FIN AL F I V E- Y E AR REV I E W E LLS WO R TH A FB, SOUTH D AK O TA

UNITED STATES AIR FORCE

AIR COMBAT COMMAND

SEPTEMBER 23, 2005 FXBM 20047001



# 3057 0 01

# EPA CO N CURRENCE with the 

# ELLSWORTH AIR FORCE BASE FIVE-YEAR REVIEW SEPTEMBER 2005
In accordance with Section 12t of the C o mprehensive Environmental Response, Compensation, and Li,' lbility Act (CERCLA), as amended by the Superfund Amendments and Reauthorization Act of 1986 (SARA); and the Federal Facilities Agreement (FFA) signed January., 1992. Ellsworth Air Force Base (EAFB) is required to conduct a five year review of al) , remedial actions which result in any hazardous substances, pollutants, or contaminants remaining at the site, to assure that human health and the enYironment are being protected by the remedial acti o ns being implemented. On September 27, EAFB suhmitted its five year review to the US EPA Region 8 office and the South Dakota Department of Environment and Natural Resources (SDDENR). In consultation with the SDDENR, EPA has reviewed this five year review and concurs with the findings made herein.

CONCURRENCE:



# Max H. Dodson Assistant Regional Administrator Date Ofl]ce of Ecosysiems Pro tection

and Remediation



# 3 05 7 00 2Ellsworth Air Force Base Final Five
- Year Review 

### T ABLE O F CO NTENT S S ecti on Pa_e

E PA C ON CU RRENCE 1.0 I NTR O DUC TI ON .............................................................................................. ..................... 1 1 . 1 P UR P O S E OF THE RE VI EW ...................................................................................... 1 1 .2 REV I EW P RO C E S S ..................................................................................................... 1 1.3 BASE CLOSURE CONSIDERATIONS ...................................................................... 2 2 .1 ) SI T E CHR O N O L O G Y ........................................................................................................... 3 3 . t ) B ACK GR O UND ...................................................................................................................... 8 3 . 1 BA SEWIDE ................................................................................................................... 8 3.2 OPERABLE UNIT 1 FIRE P ROTECTION TRAINING AREA (FPTA) .................. 10 3.2.1 Physical Setting ............................................................................................. 10 3.2.2 Land and Resource Use ................................................................................. 11 3.2.3 History of Contammatlon .............................................................................. 12 3.2.4 Initial Response ............................................................................................. 13 3.3 OPERABLE UNIT 2 LANDFILL 1 AND LANDFILL 6 .......................................... 13 3.3.1 Physical Setting ............................................................................................. 13 3.3.2 Land and Resource Use ................................................................................. 14 3.3.3 History of Contamination .............................................................................. 15 3.3.4 Initial Response ............................................................................................. 17 3.4 OPERABLE UNIT 3 LANDFILL 2............................................................................ 17 3.4.1 Physical Setting ............................................................................................. 17 3.4.2 Land and Resource use .................................................................................. 17 3.4.3 History of Contamination .............................................................................. 17 3.4.4 Initial Response ............................................................................................. 19 3.5 OPERABLE UNIT 4 LANDFILL 3............................................................................ 19 3.5.1 Physical Setting ............................................................................................. 19 3.5.2 Land and Resource Use ................................................................................. 20 3.5.3 His t ory of Contamination .............................................................................. 20 3.5.4 Initial Response ............................................................................................. 23 3.6 OPERAB LE UNIT 5 LANDFILL 4............................................................................ 23 3.6.1 Physical Setting ............................................................................................. 23 3.6.2 Land and Resource Use ................................................................................. 23 3.6.3 History of Contaminahon .......................................................................... .... 24 3.6.4 Initial Response ............................................................................................. 25 3.7. OPERABLE UNIT 6 LANDFILL 5............................................................................ 25 3.7.1 Physical Setting ............................................................................................. 25 3.7.2 Land and Resource Use ................................................................................. 25 3.7.3 History of Contamination .............................................................................. 26 3.7.4 Initial Response ............................................................................................. 26 3.8 OPERABLE UNIT 7 WEAPONS STORAGE AREA ................................................ 27

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# 3057 003Ellsworth Air Force Base Final Five
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### TABLE OF CONTENTS (c o ntin u ed) Se c ti o n Pa_e 3.8.1 Physical Setting ............................................................................................. 27 3.8.2 Land and Resource Use ................................................................................. 27 3.8.3 History of Contamination .............................................................................. 27 3.8.4 Initial Response ............................................................................................. 28 3.9 OPER A BLE UNIT 8 EXPL O SIVE ORD N A NCE DISPOSAL A REA ..................... 28 3.9.1 Physical Setting ............................................................................................. 28 3.9.2 Land and Resource Use ................................................................................. 29 3.9.3 History of Contamination .............................................................................. 29 3.9.4 Initial Response ............................................................................................. 30 3.10 OPER A BLE UNIT 9 ................................................................................................... 31 3.10.I Physical Setting ............................................................................................. 31 3.10.2 Land and Resource Use ................................................................................. 31 3.10.3 History of Contarmnatlon .............................................................................. 32 3.10.4 Initial Response ............................................................................................. 33 3.11 O PERABLE U N

IT 10 NORTH HANGER COMPLEX ............................................. 33 3.11.1 Physical Setting ............................................................................................. 33 3.11.2 Land and Resource Use ................................................................................. 33 3.11.3 History of Contamination .............................................................................. 33 3.11.4 Initial Response ............................................................................................. 34 3.12 OPERABLE UNIT 11 BASEWIDE GROUND WATER .......................................... 34 3.12.1 Physical Setting ............................................................................................. 34 3.12.2 Land and Resource Use ................................................................................. 35 3.12.3 History of Contamination .............................................................................. 35 3.12.4 Initial Response ............................................................................................. 37 3.13 OPERABLE UNIT 12 HARDFILL 1 ......................................................................... 37 3.13.1 Physical Setting ............................................................................................. 37 3.13.2 Land and Resource Use ................................................................................. 38 3.13.3 History of Contamination .............................................................................. 38 3.13.4 Initial Response ............................................................................................. 39 3.14 FLIGHTLINE REFUELING AREA ........................................................................... 39 3.14.1 Physical Setting ............................................................................................. 40 3.14.2 Land and Resource Use ................................................................................. 40 3.14.3 History of Contamination .............................................................................. 40 3.14.4 Initial Response ............................................................................................. 41 3.15 OFF-BASE JP-4 SOUTH OF OPERABLE UNIT 2 ................................................... 41 3.15.1 Physical Setting ............................................................................................. 41 3.15.2 Land and Resource Use ................................................................................. 42 3.15.3 History of Contamination .............................................................................. 42 3.15.4 Initial Response ............................................................................................. 42 4. 0 RE M ED IA L A C TIONS ........................................................................................................ 43 4 .1 RE M ED Y SE L EC TI O N .............................................................................................. 4 3 4 .1.1 O perable Un i t 1 ............................................................................................. 4 3 4.1.2 Operable Unit 2 ............................................................................................. 48

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# . 3 05 7 0 0 4Ellsworth Air Force Base Final Five
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### T A B LE OF C ONT EN TS ( c onti nue d ) S ecti on Pa_e 4.1.3 Operable Unit 3 ............................................................................................. 48 4.1.4 Operable Unit 4 ............................................................................................. 49 4.1.5 Operable Unit 5 ............................................................................................. 49 4.1.6 Operable Unit 6 ............................................................................................. 50 4.1.7 Operable Unit 7 ............................................................................................. 50 4.1.8 Operable Unit 8 ............................................................................................. 51 4.1.9 Operable Unit 9 ............................................................................................. 52 4.1.10 Operable Unit 10 ........................................................................................... 52 4.1.11 Operable Unit 11 ........................................................................................... 52 4.1.12 Operable Unit 12 ........................................................................................... 53 4.1.13 Flightline Refueling Area .............................................................................. 54 4.1.14 Off-Base JP-4 South of Operable Unit 2 ....................................................... 54 4.1.5 North Docks .................................................................................................. 54 4.2 REMEDIAL ACTION IMPLEMENTATION ............................................................ 54 4.3 OPERATION AND MAINTENANCE ACTIVITIES ................................................ 55 4.3.1 Operation and Maintenance Procedures ........................................................ 55 4.3.2 Summary of System Downtime and Operation and Maintenance Issues ...... 63 4.4 SYSTEM OPTIMIZATION ........................................................................................ 63 4.4.1 Operable Unit 1............................................................................................. 63 4.4.2 Operable Unit 4 ............................................................................................. 64 4.4.3 Operable Unit 11 ........................................................................................... 64 4.4.4 JP-4 ................................................................................................................ 65 4.4.5 Flightline Refueling Area .............................................................................. 65 4.4.6 North Docks .................................................................................................. 65 5. t ) F I VE-YEAR REVIEW P R OCE SS ...................................................................................... 7 0 5.1 TEAM MEM B ERS ..................................................................................................... 70 5.2 DOCUMENT REVIEW .............................................................................................. 70 5.3 FIVE-YEAR REVIEW TASKS .................................................................................. 73 6.0 FIVE-YEAR REV I EW F I NDING S ..................................................................................... 74 6. 1 C H AN GE S I N STA ND A RD S AN D TO B E CONS ID E RED C R I TER IA ................. 74 6.2 CHAN GE S IN EXP O S URE PA T H WA YS ................................................................ 74 6. 3 TOX ICI TY AN D O T HER C O NTA M INAN T C H A RAC TERI STICS ...................... 7 5 7. (t A SSE SS MENT ...................................................................................................................... 9 1 7.1 REMEDY OPERATION ............................................................................................. 91 7.1. 1 HASP and Co n ting e ncy Plan ........................................................................ 91 7.1 2 Institutio n al Contro l s and Oth er M e as ures .................................................... 91 7.1.3 Rem ed ial Actio n Performance ...................................................................... 91 7.1.4 Op eration and M a inte n a nce ........................................................................... 94 7.1.5 Op eration and Maintenance Costs ................................................................. 94

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# 3 05 7 005Ellswo r th Air Fo r ce Base Final Five
- Year Review TABLE OF CONTENTS (e o ntin u ed) Se c tion Pa-Eg-e7 . 1 .6 Re m ed ia l Acti on Op ti m iz atio n ...................................................................... 95 7 . 1 . 7 Indicato rs of Pot e ntial F ailur es ...................................................................... 9 5 7 .2 VALI D IT Y OF A SS U M P T IO N S ............................................................................... 96 7 .2. 1 C h an ges in TBC C rit e ria ............................................................................... 96 7 .2.2 C h ang es in E xp o s ure Pathw ay s ..................................................................... 9 6 7 .2. 3 C h ang es in To x icity an d Co n taminant C h aract eri s tic s ................................. 96 7 .2. 4 C h ang es in Ris k A ssess m e nt Me th o d ........................................................... 9 7 8.0 DEFICIENCIES AND MODIFICATIONS ........................................................................ 99 9.0 RECOMMENDATIONS AND FOLLOW-UP ACTIONS .............................................. 100 9 . 1 REC OMMEND ATI ON S FROM 2 0 0 0 FI V E -YEA R REV I EW ............................... 100 9 .2 2 00 5 F I VE - YEA R RE V IEW RE C OMME N D ATI O NS ........................................... 10 2 9 .2. 1 O U-1 ............................................................................................................ 10 2 9.2.2 OU-2 ............................................................................................................ 102 9.2.3 OU-3, OU-5, OU-6, OU-8, and OU-12 ....................................................... 103 9.2.4 OU-4 ............................................................................................................ 103 9.2.5 OU-7 ............................................................................................................ 103 9.2.6 OU-9 ............................................................................................................ 104 9.2.7 OU-10 .......................................................................................................... 104 9.2.8 OU-11 .......................................................................................................... 104 9.2.9 Flightline Refueling Area (SS-08, ST-10, ST-14) ....................................... I06 9.2.10 JP-4 Jet Fuel Release ................................................................................... 106 9.2.11 North Docks ................................................................................................ 106 10.0 PR O TEC T IVENE SS S T AT EMENT S .............................................................................. 1 0 7 1 0 .1 OU-1 .......................................................................................................................... 1 0 7 10.2 OU-2 .......................................................................................................................... 107 10.3 OU-3 .......................................................................................................................... 107 10.4 OU-4 .......................................................................................................................... 107 10.5 OU-5 .......................................................................................................................... 10 8 10.6 OU-6 .......................................................................................................................... 108 10.7 OU-7 .......................................................................................................................... 108 10.8 OU-8 .......................................................................................................................... 108 10.9 OU-9 .......................................................................................................................... 109 10.10 OU-10 ......................................................................................................................... 109 10.11 OU-11 ........................................................................................................................ 109 10.12 OU-12 ........................................................................................................................ 109 11.0 NEXT REVIEW .................................................................................................................. 110 1 2 .0 MI SC ELLANE OUS C O MMEN T S ................................................................................... 111

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# 3 0 57 006Ellsworth Air Force Base Final Five
- Year Review 

### LIST OF TABLES T a Me Pa_e 2-1 History of Ins t allation Operations at EAF B .............................................................................. 4 2-2 Key Regulatory Actions Impacting EAFB ................................................................................ 6 2-3 Site Closure Status ..................................................................................................................... 7 4-1 Summary of Applied Remedial Alternatives for EAFB .......................................................... 44 4-2 OU-1 Clean-Up Goals, Soils (ug / kg) ...................................................................................... 46 4-3 OU-1 Clean-Up Goals, Ground Water (ug / L) ......................................................................... 47 4-4 Remedy Implementation ......................................................................................................... 57 4-5 Summary of Operational Downtime and Operations and Maintenance Issues ....................... 66 5-1 Documents Reviewed During the EAFB Five-Year Review Process ..................................... 71 6-1 Federal and State ARARS Applied to Ellsworth AFB, South Dakota .................................... 76 6-2 Changes in Chemical-Specific Standards ................................................................................ 80 6-3 Changes in Action-Specific Standards .................................................................................... 83 6-4 Changes in Location-Specific Standards ................................................................................. 83 6-5 Summary of Exposure Pathways Evaluated for the Human Health Risk Assessment for Current On-Site Land Uses at Ellsworth AFB ........................................................................ 84 6-6 Summary of Exposure Pathways Evaluated for Human Health Risk Assessment for C

urrent Off-Site Land Uses at Ellsworth AFB ........................................................................ 85 6-7 Summary of Exposure Pathways Evaluated for Human Health Risk Assessment for Future On-Site Land Use at Ellsworth AFB ............................................................................ 86 6-8 Summary of Exposure Pathways Evaluated for Human Health Risk Assessment for Future Off-Site Land Uses at Ellsworth AFB ......................................................................... 87 6-9 Chemicals of Concern at EAFB that Resulted in the Application of a Remedial Action ....... 88 6-10 Toxicity Values for Chemicals of Concern at EAFB .............................................................. 89 LIS T OF FIGURES Fi_ [ gure

3-1 Ba se Ar e a M ap 3- 2 OU Loca ti on M ap 3-3 Surfac e W at e r Fl o w 3-4 OU -1 A re a 3-5 OU-1 Soil 3-6 OU-1 Ground Water 3-7 OU-2 Area Map 3 - 8 OU-2 Soil Concentrations 3-9 OU-3 Site Map 3-10 OU-3 Soil 3-11 OU-4 Soil 3-12 OU-4 Ground Water 3-13 OU-5 Site Map 3-14 OU-5 Soil 3-15 OU-5 Ground Water 3-16 OU-6 SoilEllsworth Air Force Base Final Five
- Year Review 

### LIST OF FI GURES (c o ntinued) F_._ure

3--17 OU-6 Ground Water 3-18 OU-7 Area 3-19 OU-8 Ground Water 3--20 OU-8 Soil 3--21 OU-9 Soil 3--22 OU-9 Ground Water 3--23 OU-10 Soil 3-.24 OU- 10 Ground Water 3--25 OU-11 Area 3-.26 OU-11 Ground Water 3-.27 OU-11 Ground Water 3-.28 OU-11 Ground Water 3-.29 OU-11 Ground Water 3-.30 OU-11 Ground Water 3-.31 OU-12 Soil 3-.32 OU-12 Ground Water 3-.33 Flightline Refueling Area (FRA) 3-.34 FRA TPH in Ground Water 3-35 Current FRA Contaminant Concentrations 3-.36 JP-4 Site Contaminant Concentrations 4-.1 OU-1 Soil Area of Attainment 4-2 OU-1 Ground Water area of Attainment 4-,3 OU-2 Area of Attainment 4-4 OU-3 Area of Attainment 4- 5 OU-4 Area of Attainment 4-6 OU-5 Area of Attainment 4-7 OU-6 Area of Attainment 4-8 OU-7 Area of Attainment 4-9 OU-8 Area of Attainment 4-10 OU-I 1Area of Attainment-1 4-11 OU- 11 Area of Attainment-2 4-12 OU- 12 Area of Attainment L I ST OF APPEND IC E S Appendix

A Pub l i c Noti c e of F iv e - Ye ar Re vi ew B Co py of Ba se Continuing Order

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- YEARREVIEW2005 . DOC vi 30 5 7 008 Se ]gtembel ' 2005Ellq worth Air Force Base Final Five
- Year Review 1. 0 INTRODUCTION The United States Air Force has completed the second five-year review of the remedial actions at Ellsworth Air Force Base (EAFB), located in Meade and Pennington Counties, South Dakota. This review was conducted from April 2005 through August 2005. This report documents the results of the review. The purpose of the five-year review is to determine whether the remedy at a site is protective of human health and the environment. The methods, findings, and conclusions of reviews are documented in the five-year review report. In addition, the report identifies deficiencies found during the review, if any, and makes recommendations to address them. Finally, the report makes recommendations for future optimization and management of the environmental restoration program . 1.1 PURPOSE OF THE REVIEW This review is required by statute. Five-year reviews must be implemented in accordance with the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) and the National Oil and Hazardous Substances Pollution Contingency Plan (NCP). CERCLA §i21 (c), as amended, states:

" If the President sele c ts a r e m edial action that results in any hazardous substan c e s, pollutants, or contaminants r e maining at the site , the President shall review su c h remedial action no less o ft en than each five yea rs a ft er the initiation of such remedial action to ass u re that hu man health and the environment are being protected by the remedial acti o n being i m ple m ented . " The NCP part 300.430(f)(4)(ii) of the Code of Federal Regulations (CFR) states:

" 'Ira remedial a c tion is sele c ted that results in hazardous substan c es, pollutants, or c onta m inant s remaining at the site above levels that allow f o r unli m ited use and un r estricted exp osure, the lead agency shall re v ie w such action no less often than eve ry five y ea rs a ft e r the initiation of the sele c ted re m edial a c tion . " 1 . 2 REVIEW PROCESS Contractors prepared portions of this review for the Air Force. The Air Force, using its contractual arrangements via the Omaha District Corps of Engineers Environmental Restoration Services Contract (ERS), contracted with Earth Tech, Inc., to provide information for all or part of report sections 4, 5, 6, 7, 8, 9, 10, and 12. In addition, RD Todd & Associates was contracted to Earth Tech, Inc., to assist in the development of all or portions of report sections l, 2, 3, 4, 6, and 7. This is the second statutory five-year review for EAFB. The first five-year review was completed in September 2000. Because hazardous substances, pollutants, or contaminants remain at the site above levels that allow for unrestricted use and limited exposure, a five-year review was required. The review covers remedial actions taken at 12 operable units (OUs) at EAFB. In addition, reviews were conducted for two non-CERCLA sites undergoing remedial action under State of South Dakota programs. The sites reviewed include:

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# 3057 009Ell s worth Air Force Base Final Five
- Year Review CERCLA Sites: OU- 1 Fire Protection Training Area OU-2 Landfills Nos. 1 and 6 OU-3 Landfill No. 2 OU-4 Landfill No. 3 OU-5 Landfill No. 4 OU-6 Landfill No. 5 OU-7 Weapons Storage Area O U-8 Explosive Ordnance Disposal Area (Pramitol Spill) OU-9 Old Auto Hobby Shop A rea OU- 10 North Hangar Complex OU- 11 Base-wide Ground Water (Including A O C-24) OU-12 Hardfill No. ! Non-CERCLA Sites: JP-4 Release south of Operable Unit 2 JP-4 Release Flightline Refueling Area 1 .3 BA S E CLOSURE CONSIDERATIONS The D ep artm e nt of D e fe n se i ss u ed it s r e commen d a tio ns on b a se re alignm e nt an d clo s ur e o n M ay 13, 2 00 5. Ellsw o rth AFB w a s p ropo se d fo r c l osure o n th a t li s t . Subse qu e n tly, the Ba se Re a l ignm e nt and Clo s ure Commi ss ion revi ewe d the Do D rec omm e ndation s an d re mov e d E l lsw o rth A F B from the c lo s ure l i s t . The c l o s ure l i st w a s s ub m itt e d to the Pres i de nt on Sep tember 8 an d w a s ap prov e d b y the Pr es id e n t in S ep t e mbe r . Congr ess ional ac tio n on the clo s ure li st i s pe n d ing .

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# , 1 30 5 7 0 1 0Ells_* orth Air Force Base Final Five
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### 2.0 S IT E CHR ONO LOG Y E l lsworth A FB was officially activate d in July 1942 as the R apid City A rmy Air B ase. It became a permanent facili ty in 1948, wi th the 28 tt

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### strategic Reconnaissance Wing as its, h ost unit. Throughout its history, E AFB has been the base of operations tbr a number of types of aircraft and missile systems. Presently, the 28_hBombardment Wing (BI-B bombers) is the host unit. The following three tables provide a summary of the History of Installation Operations at EAFB (Table 2-1), Key Regulatory Actions Impacting EAFB (Table 2-2), and Site Closure Status (Table 2-3).

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# , 3 0 57 011Ellsworth Air Force Base Final Five
- Year Review TABLE 2-1 HI ST ORY O F INSTALLA T I O N OPERATI O N S AT EAFB (from Management Action Plan EAFB , South Dakota-2004) Period I Types Of Operations Weapon System [ Waste Generating Activities Pre- 1939 R an g eland None None 1939-1941 Rapid City Airport None Fuel / oil storage 1941-1942 EAFB construction None Const ru ction / demolition B- 17 Bomber 1942-1945 Bomber Training Wing crew training, EAFB landfills, airplane and automotive weapons storage fuel storage, hangars, machine shops for bombers (solvents, oils, metals). 1945-1946 Weather Reconnaissance Reconnaissance Weapon storage areas, landfills, water Squadron tra ining treatmen t facility, fue l / o i l s to ra ge. 1946-1947 Inactive None N o ne Weap o ns sto rage area , lo w- l eve l nuc l ear waste sto rage area , exp l osive ordnance 194 7-19 57 B o mber W i ng B-36 B o mbers d i sp o sal area, fire prot ec tio n train i ng areas, machine sh o ps, fue l / oil s to rage, fue l pump h o uses, s l udge burial , l andfi ll s. Weapons sto rage area , l andfi ll s , lo w- l eve l nuc l ear waste s to rage area, exp lo s i ve ordnance disp o sal area, fire prot ec tio n 1 9 5 7-19 5 9 B o mber W i ng B- 5 2 B o mbers trai n i ng areas, mach i ne sh o ps , fue l / oil st o rage, fue l pump houses , s l udge buri al, buried t anks. B-52 B o mbers Weap o ns s to rage area , lo w- l eve l nuc l ear waste st o rage area, l andfil l s, exp lo s i ve Titan I mi ssi l es B o mber W i ng KC-13 5 T ankers o rdnance disp o sal area, fi r e prot ecti o n 196 0 -196 5 M i ssile W i ng EC-13 5 trai n i ng areas, mach i ne sh o ps, fue l / oil Rec o nnaissance s to rage, fue l pump h o uses, s l udge buri al, T-38 T rai ners vario us dumping areas, bu ri ed t anks, lo w- l evel nuc l ear waste. M i nutemen Oi l / water separato rs, l andfi ll s, buri ed M i ss il es fue l / oil tanks , fire prot ectio n trai n i ng areas , B-52 B o mbers burn p i ts , weapons sto rage area, was t ewat er 1962-199 2 44 thS trat egic Wing B -1 B ombers treatment faci l i ty, drum s t orage areas, KC-13 5 Tankers mach i ne sh o ps, fue l / oil s to rage, fue l pump UH-1 Hel i c o p t ers h o uses, exp lo s i ve ordnance disp o sal area, T-38 Trai ners lo w- l eve l nuc l ear waste. O i l / water separato rs, l andfi ll s , buri ed B-1 Bombers fue l / oil t anks, fire pro t ec tio n trai n i ng areas, KC-13 5 Tanke r s weap o ns storage area, was t ewat er treatment 1993-1994 28 th B o mbardment Wing UH-1 He l ic o p t ers fac ili ty, drum s to rage areas , mach i ne sh o p, T-38 Trai ners fue l / oil sto rage, fue l pump h o uses, exp lo s i ve o rdnance d i sp o sal area.

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- Year Review TABLE 2-1 HI STORY OF IN S TAL LATI O N OPERATIONS A T EAFB (from Management Action Plan EAFB, South Dakota-2004) Period Types Of Operations Weapon System [ Was te Generating Activities O il / w at er sep arato rs, lan dfi ll s, b u ri ed f u e l / oil tanks, fi re prot e ction training are a s, weapons storage area, wastewater treatmen t 1994 - mid 28 th Bombardment Wing B-I Bombers facility, drum storage areas, machine shop, 1995 T-38 Trainers fuel / oil storage, fuel pump houses, explosive ordnance disposal area, low-level nuclear waste. Oil / water separators, landfills, buried fuel / oil tanks, fire protection training areas, Mid-1995 28th Bombardment Wing B-1 Bombe r s weapons storage area, wastewater treatment to present facility, drum storage a reas, machine shop, fuel / oil storage, fuel pump houses, explosive ordnance disposal area.

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### TABLE 2-2 KEY REGU LAT O RY A C T I O NS IMP A C T ING E AF B (from Management Action Plan EAF B , South D ako ta-2004) Date Action Details September 1985 PA / SI Records Search Completion of PA / Records Search by EAFB June 1988 Phase II, Stage I Report became final December 1989 Phase II, Stage II Report became final O ctober 26, 1989 Proposed NPL EAFB proposed for National Priority List August 30, 1990 NPL EAFB Final Listed on NPL with 12 operable units January 24, 1992 FFA USAF, EPA, South Dakota complete FFA April 1, 1992 RI / FS Initiated in accordance with FFA July - August 1995 Public Comment Public Comment Period, OU-6 Proposed Plan. Public meeting held July 25, 1995. October 1995 OU-6 ROD ROD Execution by USAF, EPA and SDDENR September - October 1995 Public Comment Public Comment Period for OU- 1, 2, and 4 Proposed Plans. Public meeting held January 11, 1996. December 1995 - January Public Comment Public Comment Period for OU-3, 5, 7, 8 , 9, 10, 1996 and 12 Proposed Plan. Public meeting held January 11, 1996. May 1996 RODs, OU- ROD Execution by USAF, EPA and SDDENR 1,2,4 , 9,10,12 June 1996 RODs, OU-3,5,7 , 8 ROD Execution by USAF, EPA and SDDENR September 1996 R A Report, OU-6 RA Report approved by E P A February - March 1997 Public Comment Public Comment Period for OU-11 Proposed Plan. Public meeting held February 19, 1997. April 1997 ROD, OU-I 1 ROD Execution by USAF, EPA and SDDENR September 1997 R A Reports Approval by E P A of RA Reports for OU-1, 2, 3, 4 (IRA and Final Action), 5, 7, 8 and 12. 1999 WP-22 Close-out Site Closeout, approval by SDDENR September, 1999 PCOR Preliminary Closeout Report for OUs, approval by HQ EPA September, 2000 5 Year Review Report consisting of review of all OUs. Approval by EPA.

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# 3 05 7 0 1 4Ell s worth ,4it Force Base Final f " ive
- Year Review TABLE 2-3 SITE CLOSURE STATUS (from Management A ction Plan EAFB, South Dakota-1999) Final Final D raft RA F inal RA RA Re port Si te No. Construction Regulatory Report Inspection Inspection Report Approval CERCLA SITES IRA ( O U- l ) 7 / 12

/ 9 6 7 / 96 7 / 2 / 96 8 / 22

/ 96 9 / 30

/ 96 IRA (OU- 4 ) 9 / 23

/ 96 8 / 8 / 96 2 / 2 0

/ 97 5 / 9 / 97 9 / 8 / 97 O U
- 1 11 / 1 / 96 6 / 6 / 97 7 / 17

/ 97 7 / 25

/ 97 9 / 25

/ 97 R ad Re moval ( OU - 2 ) 11 / 5 / 97 12 / 2 / 97 NA 12 / 22

/ 97 NA OU - 2 9 / 23

/ 96 5 / 1 / 97 11 / 6 / 96 5 / 9 / 97 9 / 8 / 97 OU - 3 11 / 1 / 96 5 / 1 / 97 2 / 20

/ 97 5 / 9 / 97 9 / 8 / 97 O U -4 I ! / 1 / 96 4 / 15

/ 97 2 / 20

/ 97 6 / 11

/ 97 9 / 25

/ 97 O U- 5 11 / 1 / 96 5 / 1 / 97 2 / 20

/ 97 5 / 9 / 97 9 / 8 / 97 O U- 6 6 / 96 7 / 2 / 96 7 / 2 / 96 7 / 31

/ 96 9 / 30

/ 96 O U-7 9 / 5 / 97 1 2 / 2 / 97 9 / 23

/ 97 9 / 26

/ 97 9 / 29

/ 97 O U- 8 11 / 1 / 96 6 / 6 / 97 2 / 20

/ 9 7 6 / 11

/ 97 9 / 8 / 97 O U-9 l NA NA NA NA OU- 10 t NA NA NA NA OU-! 1 9 / 8 / 9 7 1 2 /1 8 / 97 1 /14 / 98 12 /1 0 / 9 9 2 /1 0 / 00 OU- 12 11 /1 / 96 5 / 1 / 9 7 11 / 6 / 96 5 / 9 / 97 9 / 8 / 97 Draf t Final Final Fin al C omp le ti o n C o ns tructi o n R egul ato ry C o mpleti o n Appro v al

R ep o rt Inspe c ti o n In specti o n Rep o rt NON-CERCLA S I TES SS- 082 NA NA NA ST- l 0 s 6 / 1 9

/ 9 7 12 /1 9 / 97 12 / 29

/ 97 ST- 144 1 2 /1 9 / 97 12 / 29

/ 97 WP-225 5 / 8 / 9 7 5 / 7 / 97 6 / I 7 / 97 9 /16 / 97 S T

-236 NA NA NA NA NA J P -4 (OU-2 ) 7 NA 3 / 25

/ 9 7 6 / 1 9

/ 97 12 /19 / 97 1 2 / 29

/ 97 IS T -178 NA N A NA 6 /18 / 97 4 / 30

/ 98 O T -189 N A NA NA N A N A OT-16 I° NA NA NA NA NA I No-Action OU; Complction occurred when ROD w a s signcd in M a y 1996. 2 Spill Sitc Jet Fuel Pump Housc 7. 3 Jet Fuel Line Leak Pump House Hydra nt. 4 Jet Fucl Spill Sitc Pump House 6. 5 Abandoned Industri a l Wastc W a ter Tre a tment Plant. 6 Abandoned WWII Petroleum Oil Lub ri cant (PO L ) Systcm S T 23 is being addressed as part of the OU I I South Docks Ground Water Rcmcdial Action. 7 JP-4 Pipclinc puncture Icak south of OU 2. 8 Bascwide UST locations. 9 Badlands Bombing Range Impact Area. Administratively closed; work proceeding under Federal F a cilities Compliance A ct. 10 Jct Fucl Spill 70 Row Hanger Complcx. Pump house 7 and US T havc bccn removed; DENR Closcout Pcnding.

