Superfund Explanation of Significant Difference for the Record of Decision : Loring Air Force Base Ou 2 Limestone ME


PB98-963129
EPA 541-R98-120
March 1999
EPA Superfund
Explanation of Significant Difference
for the Record of Decision:
Loring Air Force Base OU 2
Limestone, ME
9/30/1998

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n \ a i
LANDFILL 3
OPLRABLL UNIT 2
LX PL AN ATI ON OF SIGNIFICANT DIFFFRFNCHS
September 1998
Installation Restoration Program
Loring Air Force Base, Maine

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I)F( I.Ak A IK )N ION 1 III
F.XPl ANA HON Of SIGNIFICANT Dil i I Rl N< IS
SI TE N AM I AND LOCATION
Landfill 3, Operable Unit 2
Loiing Air Force Base (LAFB.i
Limestone, Manic
STATEMENT Ol- PURPOSE
This Explanation of Signilicant Differences (ESD) sets forth the basis for ceriain significant
changes to the remedv selected in the Operable Unit (OU) 2 Record ofIXviMon (ROD) at the
Loring Air Force Base National Priorities List sue (Sitej in Limestone. Maine.
STATUTORY BASIS FOR ISSUANCE OF THE ESI)
Under Section 1 17 (c) of the Comprehensive Environmental Response, Compensation, and
Liability Act (CERCLA). if the lead agency determines that the remedial action at a Site differs
significantly from the ROD tor that Site, the lead agency shall publish an explanation of the
significant differences between the remedial action being undertaken and the remedial action set
forth in the ROD and the reasons such changes are being made. The National Contingency Plan
(NCP) (40 CFR 300.435 (c) (2j), and EPA guidance (OSWER Directive 9355.3-02). indicate that
an ESD, rather than a ROD amendment, is appropriate where the changes in issue do not
fundamentally alter the overall remedy with respect to scope, performance, or cost. Because the
adjustments to the remedial action do not fundamentally alter the overall remedy for Landfill 3 in
OU 2 with respect to scope, performance, or cost, this ESD is being issued properly.
In accordance with the NCP (40 CFR 300.435 (c) (2) (i) (A)), this ESD will become part of the
Administrative Record which is available for public review at the LAFB Base Conversion
Agency Office, in Limestone, Maine. In addition, a notice that briefly summarizes this ESD will
be published in the Aroostook Republican and the Bangor Daily News.
OVERVIEW OF THE ESI)
OU 2 consists of two sites: Landfill 2 and Landfill 3. The OU 2 CERCLA ROD issued in
September 1994 declared there would be a CERCLA source control and soil remedial action at
Landfill 2 and Landfill 3. This ESD relates to the CERCLA remedial action at Landfill 3.
Landfill 3 is located approximately one-half mile from the West Gate on the Sawyer Road. The
landfill covers approximately 17 acres and received waste from 1974 to 1991. The selected
remedial action for Landfill 3 is containment with a cover system. It includes the following key
components:
D-l

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« Sit,- pii'| .11 ;il n <:s;
• ('tmsolidation <>I Stic soils lor suhgiadc and grading to minimize erosion and manage
n mo 11;
• Multi-lavcr cover system installation winch w ill complv with Resource Conservation
and Recovery Act (RORA) Subtitle (' and Maine hazardous waste requirements
including landlill gas assessment ami controls, and assessment ol adjacent wetlaniis;
« ( cites and warning signs inMiilialioi::
« Heed restrictions on land in the vicinity of the landfills;
• Post closure monitoring and maintenance; and
• Five-year site reviews.
In accordance with the ROD. excavated materia] from other areas at the Site will be used at
Landfill 3 as fill material to meet the subgrade design specifications for the Landfill 3 cover
system. Before material from such other areas can be used as subgrade material at Landfill 3. the
Air Force must comply with CERCLA and the NCP for any areas which are CERCLA sites. The
Air Force also must demonstrate that it has complied with the procedures set forth in the
"Technical Memorandum - A Land Disposal Restriction Evaluation of Soils Proposed as Landfill
Subgrade Materials. July 1994" (USAF. July 1994).
By this ESD, the Air Force is presenting its explanation of its decision, with concurrence from
EPA and MEDEP, to use soils excavated during an OU 8 removal action and sediments
excavated during the OU 13 remedial action as subgrade fill beneath the Landfill 3 cover system.
The Toxic Substances Control Act (TSCA) and 40 CFR Part 761 specify that non-liquid wastes
containing PCB concentrations greater than 50 parts per million (ppm) must be incinerated,
placed in a chemical waste landfill that meets certain technical requirements, or disposed of bv
some alternative disposal method that will provide adequate protection to human health and the
environment. The OU 8 soils and OU 13 sediments in question contain PCBs at concentrations
greater than 50 ppm. Therefore, the Air Force, as lead agency, has proposed construction of two
cells within the subgrade fill beneath the Landfill 3 cover system for the containment of these
soils and sediments. The cells provide a more cost-effective means of disposing of OU 8 soils
and OU 13 sediments contaminated with PCBs at concentrations greater than 50 ppm than off-
site treatment or disposal, while providing subgrade fill for the Landfill 3 cover system from the
Site.
The Air Force has requested waivers from certain of the TSCA technical requirements for
chemical waste landfills, w hich arc specified at 40 CFR § 761.75(b), for both cells. In
accordance w ith 40 CFR § 761.75(c)(4). the Air Force has submitted evidence to the Regional
Administrator of USFPA Region 1 that operation of the cells will not present an unreasonable
D-2

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i isl, «>; in|ur\ i>< ;i,in..::i	o: the cnvironnu tit In •!•• I'< °Bs v.;kmi in->ve u vimica! ii'tiii!ici:ii
1 hat I he Air I ¦< >i rr I j; 1 > ' c<11icsioi be waived arc not : ik• i. No disp< isal ot i'( 'iw.isk' will > vcm
until the requested wai\ci in Imali/ed.
The use of the eells described herein w ithin the subgradc fill beneath the I .andlill .1 cover svstem.
while a significant dilierenee in the remedy selec ted m the ()l i 2 RC )1.) lor 1 .andlill 3. does not
tundamentallv alter the overall remedv for Landfill 3 with respect to scope, performance, orcosi.
In fact, construction of the special cells at Landfill 3 will cost less than oi k site treatment or
disposal of the waste material that is contaminated with POBs at concentrations greater than >()
ppm.
DECLARATION
For the foregoing reasons, by inv signature below. I concur and recommend the issuance 01 an
Lxplanation of Significant Differences lor Operable Unit 2 at Luring Air Lorce Base. 111
Limestone, Maine and the changes stated therein.
Department of the Air Force
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Albert F. I.owas. Jr
Albert F. I .owas. Jr. y	/
Director. Air Force Base Conversion Asiencv
United States Environmental Protection Agency
Patricia L. Meaney
Director, Office of
Patricia L. Meaney
Director, Office of Site Remediation and Restoration
US Environmental Protection Agency, Region 1
D-3

