, we re retai neo for the development of temporary response
act10ns.
Fol lowing 1s a oescription of the remedial action alternatives and the
temporary response actions which were developed from the technologies
surv1ving the in1t1al screen1ng. Each, w1th the exception of the No Action
Alternative, 1S a source control measure as defined Dy the NCP.
Remedial Act10n Alternat1ves:
II.
I.
Ful J Removal and Permanent Off-site Disposal
All contaminated sol1 (approximately 7,000 cuDic yaros) on the
ROBCO site would be excavated; the laboratory and office buildings
would De demolished (approXimately 200 cubic yards of aebris); and
all material would be d1sposed off-site at an approved permanent
di sposa 1 faci Ii ty.
Partlal Removal and Permanent Off-site Disposal
All contaminated areas would be excavated except for Area B-1 on
the DRGWR property (apprOX1mately 6400 cub1C yards); the
. -laboratory and office bui Idings WOuld be demolished (approx1mately
200 cubic yards of debrls); ana the materlal woula be disposed
orf-site at an approvea permanent disposal faci11ty.
III.
No Action
No action would be taken at the contaminatea properties. Although
this al ternative does not meet the remea1al action objectives for
tne slte, lt was retained for further analysls ana consideration
as requ1red by the NCP (40 CFR Section 300.68(f)(1)(v)).
-------
Table 2
INI'l'IAL SCREENING OF ALTERNATIVE REHfDIAI, ACTION TfX:HNOLOGI~
OPERABLE UNIT IV IV
'i'ecbnoloqy Considerations Retain for
Area Considered Tillinga Effectiveness Cost Acceptable Engineering Consideration
All open land Excavation and T, P Long-term risk largely Initial cost high, Common earth moving Yes
areas except Removal eU.IIinat.ed from t.he site; long term onsite, practices effective,
8-1 mitigation required for' cost--o; total feasible, and appli-
inhalation pathway; dis- cost must inclu~e cable; highly reliable;
posal of contaminated disposal costs.' worker and equipment
material required. decontamination may
be required.
Area Exclusion T No short-term worker risk; Initial cost low, Temporarily feasible and Yes
no control over unantici- long-term cost low. applicable; uncertain
pated pathways; compatible reliability; 8Onito~inq
with existing site usage, and inspection required.
but limits use of site as t-'
long as nterial remains '-.I.
tbere.
P No short-term worker risk; Initial cost low, Uncertain long-term feas- Nob
no control over unantici- long-term cost low ibility, applicability,
pated pathways; compatible but perpetual. and reliability; perpet-
with existing site usage ual monitoring and
but limits future uses of inspection required.
site. Remedial action
objectives not aet.
Physical Barriers T Short-term worker risks Initial cost lIod- Temporarily feasible and Yes
8in1llal; limited control erate, long-term applicable; limited long-
over unanticipated patb- cost low. term reliability; lIoni-
ways; c~patible with toring, inspection, and
existing site usage, but maintenance required.
liaits use of site as
long as material remains
there.
P Short-term worker risks Initial cost mod- Limited long-term feasi- Nob
minllr1al; 11.ll1t£:d control erate, long-term bility, applicability,
over uuanl1cipated palh- cost low, but monitoring, inspection,
ways; compatible with perpetual. and maintenance required.
existing site usage but
limits future use of site
in perpetuity. Remedial
action objectives nol met.
-------
Table 2
(continued)
Technology a Consideratiolls Retain for
Ared Considered Timing Effectiveness Cost Acceptable Engineering Consideration
All open Radiation T, P Minimal risk during instal- Initial cost mod- Monitoring and main- NO
land areas Shielding lation; mitigates gamma crate; long-term tenance required; feas-
(continued) radiation only; does. not cost low. ible and reliable in
meet long-term remedial short-term basis, but
action objectives; liaUs. . long-term reliability
use of site as long as " is low; limited appli-
material remains there. cability since It miti-
gates only gamma radia-
tIon.
No T, P Exposure pathways unaffected, No cost. Feasible, but neither Yes
Action unless site is redeveloped; appliable nor reliable.
potential for serious adverse
health effects if site is re- t--'
developed; re.edial action 00
objectives not met.