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### 3.0 BA C KGROUND 3.1 BASEW I DE Ellsworth AFB is located 12 miles east of Rapid City, South Dakota, and adjacent to the City of Box Elder. Thc installation covers 4,858 acres within Meade and Pennington Counties and includes runways, airfield operations, industrial areas , housing and recreational facilities. Open land, containing individual residences , lies to the north, south, and west of EAFB, while residential and commercial areas lie to the east (Figure 3-1). On August 30, 1990 (55 FR 35509), EAFB was listed on the U.S. Environmental Protection Agency's (EPA's) National Priorities List. A Federal Facility Agreement signed in January 1992 went into effect on April 1, 1992. The FFA identified 11 potential source area Operable Units as well as a Basewide ground water Operable Unit (Figure 3-2). In addition, the South Dakota Department of Environment and Natural Resources (SDDENR) provides oversight for several petroleum release sites , which are mentioned in this report but are not addressed under CERCLA. Ground water extraction systems have been constructed to address ground water contamination associated with the JP-4 plume and the Flightline Refueling Area (FRA). Rapid City, located approximately 6 miles west of EAFB, is the second largest city in South Dakota with a population of more than 54,000 (U.S. Department of Commerce, 1992). Access to national rail lines , Interstate Highway 90, commercial airlines, and state highways has created a transportation hub in Rapid City. The economy of the Rapid City area is composed of light industry, tourism, agriculture, and a variety of service industries. EAFB is located on the border of P enningto n and Mea d e Counties, and the southernmost property line is approximately 4,800 ft north of the Box Elder corporate limits. The estimated population within a four-mile radius of the Base was 16,000 in 2005. The Base employs slightly more than 5,500 people. This consists of about 4,100 active-duty military and the remainder composed of civilian personnel. There are approximately 5,800 individuals living in the base-owned or base-leased military family housing units and dormitory rooms provided for members and their families (E A FB , Public Affairs Office, 2005). Land use on and around EAFB is a mixture of industrial (primarily on-Base), commercial, residential, and agricultural uses. EAFB is an active military installation, comprised of runways and airfield operations , industrial areas, housing, and recreational facilities. The on-Base residential areas are located along the eastern boundary of EAFB. Ranches lie to the north and west of the Base, and residential and commercial areas lie to the east. Residences and ranches lie south of EAFB. Private residences are located within a few thousand feet of the EAFB southwestern boundary. The closest residence to EAFB is approximately 300 feet southwest of Operable Unit 4 (Landfill 3). There are other residences in the same vicinity. The nearest residence to OU-1 is approximately 1 , 500 feet south of the southern edge of the FPTA, and 600 feet west of OU-2. Shallow ground water in the area is used for domestic water supplies and for livestock watering. According to the Ellsworth Air Force Base Public Health A ssessment report prepared by the Agency for Toxic Substance and Disease Registry (ATSDR), (U.S. Department of Health and Human Services, 1993) , some nearby off-Base residents use shallow (less than 70 ft below grade) private wells for both household and livestock water supplies. The Air Force has completed a detailed investigation of off-siteEllsworth Air Force Base F inal l'

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_ ,ar Review ground water to obtain data pertaining to water quality of oftZsite residential wells in support of the OU-I 1 RI. Ground water resources provide most of the water supplies required by municipal, industrial, domestic and agricultural consumers in the study area. T he Rapid City municipal distribution system obtains its water supplies from several deep high-capacity wells finished into the bottom of the Pennsylvanian Minnelusa Formation and the upper Mississippian Madison Group (Pahasapa Limestone) , three infiltration galleries finished along Rapid Creek and from a surface water intake on Rapid Creek that is more than five miles west of E A FB (USAF, 1985). EAFB obtains its potable water from thc Rapid City Municipal Distribution System. In past years, EAFB obtained its water supplies from its own wclls. A total of five wells had been installed into deep bedrock aquifers at the Base. These wells were taken out of service by the A ir Force and have been abandoned following State of South Dakota requirements. The City of Box Elder's municipal distribution system receives water from four wells more than 2 miles south of E A FB. Three of the wells are finished into the lnyan Kara Group (Cretaceous Fall River and Lakota Formations) at depths of 2,000 feet or more, and one well has been completed into the Madison Group (Pahasapa Limestone) at a depth of 4,180 feet below grade (USAF, 1985). Other than the shallow wells outside the southwest corner of the Base, it is reportcd that ranches and rural homes in the area depend on wells completed into the Inyan Kara Group at depths of at least 1,700 t_ct below land surface for water supplies (U.S. Department of Health and Human Services, 1993). Five oft-Base private domestic wells are situated within 2,500 feet of the western and southern boundaries of EAFB near OU-1. The closest well, PW05 , is approximately 300 feet west of OU-I. The closcst down-gradient private domestic supply well from OU-1 (PW01) is approximately 1,300 feet down-gradient (southeast) of the OU. The major streams near EAFB are Box Elder Creek, Elk Creek, and Rapid Creck, all of which are located in the Missouri River Basin. Box Elder Creek is an ephemeral stream, while Elk Creek and Rapid Creek are perennial streams that support a permanent fish population. Surface water runoff at EAFB discharges from the Base property through eight outfalls (Figurc 3-3). Outfalls 007, 008, and 009 flow north to the Elk Creek drainage. Outfalls 001,002, 003, and 006 flow south to the Box Elder Creek drainage. An additional Outfall (005) is located at the Base Waste Water Treatment Plant (WWTP) and discharges from the Base through Outfall 006. The outfalls carrying water north to the Elk Creek drainage have low to no flows and therefore arc not routinely monitored. The remaining outfalls are monitored on a specific schedule as specified m applicable National Pollutant Discharge Elimination System (NPDES) Permit requirements. Flow to the south into the Box Elder drainage is more significant and comprises the majority of runoff from the Base. The flows leave the Base to the south from Outfalls 001,002, 003, and 006. The water leaving the Base flows through drainageways into the Box Elder Creek segment between $22, T2N, R8E, and Haines Avenue in Rapid City. Surface water in the area is used to water livestock and it also supports limited aquatic populations. Fishing is allowed in on-Base lakes. EAFB experiences temperature variations that are typical of semi-arid continental climates. The Black Hills to the west of EAFB exert a pronounced influence on the climate in this area (National Climatic Data Center, 1992). Summer days are warm, with cool comfortable nights. The average summer temperature is 68°F, and the daily high average is 81°F. July is the hottest month, and the highest recorded temperature was I I0°F in July 1989. Winters are relatively mild, due to the protection of the Black Hills and the frequent occurrence of Chinook winds. The average winter temperature is 26°F, with an average daily minimum of 14.9°F. The coldest month, on the average is
9 3 05 7 01 7 s `v ' '' ' be' :°° >Ellsworth Air Force Base Final Five
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### January, and the lowest recorded temperature was -30°F in December 1990. Snowfall is normally light, with the greatest monthly average of about 8 inches occurring in March. Average annual precipitation is t6.3 inches. Most precipitation falls during the spring and early summer months. April through July average 2.5 in. per month of precipitation, and June has the highest monthly average with 3.3 inches. The average relative humidity is 71 percent at dawn, and 50 percent in the late afternoon. Prevailing winds are from the north and northwest at a mean speed of 11.3 mph (U.S. National Weather Service, Asheville, North Carolina). Remedial Investigations (RI) completed at EAFB at the 12 operable units resulted in the collection of media samples from soil, sediment, ground water and surface water. The primary list of analytes collected at each operable unit and at the background locations were identical. Analysis of additional site-specific analytes was conducted at OU-7 (radiological), OU-8 (explosives, dioxins and Pramitol), and OU-I (dioxins). The primary analytes included: SOIL SAMPLES STREAM SEDIMENT TC L VOC ( 824 0) TC L VOC (8240) T CL SVOC (82 7 0) TCL SV O C (8 2 70 ) TCL P es tici des / PCB s ( 8 0 8 0) T CL P es ticid es / PCB s ( 8080) T AL Me tal s T AL Me tal s Dio x in / F uran ( 1 6 13) Dio x in / Furan ( 1 6 13 ) Cyanid e (9 0 1 2 ) Cyani de (9 0 1 2 ) TRPH (8015) TRPH (8015) SURFACE WATER GROUND WATER T CL V O C ( 8240 ) T CL V O C (82 40 ) Vinyl C h lori de ( 8 0 i0 ) V inyl C h lo rid e (8010 ) T CL SV O C (82 7 0 ) T CL SV O C ( 82 70 ) Polycyclic A romatic H y drocarb on s ( 8100 ) Po l ycyclic A roma tic H y drocarb on s (8 100 ) P e ntach loro phe nol (81 5 0 ) P e n tach loro phe nol (81 5 0 ) T CL P es ticid es / PCB s (80 8 0 ) T CL P esticid es / PCB s (80 8 0 ) TAL Metal s (total & dissolved) TAL Metals (to tal and dissolved) Cyanide (9012) Cyanide (9012) TRPH (8015) TRPH (8015) 3.2 OPERAB L E UNI T 1 FIRE PR OT EC T I O N T RAINING AREA (FPTA) 3.2 . 1 Physical S e tting The topography of OU-I is characterized by a local topographic high, especially in the area where the fire training was conducted, which is bounded on the southwest and southeast by drainages that converge to from a southerly pointing apex. Surface water , which flows onto and through OU-I, originates from several separate sources. These source areas, from upstream to downstream, are discussed below and illustrated on Figure 3-3. The main drainage channel at OU-I flows from north to south along the eastern perimeter of OU-l. The main channel drains a portion of the southern area of EAFB including some of the hangar complex, runways, and OU-12. T he main channel is approximately 12-15 ft across and 3-4 ft deep. The channel is considered to be ephemeral; however, standing water was observed in the channel throughout the

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# 30 5 7 0 18Ellsworth Air Force Base Final Five
- Year Revww 1993 RI field investigation. The main drainage channel eventually empties into the upstream end of Pond 001. Flow in the drainage ditch along the southeast boundary of OU-I originates as surface water run-off from the landfill area (OU-12) to the northeast of OU-I and from drainage pipes that discharge storm water run-off from the South Docks area of the flight line and from portions of the adjoining taxiways and flight lines. Flow was measured at approximately 1 cubic foot per second (cfs) above Pond 001 during the OU-1 field investigation. A secondary shallow drainage ditch delivers surface runoff from the eastern portion of the FPTA to the main drainage channel. This secondary drainage ditch is generally dry. Two drainage culverts extend beneath the alert apron and discharge surface water from the east into the main drainage channel. The source of the discharge from these two culverts is presumed to be runoff from the alert apron. Surface water runoff from the above sources is temporarily held in Pond 001 (Figure 3-4). Pond 001 is located at the southern extreme of the Operable Unit. At the downstream end of the pond is an oil skimmer and earthen dam. On the downstream side of the skimmer, flow passes through piping beneath Kenney Road and discharges into an open drainage ditch on the west end of OU-2. The skimmer consists of a fixed overflow weir and two discharge pipes. The skimmer is designed to allow water to exit Pond 001 without allowing light non-aqueous phase liquids (LNAPL) or floating debris to discharge. In addition, a floating aerator is used in the pond to help oxygenate water. A secondary unnamed ephemeral drainage channel is located along the southwestern edge of OU-i and receives surface water runoff from off-Base west of OU-I and from runoff from the western edge of the FPTA. This ancilla ry drainage channel empties into Pond 001 beneath the main channel approximately 200 ft downstream of the main drainage channel. The flow in the drainage along the southwest boundary of OU-1 originates as sheet flow and surface run-off from fields to the northwest of OU-1. There was no measurable discharge in this drainage ditch during the OU-I field investigation although there was standing water. The slope break into the unnamed ephemeral drainage to the southwest is gentle, whereas the slope break into the unnamed mare drainage, to the southeast, is much steeper. Wetlands were found along both drainageways and along Pond 001. The relief from the topographic high of OU-1 to the pond is approximately 40 ft. 3.2.2 L and and R e so urce Us e OU
- l co n tain ed the F o rm er F i re Prote ction Train i ng A re a ( F P T A ) and i s loca ted on the so u thwest p o rti on of EA F B no rthwest of the al ert apron a nd e a st o f Ke n ny R oa d. O U
- 1 cov ers appro x ima te ly t e n acres an d con s i sted o f a c e n trally loca ted, unlin ed, berm ed b urn p it , a s t ee l ai rcra ft mo ckup an d s urroun d ing lan d. The b urn p i t are a w a s the s ourc e are a o f contaminati o n. Th i s OU i s currentl y be i n g remed iat e d an d i s clo s e d to acc ess, ex c ep t f o r Ba se pers onn e l an d con trac to rs resp o ns i ble o f the operation o f the re m ed ial s y s t ems. Un d i sturbed gra ss are a s on th e O U m ay be u sed b y local wildlife for foraging, loafing, and nesting. No specific future use has been determined for this OU. Operable Unit 1 has several habitat features, most of which are heavily influenced by human activities such as past burn usage and current maintenance. In spite of this disturbance, some natural habitat still exists in the form of grassland, weedy areas, and a small portion of wetlands, that would attract animal species that would be potential contaminant receptors. The U.S. Fish and Wildlife Service

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# • 3057 0 1 9Ell s worth Air Force Base Final Five
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### National Wetland Inventory Map (NWI) classifies the wetland community type present on OU-I as Palustrine Emergent Seasonally Flooded (PEMC). Field surveys were conducted at EAFB in 1993 for threatened and endangered species. No sensitive plant or fauna species classified as rare, threatened, or endangered in South Dakota were observed on EAFB. 3.2.3 History of Contamination The FPTA was operated by the EAFB Fire Department from 1942 to 1990 at this location. The location of the burn area within the former FPTA has changed several times over the years . Aerial photographs of EAFB dated May 28,1952, October 8, 1954, August 25,1962, and June 19,1968, show numerous areas of staining presumed to be a result of fire training activities within the former FPTA. T he training exercises conducted at the FPTA involved simulation of aircraft fires and spills. Various types of fuels, oils, and solvents were dispersed within the burn-pit area and subsequently ignited and then extinguished. Soils at OU-I contained JP-4 (jet fuel); benzene, toluene, ethylbenzene, xylenes (BTEX); and, chlorinated volatile organic compounds (VOCs). JP-4 concentrations were much higher than other compounds (Figure 3-5). Ground water at OU-I contained chlorinated VOCs, BTEX, and JP-4. LNAPLS were present in the northern and southern end of the FPTA. Dense non-aqueous phase liquids (DNAPLS) were not present at OU-1. Ground water contamination in this area did not extend beyond the Base boundary (Figure 3-6) . A quantitative risk assessment was performed for the ground water, surface water, soil, sediment, and air. The risk assessment evaluated potential effects on human health posed by exposure to contaminants from OU-I. Carcinogenic risks were estimated as the incremental probability of an individual developing cancer over a lifetime as a result of exposure to a potential cancer-causing chemical. The acceptable risk range expressed as a probability is one cancer incidence in ten thousand people to one cancer incident in a million people. This level of risk is also denoted by 1 × 104 to 1 × 10 -6. 

### Risks within the acceptable risk range may or may not warrant remedial action depending upon site-specific circumstances. Risks below this range cannot be differentiated from the background occurrence of cancer in human populations. Risks calculated in a risk assessment are excess (i.e., over background) cancer risks due to exposure from contaminants. Non-carcinogenic health risks are evaluated using a hazard index (HI). If the hazard index is less than or equal to one, the contaminant concentration is considered an acceptable level and generally assumes that the human population may be exposed to it during a 30-year period without adverse health effects. The risk assessment for OU-1 indicated unacceptable risk in the shallow ground water for the future residential exposure scenarios. The chemicals, which contributed the majority of the risk in shallow ground water, were VOCs. Of the VOCs, benzene, 1,2-dichloroethane, (1,2-DCA) l,l-dichloroethylene (I,I-DCE), 1,2-dichloroethylene (1,2-DCE), l, l,l-trichloroethane, perchloroethylene (PCE), trichloroethylene (TCE), and vinyl chloride were identified as being above their respective maximum contaminant levels (MCLs). The risk assessment indicated that unacceptable future risk exists in the soils of the burn-pit area, primarily from the potential for contaminating the underlying ground water. In order to prevent future contamination of the ground water, four VOCs were identified for remediation in soils: benzene, 1,2-DCE, PCE, and TCE. These chemicals were selected for remediation on the basis of a contaminant transport model. Remediation of jet fuel in the soil at OU-1 is also required because concentrations of jet

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# 3 05 7 020Ellsworth Air Force Base Final Five Year Review fuel (and related components) exceed State of South Dakota regulations. Risks from exposure to pesticides and dioxins / furans in surface and subsurface soils at OU-1 were well below the acceptable range and do not warrant remediation. The current and future risk from the contaminants in the sediments and surface water at OU-1 is within the acceptable risk range. Several compounds were detected in surface water at above the Federal Ambient Water Quality Criteria (FAWQC), but the risk to human health from these contaminants is within the acceptable risk range of l x 10 4 (one in 10,000) to 1 × 10 6 (l in 1,000,000) increased incidents of cancer above background. Risks within the acceptable risk range may or may not warrant remedial action depending upon site-specific circumstances. Risks below this range cannot be differentiated from the background occurrence of cancer in human populations. Risks calculated in a risk assessment are excess, i.e., over background, cancer risks due to exposure from contaminants. Because of the risk being within the acceptable risk range, remediation of these chemicals in surface water and sediment is not warranted. Remediation of the ground water is warranted based on the risk to human health from ingesting and contacting contaminated ground water. Remediation of soil is warranted based on the potential for contaminants in the soil to be transported t o the underlying ground water. Actual or threatened releases of hazardous substances from OU-1, if not addressed by implementing the response action selected in this Record of Decision (ROD), may present an imminent and substantial endangerment to public health, welfare, and the environment. An ecological risk evaluation of OU-I was based on a combination of data and literature reviews, field and laboratory analyses, analyte evaluation and screening, and preliminary risk screening. A variety of animal species may live, forage, or nest in OU-I habitats. These species include various types of invertebrates, amphibians, birds, and mammals. Terrestrial vegetation and soil faunal communities do not reveal characteristics that indicate chemical-related impacts. This finding is consis t ent with the relatively low levels of contaminan t s in the soil. Because of the altered natural environment at OU-I, rare, threatened, or endangered species are unlikely to utilize the area for more than briel, periodic habitat. Due t o the low levels of contaminant concentrations and the iden tified exposure pathways, the contaminants do not pose an unacceptable risk to these species. In addition, the limited contact these species would have with the OU-! area ensures unacceptable risk to a single individual will not occur. 3.2.4 Initial Response No CERCLA removal actions or other initial cleanup actions were completed at this OU. A new FPTA was constructed to the northeast of the OU in 1994. However, this new FPTA construction was no t done as a remedial response action. 3.3 OPERABLE UNIT 2 LANDFILL 1 AND LANDFILL 6 3.3.1 Physical Setting Surface topography at Landfill No. I generally slopes in a southerly direction from Kenney Road to the southern boundary of EAFB (Figure 3-7). Some hummocky topography and small surface depressions are visible across the area. A series of east-west trending depressions are clearly visible in aerial photographs of the area and are assumed to be the surface reflection of historical trench and fill

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### operations. The topography of Landfill 1 reflects minimal relief with a gentle southeast slope (approximately 5 to 10 degrees) toward the small southeastward flowing stream. An elongated, flat-top mound is present near the western boundary of the landfi l l. This mound is oriented in a north-south direction and is about 18 feet wide, 243 feet long, and stands about 1.5 to 2.0 feet above the surrounding topography. Parallel to the east edge is a ditch-like depression extending the full length of the mound. Surface water that flows adjacen t to and through Landfil l 1 originat es from Pond 001. Pond 001 is located upstream immediately northwest of Landfill No. 1, across Kenney Road. Pond 001 is elongat ed in shape, approximately 720 feet l ong and 180 feet wide at the widest point on the south end of the Pond. It col l ects surface water drainage from north and west of the alert apron. Precipitation that falls on the edge of the alert apron is al so discharged to Pond 001. Outflow from the pond empties to a small unnamed, sou theasterly flowing stream located along the western boundary of the l andfi l l . The stream follows a ditch that is approximately 20 feet wide and 15 feet deep. The ditch channels the stream along the weste rn boundary of Landfi l l l and eventually off-Base through a pasture sou th of OU-2. Stream flow measurements were conducted on Ju l y 21, 1993, at OU-2 surface water sample locations on this stream. The stream flow measurements indicat e that this unnamed s tream had an average discharge of approximately 1.14 cubic feet per second (CFS). The OU-2 stream flow measurements were measured during peak flow of a rain event. This stream ultimately discharges into Box Elder Creek. Landfi l l No. 6 is situated on a hillside that slopes to the east and is located just west of Pool 002 and northeast of Landfill No. 1 (Figure 3-7). The landfill boundary presented in Figure 3-7 is based upo n fill material encoun t ered in borings drilled during the 1993/1994 R I . No landfi l l material was encountered under the asphalt parking lot at the top of the hillside. Therefore, the approximate boundary of Landfill No . 6 identified during the RI is east of the boundary depicted in Installation Restoration Program (IRP) reports as presented in Figure 3-7. Surface drainage from Landfill No. 6 is toward the east to a smal l surface water body designat ed Pond 002. Pond 002 is semi-circular in shape, approximate l y 120 feet long, and 100 feet wide. This pond also co l lects surface water runoff from the weste rn one-half of the ru nway and adjacent operations areas, and from storm water drains l ocated within the alert apron. Outflow from Pond 002 empties to a smal l , ephemeral stream that drains to the south and ultimately to Box Elder Creek. Stream flow measurements were conducted on July 21, 1993, at OU-2 surface water samp l e locations on this stream. The stream flow measurements indicated that this smal l ephemeral stream had a discharge of approximately 0.24 cfs. 3.3.2 Land and Resource Use T

here is very little na tu ral undisturbed surface soil across OU-2, since the area has been used for landfill operations . Landfill No. l covers a large portion of the central and southern parts of OU-2 and the surface material in this area is predominantly comprised of cover soil. Const ru ction debris (concrete, reinforcing bar, brick) is visible i n smal l areas in the northwest corner of the landfill. Along the western landfill edge, adjacent to the ephemeral stream, twisted metal rods and pipes, concrete with reinforcing bars, flattened d ru ms, and other debris are exposed. The western edge of Landfill No. 6 is covered by an asphalt parking l ot, while t oward the eas t , Landfill No. 6 has been covered with soil. A gravel road runs from Kenney Drive t o the small dam at Pond 002 and winds through the easte rn edge of Landfill No. 6.

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- Y e ar Revtew During the RI a variety of habitat features were observed at OU-2, many of which had been altered by human activities such as past landfill operation, maintenance, and grazing. In spite of these activities, habitat still existed that would attract animal species that would be potential chemical receptors. Since the landfill has had a soil cover placed and reseeded as part of the remedial action, these grass habitats have been improved. Wetlands consisting of a retention pond and drainageway are located in the west part of OU-2. These wetlands offer shelter, foraging and nesting ha b itat for a variety of species. The U.S. Fish and Wildlife Service National Wetland Inventory Map (NW1) classifies the wetland community types present on OU-2 as Palustrine Emergent Temporarily Flooded (PEMA) and Palustrine Aquatic Bed Semipermanently Flooded (PABF). Field surveys were conducted at EAFB in 1993 for threatened and endangered species. No sensitive plant or fauna species classified as rare, threatened, or endangered m South Dakota were observed on EAFB. The construction of the landfill covers for this OU is complete. Access is restricted to Base personnel and contractors responsible of the maintenance of the cover and operation of the remedial systems. Undisturbed grass areas on the OU may be used by local wildlife for foraging, loafing, and nesting. No specific future use has been determined for this OU. 3.3.3 History of C o ntaminatio n Land fi ll No . 1 w a s ac tiv e from th e earl y 19 4 0 s t o 19 6 4 an d w a s us e d to d i sp o se o f a vari ety o f w a s t es including Ba se re fu se, incin era to r a sh, slud g e, oil , poss i b l y liquid in d u s trial w a s t es, an d h ardfil l d ebri s. A e rial ph oto analy s i s co nd uc ted b y the E PA fro m h i stori cal ph o to s ( 193 8 to 199 0) in d icat ed the typ es of di sp o s al practic es a t Lan dfi ll No . I . Thro ugh i nterpreta tio n o f these ph o t ographs, l an dfi ll mat erial s appe ar to h ave bee n p lac ed i n tre nch e s i n the e a stern tw o- thirds o f the land fi ll . The western th i rd of the lan dfill appe ars to h av e been u sed to d i spose of pri m arily h ardfi l l m a teri a ls. Th i s i s e vid e nce d b y the prese nc e of exp o sed rubb l e p il es in th i s are a . H ardfi ll h a s bee n p lac ed along the e mb ankm e n t o f the d rai n ag e ch ann e l in the wes t ern p o rtion o f the l and fi ll . Other d i sp o s al practic es at Lan dfi ll No . I includ e o pe n b urn i ng o f refuse an d debri s. Landfill N o. 6 was used fro m 19 6 2 to 19 6 5 and primarily received general Base refuse. Waste oi l , the l , and solvents may also have been disposed of at this location. No direct physical evidence of these chemicals was found at Landfill No. 6 during the 1993/1994 remedial investigation (R1) field activities. Wi thin OU-2, soils con t ained chlorinat ed VOCs, BTEX, and po l ynuclear aromatic hydrocarbons (PAHs), (Figure 3-8). The reported VOCs and BTEX chemicals represen t the residual of fuels and solvents used for aircraft and vehicle operation and main t enance at EAFB. The PAHs are the residual of incomplete combustion of motor fuels and were not a specific chemical used at EAFB. All bu t one of the reported concentrations in soil was below the 10-_ ' risk based level calculated for excess carcinogenic ri sks. Samples from monitor wells installed in the interior of Landfill No. 1 indicat ed the presence of TCE and DCE in five samples at maximum concentrations of 14 ug / L and 19 ug /L , respectively. JP-4 contamination caused by a leak in a fuel line was identified along the southern b oundary of OU-2. This JP-4 contamination has been remediated under S t ate of South Dako t a petroleum release regulations.

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### OU-2 is bounded on the west by a surface water drainage channel. This channel contains areas of wetlands. Remedial construction activities at the OU resulted in some reworking of soil and drainage channel relocation in the wetland areas. Since 2000, this portion of the channel has been graded and erosion protection (in the form of rip rap and rock-filled gabions) has been installed. Replacement wetlands were constructed near other Base lakes located near the center of EAFB. A quantitative risk assessment was performed for the ground water , surface water, soil, sediment, and air. The risk assessment evaluated potential effects on human health posed by exposure to contaminants from OU-2. The risk assessment for OU-2 indicated that the future carcinogenic risk slightly exceeded the acceptable range only from ingestion of ground water containing arsenic and beryllium. A rsenic and beryllium are considered naturally occurring at OU-2. All other current and future quantified carcinogenic risks were within the acceptable risk range. Part of the remaining site risk includes risks from exposure to surface soil contaminants. The chemicals, which contributed the majority of risk in the soil, were PAHs. Benzo(a)pyrene, a PAH, is the primary contaminant identified in the risk assessment as contributing to risk from soils. However, only one surface soil and two subsurface soil samples actually contained concentrations of benzo(a)pyrene that are of concern. Due to the heterogeneity of the landfill contents, uncertainty is associated with the calculated risk values for the surface soil. Benzo(a)pyrene was also the primary chemical contributing to carcinogenic risk in the sediments at OU-2. Five of seven sediment samples contained benzo(a)pyrene at concentrations that are of concern. [towever, the results of the risk assessment indicate that risk due to exposure to contaminants in sediments at OU-2 is within the acceptable risk range. It is typical for compounds in the surface soil to wash into adjacent drainages and to settle or become trapped in the drainage areas. Remedial action for the drainage areas outside of the landfill boundaries is not warranted. The risk assessment for OU-2 indicated that the only non-carcinogenic risk resulting in an HI above 1.0 was from ingestion of ground water containing arsenic. A rsenic detected in samples throughout the Base is considered to be naturally occurring. Results of the risk assessment indicated that surface water was not a media of current concern. Chemicals detected in the ground water which contributed to excess risk are considered to be naturally occurring. Therefore, remedial action is not warranted for the ground water and surface water at this time. Remedial action was considered warranted for the landfills based on the potential risk to human health from future releases of hazardous substances from the landfills. Contaminants in the landfills may leach downward to contaminate the underlying ground water. Off-Base residents may then ingest or come in contact with the contaminated ground water. A lso, the surface of the landfills may erode, thus exposing Base personnel doing maintenance work to disposed hazardous substances. Field surveys were conducted at EAFB in 1993 for threatened and endangered species. No sensitive plant or fauna species classified as rare, threatened, or endangered in South Dakota were observed on EAFB. In terms of ecological value OU-2 represents a highly disturbed environment dominated by the adjacent runway and alert apron. Some habitats do exist in the area including grass fields, weedy old fields, trees and wetlands interspersed among the disturbed areas. The tiered ecological assessment did not identify any chemical related impacts and a Tier III assessment was considered unwarranted.

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_ ptember2005Ellsworth Air Force Base Final Five
- Year Review 3.3.4 Initial Response Tw o rem oval ac tion s were co mp le ted a t th i s O U . A s i te in the s outhw e st co mer o f Landfill l id e n tified d uring R I g eoph y s ical inv es tigation s w a s ex cavat ed in 1997 . T h i s location contain ed remn a nts o f chemical we ap on s training m at erial s an d lo w -lev e l radioactiv e w a st e m a terial T he i de n ti fied m a terial w a s ex cavat ed an d m ov ed o ff Ba se fo r d i s po s al at a lic e n sed w a ste d i sp o s al facility . 3.4 OPERABLE UNIT 3 LANDFILL 2 3.4.1 Physical Setting The area west of Landfill 2 sl o pes very gently to the south, whereas the area east o f Landfi l l 2 slopes to the east where a dendritic pattern of ephemeral drainages has dissected the area. The southern drainage leads to Box Elder Creek. The eastward drainage at OU-3 is part of an overall northern-sloping dendritic pattern that drains toward ephemeral drainages that lead to Elk Creek. OU-3 is currently undeveloped and is dominated by relatively undisturbed grassland. Some exposed rubble was evident in full trenches in the northern portion of the OU at the time of the RI. Water uses designated for the streams include irrigation, wildlife propagation, and livestock. In addition, the Elk Creek designation includes limited contact recreation. The available habitat on OU-3 is dominated by relatively undis tu rbed grassland. OU-3 differs from most of the other operable units in that none of the site is developed. There are no buildings, parking areas, or paved roads within the OU. Trench-and-fill activities have physically altered the vegetation on a small portion of OU - 3, but the maj o rity of the OU is relatively undisturbed grass l and th a t remains a ttractive to animal species that would be potential chemical receptors. No wetlands were identified on the OU. No standing or flowing water exis t ed, and dominant plant species were not hydrophytic in any part of the OU. 3.4.2 L and an d Res o urce u s e OU-3, l o c at ed in the northeast porti o n of EAFB, c onsists o f Landfill 2. It is approximatc ly a one-acre site, the four identified trenches to the north and two disturbed soil areas in the southeast and southwest comers (Figure 3 - 9). It is currently undeveloped and is dominated by relatively undisturbed grassland. The placement of the landfill cover is comple t e at this OU. The OU is closed to access, except for Base personnel and contractors responsible for the operation of the remedial systems. Undisturbed grass areas on the OU may be used by local wildlife for foraging, loafing and nesting. No specific future use has been determined for this OU. 3.4.3 His tory o f Contamina ti o n The landfill was active for approximately one year (1964-1965) until operational concerns with trash containment ended its use. Methods used to dispose of the refuse included surface filling of a low-lying area (fill area) and trench and fill operations. Combustible trash, described as shop wastes, was burned daily in a bum pit. Four trenches located north of the fill area were used for the disposal of metal and industrial and household refuse. Possible burial sites were identified in the August 24, 1971, aerial photo,

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### but the trench origination dates are not known. Some metal debris was exposed at OU-3 and may have been the result of surface disposal of metal waste. Areas of disturbed soil in the southwestern and southeastern corner of OU-3, which may have been dump areas, were also identified in historical aerial photographs of EAFB. A sign had been located within the boundary of OU-3 indicating a missile disposal / burial site (USAF, 1988). T he missile disposal site is basically scrap metal salvaged from a test flight and is not a source of chemical release to the en v ironment. According to the USAF, the missile dates from a test firing in the mid-1960s. Information on the missile is still classified at this time. Soil and soil vapor samples from OU-3 indicated the presence of VOCs, BTEX, methane (soil vapor only), and semi-volatile organic compounds (SVOCs) (soil only). See Figure 3-10. The calculated carcinogenic risk level for surface soil was 1 × 10 -6, 

### due to the presence of SVOCs . This was considered within the acceptable range. The reported VOCs and BTEX compounds are residual from fuels used at EAFB and from solvents used in maintenance and repair of aircraft and other vehicles. The most commonly reported compound, in soil vapor samples, in the trench-area samples was tetrachloroethylene (PCE) with a maximum concentration of 0.192 parts per million (ppm) near the middle part of the western trench. Toluene and xylenes were also reported in soil vapor samples, at concentrations up to 38.23 ppm, total reported benzene, toluene, ethylbenzene, and xylenes (BTEX) concentrations up to 99.53 ppm, and trichloroethylene (TCE) at concentrations up to 0.297 ppm. Methane was reported at concentrations up to 50,722 ppm, primarily in samples for which other compounds were also reported. The lower explosive limit for methane is 50,000 ppm, with an upper explosive limit of 150,000 ppm. The PCE and TCE identified at this OU are the residual from equipment maintenance and de-greasing operations related to aircraft and vehicle repair and maintenance. Toluene was reported in two soil vapor samples collected from the burn-pit area at concentrations of 0.53 ppm and 1.21 ppm, respectively. Xylene, methylene chloride, Dichloroethene (DCE), and TCE were reported in samples at concentrations of 1.10 ppm, 0.57 ppm, 1.14 ppm, and 0.003 ppm, respectively. TCE was also reported in a sample at a concentration of 0.014 ppm. TCE was reported in six soil vapor samples collected from the southwest corner of OU-3 at a maximum concentration of 0.169 ppm. One sample had a reported total DCE concentration of 0.264 ppm. Soil samples contained acetone, acetonitrile, VOCs (total 1,2-dichloroethene was reported as high as 12.0 ug

/ kg), jet fuel concentrations as high as 170 mg / kg, SVOCs, and pesticides. Ground water samples indicated the presence of chlorinated VOCs and petroleum constituents. In the trench area, nine VOCs were reported above quantitation limits for ground water samples. Vinyl chloride was reported in two of the samples (tl.0micrograms per liter [ug /L ] and 4.2ug / L), and 1,2- dichloroethane was reported in one sample at 17.0 ug / L. Downgradient from the fill area, VOC samples were obtained from three monitoring wells, but because of insufficient water, no other constituents were analyzed in one of the wells. A total of six VOCs were reported: PCE, TCE, total 1,2-dichloroethene, benzene, ethylbenzene, and xylenes. A quantitative risk assessment was performed for the ground water, surface water, soil, sediment, and air. The risk assessment evaluated potential effects on human health posed by exposure to contaminants from OU-3.

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# 30 ,5 7 0 2 6Ellsworth Air P ) .-ce Base Fina/ Fi w '
- Year Review The risk assessment for OU-3 indicated that the current and future total carcinogenic site risk, calculated using average exposure assumptions, is within the acceptable risk range for the residential scenario. Total current and future carcinogenic risk calculated using the RME exposure assumptions is greater than ! × 10
- 4. The majority of the total carcinogenic site risk for the residential scenario is from exposure to VOC and arsenic in the ground water. The current and future non-carcinogenic risk is due to naturally occurring selenium in ground water. However, due to the heterogeneity of the landfill contents, great uncertainty is associated with the calculated risk values. Based on the OU-3 risk assessment, the calculated carcinogenic and non-carcinogenic risks for ground water is 2 x I0 - a and 4.8, respectively. The calculated carcinogenic risk level for surface soil is I × IO 5, due to the presence of SVOCs. This is within the acceptable risk range. Based on this calculated acceptable risk, and the low concentrations of contaminants detected in surface soil samples, remediation was not warranted for surface soil as part of OU-3. Remedial action was warranted for the landfill based on the uncertainty associated with the calculated risk values. Based on the OU-3 risk assessment, the calculated carcinogenic and non-carcinogenic risks for ground water exceed the acceptable carcinogenic and non-carcinogenic risk ranges. However, remediation is not warranted for ground water at OU-3. The sporadic reported concentrations and lack of localizations of contaminants detected in ground water at OU-3 result in the risk assessment model estimates developed for this site being highly conservative and therefore present uncertainty for interpretation of risks for these contaminants within an OU-wide context. The data do not support the existence of plumes of these contaminants, therefore monitoring of the ground water will provide for the protection of the environment and human receptors as degradation of the COC (vinyl chloride) is monitored overtime. T

he potential sources for the chemical COCs at OU-3 are the landfill and trenches, which cover about o ne acre. The Tier I and I1 ec o logical risk evaluations determined that this area was too small t o present a significant ecological risk and the site was not recommended for a Tier Ili assessment. 3.4.4 Initial Response No CERCL A removal actions or other initial cleanup actions wcre performed at this OU. 3.5 OPERABLE UNIT 4 LANDFILL 3 3.5.1 Physical Setting OU-4 consists of Landfill No. 3, which is approximately 35-40 acrcs in size and is located in the southwestern corner of EAFB. The topography at OU-4 is fairly level, with a slight slope toward the south and e a st, a nd a few broad, shallow depressions. The western portion of the OU slopes gently toward the west. A series of east-west trending depressions are visiblc on aerial photographs, and are assumed to be the surface reflection o f historical trench and fill operati o ns. A shallow aquifer has been identified at depths of 10 feet to 50 feet beneath the ground surface at EAFB. T

he top of the shallow aquifer at OU-4 varies seasonally, but is generally 14 ft to 32 fl below the ground surface. This ground water is classified as having a beneficial use as a drinking water supply suitable for human consumption (ARSD 74:54:01 , Groundwater Quality Standards). The shallow aquifer may also discharge to the surface. However, no known seeps or springs were identified at OU-4.