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i \!'i W A I l( l\ OF SK.MIK AM L11 i I KIM h
(Jperahlc [ nil 2
lorino air i orc l ham:
MMKSTON'K. MAIM:
I. INTRODKl'lON
Silt Nairn awl Location
Sue Name:	1 .andllll 3
()perablc I nil 2
I .oring Air Force Base 11 .AFB >
Sue Focation:	Limestone. Maine
B.	Load and Support Agencies
Lead Agencv:	Lnited Slates Department o| tiie Air Force iAir Force!
Support Agencies: Lnited States Lnvtronmentai Protection Agencv (LPAi
Maine Department ol Lnvironmentai Protection (MLDLP)
Pursuant to the Comprehensive Lnvironmentai Response. Compensation, ami Liability Aei
(CLRCLA) §120 (e) (42 USC § 9620 (el ]. the Air Loire. LPA and ML 1)1:1' entered into a
Federal Facility Agreement (FFA), dated January 30. 1991, amended December 1993 and
January 1995. regarding the cleanup of the LAFB National Priorities List (NPL) site (Site). The
FFA sets forth the roies and responsibilities of each of the parties.
C.	Legal Authority
I inier C'I:RC'L.\ § I 17 t e| j42 I SC' § 96 i 7 ic)j. tlie National Contingency Plan (N'CP) [40 CFR
§300.435 fc)|. .mil LPA guidance iOSWHR Directive 9355.3-02). il the lead agencv determines
that differences in the remedial action significantly change but do not fundamentally alter the
remedy selected in the Record of Decision (ROD) with respect to scope, performance, or cost,
the lead agency shall publish an explanation of the significant differences between the remedial
action being undertaken and the remedial action set forth in the ROD and the reasons such
changes are being made.
D.	Summary of this Explanation of Significant Differences
The 1994 ROD for OU 2 selected a remedial action for Landfill 3 which included a multi-layer
cover system. Fxcavated material from other areas at the Site may be used at Landfill 3 as fill
material to meet the subgrade design specifications for the cover system. Before material from

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( ! k C I .-*\ .,i jt ¦ : u \' I! ' • m . 111 \ . i: -¦. i wh i el i . 111 ¦ ( I i\ ( I \ ^;t¦ v i i,,, . \ ir I ^ v : .i K, > i11< is;
demons! raic ili;ii i1 si,is complied v\ ;ih the pioi-i-tiuiv^ vol loitls in l !ii' " ! 'echoica i XirnioK.iulihi
A Land I )ispi>s;ii Rcsint li<>ii I a;i!u;ilh>n o| Soils Proposed as Landfill Subgradc Materials. Jui\
IW-I" (( SAI J111\ I <)')-\
B\ this i.SI). I he . \: i porcc is presenting lis explanation of lis decision, with concurrence from
I.I'.\	and Mid )1 P. io use sods excavated during an ( H !S removal action and s^iuncnis
excavated during t he ()( ! 3 re medial ael ion as subgradc fill bene a ill I he 1 .and I d I 3 co\ ci sv su-m
The Tonle Suhvnimvs ( ontioj \ct i I S('A ) ami -ill CFR Pari ~(j| specify dial non-!urn k¦ wastes
containing P< 'B concentrations greater ihan 50 parts pei' nnliion (ppm) nuisi he incinc; akM
placed in a clicniic.il waste iandl d, thai meels certain technical reouuements. t n disposed of in
some alternative disposal method dial w ill provide adequate protection to human lieaidi aim im
environment. Tlie Ol N soils anil ()l' 1 3 sediments in question contain P( 'Bs at concent! al ions
greater than 50 ppm. Therefore, the Ait' Force. as lead agency, has proposed construction of two
cells w ithin the subgradc fill beneath the Landfill 3 cover sy stem lor the containment of these
soils and sediments. The cells provide a more cost-effective means of disposing ot OPS soils
and HI' i 3 sediments contaminated with P( 'Bs at concentrations greater than 50 ppm than of'l-sitc
treatment or disposal, while providing suhuradc fill lor the Landfill 3 coxcr swiem from ;ik Sir
Tiic Aij Force has requested \v»i\ ers from certain of the TSCA technical requirements loi
chemical waste iandfdK which arc specified at 40 CFR 5j 7M .75(h). for both cells. In
accordance with 40 ( PR ^ 7b 1.75ic )(41. the Air Force has suhmilled evidence to die Regional
Administrator of I Si PA Region ! thai operation of the cells will not present an unreasonable
risk of injurv to human health or the environment from PCBs when those technical requirements
that the Air Force has requested be waived are not met. No disposal of PCB waste will occur
until the requested waiver is finalized.
E. Availability (if Documents
This FSD will become pari of die Administrative Record File forOl'2. This LSI), along w ith
the supplemental documentation meiuded in the Administrative Record File, .ire available lo1
review at the:
Air Force Base Conversion Agency
5100 Texas Road
Limestone. Maine 04750-9743
Phone: (207) 328-7109. Fax: (207) 328-7131
Hours: 7:30 a.m. to 4:30 p.m.. Monday through Friday
II.	SUMMARY OF SITE HISTORY, RESPONSE ACTIVITIES AND SELECTED
REMEDY
A. Site History