B-1 Excavatioll and T, P Long-term risks from soils Initial cost high, COlllllOn earth-lioving prac- Yes
Removal in 8-1 eliminated; .iti- long-term onsite tices effective, feasi-
gat ion required for in- cost--O, total ble, and applicable;
halation pathway; disposal cost must include special provisions re-
of contaminated material disposal cost. quired for buried com-
required. aunication lines; worker
and equipment decontam-
ioatioll may be required.
Area '1', P No short-tera worker risk; Initial cost low, Uncertain feasibility, Nob
Exclusion no control over unantici- long-term cost applicability, and reli-
pated pathways; compatible low, but perpetual ability; monitoring and
with existing site usage; if permanent. inspection required.
but restricts certain future
uses of site.
Physical Borriers
T
Short-term worker risks
mtnimal; limited control
over unanticipated path-
ways; compatible with
existing site usage, but
limits future use of site
as long as material remains
there.
Initial cost mod-
erate, long-term
cost low.
Temporarily fe3sihle and
applicable; limited lon9-
term reliability; moni-
toring, inspection, and
maintenance l'equired.
Yes
-------
Table 2
(continued)
'l'echnology Considerations Retain for
Area Considered Till1nga Effectiveness Cost Acceptable Engineering Consideration
--
8-1 Physical P Sbort-term worker risks Initial cost mod- Limited Jong-term feasi- Nob
(continued) Barriers minillal; limited control erate, long-term bility, applicability, and
(continued) over unanticipated patb- cost low, but reliability; perpetual mon-
ways; compatible with perpetual. itoring, inspection, and
existing site usage but ' , maintenance required.
limits future use of site fl
in perpetuity. Remedial
action objectives not met.
No T, P Exposure pathways unaffected No cost. Feasible, but neither Yes
Action unless 8-1 i5 redeveloped; applicable nor reliable.
potent1al for serious adverse
health effects if 8-1 i5
redeveloped; existing site t-'
use limits exposure patb- I.D
ways, remedial action objec-
lives not lIet.
Office and Structure T, P Long-term risks froll build- Initial cost high; Common demolition prac- Yes
l.c.b Buildings Demolition in9S eliminated, mitigation long-term onsite tices effective, feas-
required for inhalation cost--o; total ible, and applicable;
pathway; disposal of con- cost lIuSt include highly reUable; worker
taminated waterial required; disposal cost. and equipment decontam-
consistent with expected re- ination .ay be required.
development of s1te; pre-
vents scavenging of contam-
- inated materials; potential
loss of histor1C information.
Structure T, P Long-term risks probably Init1al cost very structural contamination Nob
Decontamination eliminated; lIitigation high; 10ng-teI1l applicable but may not be
required for inhalation low; total cost feasible; reliability and
pathway; disposal of con- must include dis- effect1veness uncertain;
taminated material required. posal cost. monitoring and worker and
Not consistent with future equipment decontamination
redevelopment of site. May requhedj structural com-
avoid potent1al loss of petence of buildings
historic resources. unknown.
-------
Table 2
(continued)
Technology Thilnga Considerations Retain for
Area Considered Ef fecti veness Cost Acceptable Engineering Consideration
Of fiee and Physical T Sbort-term worker risks Initial cost mod- Structural contamination Nob
T.el:, Buildings Barriers ~inimal; limited control erate, long-term applicable, but may not
(continued) over unanticipated patb- cost low. be feasible; reliability
ways; cODlpatible witb and effectiveness uncer-
existing site use, but ;, tain; monitoring and
limits use of site as worker and equipment de-
long as material remains contamination required;
tbere. structural competence
of buildings unkuown.
p Short-term worker risks Initial cost lIod- Limited long-term feasi- No
lIini8lal; Hmlled control erate long-term bility, applicability,
over unanticipated path- cost low, but and reliability; moni-
ways; compatible with pel"petual. toring, inspection, and
existing site use, but maintenance required.- N
limits future use of site 0
il1 perpetuity. Remedial
action objectives not met.
No Action T, P Exposure pathways unaffect- No cost. Feasible, but neitber Yesc
ed unless buildings become appliable Dor reliable.
occupied, in wbicb case
potential for severe ad-
verse health effects would
increase. No control over
unanticipated pathways;
remedial action objectives
not met.