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### 3.5.2 Land and Resource Use Field surveys were conducted at EAFB in 1993 tbr threatened and endangered species. No sensitive plant or fauna species, classified as rare, threatened, or endangered in South Dakota were observed on EAFB. OU-4 is predominately grassland habitat, much of which has been disturbed by human activities , such as past landfill operation and current maintenance. Despite the disturbance, habitat still exists that would attract animal species that would be potential contaminant receptors. In t roduced grasses dominate existing vegetation on OU-4. Crested wheatgrass ( Agropyron cristatum ) covers most of the OU-4 investigative area, including the area over the former landfill . The landfill covers approximately half of the OU, but the only remaining visual evidence of the landfill is the rough and uneven terrain resulting from trench and fill activities. Small patches of other grasses, such as smooth brome (Bromus inermis ) and Kentucky bluegrass ( Poa pratensis ), are also present within the crested wheatgrass field. A number of forb species, such as yellow sweet clover (Melilotus officinalis ), skeletonweed (Lygodesmiajuncea ), purple coneflower ( Echinacea angustifolia ), scurfy pea ( Psoralea tenuiflora ), and cowboy's delight ( Spharalcea coccinea ), are present as well. Cons truction of the landfill cover at this OU is c o mplete . Access to the OU is restricted to Base personnel and contractors responsible for the maintenance of the cover and tb r the completion of long term ground water monitoring and operation of the remedial systems. Undisturbed grass areas on the OU may be used by local wildlife for foraging, loafing and nesting. No specific future use has been determined for this OU. 3.5.3 History of Contamina tion The landfill was primarily active between 1965 and 1976 as a trench and fill operation. Disposal trenches were approximately 13 to 15 ft deep. A recent examination of 1946 and 1952 aerial photographs of EAFB indicated that some landfill activity may have occurred prior to 1965. Also records indicate that one open trench was used for disposal of construction demolition debris during the mid-1980s. Digested wastewat er treatmen t p l an t bi o so l ids was also added to the landfi l l at this time. S ol id was t e ge n erat ed on-Base has been disposed of by contrac t at an off-Base sanitary lan dfi l l since 1976. Shop wastes ( l iquids and paints), industrial sewer sludge and oils, and miscellaneous refuse were placed in Landfill No. 3 . During the mid-1970s, a gravel-filled waste-oil pit was operated in the sou thwes t co m er of the OU for abou t one year. These was t es are thought t o be the source of the VOCs and SVOCs identified during the RI. The con t ents of approximate l y 100 55-gallon d ru ms containing waste oil and fuel were placed in the was t e-oi l pit. Prior to 1982, the southwes t corner of OU-4 was also used as a staging area for 55-gal l on drums con t aining was t e oil and fue l . The southwes t corner of OU-4 was used to stage asphalt rubble. The asphalt rubble was removed in the fall of 1993. The exact locations of the waste pit and drum staging area are no t known, bu t are presumably in the vicini ty of the former asphalt waste p i l e area. During 1982 and 1983, OU-4 was used as a disposal site for soil con t aining Pramitol, a herbicide, and sodium chromate, a l aunch faci l ity coolant. Soil at OU-4 contained elevated VOCs, semi volatile organic c o mpounds (SVOCs), and pesticides within the EAFB boundary (Figure 3-11). Ground water contained chlorinated VOCs, SVO C s, and pesticides (Figure 3-12). Contaminated ground water within this OU moved from the landfill, located within the original Base boundaries, to an adjacent area within the OU, which is now owned by the Air Force. The VOCs and SVOCs were residuals from shop wastes disposed at the OU. The pesticides r esiduals are the resul t of normal ground keeping use on EAFB.Ellsworth Air Force Base Final Five
- Year Review Sixteen separate VOCs were reported in soil samples from OU-4. Toluene was the only reported VOC in surface soil samples. Acetone, toluene, ethylbenzene, xylenes, octamethylcyclotetrasiloxane, trichloroethene (T C E), and 1,2-to t al-dichloroethene were the most commonly reported VOCs m subsurface soil samples. Four soil samples taken from locations within Landfill No. 3 contained PAH, o-cresol and p-cresol. Benzo(a)pyrene was reported in three surface soil samples. Twen ty different pes ticides and two PCBs were reported in soil samples. The highest frequency of reported pesticides was from surface soil samples collected within Landfill No. 3 . Reported pesticides are believed t o be a result of normal pesticide application practices on the surface, rather than disposal of was t e product. No specific source was identified in Base records for the PCBs. Eight inorganic compounds were reported above background in OU-4 surface soil samples. Calcium and magnesium were the inorganic analy t es most frequently reported above background concentration. Sixteen inorganic analy t es were reported above background levels in OU - 4 subsurface soil samples . Lead, silver, and zinc were reported at 4, 250, and 18 times, respectively, above the background range in one subsurface sample. These inorganic elements are from naturally-occurring materials con t ained in the Black Hills Soil Complex and base rock materials. Reported dioxin /furan included: 2,3,7,8-tetrachlorodibenzofuran; i,2,3,4,6,7,8-heptachlorodibenzo-pdioxin and furan; and oc t achlorodibenzo-p-dioxin and furan. The international toxic equivalents were below the !,000 picograms per gram (pg / g) level of concern for residential soil. One sedimen t sample was taken during the 1993 RI. This sample was taken from an off-Base ephemeral stream channel down-gradien t of OU-4. Reported analytes included acetone in the duplicate analysis only, eight separat e PAH compounds, three pesticide compounds, and inorganic compounds. TCE and total dichloroe thene (DCE) were the most frequently reported VOCs in ground water samples. TCE, vinyl chloride, and 1,2-dichloropropane were reported in samples taken from the shallow aquifer at or above the Maximum Contaminan t Level (MCL). Sample resul t s from OU-4 monitoring wells indicate ch l orinated hydrocarbons were reported in ground water samples from four general areas. The firs t area extends from the center of Landfill No. 3 south past the Base boundary a distance of approximately 2,600 fee t . The second area is in the southwestern corner of the landfill, and extends off-Base to the south and southwes t . There is some indication that these two areas may be in t erconnec t ed. The third area is an isolated occurrence in the northeast corner of the OU. A fourth area is in the vicinity of the control tower. Nineteen different SVOCs analy t es were reported in ground water samples from OU-4. Bis(2-chloroethyl)ether and 1,4-dichlorobenzene were the most frequen tly reported SVOCs in ground water samples. 1,2,4-trich l orobenzene was reported once above the MCL of 70 ug / L. Pentachlorophenol was reported once at 1 ug / L, equal t o the MCL. Fourteen different pesticides were reported in eigh t ground water samples. Aldrin, alpha-BHC, be t a-BHC, heptachlor, and heptachlor epoxide were the most frequently reported pesticides in OU-4 ground water samples. The highest reported pesticide value was for prometon, which was reported once at a concentration of 0.95 ug / k. Seven t een inorganic compounds exceeded background ranges in ground water samples. Antimony, cadmium, manganese, lead, nickel, and selenium were reported at values that exceeded the MCL in at

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### least one sample. However, antimony, manganese, and selenium were also reported in background samples above the MC L , and are believed to naturally occur at higher concentrations in the area. A quantitative risk assessment was performed for the ground water, surface water, soil, sediment, and air. The risk assessment evaluated potential effects on human health posed by exposure to contaminants from OU-4. The risk assessment for OU-4 indicated that the chemical, which contributed the majority of the risk in the soil, was benzo(a)pyrene, a polynuclear aromatic hydrocarbon (PAH). However, only three of five samples had reported benzo(a)pyrene concentrations in excess of the reasonable maximum exposure (R_I V IE) 10 -6 

### risk range. None of the sample concentrations exceeded the central tendency / average risk range. However, due to the heterogeneity of the landfill contents, uncertainty is associated with the calculated risk values for the surface soil. The following compounds were identified in the risk assessment as contributing to unacceptable current and future risk (risk drivers) in ground water on-Base: vinyl chloride, I,I-DCE, TCE, n-nitroso-di-n-propylamine, bis(2-chloroethyl)ether, 1,4-dichlorobenzene, aldrin, alpha-BHC, andheptachlor. In addition, 1,2,4-trichlorobenzene, cadmium, and lead were reported above the MCL in onBase ground water samples. Total-l,2-DCE was reported above the MCL for cis-l,2-DCE in on-Base ground water samples. Vinyl chloride, I,I-DCE, TCE, 1,2-DCA, and alpha-BHC were identified as current and future risk drivers in off-Base ground water. In addition, lead and total-l,2-DCE were reported above the MCL in off-Base ground water samples. Remediation of the ground water was warranted based on the risk to human health from ingesting and contacting contaminated ground water. Remedial action also was warranted for the landfill based on potential risk to human health from future releases of hazardous substances. If not remediated, contaminants in the landfill could leach downward to contaminate the underlying ground water. Off-Base residents could then ingest or come in contact with the contaminated ground water. Due to the potential heterogeneity of the waste materials present within the landfills, a complete characterization of waste materials present was not possible during the RI. This adds a degree of uncertainty to the risk assessment for the landfill contents. Rather than attempting to fully characterize landfill contents and gain more certainty in the risk assessment, the Air Force utilized guidance developed by EPA titled Presumptive Remedy for CERCLA Municipal Landfill Sites (OSWER Directive 9355.0-49FS). The presumptive remedy for landfills is containment (capping) of landfill contents. Using the presumptive remedy strategy, a quantitative risk assessment is not necessary to evaluate whether the containment remedy addresses all exposure pathways and contaminants potentially associated with a landfill. Rather, all potential exposure pathways can be identified using the conceptual site model and compared to the pathways addressed by the presumptive remedy. Containment of the landfill contents addresses exposure pathways and risks normally associated with landfills. The contaminant exposure pathways for the potential risks associated with the landfill contents at OU-4 include (1) direct physical contact with the landfill contents, and (2) consumption or contact with ground water that may become contaminated. In terms of ecological value OU-4 represents area that has been highly disturbed. The area has overgrown with a wide variety of grasses and herbaceous plants. The Tier I and II ecological risk assessment identified a number of invertebrates, small mammals, birds, larger mammals, and reptiles that may forage, live, or nest in the area. Terrestrial vegetation and soil faunal communities did not reveal patterns indicating chemical-related impacts. Therefore, a Tier III investigation was not considered warranted.

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# 30 ,5 7 036Ellsworth Air Force Base Final t '7_v- Year Review 3.5.4 Initial Response No CERCLA removal actions or other initial cleanup actions were performed at this OU. 3.6 OPERABLE UNIT 5 LANDFILL 4 3.6.1 Physical Setting OU-5 consists of Landfill 4 and approximately 50 adjacent acres near the northern perimeter of EAFB. Landfill No. 4 is approximately a 10-acre area located at the northern end of Scott Drive. Topographically, the southern portion of the landfill slopes slightly to the north (Figure 3-13). The northern portion of Landfill No. 4 slopes steeply to the north-northeast and the weste rn portion of the OU slopes toward the west. Several incised valleys exist to the north and west of Landfill No. 4. These valleys car ry storm water runoff off-Base, north and northwest of OU-5 into several unnamed ephemeral tributaries of Elk Creek. Two ephemeral ponds along an erosional gully were identified during the field survey. The "ponded" areas are within the natural drainage way where the water source is surface ru noff. The erosional gully originates on the steep face of Landfill No. 4. It collects surface ru noff from the surrounding hilly terrain and carries it to the north, off the OU and the Base. Southwest of the landfill, the topography is fairly level with a slight rise associated with a Base perimeter service road. Landfill No. 4 had exposed fill areas throughout most of the former disposal areas. 3 . 6 . 2 L a n d a n d R eso u rce Use Crested wheatgrass fields and mixed grass prairie dominated the habitat on OU-5 during the RI. OU-5 differs from the majority of the operable units in that none of the site is developed. There are no buildings, parking areas, or paved roads within the OU. Because of the lack of development, over half the OU contained grassland that was attractive to animal species that would be potential receptors. Field surveys were conducted at EAFB in 1993 for threatened and endangered species. No sensitive plant or fauna species classified as rare, threatened, or endangered in South Dakota were observed on EAFB. The only wetlands identified on OU-5 are part of an isolated drainage system associated with the erosional gully. They consist of two small ephemeral ponds located in depressions along the erosional gully. The ponds are highly degraded and are unlikely to provide any wildlife habitat. Both ponds were heavily used by cattle; compacted soils and trampled vegetation were common around the ponds. In addition, both ponds were scattered with debris from the landfill, such as tires, rubble, and scrap metal. Remedial construction activities at this OU have been completed. Accessed to the site is restricted to Base personnel and contractors responsible for the maintenance of the landfill cover and long term monitoring of ground water. Undisturbed grass areas on the OU may be used by local wildlife for foraging , loafing and nesting. No specific future use has been determined for this OU.

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### 3.6 . 3 H istory of Contaminati o n Waste was disposed of at OU-5 fro m the 1940s thro ugh 1990. This landfill was used primarily for the disposal of construction demolition and hardfill materials; however, reports and visual observations from Installation Restoration Program (IRP) studies noted that this site was also used for general refuse and drum disposal. The Base Commander terminated waste disposal activities at this landfill after 1990. Polynuclear aromatic hydrocarbons (PAHs) at estimated values below the sample quantitation limit (48 ug / kg to 250 ug / kg) and JP-4 jet fuel, in one surface soil sample (SB930502) at 190 mg / kg , were reported in soil samples collected from OU-5 (Figure 3-14). Jet fuel was also reported at a concentration of 100ug / L in one ground water sample collected during the investigation (Figure 3-15). T he PAH compounds are attributed to the incomplete combustion of jet and motor vehicle fuels. A quantitative risk assessment was performed for the ground water, surface water, soil, sediment, and air. The risk assessment evaluated potential effects on human health posed by exposure to contaminants from OU-5. Part of the site risk present at OU-5 includes risk from exposure to surface soil contaminants from within the landfll. In addition, due to the heterogeneity of the landfill contents , there is some uncertainty associated with the calculated risk values for the surface soil. The risk assessment for OU-5 indicated that the carcinogenic current and future risk was within the acceptable risk range of 1 × 10. 4 to 1 × 10 -6, 

### and there were no non-carcinogenic risks resulting in an HI above 1.0. Results of the risk assessment indicated shallow ground water and surface water were not media of current concern. Therefore, remedial action is not warranted for the ground water and surface water at this time. The ground water at OU-5 will still he retained as part of the Base-wide ground water evaluation for OU- 11. Remedial action is warranted for the landfill based on the potential risk to human health from future releases of unidentified hazardous substances in the landfill. Contaminants in the landfill may leach downward to contaminate the underlying ground water. Off-Base residents may then ingest or come in contact with the contaminated ground water. Also, the surface of the landfills may erode, thus exposing off-Base residents to contaminants in both surface water and air. Due to the potential heterogeneity of the waste materials present within the landfill, uncertainty is associated with the calculated risk values for surface soil. The ecological evaluation of OU-5 was based o n a combination o f data and literature reviews, field and laboratory analyses, analyte evaluation and screening, and preliminary risk screening. A variety of potential receptors were identified that could nest and / or forage in OU-5 habitats. These range from the soil fauna identified with pitfall traps to aquatic inve rtebrates in the ephemeral ponds to birds and mammals. Those species preferring grassland and tolerant of disturbed, weedy areas would be expected to be more common. Rare, threatened, or endangered species are unlikely to utilize OU-5 for more than very transitory habitat. Terrestrial vegetation and soil fauna communities at OU-5 were statistically different from those at an off-Base reference area. While not confirming effects of elevated chemicals (differences may in fact have

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# ao57 oa'Ellsworth Air Force Base Final l "z ve - Ycar Review been due to differences in physical disturbance), thc differences were sufficient to conduct a Ticr II evaluation (based on terrestrial vegetation) and then a preliminary risk screen (based on soil fauna data). The preliminary risk screen identified the tbllowing analytes as chemicals of concern at OU-5: silver, endrin, heptachlor epoxide, arsenic, beryllium, and mercury. The metals are considered naturally occurring elements in the Black Hill Area soil complex; the pesticides are though t to be residuals from on-Base pest control practices. The landfill that is a potential source of the COCs at OU-5 covers an area of about ten acres. This is considered too small to present significant ecological risk, and an OU-specific Tier III assessment was not completed. However, the identified COCs were carried over ['or evaluation in a Basewide ecological risk assessment. 3 . 6. 4 Initial Response No CERCLA removal actions or other initial cleanup actions were performed at this OU. 3.7 . OPERABLE UNIT 6 LANDFILL 5 3.7.1 Physical Setting OU-6 consists of Landfill No. 5, which is approximately seven acres in size and is located in the southeastern comer of EAFB. The topography of OU-6 is characterized by an cast-west drainageway and a north-south stream. The east-west drainageway is located m the southern portion of OU-6, and drains surface water off OU-6 t o the southeast. It also includes a storm sewer discharge. The stream along the eastern boundary of OU-6 drains surface water off site to the south. This drainage is fed by Gateway Lake, located approximately 1,000 ft up-gradient of OU-6, and by discharge from the Base WWTP. This drainage collects approximat ely two-thirds of tile storm water runoff from the Base. One of the more importan t wildlife habitat features on OU-6 is the wetlands vegetation associated with these drainages. 3. 7 . 2 L and and Reso urce U s e Two distinct types and areas o f fill material were tbund at OU-6. The first type of fill material was clean fill used on the eastern portion of the OU, probably during cons truction of the golf course, and consists of re-worked soil and organic material. The organic material was described in the field as black organic humus type material resem b ling WWTP sludge material and plastic, and may have been used as a soil amendment when the golf course was built. The second type of fill material is landfill material, which consists of construction debris and demolition debris. Construction and / or demolition debris consists of broken concrete, broken brick, asphalt, and wood. Field surveys were conducted at EAFB in 1993 for threatened and endangered species. No sensitive plant or fauna species classified as rare, threatened, or endangered m South Dakota were observed on EAFB. R emedial actions at this OU have been completed. Access to the area is restricted to Base personnel and contractors responsible for the maintenance of the landfill cover and for long term monitoring activities. Undisturbed grass areas on the OU may be used by local wildlife for foraging, loafing and nesting. No specific future use has been determined for this OU.

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### 3.7.3 History of Contamination Th e land fi ll at OU - 6 (Lan dfi ll No. 5 ) w a s activ e f rom 19 6 0 to 1980 an d p rimarily u se d to di sp o se of con s truction an d de molition d ebri s. H ardfill ( i .e., concr e t e, a sph alt ) w a s plac ed along the rail l in e to stabilize erosion. I n a ddi ti o n, reports state di g ested sewage sludge, m isce l laneous refuse, and possibly shop wastes may have been disposed of at this landfill (USAF, 1985). However, no direct physical evidence of miscellaneous refuse or industrial / shop waste has been found at OU-6. Polynuclear aromatic hydrocarbons and pesticides were reported in soil samples collected from OU-6 (Figure 3-16). Levels of VOCs and metals contaminants observed in the ground water at the site were below Maximum Contaminant Levels (MCLs) or considered to be representative of background levels (Figure 3-17). PAHs are the residuals of incomplete motor and jet fuel combustion. The pesticides are residual from normal grounds keeping use on Base. Acetone, pentane, styrene, benzene, toluene, xylene, naphthalene, bis (2-ethylhexyl) phthalate, and heptachlor epoxide were reported in at least one sample collected from surface water locations during the RI investigation. A quantitative risk assessment was performed for the ground water, surface water, soil, sediment, and air. The risk assessment evaluated potential effects on human health posed by exposure t o contaminants from OU-6. The human health risk assessment evaluated potential effects on human health posed by exposure to sources and / or releases associated with Landfill No. 5. The assessment considered the possibility of multi-media sources including ground water, soil, surface water, sediment, and air. Results of the baseline risk assessment indicated shallow ground water and surface water were not media of concern. Identified risk driver chemicals of concern for OU-6 included: PAH in surface soil, manganese in soil, and arsenic in sediment. The calculated current and future carcinogenic risks for OU-6 were within EPA's acceptable range of 10-4to 10 -6. 

### A variety of potential receptors that may live, forage or nest in OU-6 habitats was identified. These range from ben thic invertebrates and amphibians in the drainage channels t o birds and mammals. Terrestrial vegetation and fauna communi ties did not show patterns indicating elevated chemical exposure-related impacts. This finding was considered consistent with the relatively low levels and limited distribution of elevated chemical concentrations in soil, and the active and disturbed nature of the site observed during the RI. Tier III investigations were not completed at this site but the COCs were carried over to the Basewide Tier llI assessment. OU-6 is bounded on the east and south sides by surface water drainage channels. These channels contain areas of wetlands. Remedial construction activities at the OU resulted in some reworking of soil and drainage channel relocation in the wetl and areas. Replacement wetlands were constructed near other Base lakes located near the center of EAFB. 3.7.4 Ini tial Response No CERCLA removal ac tions or o ther initial cleanup acti o ns were performed at this OU.

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_ 3 . 8 O PE RA BL E UNIT 7 WEA PO NS ST O RA G E A REA 3.8.1 Physical S etting The Weapons Storage A rea, now known as the Munitions Storage Area, covers approximately 65 acres at the northwest corner of EAFB. The topography at OU-7 gently slopes toward the west and southwest away from the high plateau located in the northeastern corner of the WSA. Surface-water drainage from OU-7 generally flows into drainages directed to Box Elder Cre ek. Some s urface water flows oft-Base to the east, northeast, and southeast of the OU. OU-7 surface geology g eneral l y cons i sts of a surface layer of silty clay, appro ximately 3 to 6 feet thick, underl ain by a layer of silty sandy gravel to clayey gravel, 4 to 27 feet thick . These layers overlie the Pierre Shale Formation. Depth to shallow ground water at OU-7 ranges from approximately 10 to 31 feet. The shallow aquifer at EAFB is considered a potential drinking water source and possibly discharges to the surface. The ground water is classified as having a beneficial use as a drinking water supply suitable fo r human consumption (ARSD 74:54:01, Groundwater Qual ity Standards). 3 . 8.2 L and and R e source Use Field surveys were conducted at EAFB in 1993 for threatened and endangered species. No sensitive plant or fauna species classified as rare, threatened, or endangered in South Dakota were observed on EAFB. Remedial ac tions implemented a t the OU c o n sisted of the application of institutional controls and ground water monitoring. A removal action was completed to remove low level radiological waste materials buried at this OU. The material was removed and disposed of according to current EPA and Nuclear Regulatory Commission requirements . 3.8.3 His tory of C ontamina tion OU-7 includes the Low-Level Radioactive Waste Burial (LLRWB) site located in the Munitions Storage Area (MSA) at the northern end of the Base. The MSA is currently active. The complex included two storage buildings with vaults, a maintenance building, three other assembly / maintenance buildings, several storage igloos, two waste burial pit areas, five wastewater underground storage tanks (USTs), and 16 heating fuel USTs (Figure 3-18). The wastewater USTs were used to store water from the wash-down and cleaning of nuclear weapons that drained through the floor drains into the USTs. Radioactive wastes were generated at EAFB between 1952 and 1962. The five wastewater USTs and 16 heating fuel USTs were removed in 1993 as part of a Base tank removal program. Although historical records indicate that there were two was t e burial pits, the exact locations are not known. No available information has indicated that any ordnance or explosive radioactive wastes were disposed of at OU-7. A qu a nti t ative risk assessment was performed for the ground water, surface water, soil, sediment, and air. The risk assessment evaluated potential effects on human health posed by exposure to contaminants from OU-7. Scattered detections of VOCs were rep o rted in surface soil samples at OU-7; concentrations were below 10 -6 risk based concentrations for Human Health Risks. Radionuclides were determined to be present

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### within the normal background range due to natural variations in soil types and geological characteristics. The residual VOCs at the OU were attributed to the use of these chemicals in the maintenance of weapon system components and equipment. Some surface soil samples had concentrations of gross alpha and gross beta radioactivity exceeding the soil background range. However, the risks associated with ingestion and inhalation of, and dermal contact with, these contaminants by potential future residents and construction workers are very small and within the acceptable range (1 x 10. 4 to 1 x 

### 10-6 or less). Risks associated with construction worker exposure to gross alpha and gross beta and several inorganic analytes (especially manganese) in UST pit soils are also minimal and within the acceptable range. Although VOCs, inorganics, and radionuclides were detected in sediment, the risks to potential future residents and construction workers from ingestion, inhalation, and / or dermal contact are within the acceptable range. There are no unacceptable risks to potential future residents and construction workers from ingestion and inhalation of, or dermal contact with, contaminants in surface water or ground water. Based on the minimal risks associated with contaminants in soils and ground water at the site, limited institutional controls for these media are warranted. Results of the Tier I and II ecological risk assessment indicated that OU-7 does not exhibit significant ecological value due to its highly disturbed environment (OU-7 primarily consists of buildings, roads, and paved areas). There are small areas of potential grassland and wetland habitats at the OU. Several animal species may live, forage, or nest in OU-7 habitats. These species include various types of invertebrates, amphibians, birds, and mammals. Terrestrial vegetation and soil faunal communities do not reveal characteristics that indicate chemical-related impacts. 3.8.4 Initial Response No CERCLA removal actions or other initial cleanup actions were performed at this OU. 3.9 OPERABLE UNIT 8 EXPLOSIVE ORDN AN C E DISPOSAL AREA 3.9.1 Physical Setting OU-8 is the current designation for the area surrounding and including the explosive ordnance disposal (EOD) Area. OU-8 was divided into two distinct areas of investigation. Area 1 is the actual EOD Area. A rea 2 consists of the Debris Burial Area where waste from the EOD Area was buried . Sediments in drainages within and adjacent to the EOD Area are also included in OU-8, which is located in the extreme northeast comer of E A FB. The EOD Area was approximately 600 ft by 1,350 ft and located in sloped rugged terrain. Service roads parallel the two north-south trending ridges located along the eastern and western edges of this site. The area within the confines of these service roads is where explosive ordnance demolition was formerly conducted. In addition, it is reported that an herbicide spill occurred in May 1982. Terrain in this area slopes predominantly toward the north. An unnamed ephemeral drainageway exists along the east and west edges and in the central portion of this area. This drainageway conducts surface flow off the site in a northerly direction. The Debris Burial Area was approximately 300 ft by 150 ft and located on a ridge south of the EOD Area, in a less rugged area. Spent shell casings (from small arms) were visible at the surface in this area. The terrain surrounding the ordnance burial area slopes gently toward the east.

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# 3 05 7 0 3 6Ellsworth A ir l '_ rce Base Final l 'T ve - Year Review The wetlands on OU-8 consist of ditch wetlands along portions of the two drainages, and three small impoundments created by the construction of the earth berms. The wetlands along the westernmost drainage begin north of the first berm; a narrow ditch wetland, approximately 2 feet wide, widens into a cattail slough created by the construction of the second earth berm. The vegetation in the ditch is visibly different from the surrounding vegetation and is dominated by hydrophytic species such as saltgrass (D & tichlis spicata ), foxtail barley, and curly dock (Rumex crispus ). Vegetation in the slough is also dominated by hydrophytic species such as cattail ( Typha sp.), saltgrass, foxtail barley and curly dock. Farther north, just south of the third berm, is a second slough. 3.9.2 Land and Resource Use The habitat on OU-8 is dominated by mixed grass prairie. OU-8 is not developed; there are no buildings, parking areas, or paved roads within the OU. Base activities, such as the detonation of active explosives and the burial of debris created by explosives detonation, had visibly altered only a small portion of the OU-8 habitat. The most disturbed area on OU-8 is the EOD Area, which collectively refers to a burn pit area, bum furnace area, and a detonation area. The majority of the EOD Area is characterized by native black surface soil and ver y little vegetation. Field surveys were conducted at EAFB in 1993 for threatened and endangcred species. No sensitive plant species or fauna species classified as rare, threatened, or endangered in South Dakota were observed on EAFB. This OU has had the selected remedy completed. Access is restricted to Base personnel and contractors responsible for the operation of the remedial systems. Undisturbed grass a reas on the OU may be used by local wildlife for foraging, loafing and nesting. No specific future use has been determined for this OU. 3.9 . 3 History of Contamination The three processes were used to destroy munitions at EAFB: (1) open detonation; (2) open burning; or (3) detonation within a burn furnace. In open detonation, an explosive charge was used as a donor chargc to detonate a particular explosive ordnance item at ground surface or in a shallow pit. In open burning, munitions were placed on top of a combustible material (such as wood) within a 4 ft. deep burn pit. Approximately 20 to 40 gallons of diesel fuel was poured on the munitions and combustible material in order to promote combustion. A burn furnace was considered the safer and more expeditious method of burning such items as small arms ammunition, delay elements, or primer detonators. The burn furnace consists of a diesel-fired furnace mounted on a concrete structure. Munitions were led into the furnace through a feed chute. A smokestack and vent allow smoke and vapors to leave the furnace. If munitions were treated in the burn furnace, personnel would start a diesel fuel fire in the combustion chamber of the furnace. When operating temperature was reached, personnel slowly fed munitions into the feed chute. All burn furnace, burn pit, and detonation site residue has been transferred to the debris burial area just south of the explosive ordnance disposal area. Off-spec munitions are currently shipped off-Base as hazardous waste. Product charactcristics from the treatment processes, i.e., open burning, and open detonation, are also an environmental concern. Literature research indicated that the bulk of open burning and open detonation treatment residuals are evolved in gaseous or airborne particulate form. The gaseous components include CO, NO_, N2, SO2, and CO2. Particulates may include MgO, H20, and HCL. In addition, trace quantities

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### of primer compounds could result in the evolution of PbO. Solid residuals remaining after treatment are primarily metal casings, soot and a residual ash. Approximately 100 gallons of prometon (Pramitol 25E) was reportedly released at the EOD area in May 1982. In June 1982, approximately 200 cubic yards of prometon-impacted soil was excavated from this site and transported to Landfill No. 3 (OU-4). Earthen dams were constructed of native soil in 1983 in order to prevent off-Base movement of residual prometon. Approximately one year later, Base personnel visually observed what they considered to be prometon leaching from OU-8 into ephemeral, surface-water drainageways (USAF, 1989). Sampling was not performed to verify the existence of pramitol leachate. During a site inspection in May 1992 it was observed that the earthen dams had been breached and were no longer impounding surface water flow. These dams were rebuilt as part of the remedial actions at OU-8. Volatile organic chemicals and SVOCs were detected in ground water during the remedial investigation (RI). The reported concentrations of these contaminants were less than or equal to 2 ug / L. Antimony and selenium were reported above the MCL in one or more ground water samples (Figure 3-19). Toluene was the only VOC detected in soil samples collected in the EOD area during the RI. PAHs and phthalates were also detected in the soil. PAHs typically result from incomplete combustion of organic materials. Dioxins in the soil correlated with combustion activities in the EOD area. Dioxin concentrations were well below action levels of 1,000 picograms / kg ( g g / kg) for residential soils (Figure 3-20). The risk assessment for OU-8 indicated that there are no unacceptable non-carcinogenic or carcinogenic risks at the OU under current land use conditions resulting from activities conducted at OU-8. A quantitative risk assessment was performed for the ground water, surface water, soil, sediment, and air. The risk assessment evaluated potential effects on human health posed by exposure to contaminants from OU-8. The risk assessment for OU-8 indicated that there are no unacceptable non-carcinogenic or carcinogenic risks at the OU under current land use conditions resulting from activities conducted at OU-8. Dioxins in surface soil were the only chemicals identified in the RI present at 

### concentrations greater than 10 -6. 

### Risk associated with the dioxins in the surface soil is in the 10-5 range . Non-carcinogenic and carcinogenic risks were also identified for the OU from naturally-occurring inorganic chemicals in the soil and ground water; however, risks from naturally-occurring chemicals are not considered for remediation. Chemicals detected in the ground water that contributed to excess risk are considered to be naturally occurring. Therefore, remedial action is not warranted for the ground water at this time. The ground water at OU-8 is included as part of the Base-wide ground water evaluation for OU-I 1. An ecological risk evaluation of OU-8 was based on a combination of data and literature reviews, field and laboratory analyses, analyte evaluation and screening, and preliminary risk screening. Due to the low levels of contaminant concentrations, the contaminants do not pose an unacceptable risk to these species. In addition, the limited contact these species would have with the OU-8 area ensures unacceptable risk to a single individual will not occur. 3.9 . 4 Ini tial Res pon se No CERCLA removal actions or other initial cleanup actions were performed at this OU.

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_ rce Base Final t :) ve - Year Review 3.1 0 OPERABLE UN|T 9 3.10.1 Ph y s ical S etting T he O U-9 s tu d y are a con s i s t s o f the O l d Auto H o bb y Sh o p and the s urroun d in g are a . O U-9 i s appro x i m at e ly 90 acres in s i ze an d i s locat ed i n the s outh -c e ntral se ction o f the b a se, s outhwes t o f Heritag e Lake. S urfac e to po graph y i s rel ativ e ly fi at in the wes t ern p ortion o f the s tu d y are a , s loping g e ntly to the e a s t at a gra d i e nt o f appro x imat e ly on e perc e nt . In the v i cinity o f the unnam ed ephe m eral s tre a m, wh ich i s prese nt al o n g the e a s t b oun d ary o f O U-9 , to p ograph y i s much s t eeper, s lo p ing 5 - 2 0 de grees in w ard to w ards the s tre am o n e ither s i de. R uno ff in the O U-9 s tu d y are a fl o ws al o ng drainag e ditches a n d un der groun d sto rm sewer lin es, e a s tw ard to the ephemera l s tre am an d the n s outh to G at ew ay Lake. T he s tre am an d G at ew ay Lake are p art o f a drainag e s y s t e m th at coll e ct s s to rm w a ter runo ff from the c e nt er of the Ba se an d d i re ct s it s outhw ard throug h a seri es o f re t e ntion lakes ( Ban d it Lake, Heritag e Lake, G at ew ay Lake) a nd int erconn e ctin g ephe m eral s tre am s ( F igu re 3- 2 ) . 3.10.2 Land and Resource Use OU-9 is l ocated in the south-central portion of EAF B in one of the older a nd more developed sections of the Base. Buildings and surface streets along the weste rn part of the study area and asphalt lots and undeveloped grassy areas along the easte rn and northeaste rn portion of the site generally characterize the area. Vegetation in the developed parts of the site is primarily limited to grassy areas alongside roads and buildings. The operable unit has traditionally been associated with the Old Auto Hobby Shop, located in the center of the study area on the southeast corner of Ryan Street and George Drive. The Auto Hobby Shop was razed in 1985. Another razed building in the area was the former location of a jet engine test stand located approximately 150 fl northwest of the Auto Hobby Shop. Buildings and surface structures surrounding the Auto Ilobby Shop include Building 601 (jet engine repair) to the west, Building 605 (former hangar) to the southwest, Building 805 (warehouse storage) to the south, the present jet enginc test facility to the east, and a one million-gallon water storage tank to the north. Field surveys were conductcd at EAFB in 1993 tbr threatened and endangered species. No sensitive plant or fauna species classified as rare, threatened, or endangered in South Dakota were observed on EAFB. The U.S. Fish and Wildlife Service National Wetland Inventory Map (NWI) that includes Ellsworth A ir Force Base classifies the wetland community type present on OU-9 as Palustrine Emergent Seasonally Flooded (PEMC). Gatcway Lake and a portion of the drainage just south of OU-9 are classified as Palustrine Aquatic Bed Semipcrmanently Flooded (P A BF). A quatic Bed wetlands are dominated by plants growing primarily on or below the surface of the water in most years. Two wetland areas arc located on OU-9. The first is a drainage that enters the OU via a culvert under George Drive in the northeast portion of the investigative area. The drainage flows to the southeast through the eastern portion of the OU and eventually passes through a culvert under Ellsworth Drive, to exit OU-9. The second wetland present on OU-9 is a small kidney-shaped depression wetland located south of where the drainage passes under Ellsworth Drive. Two wetlands located off OU-9, a drainageway just south of the OU investigative area, and a fringe wetland around Gate w ay Lake are also characterized with OU-9 because they are adjacent to the OU and receive runoff from it. This OU is currently undergoing remediation under the OU-I 1 remedial action, and remains a functional portion of the Base. Access is available to Base personnel working at the various shops or buildings in thc OU, and to Base personnel and contractors responsible for the operation of the remedial systems. Limited undisturbed grass areas on the OU are available to local wildlife for foraging, loafing, and

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### nesting. No specific use changes have been directed for this area as a result of the selected remedial actions. 3.10.3 History of Contamination A number of different contaminant sources are present within and upgradient of the OU-9 study area which have the potential to impact environmental media at the operable unit. OU-9 consists of roughly equal portions of industrialized and undeveloped areas. Gateway Lake is also included as part of OU-9 and is located in the extreme southeast corner of the OU. The types of potential contaminant source areas at OU-9 include: Building Operations, underground storage tanks (USTs), the former Quartermaster Gasoline Dispensing Area, the former fuel transfer line, industrial waste lines, jet engine test facilities, and upgradient source areas. There is no known documentation of major spills or releases at OU-9. Srnail volumes of fuels, oils, and solvents may have been released to the environment over time through incidental spills, leaks, and / or poor waste handling and disposal practices. Low concentrations of VOCs, primarily BTEX, were found in soils (Figure 3-21). BTEX and chlorinated VOCs were detected in ground water (Figure 3-22). Because an upgradient source was suspected, ground water cleanup was addressed in OU- 11 (the Basewide ground water Operable Unit). A quantitative risk assessment was performed for the ground water, surface water, soil, sediment, and air. The risk assessment evaluated potential effects on human health posed by exposure to contaminants from OU-9. The risk assessment for OU-9 indicated that the risk for the future industrial land-use scenario, which is similar to the current land-use, is within the acceptable risk range. For non-carcinogenic risk, the HI was 0.4, which is acceptable. For carcinogenic risk, the calculated risk value was 5 × 10
- 8,which indicates that there is no unacceptable current or future risk due to carcinogenic compounds. Using reasonable maximum exposure (RME) values, the risk for the residential land use scenario is within the acceptable risk range. The risk for this scenario using average exposure values is also well within the acceptable risk range. The future industrial land-use and residential land-use risks do not warrant remediation, particularly given the most likely future land use will be industrial, and the soils are being remediated under State of South Dakota petroleum release regulations. Potential risks posed by exposure to shallow ground water and ingestion of fish in Gateway Lake are being addressed as part of OU-II and are not being addressed as part of OU-9. Because of these conclusions, remediation is not warranted for surface water, sediment, and soil at OU-9. The ecological risk evaluation of OU-9 was based on a combination of data and literature reviews, field and laboratory analyses , analyte evaluation and screening, and preliminary risk screening. Results of the evaluation indicate that most of OU-9 , other than Gateway Lake, does not present significant ecological value due to its highly disturbed environment (OU-9 consists primarily of buildings, roads, and paved areas). There is a small area of grassland and wetland habitat (including Gateway Lake) near the eastern boundary of OU-9. A variety of species was identified that could use OU-9 habitats, from snails and frogs inhabiting the wetland areas to birds and mammals. These species, along with terrestrial vegetation and soil faunal communities , do not reveal characteristics that indicate chemical-related impacts.