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I i)C loHlKT I -Ail"). II: III 11 I i least em M.I I III'. IS . .I.le.v'il « I! I | jli- M>tllii .;; H i easi li\ i I , I i |
I .Milestone. on the norih hv the low ns ol ( Vv, el; ;.i.v- ('onm >i. ami on ilie w c-; ,n ;;ic ( "n\ oi
('aribou. The base is approximately thtce nni^ v. est of ihe I lined Sialcs/( amu'ean border and
covers approximately 9.000 acres.
As in tied abo\e. I lie Sue is a MM . site. I here arc curronllv sen oral areas oi coiuvrn muter
in\ esi iyai ion wniim I lie Siie. which ban- been o; eam/cd into (Jpcral Me I nil-- «< )l si I'. >r
investigation am! re median* in purposes. This I-.Si) re laics to the remedial aclion ai I .and fill 3 in
< )i :.
Because ol I he base s prinian mission, [.Alii persi >nnci were engaged in \aru>us operations. .1
number ol w inch required die use. handlme. sioraue. or disposal oi hazardous vitCsianees. In 11u•
past, die.se hazardous substances entered tne cn\ ironmeni through accidental --pi,is. teaks in
supply piping, iandfilling operations, burning ol hi|iml wastes during Iirc-1;amine exercises, and
the cumulative effects of operations conducted at the base's fhghtline and industrial areas. .As
part of the Department of Defense's Installation Restoration Program ilRPl. the Air Force
initiated activities to identih . evaluate, ami remediate lormer disposal or spill sites containing
hazardous substances. After initiation of these acii\ ilics. the base was placed on the N'PF. ami
the Air Force. FSFPA ami MliDF.P agreed to its remediation 111 accordance with the FFA.
Following the signing ol the FFA. FAFB was placed on the F.S. Congress Base Closure Fist and
was closed in September 1994.
'idle topography of FAFB is gentb miling. with sewiai brooks culling through the terrain. The
mam base elevations range from 74b leet above mean sea level (.VlSl.i on the mam runwav to
approximately 570 feet above iMSF in the southwest portion ol the base.
Fandfill 3 is located approximately one-half mile from the West Gate on Sawyer Road and
covers approximately 17 acres. During parts of the year, groundwater contacts the landfilled
wastes. Several small wet areas (i.e.. less than one acre in size) have been identified on the
periphery of Fandfill 3. An approximately five-acre wetland is located west of Fandfill 3. This
wetland is at a higher elevation than Fandfill 3.
The area occupied by Fandfill 3 was mined c\tcnsi\e!v for gravel during construction of the base
runw ay and flight 1 ine areas. Fandfill 3 recencd waste from llJ74 to 1991. Hazardous w astes are
not known to have been placed at Fandfill 3. However, small quantities of w astes regulated
under the Resource Conservation and Recovery Act of 1976 (RCRA) (42 I'SC 6901 ) (i.e..
waste oil/fuels, solvents, paints, thinners, hydraulic fluids) may have been buried in the landfill
prior to enactment of RCRA. Fandfill 3 was closed in 1991 and covered with a 6-inch layer of
native soil. Since 1994, Fandfill 3 has received non-hazardous waste material (primarily
petroleum-contaminated soil) from various soil removals across the Site. The waste material
provides subgrade fill ("or the cover system planned for completion in 1999.
For example, approximately K0.000 cubic yards icy) of sediment contaminated with PC'Bs at
concentrations less than 50 ppm were placed at Fandfill 3 in 1997 in accordance with the OL' 13

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pi an no I hi'	. i. : i: ¦ ii ; ..nisiii.-i .1 111 i1'.s ¦ a i1- r, ^ ¦ >1 i I ;c m'i ; i 1: ic n: -• ; ¦ >1 i; k' <¦ )\ , ;
remedial ;k*iu»:i ii.r. e l'( T; cniicei.:r.ili«<:is L ; i.:- i" pj 1:11.
H. I n vestigal inn I i is(nr\
The 1 n vi'M 1 !.';M n >r frstorv <>i L.uullii1 ; is m; ; 1 •! 1 : -v;! .is jojlou v.
•	! ii ! "s-i. ;i f' ¦ ¦- i: 11 i; 11;;: '• Avh'^iik'ii' w.is coinHc.cvi dctai I in;: In st. >nc a I i 1,: /;: >) 11 ^ n ; i u-; i
!K.av ,ii!-< .i-!v' Jisp. >s.i, practices a 1 1 \M ; ¦ i !; \ i ! i 1! i. ins.;
•	1 n ii 1; 1 i Site I i 1 \ 111 ^ a 11' n ho Id work 10 determine • ; contaminants w oil' prcscni al 1 .aii.liili 3
v. a s 1 ¦< ii)..:; i. 1 ,i j ;;: ! 1S 1 Wi'vi in. |«),SN 1,
•	An kl process commenced in 19XS and continued mlo 1993.
•	LAFB was added In llic N'PF in February llJ9().
•	'! i:c ! SAP eniercd m'.o a Federal faci!it\ Ai-rcemeni ;cct Managers to make minor modifications, such ;.s schedule ad|iistmcnls am:
removal o! 'petroleum contaminated sites from the agreement.
•	A Focused Feasibility Stud}' was completed in 1994 for Landfill 3 to determine alternatives
for remediation ol contamination based on information presented in the RI report, and a
Proposed Plan w as submitted for public review in Jul)' 1994.
•	The Air Force and the FPA signed the 0l:2 ROD September 30. 1994. The Maine DEP
provided a letter of concurrence on this ROD.
C. Selected Remed\
The selected remedv for Ol "2 is containment using a cover system. The major components ol the
remedy for Landfill 3 include:
•	Site preparation;
•	Consolidation of Site soils for subgrade and grading to minimize erosion and manage runoff;
• Multi-laver co\oi s\siem installation which will comply with RCRA Subtitle C and Maine
hazardous waste requirements including landfill gas assessment and controls, and assessment
ol adjacent wetlands;

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' V ; i • I;:" -: v . 1: .1. ¦" < " I'
• I Veil iv.slriv'iioiis nn 11 • ilk1 vicinit'. ('] tin- !; i; u I i i i! -.
• 1'iM closure i Mi imii >;: :ig am! i:ia:nlc;n:iac: .11;.I
• Fi\c-veai vile IV\ lews.
111. M).S( RDM ION OI s|(,\ll )( W I DILI LRf \CLS Wl) BASIS 1 "OK I liO.sL
Dii 11 ri:n( i s
SuniiiKin and Basis oi'Significant Differences
'flic selected remedy for Landfill 3. as outlined m Section II.(' and set form in the (H '2 ROD.
includes the consolidation of soil's and sediments excavated from oilier locations at 1 he Site for
use as subgrade fill under the Landfill 3 co\cr system. The difference between the reniedx
selected in Tie ( H "2 ROD ami the ivmcd\ 10 he taken ai I ..dull ill 5 iv the construction wninr die
i ¦ i! beneath tins ei' \ e; s\ siein ol n\o ceil s dial a: e designer 10 nit el the -iO C f R S
76i 75(h» technical ivijiiuvineni.s li>r chemical wasle landfilK icxeepi those requiiemenis
speciiicallv waived h\ the I:PA Regional Administrator 1
These cells allow lor the use ol soils am! sediments irom othei locations at the Site as subgrade
fill, as provided for in the Ol '2 ROD. while providing a cost-cflective alternative disposal
method lor such soils and sediments that contain LCBs at concentrations greater than 50 ppm.
Approximately 400 cy of soil from the Underground Transformer Site at OU8 ami 2,150cy of
sediments from OU 13 contain PCBs at concentrations greater than 50 ppm. One of the cells has
a capacity of about 2.000 c\ and contains sediments e.xca\ aied during the O!' I 3 remedial action:
the other cell has a capacity ol about 600 c\ and will contain soils excavated during an OUS
removal action as well as OU 13 sediments. OfLsitc treatment or disposal ol this approximately
2.550 cv of PCB-contaminated soils and sediments has an estimated cost of S765.000. or roughly
S300/cv. Disposal of these sods and sediments in the two cells has an estimated cost of $X6.0(M).
'I'he Air force has asked fi >r wan cr of certain ol the 40 CTR s 7M.75ih: technical requirements
for each cell. It also has submitted evidence that operation of the cells would not present an
unreasonable risk of injury to health or the environment Irom PCBs if the requested waivers were
granted 111 the Technical Memorandum. I'nlxchlormatal Biphcnyl (I'CB) Wa.stc Cell at Landfill j
(L'SAF 1997). The specific technical requirements lor w hich the Air Force requested waivers for
each cell, and the justifications for such waivers, are discussed below . In accordance with 40
CFR § 761.75(c)(4). the Regional Administrator of FPA Region 1 has found that operation of the
cells will not present an unreasonable risk of injury to human health or the environment from
PCBs if those technical requirements that the Air Force has requested be w aived are not met. O11
the basis ol this finding, the Regional Administrator has waived those specific requirements. See
Attachment.