All Removal Offsite Oisposal P Offsite tran~port increases Initial cost high, Common handling, trans- Yes
An:ds risk of exposure. long-term onsite portation, aDd disposal
cost low. practices feasible,
applicable, effective,
and reliable; permanent
disposal site not avail-
able at tbis time.
Onsit<: lJisposal 1> Permanent dedication of Initial cost high, Feasible but neitber Nob
site as a radioactive long-term cost applicable nor reliable
vaste disposal facility moderate to low, in an urban area.
to the exclusion of all but perpetual.
otber uses; long-term
health risks low.
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Area
Technology
Considered
Thilnga
All Removal
Areas
(ccmtinued)
OnsHe
Storage
OffsHe
Storage
T
Table 2
(continued)
Ef feet !veness
Considerations
Cost
T
Additional handling increases Initial cost
exposure risk, mitigation moderate, short-
required; material is con- term cost low,
tained; eliminates wost ex- long-term onsite
posure pathways; temporarily cost--O, total,
restricts full use of site. cost must inclu&e
removal and per-
manent disposal
costs.
Additional handling increases
exposure ri~k, mitigation
required; material is re-
moved from site; eliminates
exposure pathways; full use
of site possible; offsite
lIIpacts minor.
Initial cost mod-
erate, short-term
cost low, long-
term onsite cost--
0; total cost
must include re-
moval and perma-
ment disposal costs. .
a .
Temporary (T) or P~rmanent (~) solution.
b
Rejected dlternatives are presented in Table 3-4.
cRetained for further analysis and consideration as
UO'!'E:
Se~ Figure 3 for area locations.
liE/IVANDV/042
required by the NCP.
Acceptable Engineering
Retain for
Consideration
Common construction and
handling practices feas-
ible, applicable, and re-
liable; ~ost implementable
option in short-term;
monitoring of storage site
required.
Yes
Common construction and
handling practices feas-
ible, applicable, and
reliable; temporary,
storage area must be
avallble.
Yes
IV
I--'
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22
Table 3
SUMMARY OF REJECTED ALTERNATI\~
REMEDIAL ACTION TECHNOLOGIES
OPERABLE UNIT IV/V
Technology
Timinga
,
Decontamination of structures
T, P
Onsite disposal
p
--.
Reprocessing
T, P
Radiation shielding
T, P
Area exclusion
P
Dilution
T, P
Ventilation of enclosed areas
T, P
Sealants
T, P
Physical barriers
P
aT" .
J.I!U.ng:
Reasons's) for Rejection
Uncertain reliability and effective-
ness; high costs; condition of
bUildings makes reuse infeasible.
Inconsistent with long-term
property use. Maintaining
security of site for 250 to 1,000
years as per the 40 CFR 192
standards is unfeasible in an
urbanized area. Reliability and
effectiveness uncertain in an
urbanized area.
Not feasible or applicable because
of high costs, low concentration of
waste, and residual waste disposal
problem. Reliability of reproces-
sing is unproven.
Limited applicability to condi-
tions of the site; low long-
term reliability.
Limited long-term reliability of
effectiveness.
Does not eliminate contamination
pathways; not applicable to the
problem or reliable.
Not applicable to present site
conditions. Low long-term effec-
tiveness and reliability for
future conditions.
Not applicable to present site con-
ditions. Low long-term effective-
ness and reliability for future
conditions.
Low long~ter.m reliability and
effectiveness.
temporary (T) or permanent (P) solution
DE/IVANDV/044
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23
Temporary Response Actions:
I.
Cap Al I Contdmination
All of the contam1natea areas would be capped; the laboratory and
office would be aemolished and the debris capped 1n place in order
to min1m1ze further m1gration or disperson of the contamlnatea
ma te ri a I . '
2.
Fence tne Contaminated Areas
All of the contaminated areas and the laboratory and office
bui la1ngs would be fenced to prevent human intrusion into the
contamlnated areas.
3.
Consolidate and Cap All Contamination
All contaminated material, including the building debris, would be
consoliaatea and capped within Area A of the ROBCO property.
4.
Temporary On-site Storage
5.
All contaminatea material, including the building aeDris, WOUld be
consolidated and stored ln a temporary fac1lity which would be
cons truCted ,on the ROBCO property.