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_ T ve - Year Re _' iew 3 . 10.4 Initial Response No CERCLA removal actions or other initial cleanup actions were performed at this OU 3.11 OPERABLE UNIT 10 NORTH HANGER COMPLEX 3 . 11.1 Physical Setting OU-10 is the North Hangar Complex, a 75-acre site located in the central portion of the Base, northeast of the primary instrument runway. The land surface is relatively flat at the North Hangar Complex and slopes gently toward the southeast at a gradient of approximately 1 percent. The gradient in the surrounding area slopes to the south. The majority of OU-10 is paved, although grassy areas are present southwest and northeast of the site and between the hangar rows. No surface wat er bodies are present at OU-10. Storm water runoff within the hangar area is collected in underground storm-water drains. Storm-water lines at Rows 60 and 70 drain to the south beneath the runway, eventually emptying into an unlined drainageway that runs through the center of OU-12. This drainageway ultimately drains to an oil / water separator at Pond 001 adjacent to OU-I . Storm-water lines at Rows 80 and 90 drain to the west, beneath the runway and ultimately to an oil / water separation pond adjacent to the west property boundary. 3.11.2 Land and Reso urce Use There are no permanent surface waters or wetlands on OU-10. There is virtually no natural habitat on the OU t o support breeding, foraging, or sheltering of wildli[?. The vegetation on OU-10 was not compared statistically to a reference area, but based on simple observation, the small grass median strips on OU-10 are entirely different from any reference area evaluated because they are mowed and managed. Field surveys were conducted at EAFB in 1993 for threatened and endangered species. No sensitive plant species nor thuna species classified as rare, threatened, or endangered in South Dakota were observed on EAFB. 3 .11.3 Hi s to ry of Co n ta mi na ti on T he No rth H an g ar Comp l ex w a s con structe d in the 19 5 0 s and i s comp o se d of five ro ws o f ai rcra ft rep ai r an d main te nanc e h angars. Mo st of O U-1 0 is p av ed w ith concrete w i th s om e gra ss y are a s between the h ang er ro ws. No s urf ace w at er i s prese nt at O U-1 0. The are a co n tain s a s y s t e m o f u nder groun d jet - f u e l h y drant lin es th a t de liv er fu e l to d ocking ai rcraft . The pri m ary s ourc e o f co n tamination a t OU -10 i s th e f u e l di stri b u tion s y s t em. A dd i tional contaminant s ourc e ar e a s includ e the ai rcraft m ain te nanc e are a s an d un der groun d i ndustrial was t e li nes . It was rep o rted th at was t e pro d uct s u se d fo r aircraft mai n t e nanc e m ay h av e bee n w a shed d o wn fl oo r drain s in the main te nanc e b u i l d ing s. The re m e dial inv estigation f ocu sed on de t ermining i f these w a s t e pro d uc ts were the n di s ch ar g ed into the s oil be n e ath the maint e nanc e are a and to determin e if co n ta minant s h a d l e aked from the un der groun d in d u strial w a ste li nes. O U-1 0 c o ntain s a s y stem o f und er groun d je t-fu e l h y drant lin es th a t del iv er fue l to docking ai rcra ft an d un der ground i n dus tria l w a s t e l in es a ss ocia te d w ith ai rcra ft mai n t e nanc e. Organic s rep o rt ed i n s oil s amp l es inclu ded V O C s, S V O C s a nd je t f u e l ( F igu re 3-23). The pred ominant VOC s were B TE X comp oun ds. Gro un d w a ter co ntamina tion a ss ociat e d w ith O U-1 0 w a s a dd r essed w i th in O U-11 ( the Ba sew i de groun d w a ter Operab l e U nit ) f o r remed iati o n ( F igu re 3 -2 4 ).

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### A quantitative risk assessment was performed for the ground water, surface water, soil, sediment, and air. The risk assessment evaluated potential effects on human health posed by exposure to contaminants from OU-10. The risk assessment for OU-l0 indicated that the risk for the future industrial land-use, which is similar to its current use, is within the acceptable risk range. For non-carcinogenic risk, the HI was 0.006, which is acceptable. For carcinogenic risk, the calculated risk value was 2 × 10 -6, 

### which indicates the risk is within the acceptable risk range. Potential risks posed by exposure to shallow ground water are being addressed as part of OU-I1 and are not being addressed as part of OU-10. Because of these conclusions, remediation is not warranted under CERCLA for soil at OU-10. An ecologicaI risk evaluation of OU-10 was based on a combination of data and literature reviews, field and laboratory analyses, analyte evaluation and screening, and preliminary risk screening. Various types of invertebrates, amphibians, birds, and mammals may live, forage, or nest in OU-10 habitats. These species, along with terrestrial vegetation and soil faunal communities, do not reveal characteristics that indicate chemical-related impacts. This finding is consistent with the relatively low levels of contaminants in the soil. Because of the altered natural environment at OU-10, rare, threatened, or endangered species are unlikely to utilize the area for more than brief, periodic habitat. Due to the low levels of contaminant concentrations, the contaminants do not pose an unacceptable risk to these species. In addition, the limited contact these species would have with the OU-10 area ensures unacceptable risk to a single individual will not occur. Findings of the RI indicate that the contaminants at OU-IO are not altering the ecology to noticeable levels. A Base-wide ecological risk assessment will be conducted as part of OU-11, and OU-IO will be included in this Base-wide evaluation. 3.11.4 Initi al Res pon se No CERCLA removal actions o r other ini tial cleanup actions were perf o rmed at this OU. 3. 1 2 O PERABLE UN IT 1 1 BASEW I DE G ROUND WA T ER 3.12. 1 Phys ic al Se ttin g OU- II is the Basew i de Gro und Wat er Operable Uni t . T he phys i cal charac t eris tics o f this OU are c o nsisten t w i th th o se describe d f o r the Base as a wh ol e in the in tro duc tio n to Secti o n 3. 1 ab ov e, and as desc ri bed in spec i fic O U sec tio ns. Investi gatio ns c o mple t ed at OU-1 1 were des i gned to fi l l i n data gaps at spec i fic l o catio ns acro ss the Base that had been i nc l uded in specific OU i nvestigatio ns. T he OU- I 1 areas o f investi gatio n are sh o wn o n Figure 3-2 5, and are defined as: • A Basew i de gro und wat er study. • A Basew i de eco l ogical evaluatio n.

• T he area surrounding well MW93BG04 ( T his i ncluded AOC-24).

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# 3 05 7 0 4 2Ell _* orth Air Force Base Final Five
- Year Review * The area surrounding well MW93BG05 (This included AOC-24). • Up-gradient of OU-6, near MW930602. • The South Docks Area. • The northern edge of OU-12. • Additional investigations at OU-7. • The Pond 003 Area. 3.12.2 Land and Resource Use Land uses in this OU range from open grassed areas to industrial areas covered with roads, buildings, and pavement. Field surveys were conducted at EAFB in 1993 for threatened and endangered species. No sensitive plant or animal species classified as rare, threatened, or endangered in South Dakota were observed on EAFB . 3 . 12.3 History of C o n t a mi n ati on Ba sed on the ri sk a ssess m e n t an d an ev a luati o n of the d ata c o l l e c ted a s p art o f th e Ba sew i de G round W at er Stu d y an d the stu d i ed of the a dd itional are a s li s t e d ab ov e, it was de t ermi ned d uring the R I proc ess th a t th r ee are a s w arrant ed remed ia ti o n a s f ol l o ws: the are a s urro un d ing we ll B G O4 , the ar e a s ur rou ndi ng well B G O 5, an d the S ou th D ocks A re a . I n a dditio n, lo ng-t erm m on i t oring w a s r e com mended f o r groun d w at er at OU - 8. The other are a s inv es ti g a ted (u pgra d ien t O U- 6, no rthern edg e o f O U -1 2, O U- 7 [a ddition a l i nvesti gati on], a nd the P ond 0 0 3 area ) d i d not w arrant remed ia ti o n a n d were not incl ude d o r d i s cu ssed in the O U- 11 ROD. To fa c ili tat e pro je c t pl anning , OU-II w a s d ivi de d in to two p arts, A re a l an d A re a 2. Ar e a 1 i s the South D ocks S tudy A re a . Th i s inclu des the South D ocks an d are a s o f ground w at er contami n a tion in O U-9 th a t were d eferred t o O U-I 1 . Groun d w at er c o nta minatio n at OU-1 0 w a s a ls o deferred to O U-I 1 f o r remed iation ; h o we v er, groun d w a ter con t amina ti on at OU-10 i s th e res u lt o f petrol e um pro d uc t re l e a ses an d i s be ing a ddressed throug h the S ta te of S ou th D ako ta petro leum re l e a se re gu l a tion s. C on tamina ted ground w ater i n A re a 1 li es en ti re ly o n-Ba se. Remed ial a ltern ati v es de v e lo ped f o r th i s are a are referre d to coll e c tiv e l y a s the "So uth Do cks" al tern a ti v es si nc e the S ou th D ocks i s the pri m ary are a of con tamination in A re a I . A re a 2 i s the are a arou nd B G0 4 an d B GO5, wh ich inclu des are a s where groun d w at er c on tam i nation w a s f oun d to le av e the B a se a lon g the e a stern b ou nd ary. Area 1 T he So uth Docks i s l o cat ed i n the c en tral p art o f the Ba se be twee n OU-9 , OU -10 , an d the fl i gh tlin e. M a j o r b uil d ing s in the are a inclu de the Pri d e H angar an d h angars in R o ws 20, 3 0 , 40 , a nd 5 0 , F igure 3- 2. H i s to rical a erial ph otographs i nd ica te th a t the Pri de H angar a nd the h an g ars in th e S outh Do ck s A re a h av e bee n i n p lac e s in ce the l at e 194 0s to e arly 19 5 0 s. H i sto ric all y, the h an g ars h av e bee n u se d for the docking a n d mai n t e nanc e o f ai rcra ft. The Prid e H angar w a s m os t re c ently u sed f or storag e, main te nanc e of mi ss il e - s upp o rt e qui p m e n t, f o r of fi c es, a nd meetin g roo m s, in 1 99 2, se v eral u nder groun d sto rag e tanks (U STs) were remo v ed f ro m the Pri de H a n gar. H an g ars in the South D ocks are n o w u sed f o r s tora ge an d
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### maintenance of various support equipment, including aircraft refueling vehicles, fire-fighting vehicles, grounds-keeping equipment, and periodic parking of aircraft. Other potential sources in the area include industrial waste lines, equipment wash racks, and historical chemical handling disposal practices. However, no specific incidents of hazardous material spills have been documented. Contaminated ground water in Area 1 is located entirely on-Base, Figure 3-26 to 3-30. Area 2 The BG04 Study Area is located in an open grass area at the northeast edge of EAFB, approximately 1,500 ft south of the explosive ordnance disposal (EOD) debris burial area perimeter (OU-8). A firing range is located approximately 1,200 ft to the northwest and a housing tract is located approximately 800 ft to the east of monitoring well MW93BG04. Area 2 includes the areas where ground water contamination has moved off-Base along the eastern boundary. Off-site contamination associated with these areas has also been referred to as Area Of Concern 24 (AOC-24). The contaminant of concern associated with Area 2 is TCE and its associated breakdown products. The contaminant plume has been defined and currently extends approximately 5 miles to the east-southeast of the Base boundary. Twenty-five private water supply wells in the plume area have shown TCE levels in excess of the 5 ug / L MCL. The Base has installed a water line to properties within the plume area to provide an alternate water supply until the TCE plume is remediated. See Figure 3-30. The BG-05 Study Area is located in a housing area in the east-central portion of EAFB, approximately 300 ft east of LeMay Boulevard and continues off-Base to the east. There are no known sources in the immediate vicinity of well BG05. Ground Water at OU
- 8 Ground water at OU-8 was evaluated as pa rt of the OU-I 1 remedial investigations. Detailed descriptions of the OU-8 area are described earlier in this document. It was determined that remediation of ground water at OU-8 was not warranted; therefore a detailed analysis of alternatives was not completed for ground water media at this OU . However, to comply with State landfill closure requirements, compliance monitoring was implemented to verify that chemical concentrations in the ground water do not pose unacceptable risk. Volatile organic compounds, SVOCs, and petroleum hydrocarbons were detected in ground water samples from the South Docks Area. Trichloroethene (TCE) was the most frequently reported compound in the ground water samples along with its breakdown products. The ground water at OU-I 1 also is impacted by petroleum releases associated with refueling of airplanes at the flightline refueling area (FRA). No commingling of hazardous substances occurred at this site; therefore, remediation activities associated with the FRA are being addressed under the State of South Dakota petroleum release regulations. A quantitative risk assessment was performed for the ground water, surface water, soil, sediment, and air. The risk assessment evaluated potential effects on human health posed by exposure to contaminants from OU-I 1.

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# 30 5 7 044Ellsworth Air [ _b rc ' e Base Final Five
- Y e ar Review At Area 1, the total carcinogenic risk to potential future residents from ingestion, inhalation, and dermal contact with contaminated ground water was estimated at 1.77 × 10-4. This risk level exceeds thc acceptable risk range of 1 x 10 4 to 1 x 10 _'. At Area 2, the total carcinogenic risk to potential future residents from ingestion, inhalation, and de r mal contact with contaminated ground water was estimated at 2.27 x 10
- 5. This risk level is within the acceptable risk range. However, the ground water in Area 2 contains contaminants at concentrations greater than the MCL and contaminants have moved beyond the Base boundary. Remediation of ground water in Areas 1 and 2 was considered warranted because of the unacceptable risk to human health for exposure to contaminated ground water and to prevent further offsite movement of ground water containing contaminants at concentrations greater than the State of South Dakota Groundwater Quality Standards or Federal Drinking Water MCLs. An ecological risk assessment was not conducted for OU-I 1 specifically since this was a ground water OU. However a Tier III ecological assessment was conducted as a Basewide evaluation using data from the Tier I and 1I evaluation completed at other OUs. The result of this Basewide ecological assessment indicated that there was little to limited risk to ecological communities evaluated at EAFB from the site-specific exposures at individual OUs. No remedial actions were recommended as a result of the estimated ecological risks fbr an individual OU or for the Base as a whole. 3.12.4 I n itial Res po nse No C ER C LA removal actions or other initial cleanup actions were performed at this OU. 3.13 O PERA BL E UNIT 12 HARD FI L L 1 3.13.1 Ph ysi c al Setti n g OU-12 is located in the southern half of EAFB, immediately north of the Alert Apron and southwest of the runway. OU-12 is designated as Hardfill No. 1, which is approximately 14 acres in size. Surface topography at OU-12 generally slopes inward toward an ephemeral stream that flows in a southerly direction from the Primary Inst ru ment Runway to the northern boundary of the alert apron. The drainageway through OU-12 is unlined. Hardfill areas on the east bank of the stream encroach into the drainageway and also serve as rip-rap in some places. The drainageway has undergone extensive channelization in order to divert water from the alert apron. The primary drainage is part of a stormwater drainage system that originates in the north part of OU-12. The source of water is stormwater runoff from the ru nways and surrounding areas, which collects in a french drain north of OU-12 and drains into OU-12 via a culvert. The drainage runs through the center of OU-12 and is ponded toward the south end. The drainage is channelized around the alert apron, and continues south through OU-1 and OU-2 before exiting the Base. It is less than 10 feet wide along much of its length and typically contains 6 to 18 inches of slowly moving water. The pond is approxi m ately 80 ft wide at its widest point and over 700 ft long. A small, tributary drainage originates to the west of the primary drainage and joins with it north of the pond. This smaller drainage is fed by runoffffom the west. At the south end of OU-12, the ephemeral strcam is more characteristic of a pond, which may contain water year round. There is minimal obse r vable water flow within the ponded portion of the drainageway.

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# 3057 045Ellsworth Air Force Base Final Five
- Year Review 3.13.2 Land and Resource Use Operable Unit 12 contains a variety of habitat features, some of which have been heavily influenced by human activities such as landfill operations and aircraft usage. In spite of this disturbance, some habitat still exists that could attract animal species that would be potential contaminant receptors. The most disturbed areas on the OU are the hardfill areas, used to dispose of construction debris and concrete rubble. The largest hardfill area is located just west of the pond (widened drainageway) in the south part of OU-12. Another smaller hardfill area is located just to the east of the pond, and a third hardfill area is found farther north along the primary drainage. The hardfill areas are sparsely vegetated by weedy species such as annual sunflower (Helianthus annuus ), summer cypress ( Kochia scoparia ), and bindweed. The only developed area on OU-12 consists of two small buildings and a circular gravel drive located in the southwest corner of the OU. A few dirt and grass field access roads are also located in the OU. Operable Unit 12 is bordered on three sides by a formerly used runway, the current runway, and the alert apron. Although not on the OU, these features may affect the accessibility and attractiveness of wildlife habitat on OU-12. Field surveys were conducted at EAFB in 1993 for threatened and endangered species. No sensitive plant species nor fauna species classified as rare, threatened, or endangered in South Dakota were observed on EAFB. This OU is closed to access, except for Base personnel and designated contractors. Undisturbed grass areas on the OU may be used by local wildlife for foraging, loafing and nesting. No specific future use has been determined for this OU. 3.13.3 History of Contamination H i s torical aerial p h otograp hs indicate th e area h a s b een u s ed fo r dumping of con s truction debri s s uch a s w ood , metal, concrete, an d a sph alt s ince th e 1940 s. Con s truction debri s w a s vi s i b le over p ortion s of O U-1 2, alth oug h much of th e former di s po s al area i s covered b y vegetation . Di s po s al of h a z ardou s material s h a s not b een d ocumente d at O U-1 2; h o w ever, th e area w a s de s ignated a s an o p erab le unit b a s ed on h i s to rical di s po s al practice s at th e Ba s e . T h i s lan dfill receive d b uilding and road d emolition rubb le from maintenance an d repai r activitie s on th e Ba s e . H i s to rical reco rds in d icate d th at th e lan dfill w a s u s ed fo r d i sp o s al of th i s d emolition rubb le only , and di d not receive h azard ou s w a s te s. T h e inve s tigation sh o w e d th e pre s ence of V O C s , S VO C s , j et fuel , and pe s ticide s , b ut throug h s ite ch aracterization it w a s found th at th e s e contaminant s w ere related to fl ig h tline runoff rath er th an landfill d i s po s al p ractice s ( Figu re 3-31 ) . Level s of contaminant s o bs erved in th e ground w ater at th e s ite w ere b elo w Ma x imum Contaminant Level s . A s ingle up-gradient w ell rep o rte d TC E in a groun d w ater s ample at a concentration of 7 ug / L (Figure 3-3 2). A quantitative ri sk a ss e ss ment w a s p erfo rme d fo r th e ground w ater, s urface w ater, s oil , s e d iment , and ai r. Th e ri sk a ss e ss ment evaluate d potential e ff ect s on h uman h ealth p o s ed b y e x po s ure to contaminant s from OU-12. The risk assessment for OU-12 indicated that the total carcinogenic site risk is within the acceptable risk range for the residential (future) scenario and is less than 1 x 10 -6 for industrial (current) scenario. The majority of the total carcinogenic site risk for the residential scenario is from exposure to surface soil contaminants from within the hardfill. The non-carcinogenic His are below the reasonable maximum

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# 30 5 7 04 6Ellsworth Air Force Bas ( ' Final I:ive
- Year Review exposures (RME) of 9 x 10 5 for current industrial land use and I × 10 J tbr future residential land use. The average His for both curren t industrial land use and future residential land use were 3 × 10 6 and 5 × 10 2, respectively. However, due to the heterogeneity of the hardfil l contents, great uncertainty is associated with the calculated risk values. Arsenic and benzo(a)pyrene in the sediment of the drainage areas also contributed to the total site risk. Based on the risk assessment (risk calculat ed for sediment is 3 x 1 0-6), and other factors such as maximum concentrations, distribution, de t ection frequency, etc., remediation is not warranted for sediment at OU-12. The risk to human health from the ingestion and use of the shallow ground water is 2 x 10 6 . This is on the lower end of the acceptable risk range. Based on this calculat ed acceptable risk and low concentrations of contaminants detected in ground water samples, remediation is not warran t ed for ground water. The calculated risk level for the surthce wat er at OU-12 is 8 × I0 -s, which is below the acceptable risk range. Remediation is no t warran t ed for surface water as part of OU- 12. A variety of potential recep t ors were identified that may live, forage or nest in OU-12 habitats. These range from benthic invertebrates and amphibians in the drainage channels t o birds and mammals. Terrestrial vegetation and fauna communities did not show patterns indicating elevated chemical exposure-related impacts. This finding was considered consis t ent with the relatively low levels and limited distribution of elevated chemical concentrations in soil, and the active and disturbed nature of thc site observed during the RI. Tier Ill investigations were not completed at this site but the COCs wcre carried over to the Basewide Tier 111assessment. A surface wat er drainage channel runs through and along the sou thern boundary of OU- i 2. This channel contains areas of wetlands. Remedial construction activities at OU-12 resulted in some reworking of soil and drainage channel relocation in the wetland areas . Replacement wetlands werc constructed near other Base lakes located in the center of EAFB. Remedial action was warranted for the hardfill based on the potential risk to human health from future releases of hazardous substances from the hardfill. Con t aminants in the hardfill may leach downward t o contaminate the underlying ground water. Off-Base residents may then ingest or come in contact wi th the cont a minated ground water. Also, the surface of the hardfill may erode, thus exposing off-Base residents to contaminants in bo th surface water and air. 3.13.4 Initial Resp o nse No CERCLA removal actions or o ther initial cleanup ac tions were performed at this OU. 3.14 FLI GH TLINE REFU E LIN G AREA The Flightline Refueling Area consists of three adjacent sites (originally designated SS-08, ST-10, and ST-14) surrounding seven jet fuel pump houses. The study area is located between the operable apron and the primary instrument runway in the central part of the Base (Figure 3-33).

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### 3.14.1 Physical Setting Soils at the site are described as typically consisting of tan, hard silty clay from 3 to 12 ft below ground surface, underlain by loose to dense clayey sands and gravels to sandy gravels ranging in thickness from approximately 5 to 15 ft. These sediments are typical of the relic channel deposits, which are presen t over portions of EAFB. Unconsolidated sediments are underlain by hard, gray to black weathered shale, which is typically present at depths ranging from 18 to 24 ft below ground surface. At an abandoned soil boring drilled approximately 50 feet northwest of Pump House No. 5, sands and gravels were not observed and weathered shale bedrock was encountered 8 ft below ground surface, suggesting a localized pinching-out of unconsolidated channel deposits in this area. Overall, the shale bedrock surface appears to slope t o the southeast. Depth to ground water typically ranges from 13 to 20 fi below ground surface. Ground water elevations in the wells indicate a gradient to the southeast, similar to the slope of surface topography. Ground water is present within the sand and gravel sediments approximately 2-5 ft above the weathered shale bedrock interface. 3.14.2 L and and Resource Use This area consists of a grassed field with three pump houses located east of the runway (Pumphouses 4, 5, 6, and 7 and their associated USTs have been removed). The area has been graded flat and matches the grade of the flightline. The only above-grade structures are the pump houses and adjacent piping controls associated with each pump house. The pump houses dispense JP-4 for aircraft refueling from underground storage tanks adjacent to each pump house. Previous fuel release incidents which occurred at all of the pump houses between 1972 and 1984 were reported in the IRP Phase I Records Search (1985), and sampling was performed during the IRP Phase II investigations (Stage 1-1987 and Stage 2 - 1989) which identified petroleum hydrocarbons in the soil and ground water samples. 3,14 . 3 H is to ry o f Contaminati o n The most commonly reported VOCs were benzene, ethylbenzene, and xylenes, with isolated occurrences of non-JP-4 related compounds (chloroform, methylene chloride, TCE, 1,1,1-trichloroethane, tetrachloroethylene, and l,l,2,2-tetrachloroethane). (Note that because some samples contained elevated petroleum hydrocarbon concentrations, which required sample dilution for analysis, the chlorinated VOC detection limits for some samples were greater than regulatory MCL.) TPH JP-4 (extractable and purgeable fractions) was reported in samples from 14 of the wells. The distribution of extractable TPH JP-4 in ground water samples at the time of the Corrective Action Plan investigation is shown in Figure 3-34. A summary of reported petroleum hydrocarbon compounds in ground water samples relative to the pump house locations is provided below: • Pump House No. 1 - Benzene (12 ug / L), ethylbenzene (16 ug / L), xylenes (1.3 ug / L), and purgeable TPH JP-4 (280 ug / L) were reported in the sample from well MW87CP01. Ethylbenzene (140 ug / L) and purgeable TPH JP-4 (1,300 ug / L) were reported in the sample from MW93CP 14. • Pump House No. 2 - Benzene (27 ug / L), ethylebenzene (270 ug / L), xylenes (210 ug / L), and extractable and purgeable fractions of TPH JP-4 (9,400 and 5,700 ug / L, respectively) were reported in the sample from well MW87CP02. Ethylbenzene (300 ug / L), xylenes (830 ug / L),Ellsworth Air Force Bas e Final F ive
- Year Review and extractable and purgeable fractions of TPH JP-4 (16,000 and 1t,000 ug / L, respectively) were reported in the sample from welt MW89CPI2. Purgeable TPH JP-4 (180 ug / L) was reported in the sample from well MW93CPI0. • Pump ttouse No. 3 - Benzene (26 ug / L), ethylbenzene (220 ug / L), xylenes (190 ug / L), and extractable and purgeable fractions of TPH JP-4 (5,300 and 2,600 ug / L, respectively) were reported in the sample from well MW87CP03. Benzene (620 ug / L), ethylbenzene (130 ug / L), xylenes (120 ug / L), and extractable and purgeable fractions of TPH JP-4 (30,000 and 12,000 ug / L, respectively) were reported in the sample from well MW89CP09. A concentration of I I0 ug / L purgeable TPH JP-4 was reported in the sample from well MW93CPI8. • Pump House No. 4 - Benzene (66 ug / L) and purgeable TPH JP-4 (180 ug / L) were detected in the sample from well MW87CP04. Ethylbenzene (6 ug / L), xylenes (14 ug / L), and extractable and purgeable fractions of TPH JP-4 (5,900 and 2,000 ug / L, respectively) were reported in the sample from well MW93CP20. Wells MW89CPI0 and MW93CP07 were not sampled due to the presence of LNAPL. • Pump House No. 5 - Benzene (190 ug / L), ethylbenzene (130 ug / L), xylenes (120 ug / L), and extractable and purgeable TPH JP-4 fractions (13,000 and 3,600 ug / L, respectively) were reported in the sample from well MW87CP05. Benzene (1,900 ug / L), ethylbenzene (140 ug / L), xylenes (500 ug / L), and extractable and purgeable fractions of TP[I JP-4 (9,200 and 10,000ug / L, respectively) were reported in the sample from well MW89CPII. Benzene (24 ug / L) and purgeable TPH JP-4 (540 ug / L) were reported in the sample from well MW93CP 1I.

• Pump House No. 6 - The purgeable fra ction ofT P H JP-4 was reported in the sample from well MW93CP06 at a concentration of 600 ug / L. • Pump House No. 7 - The purgcable fraction of TPH JP-4 was reported in the sample from well MW93CP15 at a concentration of 520 ug / L. Current contaminant concentrations are reported on Figure 3-35. 3.14.4 Initial Respons e No CERCLA removal actions or other initial cleanup actions were perfonned at this area. 3.15 OFF-BASE J P-4 SOUTH OF OPERABLE UNIT 2 3.15.1 Physical Setting Surface topography generally slopes in a southerly direction from the southern boundary of EAFB. Surface water flows through the off-Base area in a small stream originating from Pond 001. Stream flow measurements were conducted on July 21, 1993, at OU-2 surface water sample locations on this stream. The stream flow measurements indicate that this unnamed stream had an average discharge of approximately I. 14 cfs. The OU-2 stream flow measurements were measured during peak flow of a rain event. This stream ultimately discharges into Box Elder Creek.

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### 3.15.2 Land and Resource Use The off-Base area is a grass-covered pasture located adjacent to the south boundary of OU-2. The grasses are primarily crested wheatgrass and smooth brome. Wetlands in the area consist of a retention pond at OU-1 and its drainageway, which flows off-Base along the western edge of this study area. 3.15.3 History of Contamination JP-4 contamination caused by a leak in a fuel line was identified along the southern boundary of OU-2 in 1989. The fuel line was punctured during the Stage 2 IRP field investigations at OU-2. The 12-inch fuel line was shut off within 30 minutes and a trench was excavated to repair the line. Base records indicated fuel was recovered with buckets and rags. No record of the fuel volume leaked was reported. This JP-4 contamination is being remediated under the State of South Dakota petroleum release regulations. Total petroleum hydrocarbon, as jet fuel, was reported in soil samples at concentrations ranging from 170 to 2,000,000 ug / kg. The results indicated that the highest concentrations were in samples collected from moist sand and gravel deposits south of the landfill perimeter. Total BTEX in ground water samples was rep o rted at concentrations ranging from below de t ec ti o n l imi t s to 9 ug / L. Ground wat er samples were not analyzed for oil and grease or TPH during the RI investigations. However, data collected during the IRP Phase II investigation indicated that ground water samples had reported concentrations of 1 mg / L to 49 mg / L ofoil and grease. Plume concentrations are shown on Figure 3-36 3.15.4 Initial Response No C ER CLA re moval action s o r other initial cl e anup action s were comp l e t ed at th i s OU.

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- Year Review 4 .0 REMED IAL AC TI ON S 4.1 RE M E D Y SE L ECT ION This section describes the remedies selected at each of the 12 operable units. The remedies are summarized in "Fable 4-I . 4.1.1 O p e rable U n it ! Based on the requirements of CERCLA, comparative analysis of the nine criteria, public comments, and " in consultation with EPA and the Sta te, the Air Force determined that source area soil treatment and ground water treatment was the appropriate remedial action. This alternative includes institutional controls in conjunc t ion with physical modification of the OU to reduce potential risk. Major components of the remedy specified in the record of decision (ROD) were:

• C o ntinued operation of the remedial system instal led as part of the IRA which consists of (1) eight SVE wells to remediate a portion of the source area soils, and (2) four dual-phase ground water wells and all existing collection trench to remove contaminated ground water near the s ourc e are a • Instal l ation and operation o f four additional SVE wells, seven dual phase ground water wells, nine ground water extraction wells, and a dual phase extraction trench. • Treatment o f soi l g a s a nd contaminated ground water at the IRA treatment plant. Discharge of plant effluent to surface water, underground injection, or the Base wastewater treatment plant.

• Implementation of institutional controls (deed and l a nd use restrictions) to restrict the future use of the area while ti le remedy is being implemented. • Lo ng-term ground water monitoring to identify development of future risks associated with the OU. Long-term maintenance of the remedial actions. The objective of this a ltern a tive is to decrease soil contaminant concentrations within the burn-pit to the levels listed in Table 4-2 and to remediate the shallow aquifer to levels listed in Table 4-3. The area targeted for SVE is the burn-pit area (Figure 4-1). Additional SVE wells were placed in the bum-pit area to remove soil contamination that was not addressed in the IRA.

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### TABLE 4-1 SUMMARY OF APPLIED REMEDIAL ALT E RNATIV E S FOR EAFB Reme dial Action OU-1 OU-2 OU-3 ] OU-4 OU-5 I OU-6 [ OU-7 OU-8 OU-9 OU-10 t OU-11 [ OU-12 INSTALLED REMEDY No Action X5 X5 Soil Vapor Extraction X Ground Water Extraction Wells X X X X _ X Ground Water Extraction Trench X Monitored natural attenuation X Alternative water supply X Earthen Cover X X X X X X X Realignment of Storm-water channel X X Pre-Design study ,for landfill gas X X INSTITUTIONAL CONTRO L S Deed Restrictions 2 X X X X X X X X X X Continuing Order 3 X X X X X X X X X X Wetland loss mitigation X X Records Search / removal action 4 X Fencing X X X X X X x x x O PE RA TI ON / MAINTENANCE Long Term Operation / Maintenance X X X X X X X X NA NA X X Program Long Term Monitoring Program X X X X X X X X NA NA X X Notes: Extraction of ground water containing low levels of TCE was done as a voluntary removal and not a ROD requirement. z Deed restrictions would be placed on any property transferred from Air Force ownership-this has not occurred a t any of the areas listed above. 3 The continuing order is a Base Commander level directive specifying access and use restrictions on the OU areas. 4 This records search / removal action was related specifically to low-level radiological waste material disposal areas within the OU. Ground water extraction and monitoring at this site was deferred to OU 11 the Basewide ground water OU.