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B. I )e.script ion of .Significant I'iflrrenccs
I Ik* I< >11< »v. i!;m\ i i •;: ii : i! I In- rcj!iilal< si \ icq.iiicmcnts lor a cncm ical w asu- la ir i i 11 i .md
i1csentit' Ii< >\\ tlis|*< is;i| s i; snifs and sediment Iron; ()l s and ()l IconlauunL' I'( B concentrations
LiivaliT thai: 5(1 ppni in Hit/ sj\viall\ designed and «.•«»n>>lruv*lc j hiiii.'a io iiealth or i Ik- cn\ ironincnt trom |'( 'Bs.
1 lie i equi:viiit.'ills i jxtctl in 41. /s I'H a chcmica 1 wasic lainilili used I< >: ;itspiI o-
) '< B w .iMi' ,:H >111.111•;i; !/c>; i!. I.'ic loilov. in:.' para:' i ap;l v
•	Soils in S\ ntlid ic \!( niiu anc I .incrs: ! In ai.i! 11) siu- mil si i v !. v; vd u' :v:.ii v e
' inpen v. \idle si Is v, ill. |, ; i '¦ j It1 w 111 ;j pa I a: ik'lt'i s v p ,;si - ]v\'i i ! j .-..i-. i .| ¦ ¦ i . w i'': ;•
11ia\tmm:i pcn:icabii;i\ * ¦'. j \ it) Ci 1d see. A s\ n: he I ic i urn iPrane i 11 icr s; ;il! M va 11 sv; w | j-|
lhe h vdroh>l:le or gcolog ic conditions rcqii ire such a iiner to provide eipiivaieni pernieaivin\.
The liner must have a minimum lliiekness of 3') mils, w ith adequate soil underlining and soli
cover to prevent damage to the liner.
•	Ihdrolotiie Conditions: I he bottom of ihe iand; di line: system m u.st lv 5< • !,-=•: ;.bo\c !l,c
historical liiyh yroundwalcr table. Hoodplains. shore lands ami tjroundu ak - recharge a:cas
must he avoided. ami there must he no livdrauJic eonneeiion between the ian11!ill site and
standing or Ho v. mp surfaci w a;er
•	Sue face Wale i' Protect inn: The landfill sits' musi he protected In m: a )00- \ ear fiood. .sad
drainage diversion structures must he able to accommodate runoff i rom a 25- \car. 2 - In v
storm.
•	Topography: The landfill must be sited in an area of low to moderate relief to minimi/e
erosion and prevent landslides.
•	Surface Water Monitoring: .Surface water samples must be collected from designated areas
prior tc ooinmencinc operations, monthly during disposal operations, and semi-annualK' after
dispi is.;; operations .av complete. Surface water samples should be anai\ a\S »or P( 'Bs. pi I
speciI k cosidiiv :a:icc. ar.d ciilonnatcd oipanics.
•	Groundwater Monitoring: A minimum of 3 monitoring wells is required, (iroundwater
samples must be analv/ed for PCBs. pH. specific conductance, and chlorinated organics.
Sampling frequency is not specified in the regulations.
•	Leachate Collection System: A leachate collection system must he provided w hen semi-
solid or leachahle solid wastes are to he disposed of in the landfill. The system must he
monitored monilih for quantity and phvsicochcmical characteristics of leachate produced.
b