Temporary Off-s1te Storage
All contamlnatea material, 1ncluaing the bui Id1ng debris, would be
removed and stored in a temporary faci11ty which would be
constructed on an off-s1te location.
6.
Barricaae the Buildings
The laboratory ana office buildings would be barr1caded to prevent
entry; no temporary action WOuld be taken on the other
contaminated areas.
7.
Consoliaate in Grinding Plant and Fence Area A
Contam1natea materials from all areas except Area A would be
consolidated in the ROBCO grinaing plant and the grinding plant
would be secured to prevent entry; a fence would be erected arouna
, . Area A.
8.
Apply Instltutional Controls
Instltutional controls such as zoning or aeea restrictions would
be applied to prevent m1suse of the contam1nated properties.
9.
No Temporary Action
No tempordry action ~~uld be taken at either the contaminatea lana
or the laooratory or the office.
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24
The EPA determined that a detailed analysis of temporary response
actions that did not meet the temporary response action obje:tives or their
corollaries was not necessary. As discussed in detail in the Feasibility
Study, only four of the temporary response actions, Nos. 3, 4, 5, and 7,
satisfied all of the temporary response action objectives. These were
retained for detailed analysis.
The remedial action alternatives and temporary response actions span the
NC? range of alternatives as described at 40 CFR Section 300.68(f).
Alternatives I and II are alternatives for treatment or disposal at an
off-site facility. Alternative II attains applicable or relevant and
appropriate Federal public health or environmental requirements. Alternative
I exceeds these requirements. Alternative III is the No Action Alternative.
The t2mporary response actions fit into the category of alternatives that do
not attain applicaJle or relevant and appropriate Federal pUblic health or
environmental requirements but reduce the likelihood of present or future
threat from the hazardous sUJstances and that provide significant protection
to public health, welfare, or the environment 40 CFR Sec. 3QO.58(f)(1)(iv).
A permanent remedial action alternative was not developed in this category
(41 eFR Sec. 301.63(f)(1)(iv)) be:ause, pursuant to Sec. 301).63(i)(5), the
EPA determined that it was not practicable or appropriate when cost-effective
and more relia~le alternatives could 1e developed to both attain or exceed
relevant and appropriate requirements.
Consistent with 40 CFR Section 3Q1.68(h), the remedial acti~n
alternatives and the temporary response actions remaining after the initial
scre~ning were evalua!ea in d~!ail. The faC!0rS used t~ evaluat~ the
remedial action alternatives and the temporary response acti0ns were cost,
Y'21n:;ility, tech'1.)logy, a:hinist:'3.tive and ot1er concerns, anj th2ir
relevant effect on public health, welfare, or the enviro~ment. Results of
t1(2 evalJdtion are sumiHrized jeloH.
Remedial action alternatives:
I.
Full Removal with Permanent Off-site Disposal
High reliability due to the permanent re~oval and safe disposal of the
contaminated material; moderate to hig~ technological feasihility with
some difficulty posed by the removal of the contaminated soil on the
DRGWR right-of-way; ~igh administrative concern due to lack of disposal
site; eliminates public health and welfare risk ~f long-term exposure
but slightly increases short-term exposure during removal operations;
el iminates off-site migration potential thereby rem~ving threat of
furt~er environmental cont~~ination.
II. . Partial Rem)val ~ith Perma'1ent Off-site Disposal
Hig'1 relia')ility 1ue to t~)e permanent removal and safe disposal of the
':ontal1in3~~j '11~terial; high technologit:al feasibility; high
administrative concern due to lack3f disposal site; eliminates public
health and welfare risk of long-term exposure in all areas but the DRGWR
right-ot-way, hut slightly i~creases short-term exposure during removal
operations; eli~in~tes off-site migration potential only from excavated
areas and buildings thereby decreasing threat of further environmental
contamination,rather than completely eliminating it.
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25
III. No Action
Low reliab1lity due to the lacK ot control ot future site activities;
h1gh technolog1cal feasib1 11ty since doing noth1ng requires no
Soph1st1cated technology; no administrat1ve concern since there are no
pol1tical or 1nst1tutional Darriers to inaction; mOderate public health
and welfare risk of long-term exposure in present state but 1f material
, ,
is mishandled, public health and welfare r1sk becomes much greater; does
not remove threat of turther environmental contamination.