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### Ground water wells and a collection trench were installed to remcdiate the contaminated shallow aquifer at OU-1 to the levels listed in Table 4-3. The number and placement of wells and / or trenches was evaluated during system design. The ground water wells and the trench collec t and r e move contaminated ground water at OU-I (Figure 4-2). At the time of remedial design, the aquifer was expected to be remediated in 10-15 years. Extracted soil gas, condensate from the SVE wells, and ground water removed by wells and trenches contain VOCs and petroleum hydrocarbons. These contaminants are treated at the treatment plant buil t for the IRA. Treatment of the contaminated ground water consists of oil-water separation, filtration, air stripping, and liquid phase granular activated carbon. Soil vapor was originally treated in a thermal oxidizer, but concentrations decreased to a poin t where the soil gas could be discharged to the atmosphere without treatment. The thermal oxidizer has been removed from the sys t em. The treatment plan t effluent is discharged into a drainage, which flows into Pond 001, or back to ground water via one of two re-injection trenches. The effluent is monitored prior to discharge to de t ermine the effectiveness of the treatmen t system. Effluent discharge standards and monitoring were de t ermined during the design phase and are subject to State and EPA reviews and approvals. Institutional controls were implemented to prevent human exposure t o contaminated soil and ground water. These controls include: (1) issuing a continuing order (see Appendix C) to restrict on-site worker access to contaminated soil, and to restrict or con trol temporary construction activities unless proper protective equipment is worn; (2) filing a notice with the S t ate to recommend denial of water appropriation permi t applications to install ground water wells within the area of contamination and any area which may be effected by potential contaminants; (3) filing a notice to the deed detailing the restrictions of the continuing order and ground water well restrictions; and (4) a covenant to the deed m the e v ent of property transfer. Continuing Order requirements will be in effect as long as the property is owned by Ellsworth AFB and the remedial action has no t reached remediation goals. In the case of the sale or transfer of property within OU-! by the United States to any other person or en ti ty, the Air Force will place covenants in the deed which will restrict access and prohibit disturbance of con t aminated soils or the remedial action without approval of the United States. These covenan t s will be in effect until removed upon agreemen t of the State of South Dakota, the U.S. Environmental Protection Agency, and the U.S. Air Force or their successors in in t erest. The Air Force will also include in the deed the covenants required by section 120(h)(3) of the Comprehensive Environmental Response, Compensation and Liability Ac t (CERCLA), which include (1) a warranty that the United States will conduct any remedial action found t o be required by law after the date of the transfer; (2) a right of access on behalf of EPA and the Air Force or their successors in interest to the property to participat e in any response or corrective action that might be required after the date of transfer. The right of access referenced in the preceding sentence shall include the S t at e of South Dakota for purposes of conducting or participating in any response or correc tive action that might be required after the date of transfer. A maintenance program was established to ensure the long-term integrity of the removal and treatment system. The maintenance program includes development of standard operating procedures (SOPs) t o provide for inspections, repairs, and leak response actions. A long-term monitoring program was developed and implemented during remedial action and is subject to approval of bo th EPA and SDDENR. Con t aminant concentrations from the treatment plant vapor stream

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### and treated ground water are monitored to evaluate the effectiveness of the system in removing VOCs from the contaminated media. Contaminant concentrations in the burn-pit area and in the ground water are also monitored. Continued analysis and monitoring of the ground water remedial action system performance is conducted to determine if the remediation system is reaching the established clean up goals, is approaching an asymptotic level due to physical limitations of the site, or the benefits of the remedial action no longer justify long-term operation of the system. TABLE 4-2 O U-I CLEAN-UP GO A LS S oil s (ug / kg) Analy t e Clean-up Model Goal Esti m ates (° Basis 1 ,2 - D ichl oro e th yl e n e (1 , 2 -DC E) 41 41 . 4 Ground w a te r pro te c tion B enzene 10(2 ) 2.5 Ground water protection Tctrachloroethylene (PCE) 10 10.5 Ground water protection Trichloroethylene (TCE) 10(2) 3.3 Ground water protection JP-4 500,000 (3) - State Regulation Toluene 15,000 (3) - State Regulation Ethylbenzene 10,000 (3) - State Regulation Xylene 300,00013) - State Regulation Naphthalene 25,000 (3) - State Regulation Notes: (I) Based on SUMMERS Model (Summers, 1980). _2) When the model estimates are less than standard detection limits, remediation clean-up goals will be based on standard detection limits. (3) State of South Dakota Remediation Criteria for Petroleum Contaminated Soil, T ier 1 action levels at petroleum release sites, which would require a corrective action plan or Tier 2 analysis (ARSD Chapter 74:56:05)

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- Year Review TABLE 4-3 OU-I CLEAN-UP GOALS Ground Water (ug / L) Analyte C lean-up Goal Basis 1,2-Dichloroethane (1,2-DCA) 5.0 MCL 1, l-Dichloroethylene ( 1, I-DCE) 7.0 MCL 1,2-Dichloroethylene (1,2-DCE) 70.0 MCL 1,1,1 -Trichloroethane 5.0 MC L Benzene 5.0 MCL Tetrachloroethylene (PCE) 5.0 MCL Trichloroethylene (TCE) 5.0 MCL Vinyl Chloride 2.0 MCL TPH 10,000 State Regulation Ethylbenzene 700 MCL and State Regulation Toluene 1,000 MCL and State Regulation Xylene 10,000 MCL and State Regulation

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### 4.1 . 2 Operable Unit 2 Based on the requirements of CERCLA, comparative analysis of the nine criteria, public comments, and in consultation with EPA and the State, the Air Force determined that the appropriate remedial action for Landfill 1 was the placement of a soil cover and institutional controls. The selected remedial action for Landfill 6 was institutional controls. This alternative uses access restrictions, monitoring, and other controls to reduce potential risk. See Figure 4-3. For Landfill l, major components of selected remedy are: • Installing an earth cover over the area of attainment at Landfill No 1. ,, Institutional controls to restrict future use of the operable unit. • Realignment and lining of the storm-water channel. • Providing for long-term monitoring to identify development of future risks associated with the operable unit. Providing long-term maintenance for the remedial actions taken at the operable unit. For Landfill 6, major components of Alternative 2 are: • Institutional controls to restrict future use of the operable unit. • Providing for long-term monitoring to identify development of future risks associated with the operable unit. Providing long-term maintenance for the remedial actions taken at the operable unit. 4.1.3 Operable Unit 3 Based on the requirements of CERCL A , comparative analysis of the nine criteria, public comments, and in consultation with EPA and the State, the A ir Force determined that the appropriate remedial action was the placement of a vegetative soil cover. This alte rn ative includes institutional controls in conjunction with physical modification of the OU to reduce potential risk. Major components of remedy are: • Placing a soil cover, capable of sustaining perennial vegetation, over the landfill area. • A pre-design study to examine the need for landfill gas control measures. • Institutional controls for the landfill area. • Long-term ground water monitoring, and long-term maintenance of the soil cover. T

he final Remedial Action for OU-3 consisted of landfill covers and the installation of ground water monitoring wells. Four existing monitoring wells are sampled and analyzed for VOCs, PAtts, metals, and indicator parameters (Figure 4-4).

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- Year Review 4.1.4 O perable Unit 4 The sele ct ed a lterna tiv e for the landfi l l , s oil cov er, inclu des the tb ll ow i ng m a j o r co mpo n e nt s:

• In s titu tional control s fo r the lan dfi l l are a . • Placi n g a s oil cov er cap ab l e o f s u st ai n ing pere n ni al v e g e ta tion ov er the la ndfi ll are a . • Lan dfi ll ga s moni to ring an d p a ss iv e coll e c ti o n s y ste m , a s n e c ess ary.

• Long- term monito ri ng an d main te nanc e. The se l e ct e d a l t ernativ e fo r the ground w at er, p u mp an d tre at , inclu des the fo l l o w ing ma j o r c o m p on e nt s:

• Contin ued o pe ra tion of the ground w a ter ex traction w e ll s i ns tall ed a s p art of the int eri m re m edi al ac tion (I RA ), an d tre a tm e nt o f contaminat ed groun d w at er.

• I nstal l a tion of re cov ery tre nches a nd / o r a dd i tional ex trac tion we ll s to b e a dded to the ex i s ting I RA grou n d w at er re cov ery s y ste m . • Tre atm e n t o f rem ov e d ground w a ter a t the treatme nt p lant b uilt f o r th e IRA .

• Di s ch ar g e o f tre at e d ground w at er to a s urf ac e w at er d raina ge, to the Ba se w a s t ew ater tre atm en t p lant , o r b y un der groun d in je ction . The OU-4 system includes ground water extraction wells that were install ed a s a part of a 1995 IRA project and additional wells installed as part of the final RA in 1996. Since the completion of the RA construction, two additional ground water extraction wells have been constructed to optimize the system's effectiveness . The total system consists of 28 ground water extraction wells. It also includes the ground water treatment system in Building 6908, which was built as a part of the 1995 IRA project, and 12 monitoring wells (Figure 4-5). In-situ methods of ground water remediation are being evaluated at this site as described in Section 4.4.2. 4.1.5 Operable Unit 5 Based on the requirements of CERCLA, comparative analysis of the nine criteria, public comments, and in consultation with EPA and the State, the Air Force has determined that the selected alternative is Alternative 3, Vegetative Soil Covering. This alte rn ative includes institutional controls in conjunction with physical modification of the OU to reduce potential risk. Five-year reviews of the remedy will be required because potential contaminants will remain at OU-5 following completion of remedial action. The selected alternative, Covering, includes the following major components: • Placing a soil cover capable of sustaining perennial vegetation over the landfill area. • Institutional controls for the landfill area. • Long-term ground water monitoring; and, long-term maintenance of soil cover.

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### The final Remedial Action for OU-5 consisted of landfill covers and the installation of ground water monitoring wells . A total of four monitoring wells are sampled and analyzed for VOCs, metals, and indicator parameters (Figure 4-6). 4.1.6 Operable U ni t 6 Based on the requirements of CERCLA, comparative analysis of the nine criteria, public comments, and in consultation with EPA and the State, the Air Force determined that the appropriate remedy was the placement of a vegetative soil covering. This alternative included institutional controls in conjunction with physical modification of the OU to reduce potential risk. The se l ected alternative, landfil l cover construc tion, included the following major components:

• Installation of fencing to control physical access to the landfill area. Posting the area to indicate the landfill is closed to further use.

• Implementation of institutional controls (deed and land use restrictions) to prevent future use of the area for residential use and / or limiting its use to industrial uses.

• Providing a minimum of one foot of sustainable earthen cover over the area of attainment (approximately seven acres) . • Grading and contouring the area to maintain stability and route surface water precipitation away from previously active fill areas and prevent ponding of the water. • Extending an existing stormwater drain to the south and east of the landfill area to prevent the erosion of fill material and future potential contact with contaminated sediment. • Providing and maintaining suitable vegetation to enhance evapotranspitration and reduce infiltration and soil erosion.

• Mitigating any wetlands affected by placement of the cap.

• Prov i ding for long-term ground water, surface - wat er, and sediment monitoring at the OU to identify development for future risks associated with the OU. Providing long-term maintenance of the remedial actions taken at the OU. The final RA for OU-6 consisted of landfill cover construction and the sampling and analysis of four monitoring wells. The landfill cover const ru ction was completed in 1996, and sampling of the monitoring wells began in July 1996. Two wells were installed in July 1998 to better monitor downgradient areas of the landfill (Figure 4-7). 4.1. 7 Operable Uni t 7 Based on the requirements of CERCLA, comparative analysis of the nine criteria, public comments, and consultation with EPA and the State, the Air Force determined that the appropriate remedy was a combination of institutional controls for soil and institutional controls for ground water with additional

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- Year Review monitoring. T his alternative includes institutional controls in conjunction with comprehensive ground water monitoring and monitored natural attenuation to evaluate and reduce potential future risk. The following major components comprise the soil remedy: • Institutional controls for furore land use. • An cxtensive records search will be performed that may provide additional intbrmation relating to the burial trenches. A removal action might be used to address waste within the trenches if the weight of evidence from this records search combined with previous information identifies and warrants this type of remedial activity. The ground water remedy includes the following major components: • Institutional controls for ground water use. • Implementing a long-term ground water monitoring and maintenance program. The OU-7 remedial action consisted of a voluntary action to pump and treat trichloroethylene-contaminated ground water from an existing monitoring well at the northeast corner of the Weapons Storage Area. The RA includes sampling and analysis of 4 monitoring wclls for VOCs (Figure 4-8). 4.1.8 Operable Uni t 8 Based on the requirements of CERCL A , comparative analysis of the nine criteria, public comments, and in consultation with EPA and the State, the Air Force determined that the appropriate remedy for the EOD Area was the construction of a vegetative soil cover and application of institutional controls. Thc selected remedy for the Debris Burial A rea was also placement of a vegetative soil cover and application of institutional controls. For the EOD Area, components of the selected remedy are: • Constructing an earth cover o ver the EOD Area. • Institutional controls for the EOD Area. • Long-term sediment sampling. • Long-term maintenance of the earth cover. For the Debris Burial Area, components of selected remedy arc: • Constructing an earth cover over the Debris Burial Area. • Institutional controls for the Debris Burial A rea; and • Long-term maintenance of the earth cover.

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- Year Re v iew The OU-8 remedial action consisted of the placement of cover soils over two areas and the construction of one new monitoring well. In addition, drainage facilities in the area were re-constructed to form ru noff retention basins to retain any contaminated soils that may be carried offthe OU by runoff(Figure 4-9). A total of one monitoring wells will be sampled and analyzed for VOCs, explosives, and TPH-extractables to perform long-term monitoring of ground water. Sediment is sampled and analyzed at two locations for dioxins. 4.1.9 O perable U nit 9 Ba sed on the r e qui re m e nt s o f C ER CLA , p ub lic comm e nt s , and in con s ultation w ith E PA and the Stat e , the Air Fo rc e d e t ermin ed th at the app rop riat e r e m ed y fo r ground w at er an d the fi sh -ing es tion p athw ay at O U9 w ould be be tt er addr e s se d und er O U-I l , the Ba sew id e ground w at er OU. Groun d w at er c ontamination o riginat es up gradi e nt an d e xt e n ds be yon d the b oundari es of O U-9 an d w ould be mo re e ffici e ntly ad dressed concur r e ntly wi th other ar e a s of the Ba se a s p art of OU -1 I . The " No Acti o n " alt ernativ e w a s se l e ct e d a s the ap p ro p riat e r e m e dy fo r the re maining m e dia of conc ern: s urfac e w at er , s oil , and se dim e nt . No action i s w arrant e d whe n a si t e p o ses no unacc ep tab l e curr e nt or futur e thre at to pe o ple o r the e nvi ronm e nt, whe n CE R CLA do es not provi d e cl e anup auth o rity, or whe n a p r e viou s c le anup activi ty e limina te s the n ee d fo r futur e cl e anup . Unacc ep tab l e ris k to h uman he alth or the e nvironm e nt f rom the contaminant s r e lat e d to OU -9 do es not ex i s t . Cl e anup of pe trol e um-ty pe che mical s w ill be ad dresse d und e r Stat e of South Dakota pe trol e um re l e a se r e gulation s. Ba se d on the ab ov e conclu s ion s , no action w a s w arrant e d fo r so il , s urfac e w at e r, and sed im e nt at O U-9 . 4.1.10 Operable Unit 10 Ba se d on the re quir e m e nt s of C ER CLA , p ub lic comm e nt s, and in con s ultation w ith E PA an d the Stat e , the Air Fo rc e d e t ermin e d th at the app ro priat e re m ed y for groun d w at e r at O U-10 w oul d be b ett e r addr esse d und e r O U-11 , the Ba sew id e groun d w at er OU. Groun d w at er co n tamination ex t e nd s be yond the bo undari es of OU -10 an d w ould be mo re e f f ici e ntl y ad dressed concurre ntly w ith other are a s of the Ba se as part of O U-11. T he " No Action " alt ern ativ e w a s se l e ct ed a s the ap p rop riat e r e m ed y fo r the r e maining m ed ia of conc ern, s oil . No action i s w arrant e d whe n a s it e p os es no unacc ep tab l e cur r e nt o r future thre at to pe o p l e o r the e nvironm e nt, whe n C ER CLA d o e s not provid e cl e anup auth ori ty , o r whe n a pre viou s cl e anup activi ty e liminat es the n ee d fo r future c l e anup . The lo w l e v e l s of contamination in the s oil at O U-10 do not po se an unacc e ptab l e ri s k to h uman he alth o r the e nvi ronm e nt . Cl e anup of pe trol e um-ty pe che mical s w ill be addr esse d un der S tat e of S outh Dakota p e trol e um re l e a se re gulation s. Ba se d on the ab ov e conclu s ion s, no action was warranted for soil at OU-10. 4.1.11 Operable Unit 11 Ba sed on the r e quir e m e nt s of C ER CLA , comparativ e analy s is of the nin e crit eria , p ub lic comm e nts , and in con s ultation w ith E PA an d the Stat e, the Ai r Forc e de t ermin e d th at the ap p ro p riat e r e m e dy for ground w at er at O U-11 w ou l d be ground w at er ex traction and tre atm e nt w ith containm e nt . O U-II re m e dial alt ern ativ es were de v e lo pe d fo r A re a 1 an d A re a 2.

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- Year Review The selected alternative for Area 1 is ground water extraction and treatment with containment, including the following major components: • Removal and containment of ground water containing contaminants at concentrations above MCLs. • Ground water treatment and discharge. • Institutional controls and long-term monitoring. The selected alternative for Area 2, ground water containment / extraction and treatment, includes the following major components:• Ground water removal along the northeast Base boundary and at areas of high concentration onBase. • Gro und water treatment and discharge. • Monitored natural attenuation of off-base ground water. • Alternative water supply to off-base residents affected by contamination coming from the Base. • Additional investigation to determine the eastern extent of off-Base ground water contamination. • Institutional c o ntrols and long-term monitoring. Area 1 includes vacuum dewatering well points, ground water extraction wells and dual extraction wells to serve the Pride Hangar, Building 102, 30 Row, 50 Row, and the south end of the South Docks. Area 1 is served by the stand-alone treatment facility at FRA-PHI. This project includes daily operation of the Area 1 systems and quarterly sampling and analysis of 6 monitoring wells for TCE (Figure 4-10). Area 2 consists of the BG-04 / BG-04 West / BG-05 area at the northeast comer of the base, where a TCE plume has moved east off the base (Figure 4-11). The BG-04 / BG-04 West / BG-05 area includes 12 ground water extraction wells, with carbon or air stripping treatment. Effluent is re-injected into the ground water at BG-04 and BG-05; at BG-04 West, effluent is disposed via irrigation or discharge to the base sanitary sewer system. The project provides for the daily operation of the ground water extraction wells for containment at the base boundary in the BG-04 / BG-05 areas. Project also includes quarterly sampling and analysis of 10 monitor wells for TCE. The OU-I 1 system is expected to operate daily for a period of twenty years. 4.1.12 Operable Uni t 12 Based on the requirements of CERCLA, comparative analysis of the nine criteria, public comments, and in consultation with EPA and the State, the Air Force determined that the appropriate remedy for OU-12 was capping. This alternative includes institutional controls in conjunction with physical modification of the OU to reduce potential risk. Major components of the selected remedy are:

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• Install an earth cover over the area of att ainment at Hardfill No i. • Institutional controls to prevent future use of the area for residential use and / or limiting i t s use to industrial uses. • Developing a long-term monitoring and maintenance plan for the hardfill. The OU-12 remedial action included landfill cover soil construction at three separate areas within the OU (Figure 4-I 2). In addition, three monitoring wells are sampled and analyzed annually for VOCS, PAHs, and indicators. 4.1.13 Flightline Refueling Area The re m e dial action se l e ct e d for the flig h tlin e are a i s b a se d on the n ee d to m ee t the Stat e of South Dako ta pe tro le um re l e a se re gulation s. Re m ed ial action s at the fl ig h tlin e r e fu e ling are a con s i st of on e groun d w at er ex trac tion tre nch at Pump H ou se No . 1 , wh ich di s ch ar g es to the FRA Pumph ou se No . 1 tr e atm e nt s y ste m . It al s o inclu des tw o ground w at er ex traction wel l s at Pump H ou se No . 4 an d groun d w a te r co l l e c tion s umps a t Pumph ou ses 4 , 5 an d 6, wh ich di s ch ar g e to the tre a tm e nt faci l iti es at Building 6 908 . 4.1.14 Off-Base JP-4 South of Operable Unit 2 The re m e dial action se l e ct ed f o r the JP-4 p lum e w a s b a se d on the n ee d to m ee t S ta te of S outh Dakota pe trol e um re l e a se re gulation s. The JP-4 ex tra ction s y s t e m con s i s t s of e l e v e n dual p h a se ( w at e r / vap or) ex traction we ll s. Te n of the wel l s were in s ta l l ed in 199 6 an d on e in 1999 . Al s o , three s oi l vap or ex traction we ll s were in s tall e d in 1999 . The re m ed ial s trat e gy i s to contain the plum e and addr ess h ot sp ot s w ith in the p lum e. The dua l - ph a se ex traction we ll s were in s tal le d to r e cov er fr ee - ph a se product , impact ed ground w at er and s oil vap o r. Re cov ere d groun d w at er i s p um pe d to the c e ntral tre a tm e nt f acility in Building 6 908 . Th i s s y ste m ach i e v ed cl e anup goal s in 2 00 2 an d h a s bee n sh ut do w n s inc e th at tim e. 4.1. 1 5 North Docks The r e m e dial action se l e ct e d f or f ree - ph a se p roduct in the 8 0 R o w, beh in d D ock 74 , w a s total fl uids ext raction to re mov e the product . Tw o dua l - ph a se re cov e ry we ll s were plac ed and a p o rtab l e ex traction an d t r e atm e nt s y s t e m w a s o perat ed in 2 0 0 1 . 4.2 REMEDIAL AC T ION IMPLEMENTATION Info rmation on the imp l e m e n tation of the r e m ed i es at e ach o perab l e uni t i s s ummari zed in T ab l e 4-4 . A L TM Quali ty A ss uranc e Pro je ct Plan (QAPP ) h a s bee n imple m e nt ed for the p u rp o se of monitoring ground w at e r quality at El l sw o rth Ai r Forc e Ba se. The p lan outlin es monito ring we ll s, s am p ling p o i nt s, analytical p aram e t ers, and s amp ling s ched u les f o r all the Ope rable Uni ts at E li sw o rth Ai r F o rc e Ba se . Land f ill cov er in spe c tion s are al s o cov ere d in th i s p lan . Res ult s of the ground w at er s ampling an d land fi ll cov er in spe ction s are s ummari ze d in Long Term Monitoring Re port s s ub mitt ed to the USAC E, Ai r Forc e, S D D E N R, an d E PA on a quart erly b a s i s o r a s outlin ed in the SAP . The L TM QAPP f o r E ll sw o rth Ai r F orc e Ba se i s pe riodically re vi ewe d b y the Re m ed ial Pro je c t M anag er G roup. Ch ang es are periodically mad e in the SAP b a se d on res ult s f rom pre viou s s am p ling e v e nt s o r du e
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# 3 05 7 ff ff g, 00 ,Ellswo r th Air Fo r ce Base Final Five
- Year Review t o changing condi tions . In particular, samp l ing frequency and analytical parame t ers have been revised regularly. 4 .3 OPERATION AND M AINT E NA N C E ACTIVITI E S Operation and maintenance activi ties and down time are summarized in Sec tions 4.3.1, 4.3.2, and 4.3.3. In addi tion t o operation of pumping and extraction systems, implementation and / or modification of ins ti tutional con trols is a part of the Base operation and mainte nance program. 4.3.1 Operati o n an d Mainten a nce Pro ce dure s A System Operatio n and Maintenance (O&M) Plan is in place at Ellsworth Air Force Base which covers all operab l e uni t s that con t am ac tive remediation systems. The following t asks are covered in the plans: • Operating and maintaining the facilities within effluen t limitations. • Maintaining accurat e O&M records. • Comple ting and submitting required reports. • Ordering supplies, chemicals, replacement parts, and other materials required for facility operation. • Making regular rounds of facilities to ensure proper functioning of equipment. • Operating and adjusting facilities equipment and making required process adjustments. • Monitoring chemical storage tank levels. • Performing preventive maintenance and cleaning duties on facility process equipment, buildings, and grounds. • Performing preventive maintenance and cleaning duties on the ground water collection system (pumps, controls, and pipes), and the discharge system (controls and pipes). • Drawing samples for laboratory analysis and performing limited process control testing. • Maintaining and repairing process mechanical, electrical, and control equipment. • Planning, coordinating, and participating in major equipment overhauls. • Observing safety practices and being aware of chemical hazards, hazardous areas, and / or procedures. • Maintaining good public relations.

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### • Maintaining / renewing proper treatment plant operator certification. • Preparing budgets and annual reports. Four positions are staffed in order to perform these tasks. The position titles are Site Manager, Lead Operator, Operations Manager / Chemist, and Operating and Maintenance Technician. All operat ors have completed the 40-hour health and safety training required by OSHA 29 CFR 1910.120 and annual health and safety refresher courses as needed. Additional training, including additional safety training, is provided to O&M staff as needed. A review of the O&M manuals and procedures indicates that all manuals are appropriate for the systems installed and that all the procedures provide adequate guidance for the O&M of the systems. The O&M manuals have been updated periodically and will be updated again by October 2005.Ellsworth Air Force Base Final Five
- Year Review TA BLE 4 - 4 REME D Y I MPLEMENTATION Eilsworth Air Fo rce Base, South Dako ta R em e dia l D e s i gn C on stru cti o n Peri o d Av era g e Grou n d M a s s R e mov a l Water Pumping Ground Other Comments Dat e of ROD Remedial System Components Air Operable Unit Signatu r e S t a r t Comp l etion S tart Comple ted Rates Water (gpd) (lbs) ( Ibs) OU-I IRA August 199 5 January 1995 June 1995 4 DWs j June 1995 August 13, 1996 NAi_I NA_3_ NAi3_ 8 SV E 2 Wells 1 SVE Blower Remodeling of Buiiding 6908 and conversion of building into a CTF 3 for treatment of contaminated soil vapor and ground water . ICs OU-4 IRA August 1995 January 1995 July 1995 10 EWs 5 June 1995 August 13, 1996 NA ( 3_ NA_3! NA t 31 Offsite EWs (3)were ICs installed in June 1997. Six EWs shut down Febmar' / 2003. FRA Pumphouse NAc, January 1995 July 1995 2 EWs June 1995 August 13, 1996 13 , 000 NA_ 1 22 1 No. 4-IRA ICs 3 Sumps December 2 003 May 2004 NAI__ NA NA (_I FRA Pumphouse NA/L_ January 1995 July 1995 I EW June 1995 August 13, 1996 8,000 to t trench NA_a_ NA_. , _ EW shut down No. I-IRA I Ground Water Extraction Trench March 2000. Ground Water treatment building for treatment of contaminated ground water, Institutional controls

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i nal Five
- Y e ar Review TABLE 4-4 RE M ED Y IM PL E ME N TA TI O N E llsworth A i r Force Base, Sou th Dako t a Remedial Desig n Cons truction Period Average Ground Mass Removal Operable Unit Date of ROD Remedial System Components Water Pumping Ground O th er Comments Signature Start Completion Start Comple ted Ra t e s Air Water (gpd) (lbs) ( lbs) OU- 1 Final Remedy M a y 1996 November 1995 June 1996 12 EWs July 1996 June 6, 1997 11,000 62,000 2,500 Two Ews shut down (FR) 10 DWs January 2005. I Dual phase extraction trench 4 SVE wells Soil vapor extraction building Modifications to CTF Fencing to restrict access to OU ICs NA NA Biotreatment of soils. August 1997 November 1997 NA<21 NAI 2 / NA< 2 / NA NA Installation ofPZs_and MWs for August 1998 September 1998 NAI 2 _ NA_2_ NAt2) LTM 7. NA NA Long-term monitoring program. April 1998 Ongoing NA( 2 1 NAI2/ NA/2 I Installation of 2 Ews July 2003 Novem b er 2003 NAI31 NAI_/ NAI__ Installation of 3 Ews March 2004 September 2004 NAt31 , NAI31 NAI3/ DU-2 May 1996 November 199 5 April 1996 Landfill cap. June 1996 May 1, 1997 NA( 2 ) NA<2) NAI2! F

encing to restrict access to OU November 199 5 April 1996 Construction of draina_ , e channel June 1996 October 1996 NAI21 NAI 2 / NAt2 / October 1996 June 1997 LLRW _excavation and disposal July 1997 January 1998 NA( 2 / NA< 2 _ NA/, _ NA NA C hemical Weapons Material August 1997 February 1998 NAI2/ NAt2 1 NA¢ 2 ) !xcavation and disposal LTM program. April, 1997 Ongoing NA/2 / NA( 2 _ NA{2/ IlCs OU - 2 J P -4 NAI]_ November 1995 April 1996 Offsite easement. June 1996 December 1996 Shut Down 23,78 5 424 10 DWs in JP-4 Area. SVE blower building ICs

DW in JP-4 Area February 1998 NA o l NAc_ NAI3_ 3 SVE wells in JP-4 Area OU-2 JP-8 NAo_ JP-8 Excavation November 1996 November 1997 NA/_ NA(3, NA_ 2 SVE wells in JP-8.Ellsworth Air Fo r ce Base Final Five . Year Review TABL E 4 - 4 RE MEDY I M PL EME NT AT IO N Ellsw o rth Ai r Fo rc e B as e, S o u th Dakot a Remed i al D e s ign C o nst r uc tio n P e riod Av e rage G ro und Ma ss R em ov a l Op e rab le Uni t Da te o f ROD R emedial S y s te m Componen ts W a ter Pumping G ro u nd Oth er Comm e n ts Signa tu re S tar t C o mpletion St art Comple ted R ate s Ai r Water (Ib s ) (gpd) ( Ibs) OU - 3 June 1996 ' Landfill Cap Jun e 1996 May 1997 'NAt2! NA;> NA_ :

_ LTM Program April 1997 Ongoing lCs OU-4 FR May 1996 November 1995 July 1996 Landfill Cap June 1996 December 1996 4,000 NA < > 50 Two wells shut down in Property Acquisition 2004. 9 Ews Additional Investigation Fencing to restrict access to OU ICs MWs and PZs for LTM July 1998 September 1998 NA_:/ NA_2/ NAI 2) 2 EWs September ]999 December 1999 NAi,} NA!!I NA,_i MWs and PZ for LTM LTM program. April 1997 On_oin_ NA/: I NAI21 NAi 2 / MWs, TMWs, TIWs for 2003 May 2005 Treatability Study OU-5 November 1995 June 1996 Landfill Cap June 1996 May 1. 1997 NA/ : / NA ¢ :! NA < > Fencing to Restrict Access to OU LTM Program April 1997 Ongoing ICs OU-6 October 1995 January I995 August ]995 Landfill Cap November 1996 July 1996 NAc:I NA _. ' i NA_:_ Fencin_ to Restrict Access to OU MWs to mon i tor e ffectiveness of July 1998 Augus t 1998 NA!:/ NAI:_ NAi:> cap. LTM progra m. July 1996 Ongoing NA(2/ NAi:_ NAI:_ iCs OU - 7 June 1996 October 1996 June 1997 Removal of LLRW August 1997 January 1998 NA/2i NAI:_ NA_:_ Monitoring wells for NA monitoring Monitored natural attenuation October, 1998 Ongoing Monitoring ICs

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# 30 5 7 067Ell s worth Air Force Base Final Five
- Year Review TABLE 4-4 REMED Y IMPL EMENTA TI ON Ellswo rth Ai r Fo rce Base, S ou th Dakota Remedial Desig n Construction Period Average Ground Mass Removal Operable Unit Date of R OD Remedial Sy s tem C omponen ts Water Pumping Ground O t h er Commen ts Signature Start Comple tion S tart Co mple ted Ra tes Air Water (gpd) (Ibs) (Ib s ) OU-8 June 1996 November ]995 June 1996 Placement of Soil Cover June ]996 June 1997 NAI: _ NA/2 ) NAi 2 / Long Term Monitoring Program ICs April 1997 Onl_o!n _ OU-9 May 1996 NA NA No Action ROD NA NA NAI2_ NAI2) NAI 2 ) ICs OU- I 0 May 1996 No Action ROD NA{ 2 ) NAI 2 ) NAI2 ) ICs DU-II Apri l 1997 July 199 8 Septe mb er 1998 Off- B ase water l i n e S epte mb er 1998 Ongoing N A _2_ N A( 2_ N A( 2 ) !Off-Base Additional investigation (AO C 24) September 1997 LTM program Ongoing Installation of MWs to monitor _lume ICs OU-11 November 1996 June 1997 Installation of 4 Ews April 1997 January 1998 12,000 NAI2_ 10 Two Ews shut down BG04 Base Boundary Installation of ground water May 2005, reinjection gallery Installation of ground water treatment building ICs Installation of MWs and PZs to April 1997 December 1999 NAI2_ NA( 2 ) NA_._ monitor extraction system performance OU-I I November 1996 June 1997 Installation of 3 EWs April 1997 January 1998 88,000 NA(2) 22 BG05 Base Boundary Installation of ground water reinjection gallery Installation of ground water treatment building ICs Installation of MWs and PZs to April 1997 January, 2000 NA/3_ NA_3/ NA(3) monitor extraction system _erformance Installation of 4" EWEllsworth Air Force Base Final Five
- Y e ar Review 

### TABLE 4-4 REMEDY IMPLEMENTATION Ellsworth Air Force Base, South Dakota
R em e dial D e s i gn Cons tru c tion Period Averag e Gro u nd Mass Re m oval Operable Uni t Dat e of ROD Remedial S ys tem Components Wat er Pumping Ground Other Comments Signa t ure Start Completion S t art Comple t ed Rates Air W a t er (Ibs) (gpd) (Ibs) OU-II April 1997 November I996 March 1997 Installation of 4 EWs April 1997 Januar y . ' 1998 16,000 NAi3) 37 BG04 West Installation of ground water treatment building I C s OU-II November I996 March 1997 !Installation of 6 EWs April I997 January 1998 61 , 000 NA_2) 2,970 SVE portion of DWs South Docks Main ilnstallation of 4 DWs taken off line. Three Modification of the Pumphouse DWs shut down July No. 1 treatment building 2003. SVE blower ICs Installation of 2 EWs July 2003 November 2003 NA(_/ NA ?/ NAI_/ OU-I 1 November 1996 March 1997 Installation of 3 EWs April 1997 January 1998 NAi_/ NAIl/ NA_ 30 Row ICs OU-11 November 1996 March 1997 Installation of 3 EWs April 1997 January 1998 NA/3> NAI__ NAI3_ Shut down July 2003. 5 0 Row ICs OU-I1 November 1996 March 1997 Installation of 9 WPs April 1997 January 1998 25,000 NA NAi_/ System shut down Building 102 nstallation of vacuum and transfer August 2002. pumps in a concrete vault ICs OU-11 November 1996 March 1997 Installation of 9 WPs April 1997 January 1998 63 , 000 NA NAI_! Shut down 3 WPs in Pride Hangar Installation of vacuum and transfer 2003. pumps in a concrete vault ICs Installation of eight SVE wells June 2004 Janua ry 2004 NA 35 NA System shut down November 2004.Ellsworth Air Force Base Final Five
- Year Review 

### TABLE 4-4 REMEDY IMPLEMENTATION Ellsworth Air Forc e Bas e , S ou th D akota R emedial Desi gn Constructi on Period .... Average Ground Mass R emoval Operab le U n it Date of R OD Remedial System Componen ts Water Pumping Ground Oth er Comments Signa ture S tart C o mple tion S tart Comple ted R a tes Air Wa ter (gpd) (lb s) (lbs ) OU-I 1 NAI_I November 1996 June 1997 5 WPs May 1997 November I998 1,200 20 System shut dowr North Docks 60 ROW Vacuum pump m 1998. Mobile treatment system ICs Pump House I FP September 2001 April 2002 8,000 946 1 System shut down' in 2003. OU- 12 May 1996 November 1995 June 1996 E arthen cover over hard fill June 1996 May 1, 1997 NAI21 N AI21 NA(2_ LTM program April t997 Ongoing ICs DWs = dual extraction well, w / soil vapor extraction and ground water extraction systems i nstalled . SVE = soil vapor extraction well. CTF = central treatment facility. ICs = institutional controls. EWs = ground w ater extraction well. PZs = piezometer well. LTM = long term mon i toring. LLRW = low level radiological waste . WPs =vacuum dewatering well po i nts. NA = Not Applicable, NA(ll = Not Applicable - Non CERCLA Action . NA_2)= Not Applicable - No Soil Vapor / Ground water is extracted , NA(31= Not Applicable - Components incorporated into existing system, HA(4)= Not Applicable - IRA in c orporated into Final Remedy System,

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### 4.3.2 S u mmary of System Down time a nd Operation and Maintenan c e Iss u es Table 4-5 summarizes all major system downtime and operation and maintenance issues. 4.4 SYSTEM OPTIMIZATION The Ellsworth Air Force Base ERP team continually reviews the operational effectiveness of the remediation systems. Optimization measures are implemented to maintain or improve the systems' effectiveness. This section summarizes optimization actions at 

### the sites where remedial systems are in operation. Optimization actions which have been implemented since the year 2000 and which affect all of the operating sites included the following: • Installation of remote monitoring capability for the sites. This allows more economical monitoring of system operations from a central location. • An interactive voice response and alarm system was installed at all of the sites, allowing more rapid response to alarm conditions in mechanical or electrical equipment. • Ground water extraction wells are evaluated every 1 to 3 months for production and drawdown; selected wells are re-developed to maximize ground water production and aquifer drawdown. • The LTM program at each site has been reviewed every one to two years; the programs have been optimized and reduced in terms of frequency of sampling and number of analytes sampled and reported. 4 . 4.1 Operable Unit 1 Two additional ground water extraction wells were constructed in the southeast area of this operable unit in 2003 to improve capture of the ground water plume and increase the recovery of free product. Selected ground water extraction wells in this OU have been deactivated when ground water contaminant concentrations have been reduced below regulatory levels. One of the SVE blowers at this site was shut down, since SVE performance could be maintained by a single blower at a substantial savings in electrical consumption and maintenance. Periodic hydrogen peroxide backwashing of the liquid-phase granular activated carbon filters was initiated, to reduce biofouling of the filters and increase their usable life and efficiency. Free-product depth is measured quarterly to optimize product recovery and monitor plume characteristics. Current sensors were installed in the ground water extraction wells to allow increased recovery of free-phase product in these wells. Re-injection trenches were installed to allow injection of treatment plant effluent back into the ground water, eliminating a problem with surface discharge of effluent containing high concentrations of selenium. Quarterly sampling of soil vapor is performed to allow shutdown of clean SVE wells and concentration of SVE system performance on contaminated areas. The SVE system is monitored quarterly to detect pipe blockages resulting from condensate, which is removed as necessary to maintain optimum operation of the system. All of these measures have been implemented in the period since 2000.