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Mi | Mm in m;_: } - ;irilit ic^ ;iiui i >[',>'r;ii ii: .	, , .¦ \ ¦ ¦¦¦. c11
11'.". •' ' - ! ¦¦ ¦!. !•' be |'I;k ek .ii i M!.. ; > - ¦ i,	. : : : ii l:n: . a \ - i	¦. ¦:; i.; - ::. >¦;
v'hlr; ;ii,\
.Ai'i'i Hi 11 li:: hi -|H ( M\ :f)i . /."! icli-l i. oik' .*•: I • !• >; ti it* lVi|illlYll ier,ls :v w\ ed ;:s ii iji'j ,|S
operation til ! he iandl ili will not pieser.t ;i;i : hii'.m >nahle r;sk of ivv- 'v;iisi • "i- i v .me in iiiivri e< >r.;;u'l. :nh.iuiin>«i nr :1111: m: i>:
;'( i'i- as .i I'ts11!i i)i levelling i11 l'i i ii11k.11i'i. ,ii.ii i¦ 11\ 111 ¦¦!:; icnta> i isk s ik ie k i.:;;, vi i . >;iI aci wen
111 i 111:111 v . i k u '''< 'K' I ii; m li 11 'J I ;ii Ii i ! 1 !«' s 11!'! ik	'1 • ¦¦ r nCi 11 n ic Ml s - \ i n) T ~i i i i! I!u kesjei; ,nnl
psexeiiin •! i-'! risk <«l in id I'v in health or d;e v' i i \ i : i ': i i i k ' i i; iron) i H "Bs is k i \ e:; 'vi< •••>..
I lie technical ivqiinviilents 11 >r chc:i;k i v. :;sic :.i I: iiis v. ere wnn* :i pnuiai t!\ i. - ,ni.iress
1 || k' I k; I 111 k hiriill ills. 1 DC i lid I Il k' ilk' 111.11 Ikpk I, k' Ik o| kakikli kiki sliflace Willi'I ikkki.hkki , i' such
I: i 11 c! 111 Is. The lollou ini> sub sect ions demonstrate how the small size of the specially Uesignetl
aiul constructed cells at Lamllill 3 ami short duration of < iperation minimizes leachatc general ion
and ;il lows certain of these requirements to he w;uved while meet ink the pi oiect i\ eness standard.
! here are two d is; met ceils oi sun; ha desi^;, mcUi.ievi in this I .S i ">. I he i i is; ce 11 is des; uned a •
contain ;:ppr>i\imalcl\ 2.000 e> oi p("b waste. I: was constructed in I'aeeoidike lo the
description eontamed in the Technical Memorandum. /'( Ii Wastc C ell til l.aiullVi a {I S.AI .
I'J'h i. "!'he second cell is designed to contain approximately 600 cv of PCB waste. It w ill he
constructed ir« ! WK according to tlie de.se ma a m :n eluded in the letter. !'r,	;"i '!: \ \ ,;\:<¦ f V /•
Punts i/
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2. iluliiiln^ic ( <¦!)Oi ckll'.ds. I i It' l'i : vVslOMl Nil" I ill I; . I I ! i ' III L'l r I I i '• I . ii -|; \\ ill] 1 i I!.-
iTi w .Mr v r 11 i i )\ r i's ;i i u i I; i :r p. v. i. i :v d i i. ¦ ¦ . p i i i' i rPrn 11 > p 11 pp r pi p IP:P- p pi' ' p p '. r; il lip' rr I p
! P '' 11 IV P' 111 p I PJ . p > PiPII i 1! PP ' ' P ! i. i 'PP i p I PP' Pi. . . ! i i ¦ !l\"'i.''. I ' ¦ P ,.:. P . . P ,,; • . I.. P ' j . i 11 i i i1 i. '
li.iw no i i v i h ,i 111 ip connection 10 anv pas s <>i !	>.l ¦. i Mr: "¦ ;h • e\pia: pp coi pip-in i • tv: u r r n
P I: PPP'ilis I i ip pp i I s P i 1 I.' : PiPIiP k . I .' P; p' p ; P , <.1 i : i p p< >i > \ P. - p ,
I I P' . 11 spp k. P i "i;' i rI 11J p I 'H >p . :' I 11 i 1 p pp i k ; MP ; IP' .'I: s| ( .| ! p.p I! P: I: p p ' p : , p , i i p . p : pp- p.
s 11 1 i P' I p 11 i P ¦ p. P.' '¦ P ! ' i I i PP'. is i ¦ 11, i P k I ; s i, o; ] M | P 'i i ' I P' P , i I j i ,' i j . p C ; ''P . v i, , i . ,i p 1 ¦ P p ; 11 pi s I 11.
I. up? cr rr 11 vp; is eoxercil w 1U1 (i( I. panels imtricilialeh aiter placemen: < •: ::ir I'( 'H waste to
exclude rainwater i n Ii 11 rat n >n and miiiimi/r the formation ot leacnatc. Pl.irciecnt of ll;r l'( 'H
waste took less I liar, a week. Moismir couPppcJ w iiliin 1 ht* scdimciiN Whi aid n hvdrat iiip ike
(•( I.. therein aemaiini! the desirable iow pe:":noahi!ii\ propert ics 'j lie s;s,allot . oil v. Hi K filled
and o w ered wii i I P! 1 ii i; I ppiii.n. . UP: au i n in p J ialci \ aPr: pp.rr p.. p: P p I'( H .,sP I .c j. ¦ I..
r r i p : pi 1111 p r \ pr pi r i i 11 * Ix minimal I I u: i i i p Ir i a\ r! 1 i\ ( !¦' \ I '¦ Pi 1 I.,:' i. P ; i I \ r r s \ s i L p , p ¦
pp ••nslaiiet; in I will lunhr1 niiniins/e ram I ail m I ill rai ion im.) ilir eelK aiul ieaehaic
iieneialmi). Fhc or 11 imrrs u il; prr\riii anv learhalr Irom nnpiaiir-p lo urounilwairr.
'Mir minimum ilrpth l»> ^rountiwalrr iri|uiirmeni in 40 ('l:R s1 I .l?i h ;i ; i 11ia\ iv v. aivnl l'. >r
kioi11 eells hecauve '.he speeiail) desiiineil cells, in eo:ijtmeti'>n wiih uie niulu-!;:\er et>\er svsiem.
pirxriu mii;ration pI I'C'Hs to groundwater anri pre^enl no unreaM>nahle risk o; i;ijur\ to health or
the environment from P("Hs.
3.	Surface ^N'atcr Pr<»(i'cti .'PP .. >v ti; on ihe In e I' side
to prevent Mirlaee water rn:t-on durir>^; !;k Pj.uh ment opera' ion in nuk: i ip. pp viorn< v. i
th \ ers ton s\ siem a^sociatcit with Land l ii I 3 is sii II icicni to J i\ ert runoi i 11 oi 11 2 i Notn . 2r c.a
stoini from ivachiiig the cells.
4.	Topograph}
The PCB cells are located in an area of low relief, where the potential for landslides or erosion is
minimal or non-existent. The requirement in 4(1 (TR s; 7M .75( h k 5 ) is me! lot both cells.
5.	Surface Water Monitoring
N
-------
! ! I M
Ii)0 Col
¦ i	;
¦ , .tit¦ i. i .1 I,
: . 1 i 1 i I ! 1 ; , ¦ MI1.|
M.: iaco ak'l
; ; a': it Si;: kit e v. ;.k
iv: i cill ol ¦;() ( 1 K i ' •
(i .i i ,i , \ :
ii. < . r< mi nil w a I it M
I IlL^
\ 'ii ;i ,' i ha;: ;: iree or< >ii!k,:v ale' n n >i;m >11; i v v . ¦ I
Mil i j. v; ¦ i1 .;' i:: <'i1;i v. ;ii ^: !x1 'IV I : ;e n11:; ;i!
¦, ¦> t!u nc :¦'!, iv. ' i; i ,'i e:-¦ <¦ >i -k ¦¦ < '! K •'' '• •
7. Loaehale Collection System