Temporary Response Act1ons:
3.
Consol1dation and CapP1ng
High short-term reliab1lity; nigh technological feaslbility; high
administrative concern since agreement for on-site consolidation and
capping 1S not comp,,!ete and pUbllC acceptability for this action lS low;
decreases PUDlic health and welfare risk pending the availability of a
disposal site, but slightly increases short-term exposure during
operations; reduces threat of further environmental contamination in the
i nterlm.
4.
Temporary On-slte Storage
High short-term rellaDility; high technological feaslDility; high
aamln1stratlve conCern since agreement for on-s1te storage is not
complete and public acceptaD111ty for this actlon lS low; decreases
publ1C health and welfare risk pendlng the ava1 laDil1ty of a disposal
s1te but Sl1ghtly increases short-term exposure during operations;
reduces threat of further environmental contamination in the interim.
5.
Temporary Off-site Storage
High snort-term rellaDility; high technological feasibllity; mOderate
aaministrative concern s1nce agreement for off-site storage not
complete; removes public nealth and welfare risk at ROBCO but slightly
increases short-term exposure during operations, does not increase
si gnl ficantly short-term exposure at locati on of temporary storage S1 nce
the location will probably be part of another Denver Radium Site
property which wlll alreaay be contamlnated and strlct measures wl1 I be
taken to construct a secure facillty; removes threat of further
environmental contamlnation at ROBCO, does not lncrease threat at
location of temporary storage.
7.
Consolidate in Grinding Plant and Fence Area A
Hlgh short-term rel1aDi lity; low technological feasibil1ty due to
CHt1cUIty 1n movlng materul into the Duild1ng; hlgh administrative
concern since agreement for use of grinding plant 1S not complete and
owner is not likely to want to sacrlfice the bU1lding; public
acceptaDl 11ty for tnls action 1S low; decreases public healtn and
welfare risK pend1ng tne ava1 laD111ty'of a disposal s1te, Dut slightly
increases short-term exposure during operations; reduces threat of
furtner enVlronmentdl COntam1nat1on in the interim.
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26
For comparison with the above evaluat1on, TaDle 4 llsts the alternatives
w1th tne1r respect1ve 1nitial cap1tal costs, aeferred capital costs, annual
operation and maintenance costs, and present worth. Each cost figure for the
temporary response actions lncludes the cost ot Alternative I, the ultimate
a1sposal cost, Slnce none ot the temporary actions will be considered as the
final remeay. Assumpt10ns used 1n the aevelopment of these costs are
adaressea 1n Chapter 4 of the Feasibility Stuay.
Tne selectea remeay was chosen from these alternatives and is d1scussea
in detail later 1n" this document in the section entitled "Selected RemedY".
Cons1stency wlth Other Environmental Laws
The EPA Standards for Remedial Action at Inactive Uranium Processing
Sites, 40 CFR Part 192,serve as the remedial action oDjectives for ROBCO.
For properties contaminated with uranium processing resldues, these standards
estaollsn limlts for the gamma radiation level and annual average raaon decay
product concentration in any occupied or haoitab1e building and for the
radium concentratlon ln soi I on open lanas. Since Federal public health and
environmental requirements do not set gamma radiation exposure limits for
outdoor contamlnatea areas, the relevant and appropriate standard for the
ROBCO open lands is 40 CFR Sectl0n 192.12 whiCh states:
II Remeai a I actlons shall be conaucted so as to provide reasonable
assurance that, as a result of residual radioactive materials from any
aeslgnated processlng site:
(a) tne concentration of radium-226 in land average over any area
of 100 square meters shall not exceed the DacKground level by
more than -
(I) 5 pCl/g, averaged over the first 15
surface, ana
(2) 15 pCl/g, averaged over 15 cm thick
than 15 cm below the surface."
cm of sOlI below the
layers of soi I more
(40 CFR Section 192.12.)