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### 4 . 4.2 Operable Unit 4 Two additional extrac tion wel l s were placed i n this operable unit to increase capture in the n ortheas t area of the plume (pre-2000). Seven ex traction wells in the northern and western portion of the plume were shut down when contaminant levels were reduced below regulatory levels. An existing extraction well in the southern portion of the plume was replaced with a new well in a more favorable geologic location, which has increased ground water production and enhanced plume containment. A treatability study is being performed at this site to determine whether an innovative in-situ remediation method (reductive biodechlorination) can be more cost-effective than ground water pump-and-treat. The study involves injection of substrates such as vegetable oil and sodium lactate to foster the growth of anaerobic bacteria that break down chlorinated solvents (such as TCE) into harmless compounds. Initial work at the source area within the landfill showed positive results. The treatability study has been expanded to the ground water plume south of the landfill. One of the primary goals of the study in this area is to determine whether reductive biodechlorination can be achieved in areas where the contaminant concentration is quite low (<25 ppb) and pump-and-treat technology is limited by a thin aquifer. Column studies are also being performed in the laboratory at the site, using native soils and ground water to evaluate the effectiveness ofreductive dechlorination under controlled conditions and low concentrations . These OU-4 measures have been implemented since the year 2000 except as noted. 4.4.3 O perable Unit 11 Liquid-p h a se granular activat e d c arb on filt ers a t FRA
- P H1 were de activat ed a fter it w a s d e mon s trat e d th a t s ati s facto ry tr e atm e nt could be ach i e v ed w ith ai r s tri ppe r s alon e. Th i s produc ed a s aving s in carb on co s t s and in r e du ce d op erator lab o r f o r re gular carb on s y s t e m b ackw a sh ing an d rep lac e m e n t. An a dd itiona l ex traction we ll w a s p lac ed in the B G -0 5 s y s t e m to i ncre a se p lum e cap tur e at the b a se b oundary. T hree w e ll s in the Pri de Hangar s y s t e m were sh ut do w n whe n the contaminant l eve l s d e cre a sed below regulatory levels. The Building 102 system was shut down when the contaminant levels in the area were reduced below regulatory levels. Three extraction wells in the South Docks Main system, and the wells in the 50 Row system, were shut down when the contaminant levels were reduced below regulatory levels. An irrigation system was established at the BG-04 West system to allow productive re-use of treatment plant effluent, reducing the cost of disposal of this effluent in the base sanitary sewer system. In-situ reductive biodechlorination, involving injection of vegetable oil or sodium lactate substrates, is being implemented at a ground water hot spot at the northwest corner of the Pride Hangar. Four monitoring wells located outside the Pride Hangar are used for monitoring and for substrate injection. On a weekly basis, approximately 1 00 gallons of a 1,000-2,000 mg / L sodium lactate solution are injected into each of the four monitoring-injection wells. Three monitoring wells located inside the Pride Hangar , plus three monitoring wells outside the hangar, are used for monitoring. The monitoring wells were sampled prior to the start of injection in May, 2005, and will be sampled every two months for the 12 month duration of the test. Analytes include VOC, COD , sulfate, pH, conductivity, and oxidation-reduction potential (ORP). Selected samples are analyzed for dissolved gasses (ethane, ethane, methane, and acetylene) as well on a four-month schedule. A small SVE system was installed to address soil TCE contamination in this same area. These OU-I 1 measures have been implemented since the year 2000. All ground water issues from the other operable units have been shifted to OU-11 for ongoing long-term monitoring and remedial action operations

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# 3 0 57 0 7 2Ellsworth Air f 'b rce Base Final Five
- Year Review 4.4.4 JP -4 This system was shut down whcn ground water and soil contaminant levels were reduced below regulatory levels. 4.4.5 Flightline R e fu e ling Area Free-product removal was pertbrmed at the Pumph o use 1 area in 2002-2003, using a portable system, and resulted in the elimination of free product in that area. Ground water and free-product removal systems were installed at former Pumphouses 4, 5, and 6 when tile buildings were demolished and their associated underground storage tanks were removed in 2003-2004. 4.4.6 North Dock s Gro und water and free product recovery was performed at 80 R o w (near Dock 74) in 2001 using a portable system. The site continues to be monitored. An automated free-product recovery system will be installed at this location in Oc t ober 2005.

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### T ABLE 4-5 SUMMARY OF OPERATIONAL DOWNTIME AND OPERATIONS AND MAINTENANCE I SSU E S Ellsworth Air Force Base, South Dakota
Operable Uni t Problem Descrip t ion Resolu t ion Date o f 

### Date of I I

• Iden t ification Res o luti o n I No tesComm en t s OU-1 Wellfield 1. Biosolids from EW and DW wells were 1. Reconditioned two wells with acid in 1998 , 1. 6 / 98 & 2 / 00 1. 9 / 98 & 2 / 00 1. Well field trends are continually being fouling treatment equipment in CTF redeveloped rest of well field in 1998 and 2. 7 / 98 2. 9 / 98 monitored to determine when well 2. Inadequate number placement ofwellfield 2000 3. On-going On-going redevelopment is needed monitoring points 2. Added monitoring points to monitoring 4. 7 / 21 /

99 7 / 29

/ 99 3. Low flows fromwellfield network 5. 1 / 27

/ 99 2 / 5 / 99 4. Problems with pumps and controllers 3. See above note 5. Potable waterline break repair resulted in 4. Ongoing maintenance / preventative wellfield shut-down maintenance program 6. Motor starters burned up at extraction wells 5. Repaired waterline and re-started well field 6. Replaced motor starters at 16 wells 6908 C T F 1. Selenium exceedance in plant effluent 1. Increased frequency of plant effluent 1. Plant start-up 1. On-going FRA-PH4, 1 /10 / 99' to 1 /19 / 00 for 2. SVE Blower damaged due to scale build-up in sampling, investigated wellfields, shut down 2. 2 / 23/

98 2. 5 / 28

/ 98 Honeywell controls change-out blower housing selected wells intermittently 3. 7 / 98 3. 6 / 4 / 99 2. JP-4, 1 /14 / 00 to 1 / 21 /

00 for Honeywell 3. Problem with communication and controls 2. Repaired blower, revised inspection schedule 4. 6 / 20

/ 99 4. 6 / 25

/ 99 controls change-out between 6908 and FRA-PH4 3. Checked cable splices, replaced a section of 5. 1999 5. I / I0

/ 00 3. 6908 CTF, 1 /11 / 99 to 1 / 25

/ 00 for 4. Problems with air stripper blower motor cable, completed controls changes 6. 1999 6. 5 /18

/ 00 AI Winland incident. 5. Problems with controls for OU-1, OU - 4, JP-4, 4. Repaired air stripper blower motor 17. 7 /18

/ 00 7. 7/28 / 00 4. Site was down from 5 /18 ,/ 99 to 6 / 4 / 99, FRA-PH4, and 6908 5. Replaced Allen Bradley controllers with 8, 1 /10 / 02 8. 1 / 23/

02 problem with controls displaying incorrect 6. Cost for injecting Aquamag sequestering Honeywell controllers 9. 2002 9, 2002 site status from 7 / 98 to 6 / 4 / 9 agent, introducing phosphates to surface water 6. Replaced Aquamag with magnetic resonance 10. 2002-2004 i10. 2003-2004 5. Significant LTO cost reduction with 7. Control BUS failing periodically units 1, 2004-2005 11. 11 / 4 / 05 similar results 8. Scale accumulation in process piping, caused 7. Replaced comm. Card for JP-4 site and 6. Also cleaned other sections of piping. pressure backup repaired comm. Line 7. Significant savings in utility costs and gas 9. High utility cost to operate building 8. Replaced section of piping, flushed valve usage for building heat ventilation system 100% of time while rack 8. USAF personnel replaced with occupied 9 . Modified make-up air unit and reduced USAF equipment 10. Continued selenium exceedance in plant operation of ventilation system during effluent unoccupied time 1, Periodic problem with modem connections for 10. Construct two reinjection trenches for plant

dial-up sites effluent 1. Replaced modems with hard-wire

connections OU-I SVE System 1, Blower motor failed 1. Motor repaired 1. 7 / 2 / 01 I. 7 / 26

/ 01 !2. On-going operational issue, system 2. Water in SVE piping 2. Removed water from pipin_ with compressor 2. 1 / 28

/ 04 2 , On-going checked quarterly£11sworth Hip" F o rce Base Final Five -Y eur Review TABLE 4-5 SUMMARY OF OPERATIONAL DOWNTIME AND OPERATIONS AND MAINTENANCE ISSUES Ellsworth Air Force Base, South Dakota I Operable Unit Problem Description Resolution Date of 

### I Date of Notes / Comme n ts Id enti fic ation 

### R e so luti o n I OU - 2 Landfill Cap MinorMinorsettl e menter°si°nin coVeraboveandwastealongtre nches.Westditch, withEr°si°nalsoil, reas repaired. Settling areas re-filled 4 / 99 10 / 99 Movement of TCE plume across the south base Installation of three extraction wells to contain boundau. T CE _round water plume,

, lP-4 Site 1 . DWJP06 damaged (near free p roduct plume ) 1. Used DWJP 06 as tempo rary SVE well 7/97 1. 3/9 8 2 , Site was operated during manned hours 2, Problem with commurucation system between 2. Replace portion of communication cable, 2, 7 / 9 / 98 2. 9/23/ 98 during problem period 6908 CTF and blower building replaced modem at JP-4 site 3, 6 /14

/ 00 3. not resolved 3. Transfer pump prime o / ten lost so pump 3. Bl owe r vap o r li qu i d separat or fre quent high 3 , not re so lv e d 4, 5 / 3 b '0l 4 , I 1 /1 2/ 01 o ccas io nal ly t i: ile d level 4. Shipped blower for repair and maintemmce 4. B lower fail e d JP-8 Sp i ll Site JP-8 spill immediat ely south of OU-2 landfill Excavated all access ibl e contam i nate d soil, Remediation completed and wells were take n installed _ 'o SVE wells to cleanup residual soil off line contamination, connected to JP-4 SVE OU-3 Landfill Cap Lands l ide from OU - 5 affects north edge of cover Repairs planned 2 / 00 :Onl_oin_ .... OU
- 4 Landfill Cap None noted. We llfie l d I. L ow flows f ro m weHfieM I, Redevel o ped s eve ra l ex tracti o n wel l s in 1 9 9 8 1, 6 /9 8 & 2,/00 I 1. 9 /9 8 & 7 /00 and 2000 2, 9 / 99 2. I / 5 / 00 OU-5 Landfill Cap Landfill cover subsidence and landslide Repaired subsidence cracks in cover two times in 10 / 96 Ongoing 1997 and 1998. Installed underdrains to con t rol ground wa ter pore pressure in 2001. OU-6 Landfill Cap None noted OU-7 Ground Water Plume expanding Continued moni toring Ongoing Edge of Plume is not near base boundary . ' Monitorin_ OU-8 L an dfill Cap S o il c o ve r d i s tu r bed by Ai r F orce p er s o n n el du ri ng ISoH co ve r repa ire d, new sig n age, rest r i c ted area 9 / 99 0/99 ordnance disposal activities map developed, training, Base Continuing Order Pra irie do kz sencroachinl_ on Debris Burial Area. Reissued. OU- 9 No ac tion R O D OU- 10 No action RODEllsworth Air Force Base Final Five . Year Review TABLE 4- 5 SUMMARY OF OPERATIONAL DOWNTIME AND OPERATIONS AND M AINTENANCE ISSUES Ellsworth A i r Force Base, South Dakota Op erab l e Unit Pro b lem D escription R es o luti o n D a te of Da te o f Notes / Comments Iden t ification 

### R es o lution OU - I I Pump house No. 1 1. Problem with oil / water separator transfer 1. Converted oil / water separator to a reservoir l. Start-up 1. 12 /1 /

98 1. Hole was cut in the oil / water separator Treatment Building pump short-cycling which reduced cycle frequency of the transfer 2. 1 2/ 97 2. 2 /18

/ 99 int erior wall to convert it to a reservoir, no 2. Problem with solids from transfer piping pump 3. 1999 3. 1 / 21 /

02 free product had been collected from the passing through process equipment when i 2 . Placed franc tank in treatment system to drop system since start - up Pride Hangar system operated w i th more than out solids from transfer piping, removed bag 2. Frac tank in place from 10 /14

/ 98 to one transfer pump filter system and carbon units from treatment 12 /1 /

98, removed bag filter system and 3. Cost for injecting Aquamag sequestering process carbon units from treatment process on agent , introducing phosphates to surface water 3. Replaced Aquamag with magnetic resonance 2 /18

/ 99 OU-I 1 unit South Docks Main Problem with SD SVE heater contactor caused Replaced transfer pump and replaced heater 3/ I 0

/ 98 4 / 8 / 98 building to freeze and transfer pump to crack contactor 30 ROW None noted 50 ROW None noted B uilding 10 2 Vacuum 1. Problem with transfer pumps overheating 1. Inspected motors, serviced pumps 1. 6 / 25

/ 99 1. 7 / 5 / 99 2. Problem with pumps observed to occur Pump 2 . Problem with vacuum pump motor 2. Replaced motor 2. 5 / 20

/ 00 2. 6 / 6 / 00 with high ambient air temperatures 3, Vacuum pump frequently over-heated 3. Routed ventilation to vacuum pump cooling 4. 4 / 00 4. 4 / 00 4 . Allowed vacuum pump to operate within 4. Continued problem with vacuum pump over- fan 4, 2000 4. 7 /11 / 01 normal operating range for temperature heating 4. Replaced heat exchanger with system that 5, 9 / 21 /

01 5. I 1 / 7 / 0 1 5. Water on floor & vault circulates process water 6. 2 / 4 / 02 6. 2 /14

/ 03 ! 6. Scaling of vacuum pump cooling system 5. Placed backflow prevention valve on pump piping discharge piping and placed solenoid valve in cooling circulation piping 6. Installed access and drains to allow acid circulation throul_h coolin_ system pipin_ Building 102 None noted. Wellfield

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Date of" 

### D ate of No tes / Comments Operable Unit Problem Description Resoluti on Identification Resoluti o n

Pride Hangar Vacuum l. System operated with only one transfer pump 1. Place frac tank in treatment system to drop Start-up 1. 10 /14

/ 98 1. Site able to operate with more than one Pump due to problems at FRA-PH 1 treatment plant out solids from transfer piping to allow Pride 2. 7 / 6 / 99 2. 8 / 31 /

99 transfer pump after frac tank was placed on when more than one transfer pump operated Hangar system to operate with more than one 3. 4 / 00 3 . 4 / 00 I0 / I 4

/ 98, the frac tank was removed on 2. Problem with vacuum pump motor transfer pump 4. 2000 4. 6 / 22

/ 01 12/1 / 98 3. Vacuum pump frequently over-heated 2. Repaired motor two times 5. 2 / '4 / 02 5, 2 /14 ,/ 03 2. Site was down from 7 / 6/99 to 7 / 29

/ 99 and 4. Continued problem with vacuum pump over- 3. Routed ventilation to vacuum pump cooling 8 / 4 / 99 to 8 / 31 /

99, intermittent operation heating fan from 7 /'29 / 99 to 8 / 4 / 99 5. Scaling of vacuum pump cooling system 4 . Replaced heat exchanger with system that 4. Allowed vacuum pump to operate within piping circulates proccss water normal operating range for temperature 5. Installed access and drains to allow acM circulation throu_,h coolin_ system piping Pride ttangar Weflpoint SDPHWP01 was damaged by ' Wellpoint was replaced 1 / 99 1/99 Wellfield contractor OU-I I BG04 West Problem with motor for air stripper transfer 1. R eplaced electrical components including 3/16 / 00 4 / 28

/ 00 Site was down from 4 /16

/ 00 to 4 /2 8

/ 00, Treatment System pump and motor starter for transfer pump motor starter, repaired transfer pump motor 2. 4 / 8 / 01 2 . I 1 /2 9 / 02 intermittent operation from 3/16 / 00 to 4 /16 . '00 2. Continued problem with transfer pump motor, 2. Electrician replaced motor circuit protection 3. [ 1 / 29/02 3. 1 / 20

/ 03 had to replace motor three times 3. Placed tank to reduce pump/motor cycles 4. 9/03 4. 5/05 3. Transfer pump motor 4. Replaced valve with bronze valve 4. Three-way PVC valve for irrigation system frequently stickin_ in one position BG04 West Wellfield Chattering of motor starter for extraction ' , , ', ' ell I. Electrician replaced transformer in well 2 /26 / 0 2 5/14 / 02 control panel BG04 Base B oundary None noted Treatment Svstem BG04 Base Bounda W None noted Wellfield BG05 Base BoundarylNone noted Treatment System BG05 Base Boundary, 1. Capture of TCE plume on north end 1. Placed fourth , , ,,'ellon north end I999 1 / 4/00 Wellfield 2. Three pumps not cycling, need to increase 2. Replaced pumps with larger capacits' pumps 2. 2003 2. 2004 radius of influence for these EWs AOC 2 4 None noted OU-12 Landfill Cap Minor soil erosion. Erosion repaired .

6 9 3057 077 S _7 )te mher2005Ellsworth Air Force Base Final Five
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### 5.0 FI V E-YEAR REVIEW PROCES S 5. 1 TEAM MEMBER S Environmental Restoration Program (ERP) team members who prepared the five-year review included the following: Dell Petersen, ERP Chief, Ellsworth AFB Jim Haggins, Program Manager, Headquarters / Air Combat Command John DeYoe, Ellsworth AFB ERP Tim Pavek, Ellsworth AFB ERP Deb Morrissey, Omaha District, US Corps of Engineers Keith Anderson, Earth Tech / contractor Joe Odegaard, Earth Tech / contractor Robert Todd, RD Todd & Associates / contractor The time period covered by the five-year review was May, 1995 through July 2005. 5.2 DOCUMENT RE V IEW During this five-year review a number of EAFB RI / FS program primary documents were reviewed and relied upon for information. Table 5-1 lists those documents.



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- Year Review TAB L E 5-1 D OC UMEN TS REVIEWED DU R IN G THE EAFB FIVE-YEAR REVIEW P R O C E SS F inal Re m e dial Inv cs tigah on Rep o rt Operab l e Unit 01 at El l sw o rth Ai r F o rc e Ba s e , S outh D akota F ina l Re m ed ial I n v es ti g ati on Rep o rt Ope rab l e Un i t 02 at E ll sw o rth Ai r F o rc e Ba se, So uth D akota F inal Remed ial Inv es tiga ti on Re po rt Operab l e Unit 0 3 at E ll sw o rth Ai r F o rc e Ba se, S outh D akota Final Remed ial Inv es tigah on Rep o rt Operab l e U ni t 04 a t E ll sw o rth Air F o rc e Ba se, S outh D akota Final Re m e dial Inv es ti g ati on Rep o rt Operab l e Unit 0 5 at E l lsw o rth Ai r F o rc e Ba se, South D akota F inal Remed ial In v es ti g ati on Rep o rt Operab l e U nit 0 6 a t E ll sw o rth Ai r F o rc e Ba se, S outh D akota F inal Re m ed ia l Inv es ti g ati on Rep o rt O perab l e U n it 0 7 at E ll sw o rth Air Forc e Ba se, S outh Dakota F inal Re me d ial Inv es tigati on Rep o rt Operab l e Unit 0 8 at E ll sw o rth Ai r F o rc e Ba se, S outh D akota F inal Re m ed ial I n v es tigati on Rep o rt O perab l e U nit 0 9 at El l sw o rth Ai r F o rc e Ba se, S outh D akota Final Re m ed ial Inv es tigatio n Rep o rt O p erab l e Unit 10 at E ll sw o rth Ai r F o rc e Ba se, South Dakota F inal Re m e dial Inv estigatio n Re po rt O pe rable Unit 1 1 at E ll sw o rth Ai r Fo rc e Ba se, S outh D akota Final Re m ed ial Inv estigati on Rep o rt Op erable Unit 1 2 at El l sw o rth Ai r F o rc e Ba se, S outh D akota Final Fe a s i b ility Stu d y Rep o rt Operab l e Unit 01 at E ll sworth Ai r F o rc e Ba se, S outh D akota F inal Fe a sibil ity S tu d y Rep o rt Operab le Unit 0 2 a t E ll sw o rth Ai r F o rc e Ba se, S outh D akota Final Fe a s i b ility S tu dy Rep o rt Operabl e U n i t 03 at E ll sw o rth Ai r F o rc e Ba se, So uth D akota Final Fe a s i b i l ity Stu dy Rep o rt Operab l e U ni t 0 4 at E ll sworth Ai r F o rc e Ba se, South D akota Final Fe a s i b ili ty S tu d y Rep o rt Operab l e Unit 05 at E ll sworth Ai r F o rc e Ba se, S outh D akota F inal Fe a s i b ility S tud y Rep o rt Operable U n it 0 6 at El l sworth Ai r F o rc e Ba se, S outh Dakota F inal Fe a s i b i l ity S tu d y Rep o rt Operab l e Un i t 0 7 at E ll sw o rth Ai r F o rc e Ba se, S outh D ako ta Final Fe a s i b ility S tu d y Rep o rt Operab l e Unit 08 at E ll sw o rth Air F o rc e Ba se, S outh D akota F inal Fe a s i b i l ity Stud y Rep o rt Operab l e Unit 09 at Ellsw o rth Ai r F o rc e Ba se, S outh D akota F inal Fe a s i b ility S tu d y Rep o rt O perab l e U nit 1 0 at E ll sw o rth Ai r F o rc e Ba se, So uth D akota Final Feasibility Study Report Operable Unit 11 at Ellsworth Air Force Base, South Dakota Final Feasibility Study Report Operable Unit 12 at Ellsworth Air Force Base, South Dakota Final Record of Decision for Remedial Action at Operable Unit 01 at Ellsworth Air Force Base, South Dakota Final Record of Decision for Remedial Action at Operable Unit 02 at Ellsworth Air Force B ase, South Dakota

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### TABLE 5-1 DOCUMENTS REVIEWED DURING THE EAFB FIVE-YEAR REVIEW PROCESS Final Record of Decision for Remedial Action at Operable Unit 03 at Ellsworth Air Force Base, South Dakota Final Record of Decision for Remedial Action at Operable Unit 04 at Ellsworth Air Force Base, South Dakota Final Record of Decision for Remedial Action at Operable Unit 05 at Ellsworth Air Force Base, South Dakota Final Record of Decision for Remedial Ac tion at Operable Unit 06 at Ellsworth Air Force Base, South Dakota Final Record of Decision for Remedial Ac tion at Operable Unit 07 at Ellsworth Air Force Base, South Dakota Final Record of Decision for Remedial Action at Operable Unit 08 at Ellsworth Air Force Base, South Dakota Final Record of Decision for Remedial Action at Operable Unit 09 at Ellsworth Air Force Base, South Dakota Final Record of Decision for Remedial Action at Operable Unit 10 at Ellsworth Air Force Base, South Dakota Final Record of Decision for Remedial Action at Operable Unit 11 at Ellsworlh Air Force Base, South Dakota Final Record of Decision for Remedial Action at Operable Unit 12 at Ellsworth Air Force Base, South Dakota U.S. Environmental Protection Agency (USEPA). t989. Risk Assessment Guidance for Superfund, Volume I: Human Health Evaluation Manual (Part A). Interim Guidance. Office of Emergency and Remedial Response, Washington, D.C. EPA / 540 / I-89 / 022. U.S. Environmental Protection Agency (USEPA). 1989. Exposure Factors Handbook. Office of Human Health and Environmental Assessment, Washing t on, D.C. EPA / 600/8-89 / 043. U.S. Environmental Protection Agency (USEPA). 1989. Risk Assessment Guidance for Superfund, Volume II: Environmental Evaluation Manual (Part A). Interim Guidance. Office of Emergency and Remedial Response, Washington, D.C. EPA / 540 / I-89 / 001 U.S. Environmental Protection Agency (USEPA). 1989. Ecological Assessment for hazardous Waste Sites: A field and Laboratory Reference. EPA / 600 / 3-89 / 013. U.S. Environmental Protection Agency (USEPA). 1993. Integrated Risk Information System (IRIS). U.S. EPA Office of Research and Development, Washinston, D . C. U.S. Environmental Protection Agency (USEPA). 2005. Integrated Risk Information System (IRIS). U.S. EPA Office of Research and Development, Washinston, D.C. http:// www.epa.gov / iris. Draft-Final Program Review, Ellsworth AFB Environmental Restoration Program, Ellsworth AFB, South Dakota. 2005.

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### 5.3 FIVE-YEAR REVIEW TASKS • Review ROD documents for documentation of t he selection of the final remedial action.

• Compare comple ted remedial ac t ions to those outlined in RODS.

• Refine and incorporate remediation and closeout s t ra tegies con tained in the EAFB ERP Draft Program Review Report.

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### 6.0 FIVE-YEAR REVIEW FINDINGS 6.1 CHANGES IN ARARS AND T O BE CONSIDERED CRITERIA The principal standards applied to the remedial action process at EAFB were based on the Applicable or Relative and Appropriate Requirements (ARAR). Table 6-1 provides a summary of the ARARs reviewed for applicability to EAFB during the RI process. T his list contains chemical, action, and location specific standards determined to be ARARs for EAFB. Table 6-1 has been updated for the 2005 Five Year Review. Chemical specific standards or criteria that have changed since the first ROD was signed at EAFB are summarized in Tables 6-2 through 6-4. Chemical standards for surface water, ground water, and soil media for a limited number of analytes have changed. T hese changes are reflected in Table 6-2, which has been updated for the 2005 Five Year Review. Those changes affect the cleanup criteria forpetroleum-related compounds. The State of South Dakota regulations for remediation of petroleumcontaminated soils changed from cleanup requirements between 10 and 100 ppm TPH to a risk-based approach. This risk-based approach includes Tier 1 Action Levels for benzene, toluene, ethylbenzene, xylenes , and naphthalene, and a TPH "trigger level" of 500 ppm. The TPH criterion is not a cleanup standard, but a screening level to be used to determine whether additional investigation or other action will be required at a site. OU-I is the only OU where soil cleanup standards are specified in the ROD. TheROD for OU-I was signed in 1996 and accurately reflects the current regulations for petroleumcontaminated soil. The result of these changes is that generally higher concentrations of some organic contaminants may be considered as acceptable action or cleanup levels at petroleum release sites at EAFB. No changes were identified in the location and action specific AR A Rs. 6.2 CHANGES IN EXP OS URE PATHWAY S The exp o s ure p a thw ay s e valuat e d fo r e ach OU a t EA F B are s ummari zed in T ab l es 6 - 5 throug h 6 -8 . The e valuation s con s id ere d on- s it e an d o f f- s it e exp o s ures b a sed on cur r e n t an d futur e land u se. These p athw ay s ar e s till app ro pria te fo r u se in e valua tion of the s i te, b u t on e a dd itional p a thw ay i s und er re vi ew. Th i s i s the ai r in h alation pathw ay for T C E vapo r in res id e nc es an d in w o rk are a s, e. g ., the Prid e Hangar, th a t may originat e in contaminat ed ground w at er. Limit ed s ampling of in d oo r ai r in r es id e nc es h a s bee n c ompl e t e d w ith inconclu s iv e r es ult s. F urthe r s amp ling a nd t es ting i s un derw ay i n 2 00 5. The exposure scenarios used are conservative and probably represent a greater potential average (normally expected) exposure, than actual exposures. As an example, for landfills with earthen covers that must be mowed as part of routine maintenance, it was assumed that the covers would be mowed six times per year. In actual practice the covers are mowed at a less frequent rate (once or twice per year) , thus the estimated potential risk is greater than actual risk. The most significant change in exposure pathways is the evidence of a completed ground water pathway off-Base at OU-I 1. When the OU-11 human health risk assessment was completed no sampling had been completed east of the northeastern Base boundary. This area has been referred to as A OC-24 and the BG-04 area. Subsequent investigations have shown an extensive area where TCE-contaminated ground water has left the base. This area was investigated and is undergoing remediation as part of the OU-11 Basewide Ground Water Remedial Action. No completed exposure pathway has been identified for the flightline refueling area or the JP-4 plume area.

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# 30 5 7 082Ellsworth Air Force Base Final Five - }_ ,ar Review 6.3 TO XI C I TY A N D OTH E R CONT AMINANT C HA RACTERI ST IC S Table 6-9 provides a summary of the chemicals of concern (COCs) that resulted in remedial action being recommended for various OUs at EAFB. Although risk assessments were done in detail for each OU, the final remedial actions used applicable MCLs for ground water cleanup levels. With respect to other potential exposures, since soil covers were installed to eliminate the exposure pathway, risks are not likely to increase with changes in toxicity values. As noted in Table 6-9 six OUs (3, 5, 6, 7, 10, and 12) did not have COCs reported in concentrations at a level that would require chemical specific remedial actions being implemented at the OU. For the most part these OUs received remedial actions based on action-specific criteria needed to provide for adequate soil cover on previously closed landfill areas. The soil exposure remedy applied at OUs 2, 3, 4, 5, 6, 8, and 12 was based on the application of EPA's Presump tive Remedy for Municipal L an dfil l s, and was not spe c ific for a COC. Five COCs have had toxici ty value or l imits revisions since the RODs were completed for EAFB. Those chemicals are summarized in Tab l e 6-10. The change in the standards or chemical toxicity of the organic analytes in ground water and soil (see note above) is not expected to affect the protectiveness of the remedial actions applied at specific OUs. The current technologies applied, and possible new technologies that are under consideration, are expected to remove the COCs to the levels identified as cleanup goals. One possible exception is tile criteria for gamma chlordane (identified in ground water samples at OU-I 1), which is now twenty fold lower than the previous criteria. No specific remedial action was initiated for this COC; additional monitoring may be needed to determine if this chemical poses an environmental risk. Gamma chlordane is a bro a d - spectrum insecticide and was used extensively in agricu l ture and for termite control in the 1980s. Since that time its use has been restricted and EPA has issued a no-use restriction on food products. Chemical t oxi c ity v a lues have changed for COCs at the flightline refueling area and the JP - 4 plume area. For example, the toxicity level for benzene is lower (see Table 6-10); however, we are applying MCLs and this wil l result in lower allowab l e concentrations in ground water than the risk-based approach and the chemical toxicity values.

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• o , ,,Ellswo r th Air Force Base Final Five
- Year Review TAB LE 6-1 FE DE RA L AND S TAT E A RA R S APPLIE D TO E L LSWORT H AF B , S O U TH DA KO TA A. P o tenti ally A pp l i cable or Re l e va nt an d A ppro pria te Federal S ta nd ards, Requiremen t s, Cri teri a , a nd L imita tions
Standard Re quirernen t, Cri teri a , or Limi tatio n Ci t ation s Description A RAR Typ e Applic abi l ity to E AF B Safe Drinking W a ter Ac t of 1986 4 2 U S C 30 0 g Nati o nal Prirn ary Drinking Water 40CFRPam [ 41.11- 1 2 Specifies maximum chemical contaminant C hemical Relevant and appropri a te for Federal Regu l ations l evels (MCLs) of public water systems. Class [I a quifer. Nation a l Secondary Drinking Water 40 CFR Part 143.03 Estab l ishes secondary maxirn unl Chemic a l Relevant a nd appropriate, Standards contaminant levels (SMCLs) for public water systems. These are federally n o nenforceable standards, which regu l ate conta minants i n drinking water that prim arily a ffect the qualities. Maximum Contamin a nt Level Go a ls 40 CFR Part 141.50 & Establishes drinking water qual ity goal s set Chemic al Relevant a nd appropriate. Pub. L. No. 99-330, I00 Slat. 642 (1986) al levels of unknown or anticipated adverse heal th effects, with an adequate margin of safety, Clean Water Ac t of 1 977 33 USC 1251-t376 W a ter Qual ity C riteri a 40 CFR Part 131 Sets criteria for water qual ity based on C hemical Relev a nt and appropriate. Aquifer may toxicity to aquatic organisrns and human be a Federal Class IIA (discharge to health, surface water), C riteria an d Standa rds f or the Na tion al 40 CFR 125. 1- 3 Establ i shes c r i teri a a nd stand ards for Chemical Applicable f o r groundwater treated and Pol l u t ant Discha rge Elimi nati on technology-based requirements in pen'nits discharged to EAFB WWTP in future. u n d er the S e ctio n s 30 [ (b) and 402 o f the CWA. G eneral Pre t rea t

m ent R egulations fo r 40 C FR 403.1-4 , 8-I l, I B Es tablishes responsibi l ities of federal, state, Action Applicable for groundwa ter treated and Exi s ti ng and New S o u rces of Po ll u tion and local government and of the POTW in discharged to EAFB WWTP in future. providi n g gu idel in es f o r and de v el o p i n g , submitting, appro v ing, and m o dify i ng state pretreatment programs, 40 CFR 403.5 - 7 , 13, 15 Specifies standards for pretreatment. Guideli n es E s tab l is h ing T est Procedur e s for 40 C FR 136.1-5 and Appendices A-C Specifies analytical pro c edures for NPDES Action Applicab l e f o r any future treatment and the Anal y sis of Pol l utan ts applications an d reports d ischarge of gro und water.