: Ii 11 jt! 1!)I .:: u I I i ; ' k 0 i V
/: k " . i j .M ¦'; ;¦	k i;
¦¦ 11 a ¦' i I :c I' ¦ .
The iv.u cells ;uv in)l cxpockvi in jjonen.ic leads;.k . I he :nn: sciiinseni !o iv ised ol are
dew a toreu prior k ¦ place:: ;em ;i; ;lie ^e! N \>> n en.:, ik e ]k,k':i,;U' ;_v:'u ; a.;;. v ai kk e o. .lie: v. ; I. K
•J i \ cried j ii ¦>! i, i ]¦ iv. ii k ; i ;lv) i)! 11',! - >ug I': !. le cc;;^ in! kk -- i ;on pe;'l< kin; 1:; > ie I: a. k < I :¦ ; t'
luriiicr minimize ieachale licneiaison. -\lici the m*i!n and sediment arc one an^ulateo. ilk ceils will
he covered Willi the inu!ii-la\vi ! RCR.A 'I vpe, i ami
s \ s k'
'i
Ml HHll
!o nifu'DI Hi!
'•ii:';ace \\ aler :nI:itrakon. 1 l:nv ,i je.icr.au collodion *\ ^.ci.i is n< -i !k\ev.sar> m>! ei'.tv coll. i o,
these roast>ns. >,!io Ieachale colkviior. vwicii. reqnnvine!a in 4(i (IK i 7(>L/ 5.» . :::a\ he
w a:\ed I >: injure n > hoaM !i nr ! 1 .c o;;11.10";, Iron;
I'Cliv
portinpen l'iir onl\ a sliori pei ie :i"-Oki i' • vo11aie ran.';k
;eIis b\' one or hoili o: the loilow iiil: nielliod

An e\ea\ alor working alomo I he ed'je ol tiie oeiK w ill iilaoe w aste into the cells.
• An access ramp will be provided alone the edge ol the cells to allow trucks, dozers,
compactors, or other equipment as necessary to erne1' the cells.
"I he requirements of 40 C I K S 7M .75i' b l! X ) are met.
The siiMi)! ieanl di 11 e re nee.s to the I ()'. 2 Rf M) !or 1 .a i id fill o with respect lo scope.
peril iiin.iiKv an.! ins; a; e sinnnianzetl in ike' loiiov. table.
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( ! r::j ii i.i : R < inn i