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Table 4
REMEDIAL ACTION COST COMPARISON
OPERABI,E UNIT IV!V
Initial Deferred Annual Totala
Capital Capital O&M
AlternaU ve Description Cost Cost Cost Present Worth
1 Full removal with permanent offsite
disposal $ 0 $1,417,700 $ 0, $ 884,300
II Partial removal with permanent off- 0 1,295,000 0 807,700
sUe disposal
III No action 0 0 0 0
Temp. 3 Alternative I with temporary consol- 139,300 1,863,000 6,000 1,324,300
idation and capping I\J
-.J
Temp. 4 Alternative I with temporary onsite 686,900 1,225,500 6,000 1,474,300
storage
'l'emp. 5 Alternative I with temporary offsite 800,900 1,219,000 6,000 1,584,200
storage
Temp. 7 Alternative I with temporary cousol- 91,200 1,363,300 6 ,000 964,500
idation in grinding plant
aTeaporary present worth based on 5-year annual cost and deferred action and 10 percent interest rate.
DE/IVANDV/045
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28
In certain clrcumstances, 40 CFR Part 192 provldes that supplemental
standards may be lnvoked. See 40 CFR Sections 192.21 and 192.22.
Supplemental standards are appropriate when:
liThe estimatea cost of remedial action to satisfy 40 CFR Section
192.12(a) at a....site....is unreasonably high relative to the long-term
Denefits, ana the residual radioactive materlals do not pose a clear
present or future hazard. The likelihood that buildings will be erected
or that people wl11 spend long periOds of time at such a vicinity site
should be considered in evaluating this hazard. Remedial action wl11
generally not be necessary where residual radioactive materials have
been placed semi-pennanently in a location where site-specific factors
lim1t their hazard and from which they are costly or diff1cu1t to
remove, or where only m1nor quantities of residual radioactive materials
are involved. Examples are residual radioactive materials unaer hard
surface public roads, and Sidewalks, around public sewer lines, or in
fence post foundations."
(40 CFR Section 192.21(c).)
These supplemental Standards were cons1dered in relation to Area B-1 on
the DRGWR property because the contaminated soil is crossed by railroad
tracks and 1S situated among buried communications lines.
The relevant and appropriate standard for the laboratory and office
bUl Id1n9S and the grinding plant is 40 CFR Section 192.12(b) whiCh states:
(b) In any occupied or habitable building -
(1) The objective of remedial action shall be, and reasonable
effort shall be made to achleve, an annual average (or
equivalent) radon decay proauct concentration (incluaing
background) not to exceed 0.02 WL. In any case, the radon
decay product concentration (including background) shall
not exceed 0.03 WL, and
(2) The level of gamma radiation shall not exceed the
background level by more than 20 m1croroentgp.ns per hour.
(40 CFR Section 192.12(0).)
Even though the radon daughter concentration in the bui1aings is we!!
below the 0.02 working level standard, the gamma raaiat10n levels in all
three builaings exceed 20 microroentgens per hour. Remedial actl0n at the
buildings is' warranted, therefore, and again, the No Action Alternative, is
not justi fiaDle.
The following are other Feaeral crlteria, advisories, guidances and state
standards which the EPA considered when selecting the remedy:
- Colorado Department of Health, Rules and Regulatlons Pertaining to
Radiation Control. CRS 25-11-1-1 et seq. and implementing regulations.
- National Committee on Radiation Protection and Measurements (NCRP) and
International Commission on Radl0logical Protection (ICRP) gUlaelines.
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'29
The Colorado Department of Health regulations set alpha particle emission
limits of 300 als1ntegrations per minute per 100 square centimeters for
non-removable alpha radioactivity and 20 disintegrations per minute per 100
square Centimeters for removable alpha radioactivity. Although the alpha
raaioactivity contamination in the buildings exceeds these guidelines,
structure aecontamlnation was elimlnatea aurlng prellminary screening in favor
of structure aemolition because the .b~ildings have outllved their economically
useful llves ana they woula be torn down anyway in conjunction with
reaevelopment of the property~
The NCRP ana ICRP reconmend a maximum gamma radiation dose to the whole
body of 100 millirem per year for all sources except medical ana natural
backgrouna for chronlC exposure situations. The ROBCO exposure assessment
determined that if no action were to be taken and the ROBCO property was
redeveloped, this gUldeline woula beexceedea. Therefore, only Alternative I
and the temporary response actions are consistent with the NCRP and ICRP
guidelines. The temporary response actions are consistent only because the
material would be removed to a permanent facility before chronic exposure
occu rs.