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Standard Requirement . Criteria , o1"Limitation Citations Description ARAR Type Applicability to EAFB
( ' lean Air Act of 1983 42 USC 7401 National Primary and Secondary Ambient Air 40 CFR Part 50 I-6 , 8,9,11 , 1 2 , and Establishes national primary andsecondal T Action Applicable, Quality Standard Appendices A, H, , I, K ambient air quality standards to protect public health and welthre. National Emission Standards for Hazardous Air 40 CFR Part 6I 01 Establishes regulato W standard for specific Action Applicable lbr alternatives that would F'ollutants air pollutants, discharge to the air following treatlnen [, So l id Waste Disposal Act as am e nded by 42USC6901 R esource Conservation and R ecov ery Act of 1976 Solid Waste Disposal Facility Criteria 40 C| : R Parts 257 and 258 Sets forth revised ininimum fiederal criteria Action Relevant and appropriate lbr addressing lbr Municipal Solid Waste Landfills landfil l closure performance standards. {MSWt.Fs) for existing and new units Land Disposal Restrictions 40 CFR Part 268 Id e ntifies hazardous wastes that are Actiun Relevant and Appropriate, Alternati, ,' es restricted from land disposal and defines may include the disposal of residual those limded circumstances under which a waste due to treatlnent , prohibited waste may continue to be land disposed Guidelines lbr the Land Disp , ._sa[nfgolid Waste 40 CFR PaI'{ 2 41 100-213 Establishes requirements and procedures tbr Action Relevant and appropriate for meeting the disposaI of s o lid waste, landfill closure performance guidelines. Resource Conser:ation and Recovery Act ol 1976 Hazardous Waste Management S>stem: General 40 C F R Part 260 Establishes defindions as well as Action Applicable lbr identifying hazardous procedures and criteria for rnodification or waste during soil placement at landfills revocation of any provision in 40 CFR Parts at EAFB 260-265 [der, tification and Listing of Hazardous Wastes 40 CFR Part 261 Defines those solid wastes which are Action Applicable for identifying hazardous subject to regulations as hazardous wastes waste during soil placement at landfills under 40 CFR Parts 262-265 at EAFB. Standards Applicable to Generators of Hazardous 40 CFR Part 262 Establishes standards ¿br generators of Action Applicable to ahematives relating to _astes hazardous waste removal or offsite transport of a hazardous material. Standards Applicable to Transporters of 40 CFR Part 263 Establishes standards which apply to Action Applicable for any transport of Hazardous Wastes persons transporting hazardous waste hazardous materials off'site, within the U,S, if the transportation requires a manifest under 40 CFR Par_ 2 62 Standards for Ow ' ners and Operators of 40 CFR Part 264 Establishes standards for acceptable Action Relevant and Appropriate for Hazardous Waste TSD F's hazardous waste management, performance guidelines for landfill closure.

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Standard Require m e nt, Criteria , o r Limi tatio n Citati ons Descripti o n ARAR Type Applicability to EA FB Toxic S ubs t ances C o n tro l Act (TSCA) 40 CFR Part 761.[ Substances re gulate d under this rule A ction Applicable include , but are not limited to, soils and other materials contaminated as a result of" s pills F is h and Wi l d l i fe C oo rdina ti on Ac t 16 USC 1531-666 R e quires consultation when a fed eral Action Not an A RAR. 40 CFR 6,302(g) department or agency proposes or authorizes any modification of a stream or other water body and ad e quate provision for protection of fish and wild l ife resources E ndangered Sp e cies Ac t 1 6 USC 1531 - 1543 Requires th a t Federal agencies insu re that Location / Action Not an ARAR . Ecol o gical Assessment 50 CFR Parts 17, 402 any action authorized, funded, or carried out did not identify EAFB as having

40 CFR 6 . 302 (g) by the agency is not likely to jeopardize the critical h abitat or endangered species. continued existence of any tbreatened or e n dangered species or destroy or adversely modify critical habitat Archae o lo gi c a l and H is toric Pres ervation A c t 16 USC 469 Establishes procedures to provide f o r Location Potential ARAR. On-Base property 40 CFR 6.301(c_ preservation of historical and arch a eological was used for landfilling activities. No data, which might be destroyed through known historic or archaeological value, alteration of terrain as a result of federal although no confirmation study has c onstruction pro ject for a fed eral licensed been pertbrmed. activity or program. Archaeological Resource s Prote c ti on A c t 93 Star. 721 Requires a pernait for an excavation or Action / Location Not an A RAR . (1979) 16USC470 removal of archaeological resources from public or Indian land. Exe cutive Order 11,958 on Floodplain s 42 USC 7401 Requires federal agencies to evaluate the Location Not an ARAR. Area not in lO0-year M anag e m e nt 40 CFR 6,302 (b) & Appendix A potential effects of actions they may take in floodplain. a floodplain to avoid, to the e xtent possible, the adverse impacts associated with direct and indirect development of a floodplain Ex e cu t i v e Order on Pro t ec tion of W e tland s Exec. Order No. 11,990 Requires federal agencies to avoid, to th e A ction / Location Applic able. EAFB has identifi e d 40 CFR 6.302(a) & A ppendix A extent possible, the adverse impacts wetland areas adjacent to sites where associated with the destruction or loss of Ras were completed. wetlands and to avoid support of new construction in wetlands if a practicable alternative exists

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Standard Requirement, Criteria, or Limitation Citations Description ARAR Type Applicability to EAFB B. Potentially Applicable or Relevant and Appropriate State Standards , Requirements, Criteria, and Limitations Sou t h Dako ta A ir P ol luti on C o nt rol 74:36:01-18 Establishes pert'nit requirements for , Action Applicable construction, amendment, and operati o n of Regulati ons air discharge services South Dakota Waste ]Management 74:28:05 Estab l ishes requirements for disposal of Acti o n Relevant and appro priate for landfill Regulations hazardous waste in sanitary landfills cl o sure performance guidelines. So u th D ako ta Wa s t e M an ag e m e nt 74:27:15:03 Defines requirements for closure of solid Action Relev a nt and appropriate for l andfil l Re g ulations waste disposal facilities closure performance guidelines, S ou th Dako ta Waste Management 74:27:09:O6 Defines criteria fo r peranit application for Action Not an ARAR R eg ulati o ns otber so l id waste T S D facilities Sou th D akot a W a s te M anageme n t 7 4: 2 7:15:09 Establishes standard s for landfill c l osure A cnon Rel e vant and appropriate R eg u la tio ns and postctosure monitoring Sou th D akot a Was te btanagemen t 74:28:24:01 Establishes standard for tran sp orters of Action Relcvan t andappropriatc R e gulations waste South Dakota Water Discharge P ermit Rul e s 74:52:02 Establishes surihce water discharge perm it Action Applicable for any ground-water applications requirements treatment discharge. So u th Dak ota Water D i sc h arge Permit Rul es 74:52:03 Establishes surface water permit conditions Action Applicable for any ground-water treatment discharge S o uth D a k ot a W a t er Di sc h a rge P e r mi t Ru l e s 74 _3: ( ] E stablishes requirements [or individual a nd A cti on Appl i cable for any ground-wat er small onsite v,, astev, 'ater systems treatment discharge So u th Dakota Water Q u al i t) Standards 74:51:03:1 I Defines use of Box Elder Creek and certain Action Applicable for an_ ground-water tributaries treatment discharge So u th Dako ta Remediation (?rit eria for 74:56:05 Establishes requirements for the Chemical Relevant and appropriate for eval uating Petroleum-Contaminated So i ls remediation of soil contaminated v,ith acceptabie levels of pctroleum products petroleum products, in tile soil South Dakota G r ound Water Standards 74:54:01 Define s ground ", , rater classilqcations by Claentical Rele', , ant and appropriate i n evaluating beneficial use and sets chemical standards the beneficial use of impacted groundwater .

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Contaminant Media II Standard (ug / L) Source / Year HH / AA / AC

_ l | B H C ( al ph a) ( Hex ach lorocyclo hex an e -a lph a) Surfac e W a ter Pre viou s 0 . 031 SDS W QC 199 621 1 N ew 0. 0 26 / --

/ -- SDSWQC 20 0 53' Previous 0.063 SDSWQC 1996 B HC ( be ta) (Hex a chl or o c y c l y hex a ne - beta) S urfac e W at e r N ew 0 .0 09 1 / --

/ -- SDS W QC 2 00 5 Previous 0.096 SDSWQC 1996 B H C ( gamma ) (Lindan e ) Surfac e Wat er N ew 0 . 0 98 / 0 . 0 95 / 0. 0 95SDSWQC 200 5 Previous 20/134 SDSWQC 1996 Pentachlorophenol Surface Water New 0.27 /19 /15 SDSWQC 2005 Previous 82 /3.2 SDSWQC 1996 Lead Surface Water New
-- / 65

/ 2.5 SDSWQC 1998 Previous 2.4 /0.012 SDSWQC 1996 Mercury Surface Wat er New 0.050 /1.4 / 0.92 SDSWQC 2005 S tandard ( mg / kg ) C on taminant Media (SDDENR Action Source/Y ear levels) Pre viou s NS S DR CPCS 1991 B enzene Soil New 0.2 SDRCPCS 1995 Previous NS SDRCPCS 1991 Toluene Soil New 15 SDRCPCS 1995 Previous NS SDRCPCS 1991 Ethylbenzene Soil New 10 SDRCPCS 1995 ' Previous NS SDRCPCS 1991 Xylenes Soil New 300 SDRCPCS 1995 Previous NS SDRCPCS 1991 Naphthalene Soil New 25 SDRCPCS 1995 Previous 10-100 SDRCPCS 1995 Total Petroleum Hydrocarbons Soil New 500 SDRCPCS 1999 Contaminant Media [[ Standard (mg / L) Source/Y ear Pre viou s 0 . 003 S DGW QS : Ald e carb s ulfon e Groun d W at e r N ew 0. 00 2 S DGW QS 7 Pre viou s ND 8 SD GW QS 9 B e n z o(a )py r e n e G round Wa te r N ew 0 . 000 2 S DGW QS 9 Pre viou s ND SD GW QS 7 D alap on ( s o d ium s alt ) Groun d W a ter N ew 0. 2 SD GW QS 9

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_ve - ' f ear Review Previous ND SDGWQS 7 Di(2-ethylhexyl)adipate Ground Water New 0.4 SDGWQS _ Previous ND SDGWQS v Di(2-ethylhexyl)phthalate Ground Water New 0.006 SDGWQS 9 Dichloromethane (Methylene chloride) Ground Water Previous ND SDGWQS 7 New 0.005 SDGWQS 9 Previous ND SDGWQS 7 Dinoseb Ground Water New 0.007 SDGWQS 9 Diquat Ground Water Previous ND SDGWQS 7 New 0.02 SDGWQS 9 Previous ND SDGWQS 7 Endothall Ground Water New 0. | SDGWQS 9 Previous 0.0002 SDGWQS 7 Endrin Ground Water New 0.002 SDGWQS _ Glyphosate Ground Water Previous ND SDGWQS 7 New 0.7 SDGWQS _ Hexachlorobenzene Ground Water Previous ND SDGWQS 7 New 0.001 SDGWQS 9 Hexachlorocyclopentadiene Ground Water Previous ND SDGWQS v New 0.05 SDGWQS 9 Total Haloacetic Acids, including: Previous ND SDGWQS 7 Dichloroacetic acid, Monochloroacetic acid, Ground Water New 0.06 SDGWQS _ and Trichloroacetic acid Previous ND SDGWQS v Oxamyl (Vydate) Ground Water New 0.2 SDGWQS 9 Previous ND SDGWQS 7 Pichoram Ground Water New 0.5 SDGWQS ') Previous 0.00005 SDGWQS 7 Polychlorinated biphenyls (PCBs) Ground Water New 0.0005 SDGWQS 9 Previous ND SDGWQS 7 Simazine Ground Water New 0 . 004 SDGWQS 9 Previous ND SDGWQS7 2,3,7,8-TCDD (Dioxin) Ground Water New 3.0E-08 SDGWQS 9 Previous ND SDGWQS v 1,2,4-Trichlorobenzene Ground Water New 0.07 SDGWQS 9 Previous ND SDGWQS v i, 1,2-Trichloroethane Ground Water New 0.005 SDGWQS 9 Total trihalomethanes, including Previous 0. l SDGWQS 7 bromodichloromethane, bromoform New 0.08 SDGWQS 9 (tribromomethane), chloroform (trichloromelhane), and Ground Water dibromochloromethane (chlorodibromomethane)

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# 3057 0 89Ellsworth Air Fo r ce Base Final Five
- Year Review 

### Antimony Ground Water Previous NSI SDGWQS 7 New 0.006 SDGWQS9 Arsenic Ground Water Previous 0.05 SDGWQS 7 New 0.01! SDGWQS 9 Previous NS SDGWQS 7 [Asbestos Ground Water New 7MFL (longer SDGWQS 9 than 10 micrometers) Previous NS i SDGWQS 7 Beryllium Ground Water New 0.004 SDGWQS 9 Bromate Previous NS! SDGWQS 7 Ground Water New 0.011 SDGWQS 9 Chl o rite Gro und Water Previous NS! SDGWQS 7 New 1 SDGWQS 9 _Copper Ground Water Previous 1.3 _ SDGWQS 7 New 1 SDGWQS 9 _yanide Ground Water Previous ND l SDGWQS 7 New 0.2 SDGWQS 9 Previous 2.41 SDGWQS 7 !Fluoride Ground Water New 41 SDGWQS 9 Previous NS J SDGWQS 7 Nitrate + Nitrite (both as N) Ground Water New 101 SDGWQS 9 Silver Ground Water Previous 0.05 SDGWQS 7 New 0.1 SDGWQS 9 Thallium Ground Water Previous NS SDGWQS 7 New 0.002 SDGWQS 9 Beta particle and photon radioactivity (from Previous NS SDGWQS 7 !man-made radionuclides) Ground Water New 4 mrem / yr SDGWQS 9 Previous 15pCi / L SDGWQS 7 excluding

uranium SDGWQS 9 gross alpha Ground Water New 15pCi / L excluding' uranium and radon

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# • 3057 090Ellswortk Air Force Base Final Five
- Year Revww Radon Previous NS SDGWQS 7 Ground Water New 300 pCi / L SDGWQS '_ Uranium Previous 0.02 SDGWQS 7 Ground Water New 0.03 SDGW Q S 9 HH / AA / AC=Human I tealth-Ingestion / Aquatic Acute / Aquatic Chronic. 2 South Dako t a Surface Water Quality Criteria 1996. 3 South Dakota Surface Water Quality Cri t eria 1998. 4 Acute / Chronic ug / L. 5 NS=No Standard. 6 South Dakota Remediation Cri t eria for Petro l eum Contaminat ed Soils 1 995. 7 South Dakota Surface Water Quality Criteria 2004. ND = Non De tec t . 9 South Dakota Su r face Wat er Qual ity Cri t eria 2005. TABLE 6-3 CHANGE S IN ACTI O N- S PECIFI C STAND A RD S A ction Requirements Prerequisite Citation / Year Pre viou s Non e Ne w
T A BL E 6-4 C HAN G E S IN L O CATI O N- S PE C IFI C ST ANDARD S L ocation R equirements Prerequisite Cita tion / Year Wetland Previous None New

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# 305 7 09 1Ellsworth Air Force Base Final Five
- Year Review TABLE 6- 5 SUMMARY OF EXPOSURE PATHWAYS EVALUATED FOR THE HUMAN HEALTH RISK ASSESSMENT FOR CURRENT ON-SITE LAND USES AT ELLSWORTH AFB Y=pathway complete NA= pathway not applicable to site not at site EXPOSURE PATHWAYS OU-1 OU-2 OU-3 OU-4 OU- 5 OU-6 OU- 7 OU-8 OU-9 OU-1 0 OU-11 OU-12 CURRENT ON SITE USES Chem./ rad. Co mmercia l / I n dus t ri al L and Use. GROUND WATE R

Ingestion N N N N N N N / Y N N N N N SURFACE SOIL Ingestion Y Y N Y Y Y Y / Y Y Y Y N Y Dermal Contact Y Y N Y N Y Y / N Y Y y N Y Inhalation N N N N N / N Y Y N N N External NA NA NA NA NA NA NA / Y NA NA NA NA NA SUBSURFA C E SO IL Inge sti o n N N N N N N N / N N Y N N N Dermal Co n tact N N N N N N N / N N Y N N N I n h a l a ti o n N N N N N N N / N N Y N N N External NA NA NA NA NA NA NA / N NA NA NA NA NA SURFACE WATER Ingestion N N N N N Y N / N N N N N N Dermal Contact Y N N N N Y N / N N Y N N N Inhalation Y N N N N Y N / N N N N N Y External NA NA NA NA NA NA NA / N NA NA NA NA NA SED I MEN T Ingestion 'Y N N N N Y N / N N Y N N N Dermal Contact N N N N N N N / N N N N N N Inhalation N N N N N N N / N N N N N N External NA NA NA NA NA NA NA / N NA NA NA NA NA AIR

Inhalation Y N N N N Y N / N Y Y N N Y FAUNA

Ingestion of fish / game N N N N N N N / N N Y N N N

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_4 305 7 0 9 2 September2005Ells worth Air Force Base Final Five
- Year Re v iew TABL E 6-6 S U MMA R Y O F EX PO SU RE PA T HWA Y S E VAL U A TED F O R HU MA N H E ALT H RI S K ASS ES S M ENT FOR C URRENT OFF-SITE LAND USES AT ELLSW O RT H AFB Y= _lete NA = t o site N = n o t c o m p leted at site EXPOSURE PATHWAYS OU-1 OU-2 OU-3 OU-4 OU-5 OU-6 O'U-7 OU-8 OU-9 OU-10 OU-11 OU-12 C U RR ENT OFF - SIT E USES Chem./ Rad, R esiden tia l / Agri cu ltural La nd U s e . ] I,, G RO U N D WA TE R [ Ingestion N N N Y N N / N N N N N N Inhalation N N N Y N N N N N N N SURF AC

E SOIL Ingestion N N N N N N N N N N N Dermal Contact N N N N N N N N N N N Inhalation N N N N N N N N N N N External Exposure NA NA NA NA NA NA N NA NA NA NA NA S UB S U RF A CE S OIL

Ingestion N N N N N N N N N N N Dermal Contact N N N N N N N N N N N Inhalation N N N N N N N N N N N SURFACE WATER

I n ge s t io n N N N N N N N N N N N D ermal Contact N N N N N N N N N N N Inhalation N N N N N N N N N N N SEDIMENT Ingesti on N N N N N N N N N N N Dermal Conta c t N N N N N N N N N N N Inhalation N N N N N N N N N N N AIR

Inhalation N N N N N N N N N N N FAUNA

I n gesti o n o f fish / game N N N N I N N N N N N N

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# 3 05 7 09 3Ellsworth Air Force Base Final Five
- Year Review TABLE 6-7 SUMMARY OF EXPOSURE PATHWAYS EVALUATED FOR HUMAN HEALTH RISK ASSESSMENT FOR FUTURE ON-SITE LAND USE AT ELLSWORTH AFB _lete NA= to site not 91eted at site EXPOSURE PATHWAYS OU-I OU-2 OU-3 OU-4 OU- 5 OU-6 OU-7 OU-8 OU-9 OU-10 OU-11 OU-12 FU T URE ON-SITE USES Chem./ Rad O n-Site Residential Land Use.

GROUND WATER Ingestion y y y y y y y / y y y y y y Dermal Contact Y Y Y Y Y Y Y / N Y y y y y Inhalation Y Y Y Y N Y Y / N Y y y y y External NA NA NA NA NA NA NA / N NA NA NA NA NA SURFACE SOIL Ingestion 'Y Y Y Y Y Y Y / Y Y Y Y N Y Dermal Contac t Y Y Y Y N Y Y / N Y N Y N Y Inhalation Y N N N N N N / N N Y N N N External NA NA NA NA NA NA NA / N NA NA NA NA NA Ingestion of homegrown produce NA N N N N N N / N N N N N N S U BS U RFA CE SO IL Ingestion N Y Y y y y y / y y y y N Y Dermal Contact Y N N N N N N / N N N N N N Inhalation Y Y Y Y N Y Y / N N Y y N Y External NA NA NA NA NA NA NA / Y N NA NA NA NA SURFACE WATER

Ingestion Y Y N N N Y y / Y N Y N N Y Dermal Contact Y Y N N N Y Y / N N Y N N Y Inhalation Y Y N N N Y Y / N N N N N Y External NA NA NA NA NA NA NA / N NA NA NA NA NA SED IM E NT

Ingestion Y Y N N N Y Y / Y N Y N N Y Dermal Contact Y Y N N N Y Y / N N Y N N Y Inhalation Y Y N N N Y Y / N N N N N Y External NA NA NA NA NA NA / N NA NA NA NA NA 'AIR

Inhalation Y Y Y Y N Y Y / y y y y N Y FAUNA

Ingestion of fish / l_ame, N N N N N N N / N N Y N N NEllsworth Air Force Base Final Five
- Year Revtew TABLE 6-8 SUMMARY OF EXPOSURE PATHWAYS EVALUATED FOR HUMAN HEALTH RISK ASSESSMENTS FOR FUTURE OFF-SITE LAND USES AT ELLSWORTH AFB Y= )lete NA = _licable to not completed at site EXPOSURE PATHWAYS OU-I' OU-2 OU-3 OU-4 OU-5 OU-6 OU-7 OU-8 OU-9 OU-10' OU-11 OU-12 FUTURE OFF-SITE USES Resi d en tial

GROUND WATER

Ingestion N Y N Y N N N N N Y N Dermal Contact N Y N Y N N N N N Y N Inhalation N Y N Y N N N N N Y N SURFACE SOIL In_

, estion N N N N N N N N N N N Dermal Contact N N N N N N N N N N N Inhalation N N N N N N N N N N N SUBSURFACE SOIL

Ingestion N N N N N N N N N N N Dermal Contact N N N N N N N N N N N Inhalation N N N N N N N N N N N SURFACE WATER Ingestion N N N N N N N N N N N Dermal Contact N N N N N N N N N N N Inhalation N N N N N N N N N N N SEDIMENT

Ingestion N N N N N N N N N N N Dermal Contact N N N N N N N N N N N Inhalation N N N N N N N N N N N AIR

Inhalation N N N N N N N N N N N FAUNA

Ingestion of fish / game N N N N N N N N N N NEllsworth Air Force Base Final Five
- Year Review TABLE 6-9 CHEMICALS OF CONCERN AT EAFB THAT RESULTED IN TIlE APPLICATION OF A REMEDIAL ACTION 'Note. Presumptive Remedy Applied at OU-3, OU-5, OU-6, OU-10, and OU-12 therefore No COC listed) COC Operable Units 1 [ 2 1 3 1 4 I 5 [ 6 [ 7 I 8 [ 9 1 1 0 111 } 12 GROUN D WATER benzene X X .... X ethylbenzene ..... X toluene
- -
_ xylenes
- - X l,l,l-Trichloroethane X 1 , 2-DCE X X X X 1,2-DCA X X I,I-DCE X X PCE X X 1,2,4-- X ._ "Frichlorobenzene 1 , 4-Dichtorobenzene X FCE X X X v in

y l chloride X X benzo[a] pyrene a-nitroso-di-n- X _ropyalamine ibis (2-chloroethyl) X ether Aldrin X - _ alpha-BHC X

_ Heptachlor X
- Beta BHC - X bis(2-ethylhexyl) - - X 9hthalate T PH X - - X JP-4 X

_ gamma chlordane .... X p,p'-DDT .... X Cadmium - - - X - Lead X
- S URFACE S OI L benzene X 1,2-DCE X PCE X rCE X FPH X J P -4 X benzo[a] pyrene X :lioxins X SUBSURFA C E SOIL Low level Radiological waste X SE D IMENT benzo[a] pyrene I 

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# 3 0 5 7 096Ellsworth Air Force Base Final Five
- Y e ar Review TABLE 6-10 TOXICITY VALUES FOR CHEMICALS OF CONCERN AT EAFB

Oral Inhal a tion Oral Inhalation RfD RfC Slope Factor Slope Factor COC (mg / kg-d) (mg / m ') (mg / kg-d)" (mg / k g -d ) V alue1995 V alue2000 V alue2005, S V alue199512000 V alue 200 1 1995 2000 2005] 1995 

## 2000 I 2 005I I Value S V alue V alue V alue S V alue V alue V alue S V olatile Organic Compounds: benzene na 3.0E-3 4.0E-3 I na 1.7E-3 3.0E-2 I 2,9E-2 2.9E-2 5.5E-2 1 8.3E-6 2.7E-2 2.7E-2 I ' dichloroethane, 1,2- na 3.0E-2 2.0E-2 P na 1.4E-3 2.5E+0 M 9.1E-2 9,1E-2 9.1E-2 I 9.1E-2 9,1E-2 9.IE-2 I dichloroethylene, 1,1- 9.0E - 3 9.0E-3 5 , 0E-2 1 na 1.4E-I 2.0E-1 I 6 . 0E-I 6.0E - 1 na na na na dichloroethylene, 1,2- 2.0E-2 9.0E-3 H2 na 6.0E-2 p l 9,1E-2 na 9.1E-2 na ethylbenzene 1.0E- 1 1.0E- 1 I 1.0E+0 1.0E+0 I na na na na naphthalene 4.0E-2 2.0E-2 2.0E-2 1 na 3.0E-3 3.0E-3 I na na na na na na toluene 2, I E- 1 2.0E- 1 8,0E-2 I na 4.0E- l 5,0E+O I na na na na na na tetrachloroethytene (PCE) I.OE-2 1.0E-2 I na 4.9E-1 E na 5.4E-1 O na 2,0E-2 O trichloroethane, 1,1,1- na 3,5E-2 2.8E-1 E na 2,9E-I 2,2E+0 P na na na na na na trichloroethylene (TCE) na 6,0E-3 3.0E-4 E na 6.0E-3 3.5E-2 E I.tE-2 I.IE-2 4.0E-1 E na 6.0E-3 4.0E- I E vinyl chloride na 3.0E-3 I na 9.8E-2 I 1.9E+O 1.4E+0 I 3,0E-I 3.0E-2 I xylenes 2.0E+0 2.0E-I 1 na 1.OE-I I na na na na Pet ro leum C o mpounds: JP-4 na na na na na na na na na na na na Semi v o l a tile Organics : trichlorobenzene, 1,2,4- 1.0E-2 l.OE-2 1 na 3.5E-3 P na na na na dichlorobenzene, 1,4- na 3.0E-2 E 8.0E-1 8,0E-I I 2.4E-2 2.4E-2 H na 2.2E-2 E methylnaphthalene, 2- na na 4,0E- 3 I na na na na na na na na na benzo[a]pyrene n a na na na 7.3E+0 7.3E+0 I 6.1E+0 3.1E +0 E bis(2-chloroethyl)ether n a n a na na 1.IE _0 I. IE+0 1 1.2E+0 1.1E+O I B EHP 2.0E-2 2,0E-2 1 na na 14E-2 1.4E-2 I na na NDPA na na na na 7.0E +-0 7.0E+O 1 na na

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# 3057 097Ellsworth Air Force Base F

i nal Five
- Year Review O ral I n h ala tio n O ral I n h alation RfD RfC Slope Factor Slope Factor C OC /mg / kg " d) /m g / m_) (mg / kg -d )" (m g / k g -d ) ,


# , Val ue , s Val ueValoe"al, o , s VaI uo"al ue Val ue I s Pe sti c i de s and PCB s: aldrin 3.0E-5 3.0E-5 l na na 1.7E+I 1.TE+I I I.TE+l 1.7E+I I alpha-BHC (alpha-H CH) na na na na 6,3E+0 6.3E+0 l 6.3E+0 6.3E+0 I beta-BH C (beta-HCH) na na na na 1.BE+0 1.8E+0 I 1.9E-4 1.8E+0 I chlordane 6.0E-5 5.0E-4 5.0E-4 I na 7.0E-4 7.0E-4 l na 3.5E-1 3.5E-I I na 3.5E-1 3.5E-1 I chlordane, gamma 6.0E-5 na 5.0E-4 I na na 7.0E-4 l na na 3.5E-1 I na na 3.5E-1 I DDE na na na na na na na 3.4E- 1 3.4E- 1 I na na na DDT 5.0E-4 5.0E-4 I na na 3.4E-I 3.4E-1 I 3.4E-I 3.4E-1 I heptachlor 5 .0E-4 5.0E-4 l na na 4.5E+0 4.5E+0 l 4.6E+0 4.6E+0 I PCBs na na 2.0E-5 13 na na na na 2.0E+0 2.0E+O I na 2.0E+0 2.0E+0 I Dioxins: di°xins4 I na [ na na [ I na I na na I na 1.5E+5 1.5E+5 H I na 1.5E+5 1.5E+5 

## I H Me ta l s : arsenic 3.0E-4 3.0E-4 3 .0E-4 I na na na 1.8E+0 1. 5 E+0 1. 5 E+0 l 1. 5E+0 1.5 E+l 1. 5E+l I aluminum na 1.0E+0 1.0 E+ 0 p na 1.4E - 3 3. 5 E- 3 P na na na na na na beryllium 5.0E -3 2.0E-3 2.0E-3 I na 2.0E-5 2.0E- 5 I 4.3E+0 na na 8.4E+0 ' 8.4E+0 8.4E+0 I cadmium 5.0E-4 5.0E-4 1S na 2.0E-4 E na na 6.IE+0 6.3E+0 I chromium _ 1.0E+0 3,0E-3 3.0E-3 I na 8.0E-6 8.0E-6 I na na na na 2.9E-2 4.1 E+ 1 I cobalt na 6.0E-2 2.0E-2 p na na 2.0E-5 P na na na na na 9.8E+0 P lead na na na na na na na na na na na na manganese 5.0E-5 1,4E-4 2.0E- 2 I 5.0E-5 5,0E-5 5.0E-5 I na na na na na na thallium na na 7,0E-5 O na na na na na na na na na na = No values were found in readily available literature. Sources for 2005 toxicity values: NPDA = N-nitroso-di-N - propylamine. I = Integrated Risk Information System (IRIS) BEHP = bis(2-etbylhexyl)phtbalate, P = USEPA Provisional Peer-Reviewed Value (PPRV) (taken from Region 3 RfD = Reference dose. RB C Table, version 04 / 05) RfC = Reference concentration. N = USEPA National Center for Environmental Assessment (NCEA) (taken S = Source fro m Region 3 RB C Table, version 04 / 05;, M = Minimum Risk Level (MRL) from Agency for Toxic Substances and Value for dichloroethy l ene, 1,2 - trans . Disease Registry (ATSDR) (taken from Region 3 RBC Table, version 04/05. : Value for total 1,2-dichloroethylene. O = Other unnamed sources (taken from Region 3 RBC Table, version 04 / 04. Value for Aroclor 1254. 4 For dioxins not otherwise specified, the value for 2,3,7,8-tetrachlorodibenzodioxin is used. Source for 2000 toxicity values: Final Five Year Review, Ellsworth AFB, 5 Cadmium value for water. South Dakota, September 19, 2000. _' Chromium assumed to be Cr VI. Source for 1995 toxicity values: Final Remedial Investigation Reports at Ellsworth Air Force Base, South Dakota. 1995.El/swo r th Air Forc e Base Final PT ve - Year Revww 7. 0 ASSESSMENT 7.1 REMEDY OPERAT I ON 7 . 1.1 HASP an d C o nti ngency Pl a n All work conducted at the site is completed in compliance with the Base Wide Health and Saf e ty Plan (HASP) unless an addendum to the HASP is submitted for a particular activity or operable unit. All workers are required to attend a Health and Safety briefing and site walk over prior to commencing work at any operable unit. A Contingency Plan is also in place for all OUs. The Contingency Plan consists of an ongoing process within the Long Term Monitoring / Long Term Operations (LTM / LTO) program that wilt identify any failure of the selected remedy or remedies; establish a budget for necessary corrective action; ob t ain funding through the Air Force's project programming system; and implement the corrective action. For Operable Units that included a landfill cap as a part of the final selected remedy, quarterly visual inspections of the landfill caps are conducted and repairs are performed as needed to main t ain the integrity of the caps to assure compliance with the RODs. 7 .1.2 Institutional Controls and Other Measure s In s titu tional control s an d others m e a s ures app li ed at EA F B inclu de d a s tan d i n g o rder b y the Ba se comman der res tric ti n g pro perty u se at spe cific O U s, in stal l ation o f f e ncing an d p o s ting n ew s ign s id e ntif y ing are a s a s re s trict e d to control acc ess t o the s it es an d the de v e lo p m e nt o f appro priat e dee d r es triction languag e th at coul d be p lac ed on pro pertie s sho ul d the y be s old or tran sferred from the Ai r Fo rc e in the f uture. The deed res tricti o n s h av e not been fi l ed a s no spe ci fi c pro perti es h av e bee n s ol d o r tran s f er r e d . Ba se clo s ure w ou l d re qui re restriction s be in g reg i s t ere d on Coun ty pro perty re co rds. Ba se map s d e picting e nvi ronm e nta l ly-i mp act ed are a s are peri od ical l y u pd at e d . Contaminat e d groun d w at er plum es ar e monito red quarterl y o r se mi-annually an d da t a i s presen t e d in L TM re port s. The in s titutional control s h av e been effe ctiv e f o r contro l lin g acc ess t o the O U s, w ith on e no ted ex cep tio n. At OU - 8, ou t -of-da te o r u ns tab l e o rd nanc e w a s des troy ed ( exp lo ded) on on e occa s ion pri or to 200 0 . Prio r to detonation of the o rd nanc e, the s it e w a s gra ded a nd a sh a l lo w b urn / b la s t p it w a s c o n struc ted. Th i s excavation resulted in breaching of the soil cover placed on this area as part of the selected remedial action for the OU. This was a violation of the institutional controls established for the protection of human health and the environment. The Base made immediate evaluations of the action and repaired the cover. This effort included review of operation directives, providing for additional staff / personal training, completion of sampling and analysis of surface soil samples to determine if COCs had been released, installation of new signage, development and distribution of a new Base map showing environmentally restricted areas, and re-issuance of the Base Commander Continuing Order Policy. The institutional controls have been effective for controlling access to the flightline refueling area and JP-4 area . 7.1.3 Reme d ial Acti o n Perf o rmance The following is a summary of remedial action performance and history at all operable units including system performance and progress towards cleanup levels. Recommendations for changes in the remedial actions at each Operable Unit are contained in Chapter 9.

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- Year Review 

### OU - I The remedial system in the OU-i area consists of a combined soil vapor / ground water extraction system. Two ground water extraction wells were added to the system since the 2000 Five Year Review, to improve containment in the southeast corner of the ground water plume. The system is designed to treathighly contaminated soils and ground water as well as to contain the ground water contaminant plume onsite. Institutional controls at this site consist of a fenced perimeter with a locked gate and appropriate signs to restrict access to the OU. It appears from the LTM that the OU-I system is functioning as designed; however it is unlikely that the system will reach MCLs in the near future. It was estimated in the original design analysis that it would take 25 years to remediate soil and ground water at this site. OU-2 The remedy at the OU-2 area consists of a landfill cap to prevent movement of contaminants, creation of a drainage ditch and a LTM program. It appears that the remedy at this site is functioning as designed. Institutional controls at this site consist of a fenced perimeter with a locked gate and appropriate signs to restrict access to the OU. Two removal actions took place in the OU-2 area. Chemical weapons material training sets and low-level radioactive waste were excavated from this area and disposed off-site. Since the 2000 Five Year Review, three ground water extraction wells were constructed along the south boundary of the operable unit, to address TCE contamination in ground water. In addition, settlement has occurred in the landfill in areas where waste was placed in trenches. Soil fill is being added to restore the surface grade in these areas. OU -3 The selected remedy in the OU-3 area consists of a landfill cover and LTM monitoring. Institutional controls at this site consist of a fenced perimeter with a locked gate and appropriate signs to restrict access to the OU. One of the monitor wells in this area became unusable due to casing damage. Direct push borings have been installed to determine whether a new monitor well is required in this area. The landfill cover remedy is functioning as intended. OU -4 The remedial system in the OU-4 area consists of a landfill cap and ground water extraction system. The landfill cover is designed to prevent infiltration through buried waste while the ground water extraction system is designed to contain the plume and to remediate the plume south of the landfill. Institutional controls at this site consist of a fenced perimeter with a locked gate and appropriate signs to restrict access to the OU. The long-term monitoring data indicates that the pump and treat containment system is not completely effective, due to geologic conditions (heterogeneous soils and impermeable soils) which limit the effectiveness of this technology. Additional ground water extraction wells have been installed to enhance the effectiveness of the plume containment system. The remedial design analysis estimated that 15 years would be required to remediate the off-Base portion of the plume. Experience is indicating that the required time for remediation with pump and treat will be longer. Alternative technologies to enhance the ground water remediation are discussed in Section 4.4 (System Optimization) and in Section 9.