i 'i.11: ii: ic;:I "i appi < >\iii i.i v '
¦¦1 !J' i''' i c\ i11 m m h an(I sc. r - v
'i i' . - ¦ i;, \ " i i ?; i i i < i i: >¦ : c s s ; i , 1
. ¦!. i:1i i -n> 'e111 i.i! :< ii i if ¦ ¦ '' ;' 1
: ii: i , ii.liil! ¦ ! i' !•/«•' '¦ ¦
i i >i:! ,i i: 11; u¦ i::
ildl I II ill! :,i! .< I
sediments v. ii
i.: i)in;' l i
Min'i' ¦ k 1
V \ s ! I 1 M ! < ' ' ' i. I
' k- k:u;
r¦'i mi ( tt i
¦- ¦'¦ 1	- t ii, n .t! k . ;
! I'> ( ¦: >:kvi.¦!'.!i!';:* i^v '
r: 'i:; ; ii i .ami: i.i e in ! '¦"
I Milvjr,idc j'ii;.
I YiTormancc
T
'! Sf ¦
. i i 11
Short Term I Workers must use person.!
ITf'cctiveness ! i'l11'!!v11l'111 to pivxent c\p<-
.'niiianiiiiii
sur-tjnuic i!il ;ii
iHU'ilVJ PKk
; ii!
j i i i i I '._k' • 1!! k . 11: 1. ..	; v : .' i
; COjjsll'ik k"u UlkiiT O s \ v k" i! i
i installed ill I .iiiHlfil!
! ;k\|i 11 j'c i i ic 111 n i; i - > ¦ ( | j< . t - , . > i i -
on i Placement of (H'S so] js and Ol ' i
¦ --i'U ;'] if n t s i !i ilk' -¦; wu; eel K m :
i .and!;.! .•> v. si! iImisa' i;u
rco i i i :vi iK'i :t I'll" w > e ke i s io use
po I'M >;-¦;:! prolCC! hHI C i1111 pi i 10: i i.
| Shorl-torni adverse eeol- c;, |.,|m .••••,•;). iviia'^ic tc- '•>. .r. >.•••
.i. ncc! ;i: last ;no:v thai - ¦ \ ca: ¦¦.
No residual risks arc anticipated.
Puce! contact with the contaminants
• is prevented hy tiic
("onsti'tiction and operation of the
special cells will not delav
mstalkition of the final cover svsieni
a! I .andfill 3 ;inc will not affect the
potential for short-term adverse
ecological impacts ol the remedv.
i Ik' ^kl 1 ^k' i: ^ Wii: !k M ;i 1 kv 1 I
k'l'ii ! I ei i,;1"'! ';\ • i !;:• I ,,i!, I
C'' er s\ sicn .
I lie special eel!^ in 1 aiidI ii I 3 w
not affect the residua! risks.
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O n ;j: ii i\ i'mr i -
1 .oil:; 'It Tin II:-1 MM 11 i.i\;e! u >v. -- i:.:: : i - :i a	a ' I eae: iai- :vi;eM!i. : -¦ ii i an I i le
I'.f leeli\ cru's.s i:i11):ii i i'u ¦ 1 .:¦i j: h v'o\ ¦•! •	i 1 s-vei;.! eeiK n; I ,..'i :i : I .*• is *iot
1 ( "< m.' ! i1 u d : he 1 i.i 1 i ' ¦ ' i 1 1 . ' ''	1 e v n e; ed. ' I u \ v ; • I• ir .¦ I:;111i•
I i! I,: I :: 1!:. I I:' I:! . ; 1 / i ! 1:1 I. !: ¦ 11	I v¦. I ; ¦ ¦'H ':;: !, [
- \ S I ¦	J
] >: 1 M . !!; i;.i V'.: '; ic ; •.';¦ I e1 ^i !1 'i'	: u
I ..1 lit!; I i i e would Ix- s M.4 VM ;I K 1.	>M\iM iH.
W . S| IM'( 'U | \(,| \( A CO MM KYI'S
:.i: i
:' .i'.Ui: -J V- : Iail',, | .ai !< >! i 111 :!u S lie ill -!	111:11 add I'-.' ss; s ; ; ,L- eo; leem - : i I :e ' -! 1 i: 1: M r. i i
.11.i iv. - 1 v.11:i;::: ik-;i!!!i a: id the er.\ i! inniiciii
\ . STATI TOKV !)!•: [ KUMINATIONS
( oiisulenns: the ahuw described adjustment^ to the .selected rcmcd\ so iojdi m the il^M R()i)
loi ()1'2. t he .Air lorce hclicvcs the remedy remains protective of human health and l he
environment: complies w ilh ledcrai and Slale retiiiiremcnis ilia! are applicable or relevant and
 tiie investigations aiu, ie;i,ee;. se.eeiu'ii. i1-
i!\ :nia'nle lor rnbhc rex lew a! the loeation iisted in Seel ion I above
The .Air lorce will publish a pubiic notiee o! availability and a hnel description oi this I: SI > n.-
the Aroostook kepubliean and the Bangor Daily News.
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\ i i
K i .S
I-' i \\\ -a Ik, .. I') N ^ 'MRP I>ii I a'a :a! a	,.ao;:. I onap \a ! ; >',v A;;-;
i .\ \:: : ¦'] v , 1 i N Ai . ia11 J 'M ii< " \a )i \i K Pe: a \ ¦ i.'1 ¦. a x ;: n¦ a. ! v i ' '¦ s a -
M . ¦ 1 . : . i ¦ \ \ 1 . i 1 i ¦ : : ; ; ] - : ; ¦¦ . i i : i \ a ¦ ¦ >
I'.S. An I < ii ee I IS API9M7. Ali-K 'A/I )l> I.« nine l.cilcr i<> Miciiad N.i; ipi n^i-, i. IS! PA. ;uui
N;iji Akl.uli.ss. Mai no DI:P. Subav:: "Technical Memorandum. Pohchli-i.nakM H i ph-.-n \ i i I'< 'B i
Wasir ;; i Pa i u i 1111 a": aO Scpaaaivr P AP .
.¦\i: i < ivc ¦ I NAP ¦. ,1 A Pi\\.a P\ Poraie i .v'k'; a ¦ 'Aaa.ie V "-a;-.- . : vl d\..;aa
Nap Akiaiiiss. Maine DP P. .Siihiec'' "Proposed lJ( 'ii W t eli Plan^ ¦ i' i ¦." See'ion ; i _ \;i^: tivi
' A . P i i".'i apnea'a! Pn >ieeUop . \ p a n c v. • PS i M'A . 1 l-'N:"P a an m Pinai ( la iv lance i a Prepayn a
Vp vrlana I VciM«»n I )oc a men I A": ()SWTR ! Jireeu ve l>.'55.3-< C: June.
I AS. Pn\ in hi men l al Pre >1 eel ion Aacnc v ( P SPPA ). 1992. "Nal lonal ()i 1 aiul 11 a/aialoiis
S iihsiaiiees Pol 1 at ion ('onl i naencv Plan ( I he \C "P i : OSW P.R Direcli \ e 9200.2-IT. Januarx
a a", 'vera
>\ I s. I a
i.i u ; *
2' >. I ha Mal'e
P Si ale o i \Pai
S F-.nvr.'.»nmenial Protection Alvhcv . I 'SPPA;. P'C'X 'rpR('P \ ( omphaiica u iih Other
i... v. v \iaiaaii Interim Pinal' ; I .PAO-M)/( »- W/()()6; Atlsuisl.
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M I Vi () |, \ \ 1) |M
I ()	J' i!i:il' IV\ i!j;u Reiii'.'iia! Aui:'::n v : ai oi
I I IROl -C111 'Vait K'i;; 1 Mcanev. Direcio" OsRR -f.'js/#	¦ '
L "
FROM	Michael \alip!:\M%i. ()SRR Fcdeu! Facilities Superliind Scci'or.
Betsy Mason (MTice oi Rctr-i'iai < i>(;nsci
DATE	Sep: emhe- 2"
RF.	Waiver of I St'A Chenncai V\,i.\c Eamlllll Requirements tin I'CB \\ a>ic (Vil> at
1 ormu Air Force Base. l.imeMonc. Maine
A_ct ion Req nested
Please sign the attached Regional Administrator s landings and Waivers Cndu Regulations ot the
Toxic Substances Control Act ('Waivers") to waive certain of the 40 CFR ^ 761 75(h) technical
requirements for the construction and use of two cells for the disposal of soils sediments
containing polvchlorinmed hipbenvls (PCBs) at concentrations over 50 parts per million (pr>mj at
the I.oring Air force Base National Priorities Fist site in Fnnestone. Maine ("Site")
Background
A The or:. I SI)
The L!nited States Air Force is issuing an Explanation of Significant Differences (ESD) with
regard to the source control remedy selected for Landfill 3 in Operable Unit (OU) 2 at the Site in
conjunction w ith these Waivers The OU2 Record of Decision requires containment w ith a triple-
layer cover svstem and allows the use of soils sediments excavated from other locations at the Site
as subgrade fill under the cover s\stem The modified remedy to be presented m the F.SD
includes the construction within the subgrade fill of two cells for the disposal of soils-sediments
containing PCBs at concentrations over 50 ppm The cells allow for the use of a greater volume
of soils/sediments from the Site as subgrade fill w hile providing a cost-effective disposal method
for such soils/sediments that contain over 50 ppm PCBs. One of the cells has a capacity of about
2,000 cubic yards and contains sediments excavated during the OU13 remedial action (the
basewide sediment remedy); the other cell has a capacity of about 550 cubic yards and will
contain soils excavated during an OU8 source removal action as well as OU13 sediments
The two cells are subject to the Toxic Substances Control Act (TSCA) chemical waste landfill
technical requirements specified at 40 CFR $ 761 75(b). Finder 40 CFR § 761 75(c)(4). however,
the Regional Administrator has the discretion to waive one or more of these requirements if he
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' : ¦ :co;r |. amce w >: h !!u•; i : - -1 >: ¦ .e. ev- .c
1. • 1 ! ii and the en\ oilmen: iio:n l'< lis ! \\