The NCP allows that Federal, State, and local permits are not requirea
for on-site fund-financed remedial action or remeaial actions taken pursuant
to Federal actl0n under CERCLA Sectlon 106. Therefore, none of the temparary
response actions neea be aelayed by the permit application process or
termi na ted by a permit rej ecti on. However, the EPA expects that
non-environmental and construction permits will be required in carrying out
CERCLA Sections 104 and 106 on-slte response actions. The EPA wil I also take
steps to ensure that off-site disposal of any contaminated material removed
from ROBCO is conslstent with the EPAls off-site disposal policy, that is,
final disposal will be at a facility permitted for the acceptance of
raal0actlve waste. The radioactive material is not, at present, licensed by
elther the Nuclear Regulatory Commission (NRC) or the State of Colorado.
The EPA, after consultdtion wlth its Regional Hazaraous Waste Branch, has
determined that the non-radiological contaminants on the ROBCO property are
not sUDject to regulatlon under the Resource Conservation and Recovery Act
(RCRA). In oraer for the substances to be regulated, each must be a
commerclaJ cnemical product, manufacturing chemlcaJ lntermedlate or
off-specificatlon commercial chemical product referred to in 40 CFR Section
261.33(a)-(a). The EPA has no evidence that any non-radl010gical contamlnant
at ROBCO was once a discrete commercially produced/used and discarded
sUDstance WhlCh by design or chance came to De mlngled with other substances.
Thus RCRA regulations dO not apply to the non-radiological contaminants at
ROBCO. RCRA regulations also 00 not apply to the radium contaminatlon at
ROBCO because radioactive materlals are excluded from the statutory definition
of so 1 1 d wa s te .
The Coloraao Hlstorical Society has found the laboratory and office to De
ellgiDle for incluslon in the National Register of Historic Places. The
formation of the NRI was a significant event in the history of the radium
industry and the two buildings form a part of the original complex where the
processing of radium was initiated In 1914. The EPA will continue to
cooperate with the Colorado Historical Society by providing documentation on
tne OU11dings that lend hlstorical slgnificance to the site, ana will adhere
to the requlrements of 36 CFR Part 800.
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30
Selected Remedy
The EPA has determined that the appropriate exten~ of remedy at ROBCO is
Full Removal and Permanent Off-site Disposal, Alternative I. ThiS alternative
is a cost effective remedy t/lat effectively mitigates ana m1nimizes threats to
ana provldes adequate protection of public health, welfare, or the .
environment. As discussed in the previous section, this alternative attains
or exceeds the relevant and appropr1ate Federal public health and environ-
mental requ1r~nents tnat have been ldentified for the ROBCO s1te. In choosing
this remedy, the EPA considered cost, technology, reliability, administrative
ana other concerns, dna their relevant effects on publlC health, welfare, or
the environment.
The Ful I Removal and Permanent Off-site Disposal Alternative was chosen
over Alternative II, Partial Removal and Permanent Off-site Disposal. The
extra cost is justified in light of the increased public health protection
provided by Alternative I~. This is especially true if workers should have to
a1stUrD the Contaminatea soi I on the DRGWR property to repair the buried
communication lines.
In selecting Alternat1ve I, the EPA realizes that until a sU1table and
cost-effec,tive permanent disposal site is i4entified, which could be several
years, Alternative I cannot be implemented at ROBCO. Therefore, the EPAwill
incorporate Temporary Off-s1te Storage, as part of the selected remedy. While
Doth the EPA ana the State of Colorado are continuing to seek a permanent
disposal site, the EPA is actively pursuing an environmentally safe location
to consolidate and temporarily store the Denver Radium Site waste materials.
In the event that such an arrangement becomes avai lable, the EPA will conSider
implement1ng the Temporary Off-site Storage response action at ROBCO. Factors
that wi 11 De considered in determining whether to implement temporary off-site
storage include capacity of the storage facility, timing, ana the comparative
health ana env1ronmental threats posed by other Denver Radium Site properties
whose cleanup would be facilitated by temporary off-site storage.