i c>;un emcnts to; 1 ik- cells
H	i he I .atge; ( 'ell
i i:e -\i: force asked lor waiver ol the following technical icuuiiements to; the iari-ei cell i • i
thai chemical waste landfills be constructed on'\ ;ii low permeability clav conditions i.T; Oi |< '
'¦ i T^ibif I I). (2) that tlie bottom ofsuch landfills be 50 feet above the histoi ic hujl; ci ound w au i
la ice ( ^ 7o 1 75(3 )i: and ( 3 ) that leachatc c< >1 i ecu on s\ stems be employed i \ be ~5( r m 7 ) ¦ I;
also submitted evidence that operation oftiic cell would not present an unreasonable nsk of j:iiui\
to health or the environment from PCBs if the icquested waiveis w ere granted I -PA staff
re\ ie\ved the request and determined that compliance wnh the technical requirements rroposed
in waiver was not necessary to protect against such a risk, and that theiefoie the wa;\cis shouk:
be granted The Air force constructed the cell and placed PCB-contaminated sediments trom
Ol'l 3 in it in 1 997
<" fhe Smaller Cell
1 he Air force has asked for waiver of the s "<•! 75(b)(3) depth to historic hiuh i>roundw atei
requirement and the § 761 75 (b)(7) leachate collection svstern requirement for the smaller cell It
has submitted evidence that operation of the cell will not present an unreasonable risk ofmiurv to
health or the environment from PCBs if the requested waivers are uranted HP A stall'has
reviewed this request and determined that, as with the larger cell, compliance with the technical
icqmrements proposed for waiver is not necessary to protect against such a risk, and that
therefore the waiv ers should be granted
Basis for Findings and Waivers
HPA staff has determined that the following evidence submitted bv the Air force supports
granting the requested waivers
~	The ^ 761 75(b)(1) requirement that chemical waste landfills be constructed onlv in low
permeability clay conditions can be waived for the larger cell because the liner in that cell
will be constructed of geosvnthetic clav liner (GCL) panels GCLs are more durable than
the required 30 mil geomembrane and are "self-healing" in the event of a puncture
Moreover, the permeability of GCLs is typically on the order of 5 x 10-^ cm/sec. w hich
exceeds the requirement of 1 x 10-7 cm/sec in 40 CFR $ 761.75(b)(1)
•	The § 761 75(b)(3) requirement that the bottom of such landfills be 50 feet above the
historic high groundwater table can be waived for both cells for the following reasons: (1)
neither cell is located in a floodplain or shoreland: (2) there is no hydraulic connection
between either cell and any standing or flowing surface water, (3) there was little to no
rainw ater infiltration into the larger cell during disposal of the PCB-contaminated soils and
sediments (and therefore minimal leachate generation) because of the short length of time
-------
be ci>\ch\: ill: J1 :iiil in-* 'iitemiMat-e. sntmediateh aite; exposal to e\v\>i.Je i an".v. atu
inclination ;mn the: e'<\ Tjumize Icachate neneiation. the installation of the :!:r-ie-ia\cr
la nd 111 i ii 1.1 s\oi i: n ;' 11 • \'. 11i 111rtInn n and i11uni:n
Icachate :nia,!'a;vn and in; the noli i:iut- would pivver! :ln* mmiatior !<< yrowrc: ••• atei of
anv leachate that o nunnatmi
I 1 k \ ' ' 1 n a ; ; nn n n en lent that sja .a' 11 c !ennhatc 0. > 1'ontani; s\ >t en, ¦ 1 i. i.-r ¦ s , ; ,¦.:;
t v v. a.i I m - na'.is: : . : no.' !'( decontaminated soils ami sediments to I ^ n sjn : ¦ n" vat; he
dev. ,tU'! t*\ er svsten: ni v. h i
tun her exclude rainwater iniiitratton and minimize leachate ueneration
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i .ucing Air" bone H;isi National Priorilics list Site
Operable i nil 2. I :in<1 (11! 3
Regional Administrator^ Findings and Waivers
' infer ReHulat ions of 1 lie I o\ic Substances ( onIml An
I :n- I nil ed States A: 1 o; ce (An 1 vow i is is--,.: ¦ a a i; I , \planalaa; > ¦: s: nia; .a,.' ' i ji; i a: u ,ae>
(l-.SI)) with regard :o the source control soil ; emed\ selected foi I .iiiicir'Ii ir, ( V.vrable I r.ii 2
f < )l - ) »ii the 1 .el ins.: Ak l-orce Base Nationa' I'Monties I .isi site m I i:r.esio:K-	i Sue) I in
o; iLima. i en\ d'. sweated u a ] a::;:!;:, a in fi a• ¦ )' 2 Rea< a d of ] )L ci-ai a: i R < ¦ . - aa;en ^'cpt en: he
a A i W-l. rcqun cs containment w nil a triple-ar cr co\ ei svstem and allows ; do a.-o of soi K ar.d
sediments excavated ironi other locations a; the Site as subgrade till under ti.e cover system The
modified remedy presented in the HS1) includes the construction within the siibgrade till of two
cells for tne disposal of soils and sediments containing polvchloi inateci biphen\ is (PCBs) a;
concentrations greater than 50 parts per million These cells, with respecti\ e capacities of
approximately 2.«H)0 and 55n cubic \ards. are subject to the Toxic SuSiances Control A«.:
t 1 S( .\ i chemical waste landfill technical requu orients specifier at 4" (TR i ¦>, 75< r j
I 'nder 40 CFR § 761~5('c)(4 ). the Regional Administrator has the discretion to waive one or
more of these technical ; eauireirieiUs The finds that such requirements are not necessary to
protect against an unreasonable risk of injury to health and the em ironment from PCBs
The Air Force has requested waiver of the following technical requirements for the larger cell ( 1 j
that chemical waste landfills be constructed only in certain low permeability clav conditions (40
CFR ij 761 7>(b)( 1)). (2) that the bottom of such landfills be 50 feet above the historic high
groundwater table ($ 761 75 (b)(3)). and (3 ) that leachate collection systems be employed (^
761 75(b)(7)) It has submitted evidence that operation of the larger cell would not present an
unreasonable risk of injury to health or the environment from PCBs if the requested waivers were
granted
The Air force also has requested waiver oft 1 ) the ^ "(>i 75ib)(3) depth to historic high
groundwater requirement and (2) the ^ 761 7> (b)(7) leachate collection system requirement for
the smaller cell It has submitted evidence thai operation of the smaller cell would not present an
unreasonable risk of injury to health or the environment from PCBs if those waivers were granted
On the basis of the evidence submitted by the Air Force. 1 find that (i) the Air Force has
demonstrated that operation of the cells will not present an unreasonable risk of injury to human
health or the environment from PCBs if the technical requirements for w hich it has requested
waivers are not met, and (ii) these requirements are not necessary to protect against such a risk
In so finding. I adopt the grounds identified by the Air Force in the F.SI) for granting the
requested waivers. On the basis of these findings. I hereby exercise the waiver authority' pi o\idea
under TSCA at 40 CFR $ 761 75(c)(4) with respect to those technical requirements for which the
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I'i: lU'U'
i	CI
i l;L' C"11 S
!!¦!"( i K
JJm !' IXA'iikirs	Date
Rcmimi;i1 Adi:r;::; m
l-.l'A - \cv. 1 :^h::ui
I "I'lii-d Surav l-r.v:j»!nnicnial Pu^i.v::.iiit'iruj
I-i: MA i 2A-
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