As discussea in the previous section, Temporary Off-site Storage, since
it is an 1nterim remeay, need not attain or exceed all relevant and
appropriate Federal public health or environmental requirements that have been
identified at ROBCO (40 CFR Part 300.68(i)(5)(i)). However, by remov1~g all
of the contaminated material from the ROBCO site, it effectively mitigates or
minim1zes threats to and provides adequate protection of publ1C health, .
welfare, or the environment at ROBCO. ThiS action meets all of the temporary
response action oDjectives identified earlier.
If a temporary off-site storage facility does not become available within
a reasonable time after the signing of this ROD, the EPA has determined that
implementation of one of the temporary on-site response actions at ROBCO wil I
be necessary in order to protect public health, welfare, or the enVlronment.
Before tnis selection is made, the EPA will prepare conceptual designs of
several d1fferent on-site storage facilities, wil I conduct a more detailed
analysis of possible storage mechanisms for use inside the grinding plant, and
Wl 11 more thorougnly evaluate consolldation and capp1ng. The EPA will then
choose the most cost-effective of these options.
-------
31
This multi-solution approach allows the EPA flexibi11ty to move as
QUickly as posslole to overcome the hurales WhlCh up until now have thwarted
tile EPA's and Roblnson Brlck Company's efforts to cleanup the radioactive
contaminatl0n at ROBCO.
Operation and Malntenance
Operation and maintenance activities wlll De required to ensure the
effectlveness of any temporary response action. For any of the temporary
response actions, there will be an estimated cost of $6000 per year whiCh will
be incurred for 3 to 7 years depending upon the State's progress towards
identifying a permanent disposal site and will include such acctivities as
site inspections and possible minor structural repairs. CERCLA requires that
the State shall be responslDle for all operation ana maintenance costs beyond
the first year after completion of the temporary response action. The
Colorado Department of Health wi1 I be the agency responsible for the operation
and maintenance activities. A possible funding mechanism for the State is its
Hazardous Substance Response Fund or the cost share credit claimea by the
State for its site-related activities between January 1, 1978, and December
11, 1 980 .
Schedule
Key milestones leading to remealal action at ROBCO along with crucial
decision making dates are hlghllghted below.
(1) Complete responsible party search October 31, 1986.
- Notify responsible parties within two weeks of completion of search.
- Complete negotiations with responsible parties for either
implementation of remedial action or recovery of response costs. within
60 aays of notification.
(2) Select final remedial alternative by December 1, 1986.
- If a permanent disposal facility will De available by March, 1987, then
commence remedial design and contractor procurement for cleanup and
transportation of ROBCO material.
- If a .permanent disposal facl1ity will not be available by March, 1987,
and a temporary off-site storage facility wi 11 be available, commence
remedial design for cleanup and temporary off-site storage, proviaea
that such action does not use storage capacity needed for materials
from other Denver Radium Site properties that pose a greater current
PUblic health threat to site occupants.
- If neither of the above conditions are met, commence remedial design
for cleanup ana on-slte stabilization or storage.
Assumlng timely Congressional action to reauthorize and fund CERCLA,
remeaial aeslgn wi I I commence on December I, 1986, and is expected to be
completed in March, 1987.
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32
Future Actions
The future remeaial act1vlties that are required to complete site
response are:
(j) Selection ana, if necessary, dcquistion, and development of a permanent
disposal facility
A permanent d1sposal site for the Denver Radium waste materla1 must be
selected before the flnal remedy can be implemented at ROBCO. The State of
Colorado is responsible for this selectl0n and has stated its intention -to
take the lead on the remainlng steps toward this selection. Completion of the
process is estimated to cost over $500,000, and site acquisition and.
development costs could approach $2 million and require 5-7 years. The EPA
may, pursuant to CERCLA Sectlon 11 I(a), help the State fulfill its obligation
by sharlng in the State's capital expenditures for assuring the availability
of a permanent disposal site for the Denver Radium material.
(2) Selection and design of a temporary off-site storage facility
Tne EPA is actively pursuing a tempora~ off-site storage facility for
the Denver Radlum Site waste materials. If this arrangement becomes available
w1thin a reasonable timeframe, the EPA will decide whether or not the ROBCO
materi4l is to be included in th1S action.
(3) Selection and design of tempora~ on-site stabilization or a storage
facility
If the decision 1S made to not take the ROBCO material to a temporary
off-site storage facility, then the EPA will select and implement one of the
temporary on-site staDilization or storage optlons.
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