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- Year Revtew OU-5 The remedy in OU- 5 consists of a landfill cap and LTM monitoring. Institutional controls at this site consist of a fenced perimeter with a locked gate and appropriate signs to restrict access to the OU. The remedy's effectiveness was hampered by a landslide in the years following the cover construction. This caused breaches in the landfill cover soil, allowing surface water to infiltrate into the waste area. A system of underdrain pipes was installed in the area in 2001 to lower the ground water table at the top of the Pierre Shale, where tile slope failure occurred. Monitoring of the area has shown a reduction in ground water levels and the slide movement has been halted. OU - 6 The remedy in the OU - 6 area consists of a landfill cap and LTM monitoring. Institutional controls at this site consist of a fenced perimeter with a locked gate and appropriate signs t o restrict access t o the OU. It appears that the remedy is func tioning as designed and that ground water has not been impacted by contamination from waste in the landfill. North of the landfill an area of incinerat or ash was discovered since the 2 000 Five Year Review. Limi ted testing of the material has been performed to determine its extent and chemical characteristics. The Air Force is considering removing this material in order to eliminate any future concern about the material and to free this area for future construc tion or other land use. OU - 7 The remedy in the OU-7 area consists of institutional controls and monitored natural attenuation. Institutional controls at this site consist of a fenced perimeter with a locked gate and appropriate signs to restrict access to the OU. The plume has been delineated in the northeast corner of the MSA and in areas immediately to the north and the east. The plume is stable. The VOC concentration has been low (<25 ppb) for the past several years and has been declining. In the September 2004 sampling event, the maximum TCE concentration was 2.9 ppb which is below the MCL. A low-level radioactive waste (LLRW) removal action also was performed in this OU in 1997. The LLRW was disposed of at an offsite location. The remedy is functioning as intended. OU - 8 The remedy in the OU-8 area consists of a soil cover and LTM monitoring. Institutional controls at this site consist of a fenced perimeter with a locked gate and appropriate signs to restrict access to the OU. The remedy appears to be functioning as designed. No ground water impacts have occurred. Prairie dogs have been observed moving into the area of the cover over the Debris Burial Area. This could compromise the cover. The Air Force is considering an action to excavate and remove the buried material in this area, rendering the prairie dog issue moot. OU -9 OU-9 had a no-action ROD. OU-10 OU-l0 had a no-action ROD.

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### O U -11 The remedy in the OU-I l area consists of eight ground water extraction sys t ems that are designed t o contain low-level chlorinated hydrocarbon contamination, as well as monitored natural attenuation in the area east of the installation. It appears that the systems are functioning as designed although, due to the expanse of the p l umes, it is unlike l y that contaminant levels will reach MCL's in the near future. A fourth extraction well was placed in the BG-05 Base Boundary remediation system since the 2000 Five Year Review. A fifth extraction well is being installed at the BG-05 system in 2005 to enhance containment in this area. In-situ remediation is being implemented at the northwest comer of the Pride Hangar, where a localized area of TCE ground water contamination has been found. The remediation consists of sodium lactate and vege t able oil injec tion to achieve reductive biodechlorination in-situ. An Explanation of Significant Difference (ESD) is being executed to accomplish this i n -site remediation. An off-base wat er line conveying potable wat er to land owners impacted by the off-si t e portion of the p l ume in the AOC 24 area has been installed t o mitigate any potential risk to the public. An additional water line was constructed t o serve property l ocated south of the Base near OU-4. This water line was installed to limit the pumping of the ground water in this area as the TCE plume from the OU had moved south of the Base boundary and had been detected in private domestic wells. TCE contamination has been detected in ground water flowing from a drain line under the South Docks, and a pump is being installed to move this water to the FRA-PH l treatment facility. Further monitoring is p l anned in this area, iden tified as ST-23. This area contains UST sites and was the site of the original Civil Engineer shops in the 1940s. The monitoring is intended to locate sources of the TCE contamination and to address UST si t es in this area. OU- 1 2 The remedy in the OU-12 area consists of a landfill cover and LTM monitoring. The institutional controls at this site include a perimeter fence with locked gates and appropriate signs to restrict access to the OU. The remedy appears to be functioning as designed; however, TCE concentrations in ground water north of the OU continue to slightly exceed MCLs. Minor erosion has occurred on the landfill cover and has been repaired. 7.1.4 Op eration and Mainten anc e Operation and maintenance activities are conducted on a daily basis. Operation and maintenance consists of trouble shooting any problems that occur at any of the active remediation sites as well as scheduled preventive maintenance. Operation and maintenance activities are outlined in Chapter 4. 7.1.5 O peration and Maint en anc e Costs Operations and maintenance (O&M) costs include costs of operating the remediation systems, long-term monitoring of ground water, and landfill cap inspections at the operable units. O&M costs for the operation and monitoring of the remediation systems at OU-I, OU-4, JP-4, OU-11, and the Flightline Refueling Area were $1,0 5 9,000 for the 12-month period ending July 30, 2005. This

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# 3 057 102Ellsworth Air Force Base Final Five
- Year Review includes labor, materials, equipment, and maintenance costs for ti le remediation systems and labor, analytical costs, and reporting costs for the monitoring program at these OUs. Long-Term monitoring costs for OU-3, OU-5, OU-6, OU-7, OU-8, and OU-12 were approximately $19,000 for the period ending June 30, 2005. These costs are principally the costs for periodic sampling and analysis of monitor wells at these sites, as well as related evaluation and reporting of the monitor well data. LTM costs have been higher in past years when landfill cover problems at OU-5 were being addressed. 7.1 . 6 R e me dial A c tion Opti mi z a tion The remedial systems are continually monitored and examined for ways to optimize the system and reduce costs. This includes preventative maintenance, shutting down systems where remediation has been achieved, optimizing treatment systems (e.g., taking carbon filters off line at Pump House No . 1) and periodically changing monitoring and sampling plans to account for changes in plumes or system operations. Remedial actions arc monitored on an ongoing basis to evaluate system effectiveness and to find ways to optimize system operation. Optimization actions implemented over the past 5 years are described more fully in Section 4.4. 7.1. 7 Indi c a tors of Poten tia l Failure s There have been no chronic recurrent equipment breakdowns that could potentially impact the selected remedies. When equipment breakdowns occur the onsite O&M staff have the training and resources to deal with the problem in a timely manner. B iofouling o f ground wat er extraction wel l s is a chronic issue. Biofouling drastically decreases flow from the extraction wells and as a result makes the remedial system less effective. Extraction well pumping rates are constantly monitored to detect biofoulmg. Affected wells are redeveloped annually. High selenium in treatment plant effluent has been a recurring problem. Selenium is a naturally-occurring element in ground water in this area. Occasionally, the selenium concentration will exceed permissible standards for discharge to a surface water body. Two re-injection trenches have been constructed to allow re-injection of plant effluent from the Building 6908 facility into the ground. Under high flow conditions, the capacity of these trenches can be exceeded. When that occurs, the effluent is directed back to the surface discharge. The re-injection trenches have mitigated the selenium problem at Building 6908. At the current time, effluent disposal is alternated between the surface discharge and the re-injection trenches. The effluent from the treatment facility at FRA-PHI is also prone to occasional spikes in selenium levels. At those times, the situation is controlled by selectively shutting down extraction wells which have high selenium levels. The TCE plume at OU-4 has not been completely addressed by the ground water pump and treat system, due to the ground conditions which include narrow preferential flow paths. An additional extraction wellwas placed in this plume since the 2000 Five Year Review to enhance plume capture. In addition, an insitu remediation technique is being implemented on a treatability testing basis. The technique is in-situ reductivc dechlorination; the test includes injection of vegetable oil or sodium lactate at the source area in OU-4 and at three locations down-gradient in the TCE plume. The treatability test began in May, 2005and will extend for 12 months. The test is showing early positive results in the source area. In the downgradient areas, the effectiveness is not yet clear. The effectiveness of this technique in the down-gradient areas may bc hampered by the low TCE concentrations (<25 ppb) in the ground water in those arcas.

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### The cover at OU-5 developed a series of cracks or sinks in the 1990's. The southeast face of the OU slumped significantly in 1999. The Air Force, along with engineering and soil experts from contractor firms and the South Dakota School of Mines, investigated the site. This investigation recommended repairs to the slide area and further monitoring for additional movement. The repair work was completed in August of 2000. Ground water underdrains were installed in 2001, reducing the ground water level in this site and arresting the slide movement. The area continues to be monitored for movement of the slide mass. 7.2 V ALIDITY O F A SS UMPTI O N S 7.2.1 C h anges in ARA RS and T BC Criteria The A RA Rs and T BC cri te ria u se d to d e v e lo p the reme dial action sele ction proc ess at EAFB we r e app rop ri at e at the ti m e of F S an d RO D de v el o p m e nt . No ch ang es in the che mical , ac tion , o r location s p e cific crit eria h av e res ult e d in the n ee d to r ee valua te these A RA Rs o r T BC crit e ria . South Dakota G round W at er Quality Stan d ar ds fo r a number of contaminant s were ch ang e d f rom e ither a " No s tandard availab l e" o r a " Non- De t e ct L e v e l " to a spe ci fi c conc e ntration in 200 4 . O f these s tan d ard s, e ig ht che mical s no w h av e lo wer allo w ab l e conc e n t ra tion s, 28 h av e h ig her allo w ab l e conc e ntration s, and nin e h av e a conc e ntration s tan d ard for the fir s t tim e. The e ig ht che mical s w i th l o wer allo w able conc e ntration s and the nin e n ew che mical s we r e not spe ci f ica l ly id e nti fie d a s C O C s in the RODs. The cri t eria se l e ct e d we r e and continu e to be prot e ctiv e of h uman he alth and the e nvi ron me nt . 7.2.2 Changes in Exposure Pathways The exposure pathways evaluated as part of the human health risk assessment were appropriate for the conditions existing at the time of the completion of the RI, FS and RODs. Current conditions and anticipated future conditions on-Base and on off-Base properties are represented appropriately by these pathways and no revisions are needed. The completed ground water pathway at the BG-04 / BG-05 area off-Base to the east adds a completed pathway that was not specifically addressed in the human health risk assessment for OU-II. However, the remedial actions applied to this site have taken into consideration this completed pathway and the application of MCLs as cleanup goals will be protective of human health and the environment. The indoor air pathway is being investigated further at this time, based on the possibility of TCE vapor from contaminated ground water entering basements of residences . However, this does not represent a new pathway in terms of the risk assessment, since the original risk assessment included the inhalation pathway for those OUs where contaminated ground water would be used for showering in the future. The levels of exposure would be higher in these risk assessments than the levels observed from soil vapor moving through foundations or floors, since they result from direct volatilization into a closed bathroom. 7 .2.3 Changes in Toxicity and Contaminant C haracteristics T ab l e 6 -10 s ummari zes ch ang es in to x icity valu es app licab l e to spe cific C O C s id e ntifi e d at EAFB . The ch ang es in the re f ere n ce d o ses and s lo pe facto rs fo r the organic C O C s i de n ti fie d in T ab l e 6 -10 are not expected to affec t the overall remedial actions at EAFB. The COCs reported at EAFB are expected to be removed and / or contained by the remedies selected for EAFB. In those situations where one of the values decreased, the calculated dose or exposure concentration to receptors, and therefore the risk, would increase. Whether these changes are significant is specific to the particular chemical and exposure pathway. The assumptions made in the risk assessments were to evaluate the risk using both average and

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# 3057 104Ellsworth Air Force Base Final t :' ive
- Year Review reasonable maximum exposures (RMEs). This resulted in a conservative risk approach for the site. Marginal ly acceptable or unacceptable risks were considered when developing remedial actions. The design of the remedial systems at EAFB was completed based on the cleanup goals listed in the RODs. These cleanup goals took into consideration the results of the human health and ecological risk assessments as well as MCLs and other State s t andards. For ground water remediation, the MCLs were the primary consideration during design. Therefore, unless the MCLs change, the changes in the toxicity values used to estimate risk at the operable units wilt be reviewed while evaluating the protectiveness of the remedial decision but would not specifically drive the selection or re-design of a remedial action. 7 .2.4 C hanges in Risk A s sess m ent Meth od Human he alth ri sk a ssess m e n ts an d the ri sk s c en ario s applied at EA F B w ere appro priat e f o r the i de n tifi ed c o mp l eted p athw ay s an d curre n t an d a n ti c ip a ted f uture lan d u s e . No re vi s i o n s o r ch ang es in the a ss ump tion s appe ar appro pria te b a sed on curre nt in f o rm a tion . The dermal ri sk calculatio ns com p l e t ed in the R 1 rep o rt s were b a se d on 19 8 9 E PA Gu i d a n c e M a n ual s. Utili z a tion o f the curre nt E PA Dermal Ri s k A ssess m e nt G ui d anc e fo r S uperf u n d wo ul d li ke ly res u lt in lower calcula ted ri sks. The e cological ri sk a ssess m e nt comp l eted a s p art o f the RI proc ess a t EA F B utili zed a three -ti e r ed a ssess m e n t appro ach. The T i er I l e v e l inc l u de d e va l ua tio ns, o bservation an d a ssess m e n t of h ab itat valu es at the O U s . We tlan d an d t erres trial p la nt communiti es were e va l ua ted in the field an d augm e nt ed w ith an e c d otal and s y s t e ma tic w il d lif e o bserv ation s. The T i er I d a t a w a s u sed to e valua te the s it es i n m o re d etail un der T i er lI where e i ther sp eci es o f co n c ern were i d en tified o r s igni fi can t h ab i t a t th at could attract w il d lif e w a s prese n t e v e n th oug h T i er I fie l d da ta d i d n o t in d icat e the prese nc e o f the w i ld lif e during the s tu d y . The T i e r lI inv es tigatio ns lb cu sed o n the e valua tion o f be nth ic i n v ert ebra tes, fi sh, an d terres trial inv ertebrat es. F iel d o bservation s o f b i rds and other terrestrial f au n a were comple t ed. If in itial s cree ning of d ata und er the firs t tw o T i ers in d ica ted; either, degra ded be n th ic , fish or soi l f au na c o mmun iti es or elevated concentrations of COCs in sediment, surface water of s o ils then the site was carried to the Tier III level of investigation. The Tier III evaluation involved detailed quantitative ecological risk assessments. This approach was consistent with the USEPA guidance for the selection of assessment and measurement endpoints in ecological risk assessments. None of the individual OUs were carried over to a Tier III investigation, however a Basewide evaluation was completed. The Basewide Ecological Risk Assessment for EAFB w a s structured according to U.S. EPA guidance, and consists of four related components (EPA 1992): problem formulation, exposure assessment, ecological effects assessment, and risk characterization. T he relationship of these components is illustrated in Figure 7-1. This model provided a logical sequence from Problem Formulation (identification of Chemicals of Concern [COCs], Receptors of Concern [ROCs], exposure pathways [in the Conceptual Site Model (CSM)], and measurement and assessment endpoints), to Analysis (characterization of exposure and toxicologic a l effects), to Risk Characteriz a tion (the integration of exposure and ecological [toxicological] effects assessments). The structure of the Basewide ecological risk assessment evolved throughout the remedial investigation process. Some of the elements of Problem Formulation, i.e., identification of stressors and ecological components, were an outgrowth of the preliminary risk screens done at each individual OU. This information was reviewed and discussed with the EPA Region VIII Ecological Technical Assistance Group (ETAG). Ultimately, the Problem Formulation phase was formalized as shown in Figure 7-1, and the components of Analysis and Risk Characterization were added to the framework to support the Basewide ecological risk assessment.

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### In 1998 the USEPA issued updated ecological risk assessment methods and standard guidance that has changed since this evaluation was done at EAFB. The tiered approach used in the ecological risk assessments completed for EAFB is still one of the recommended approaches. The completed risk assessment did not identify excessive risk exposures for the Species of Concern nor were any habitats identified as needing remedial actions. The assumptions made during the ecological risk assessment were appropriate and protective of the ecological community at and adjacent to EAFB.

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### 8.0 DEFICI E N CIES A ND MO D I FIC ATI O NS In f o rma tion on p a s t defi ci e nci es an d app li ed mo d i fi cation s w a s prese n ted in T ab l e 4- 5 an d w a s d i s cu ssed in se c tion 7 . 1 . 3 . The follo w ing s um m arizes the defi ci e nci es / pro b l e m s i de nti fied during th i s fiv e -y e ar review. OU-I Continued occasional selenium discharge limit violation at the central treatmen t faci l i ty. Possible contaminant movement past extraction wells in the southeast area of the OU. OU-2 I ncreased concen trations of TCE in some sou thern boundary monitor wells. Three new ground water extraction wells were installed to address this issue. Ground water concen trations down gradient tYom the extraction wells have been reduced below MCLs. Minor settlement has occurred in the waste trenches. Soil will be used to restore these areas to grade. OU-3 No identified issues. OU-4 Increased concentrations of TCE in some bounda ry monitor wells. Containment of the plume is incomplete. Additional extrac tion wells have been ins t alled t o address this issue. A treatabili ty study has been ini tiated t o determine whether in-situ passive t echniques may be more effective than ground wat er pump and treat. OU-5 The slope failure along the southeast and north face of the landfil l has stabilized satisfactorily. OU-6 No issues iden tified. An area of buried incinerator ash is located near, but no t within, this OU. Removal and disposal of the ash is being considered by the Air Force. OU-7 No issues iden tified. OU-8 Possible impac t s on the soil cover at the debris burial area due to encroachmen t of prairie dogs. OU-9 No issues identified . OU-10 No issues identified. OU-II An additional ex trac tion well will be ins t alled in the BG-05 system t o increase the capture efficiency at the si t e. A drainage pipe in the Sou th Fligh tline area is discharging wat er containing TCE at a concentration between 5 and l0 ppb. A pump will be ins t alled to recover this con t aminated drainage and pump it t o the FRA-PHI facility for treatment and discharge. Addi tional moni t oring is planned north of OU-12 to evaluat e consis t ent TCE concentrations above 10 ppb in this area. Additional monitoring is planned in the ST - 23 area (sou th end of the flightline) t o address the TCE contamination in the South Fligh tline drain and several UST sites. OU-12 No issues identified. Routine repairs have been performed on the landfill cap.

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### 9.0 REC O MMENDA T IONS AND FO L L OW -UP AC T I ONS A Remedial Project Manager (RPM) group is in place to oversee the Environmental Restoration Program at Ellsworth Air Force Base. The group is comprised of personnel / managers from the Air Force, Corps of Engineers / Omaha District, South Dakota Department of Environment and Natural Resources, EPA Region 8, and contractors. The purpose of this group is to monitor the remedies and remedial actions selected for the 12 Operable units, and to develop revisions to the remedial action program as necessary in response to changed conditions and new technologies. As deficiencies or opportunities for optimization are identified, they are addressed by the RPM group. The group is also responsible for programming and obtaining funding for additional work at the base. This will ensure the remedies will continue to be protective of human health and the environment or continue or to progress towards being protective of human health and the environment, i.e., O&M of RA systems and LTM monitoring. This chapter reviews recommendations made in the first five year review in 2000, and presents new recommendations for future management of the ERP. 9 .1 RECOMMENDATI O N S FROM 2000 FIVE-YEAR REVIEW Based on the results of agency review comments and the evaluations completed as part of the 2000 five-year review at EAFB, a number of recommendations were suggested for evaluation and consideration prior to the next five-year review. These recommendations and their current status are su m marized below. I. Conduct a detailed evaluation of the geophysical conditions at OU-5 that have or may have contributed to the soil slide conditions observed at this OU. This evaluation should recommend a solution to the problem. Status - Complete. A corrective action consisting of underdrains to remove ground water was installed in 2002. The movement of the slide has slowed to a near standstill. Monitoring and periodic surface repairs continue. 2. Review the available dioxin data from OU-8 and compare the data to the new information published by the US EPA on dioxins and P C Bs. Review the risk implications of these changes if the data indicates that the dioxin and PCBs concentrations a r e different than action levels. Status - Complete. This information was provided in the Long Term Monitoring 2001 Annual Report for OU-8, Serial Letter No. 1-36-RD-337, dated November 7, 2001. This letter included a recommendation for additional sampling which was completed. Results were reported in the Long Term Monitoring 2002 Annual Report for OU-8, Serial Letter No. 1-48-RA-322. 3. Develop a data summary t able c o nta ining the an alytical data from the RI and the L TM programs. Compare the data set to the risk based screening levels and preliminary remediation goals levels published by EPA Regions 9 and 3, respectively. This data file should be updated with new LTM data as it becomes available. Status - Complete. For sample locations included in the LTM program, the summary table was included in the April and July 2005 LTM reports. Detected analytical results were compared to the Federal maximum contaminant levels (MCLs) and the South Dakota Ground Water Standards. If no MCL or numerical South Dakota Ground Water Standard was established, the

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# 3057 108EIIswo r th ,4Jr Force Base Uinal Five -) 'ea t" Revie _a detected result was compared to EPA Region 3 and 9 risk based screening levels. No te: These reports are outstanding for OU-3, OU-6, OU-8, OU-11 and the Flightline Refimling Area. 4. Complete an evaluation of the ground water elevations and chemical contaminan t concentrations of the plumes at OU-I, OU-2 and OU-4. The evaluation should be focused on de termining if there is an inter-relationship between the plumes and ground water flow patterns and evaluate if the remedial ac t ions installed are providing containmen t of these plumes. Status - Complete. Preliminary resul t s from a 2005 intrusive investigation indicate t hat the OU-1 plume does not reach the OU-2 area or in teract with the OU-2 plume. A previous s t udy established that t he OU-I and OU-4 plumes do not mix or interact. The OU-I plume remediation system has been effective at maintaining plume containment and removing contaminant mass from the ground water. The con tainmen t system installed on the south boundary of OU-2 has been in operation for nearly one year and has proven to be effective in containing the TCE ground water plume at this location. The OU-4 plume containment has been incomplete, due to geologic conditions which hinder the effective operation of pump and treat technology. Partly tbr this reason, the Air Force is ini t ia t

ing a treatability study of in-situ reductive biodechlorination, using sub-surface injection of substrates such as vegetable oil and / or sodium lactate. 5. Develop a decision tree / process which provides an approach to the close ou t and finalization of the remedial action process for operable units as they reach applicable cleanup levels. This could include recommendations on the duration of operation and monitoring after the systems meet remediation goals, and / or how to document asymptotic conditions. Development of a list of documents and or reports necessary to close out a site. Status This task has begun with the de-listing proposal that is currently being developed. This initiative is described more fully in Section 9.2 (below). 6. Develop a series of maps that show the changes in contaminant plume size and concentration levels over time for each OU with an active remediation system. Status - Complete. These maps are presented in the periodic LTM reports. 7. Develop a statistical evaluation of the removal rates and effectiveness of the each remedial system. Evaluations should provide estimates of percent of original contamination removed, estimated remaining contamination mass, and estimates of remaining time needed to remediate the plume. Status - Complete. This information will be submitted in a serial letter report in September, 2005. 8. The Air Force will address the issues raised during the community interview process. Status - In progress.

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# 3057 109Ellswo r th Air Force Base Final Five
- Year Review 9. Evaluate revisions to the Long Term Monitoring Plan. Status - Complete. The LTM program has been revised periodically. 9.2 2005 FIVE-YEAR REVIEW RECOMMENDATI O NS The Ellsworth AFB RPM group has undertaken an ex t ensi v e review of the overall management of the operable units, with a view toward achieving closure or deletion of the OUs where possible. In general terms, the proposed future management of these OUs involves consolidation of all ground water contamination issues into a single OU (Operable Unit 11); and deletion, i.e., removal from the National Priorities List, of most of the other operable units. This section presents detailed recommendations for each of the 12 operable units. 9 .2.1 OU-I M anag e m e nt and cle anup of c ontaminat e d ground w at er in the OU- 1 are a w a s re c e ntl y sh ift e d to O U-11 , the b a sew id e ground w at e r operab l e unit . Th i s w ill con s olidat e ongoing LT M s am p ling into O U-I 1 . In s titutional control s id e nti fie d in the RO D sh ould be maintain ed. R outin e in spe ction o f s it e acc ess contro ls cou l d be condu c t e d during l ong-t erm ground w at er monito ring program s. A l t ernativ e t e ch nologi es we re e valuat ed w ith a vi ew to w ard acc elerat ed c lo se out of th i s s it e. These includ e d wh ol es a le ex cavation and land f arming ; ex cavation and the r m al tr e atm e nt ; and in- s itu the rmal tr e atm e nt throug h e l e ctrical res i s tanc e he ating . The es ti mat e d c os t s of the c ur r e nt RA were com p ar e d w ith the co s t s of the " a c c e l e rat e d clo se out opti on s"; the acc e l erat e d o p tion s are es timat ed to be much h ig he r in co s t . EAFB re comm e nd s continu ed o peration of the ex i s ting SV E and ground w at e r s y s t e m s , w ith ongoing o p timi z ation to continu e to ma x imi ze contaminant re cov e ry . Con s id eration sh ould be giv e n to in cre a s ing the number of SV E p oint s and to in s talling additional ground w at er e xtraction we ll s to incre a se the r e moval of vap or ph a se , f ree - ph a se, an d d i ss olv e d ph a se conta minant s. Th i s w ould al s o introduc e incre a sed l e v e l s of o x yg e n into the s ubs urfa ce, he l p ing ex p ed it e the natu ral att e nuation of the pe trol e um comp o u nd s. 9.2.2 OU-2 T C E ground w at er contamination w a s d e t e ct e d s outh o f O U- 2. T hree e xtra c tion we ll s w ere i n s tall e d to a ddress the i ss u e. Ba se d on e arly monito ring res ult s, the p lum e appe ars to be bee n contain ed an d the o ffb a se plum e h a s bee n re m e diat ed. Ground w at er r e m e diation an d monito ring i ss u es we r e tran sfer r e d to O U-I 1 . The s ubs tantiv e re quir e m e nt s f o r s it e clo s ur e for th i s O U h av e bee n me t . EAFB w ill prep are and s ub mit a re comm e n d ation fo r p artial d e l e tion of the EAFB s it e, inclu d ing th i s O U . The partial d e l e tion docum e ntation w ill outlin e any p o s t-clo s ur e monitoring / in spe ction s th at n eed to be don e to as s ur e contin ued complianc e w ith the ROD and s tatuto ry complianc e, includin g com pl ianc e w ith app l icab l e in s titutional control s. These w ill includ e re comm e n d ation s for annual land fi ll c ov e r in spe ction s and limit e d (on ce e v ery 5 y e ar s ) gr o un d w ater monitorin g to provi de a ss ura n c e o f continu ed c o mplia n c e w ith s ta tu tory re qui re m e nt s. Th i s s it e w ill the n be e ligi b l e for r e moval f rom the NPL throug h a p artial d e l e tion proc ess, wh ich i n clu des pub li c i n v o lv e m en t a nd ap prova l b y E PA an d the S tat e of S outh D akota . Th i s s it e i s c o ns i dere d b ui ld abl e w ith i n the res tricti o n s app lied by the i ns titutiona l c o n tro l s. Co ns truction at the s it e w ill be lim i t e d to fa c iliti es th at can be b uilt s lab -on- gra de o r b y other m e an s th at w ill not compromi se the s o il cov er a nd wh ich are con s i s t e nt w ith the g e ot e ch nica l limitation s of the w a s t e

Li WORK IERSI 84610 1 WP_. EAFB5
- YEARREVIEW2005DOC 102 30 5 7 110 eptember2005Ellsworth Air Force Base Final Five
- Year Revi e w trenches . . Use of the site for equipment parking, shops, and other industrial pu rposes is possible provided they fall within any Base land-use restrictions for flightline, safety, and noise programs. 9 . 2.3 O U
- 3, OU
- 5, OU-6 , OU-8, and OU-12 B ased o n the risk a ssessment results from the RI and LTM monitoring results at these OUs it is apparent that no adverse ground water conditions exist . Ground water management is being transferred to OU-I I. The substantive requirements for site closure for these OUs have been met. EAFB will prepare and submit a recommendation for partial deletion of the EAFB site, including this OU. The partial deletion documentation will outline any post-closure monitoring / inspections that need to be done to assure continued compliance with the ROD and applicable statutes. These will include recommendations for annual landfill cover inspections to assure compliance with statutory and ROD requirements. These sites will then be eligible for removal from the NPL through a partial deletion process, which includes public involvement and approval by EPA and the State of South Dakota. 9.2.4 OU-4 Management and cleanup of contaminated ground water in the OU-4 area was shifted to Operable Unit 11. OU-II is the basewide ground water operable unit, and it would be most efficient to consolidate ground water contamination issues into that OU. This change would consolidate ongoing LTM sampling into OU-11. The current treatability study for in-situ reductive biodechlorination should be completed. If it is effective, this technique should be implemented at full-scale to eliminate the source area. If the in-situ technique is not effective, EAFB recommends a removal action to positively and quickly remove the source area contamination from the OU-4 landfill. Institutional controls identified in the ROD should be maintained. Annual inspection of the soil cover and routine inspection of site access controls will be conducted during mowing operations. Following site closure, this site is considered buildable within the restrictions applied by the institutional controls. Construction at the site will be limited to facilities that can be built slab-on-grade or by other means that will not compromise the soil cover and which are consistent with the geotechnical limitations of the buried waste. Use of the site for equipment parking, shops and other industrial purposes is possible provided they fall within any Base land-use restrictions for flightline, safety, and noise programs. 9 . 2 . 5 O U -7 No adverse ground water conditions exist with the exception of limited areas east of the OU, where TCE concentrations historically have exceeded MCLs. That area has low concentrations and is stable. The ground water portion of OU-7 was transferred to OU-11 (the basewide ground water operable unit) for continued management or closeout. This consolidates routine monitoring activities into OU-i l. The substantive requirements for partial deletion for this OU have been met. EAFB will prepare and submit a recommendation for partial deletion of the EAFB site, including this OU. The partial deletion documentation will outl ine any post-closure monitoring / inspections that need to be done to assure continued compliance with the ROD and applicable statutes. This monitoring is likely to be limited to annual verification that the institutional controls are in place and effective. Limited ground water monitoring should be performed. This site will then be eligible for removal from the NPL through aEllswortk Air Force Base F inal Five
- Year Review 

### partial deletion process, which includes public involvement and approval by EPA and the State of South Dakota. 9. 2 .6 OU-9 The preferred al ternative for the site was no action, and a Record of Decision incorporating that alternative was signed in 1996. There is no RA or LTM activity at this site. The Air Force will include this site in the request for partial deletion of the EAFB site from the NPL. 9.2.7 OU-10 The preferred alternative for this site was no action under CERCLA and treatment of contaminated soil under the State of South Dakota petroleum release regu l ations. A no-action ROD was signed for this site in 1996. Removal ac tivities for petroleum-contaminated soil have been completed. Limited removal of free product is continuing at the area north of the 80 Row hangars. There are no CERCLA remedial activities or monitoring activities underway or required at this operable unit . The Air Force will prepare and submit a request for partial de l etion of this site from the NPL. 9.2 . 8 O U -II Groun d wat er m anagement for Operab l e Uni t s l, 2, 3, 4, 5, 6, 7, 8, and 12 and for the Fligh tline Refueling Area was recently transferred to Operable Unit 11. Currently, the first technology of choice for remediation of chlorinated solvent contamination in ground water is in-situ biodechlorination. This consists of the injection into the subsurface of electron donors such as proprietary produc t s, emulsions of vegetable oil, sodium l actate, or even waste milk products. This technology has been deve l oped in the period since the EAFB remedial actions were developed and the RODs were signed. Generally, in the Ellsworth AFB si t es, in-situ biodechlorination is considered a potentially valuable supplemen t to the existing ground water pump and treat systems. Area 1 Operation of the pump and treat system at the Pride Hangar should continue, al ong with the aggressive biodechIorination treatment of the TCE source area at the no rthwest corner of the Pride Hangar. This source area treatment has been initiated with soy oi l and is being evaluated. This operation is expected t o reduce TCE contamination to near MCL's within 5 t o 10 years. SVE treatment for the TCE soil contamination at the northwes t co r ner of the Pride Hangar should be performed if adverse impacts on the in-situ ground water remediation can be avoided. Evaluation of possible TCE vapor in the Pride Hangar building should continue. Operation of the South Docks pump and treat system should continue as well. The extraction wells at the down-gradient end of the South Docks system, l ocated near the base drainage, should continue to be operated pending the further development of in-situ technologies for TCE remediation. These technologies include the permeable reactive barrier and the "biowall" techno l ogy currentl y being pilot tested at EAFB. Within 5 years, i t is reasonable to expec t that one or more of these technologies will have matured to the point where they can be implemented near the base drainage to effect containment. At that point, the ground water pump and treat systems could be shu t down and the minor remaining contamination could be addressed through natural attenuation and the action of the in-si tu remediation containmen t sys t ems.

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# •" 305 7 112Ellsworth Air Force Base Final Five
- Year Review 

### The monitoring in the ST-23 area should be completed and evaluated to determine whether additional remediation is warranted in this area. The monitoring in the area up-gradient from OU-12 should be completed and evaluat ed to determine whether remedial action is required in that area. Former Fire Protection Training Area: Ground water contamination in this area should be addressed through continued operation of the ground water pump and treat system. Operable Unit Four Area: Ground water contamination in this area should be addressed through a continuation of the in-situ biodechlorination treatmen t options that are being pilot-tested at this time. If, as expected, these measures are effective, they should be expanded into full-scale remediation with appropriate revisions to the Record of Decision. After the source is removed or remediated, an aggressive program of in-situ treatment can be expected to substantially eliminate the TCE contamination within 5 years. This is expected to be more effective, and in the long run less cos tly, than sole reliance on the ground water pump and treat system and is also expected to be less expensive than permeable reactive barrier technology Flightline Refueling Area: After Pumphouses 1, 2, and 3 (and their related UST's) are removed, and if free-phase contamination is present as expected, ground water collection facilities should be construc t ed in order to achieve removal of the free-phase product and ground water contamination. When the free-phase produc t has been removed, this portion of OU-I 1 should be placed into No Further Action (NFA) status with the South Dakota DENR. NFA requires that free product is absent, contaminan t concentration is stable or decreasing, and there is little current of future risk to human health and the environment. With the site in NFA status, natural attenuation will reduce the remaining concentrations of petroleum compounds in the ground water. Area 2 Efforts should continue to locate and address the source of TCE contaminants in this area. If sources are found, they can be addressed through in-situ means or, if in soil, by soil vapor extraction or soil removal and disposal. I t will be necessary to maintain containment measures at the base boundary for a period of time after the sources are addressed because of the large volume of contaminated ground wat er in the on-base portion of the BG-04 plume. Containment at the base boundary has been performed with ground water pump and treat since 1997. Those measures should continue while in-situ treatment measures (such as the permeable reactive barrier technology or the "biowall" technology currently being pilot-tested) are evaluated. Within five years, it is reasonable to expect that one or more of these technologies will have matured to the point where they can be implemented at the base boundary. This could achieve containment, preventing the movemen t of contamination off-base, without the ongoing cost of O&M for the ground water pump and treat system. With respect to the off base ground water plume, it is recommended that the natural attenuation currently underway be allowed to continue. This is in accordance with the ROD. Potential exposure has been eliminated by the installation of the water supply system, which will need to be maintained until the TCE contamination has been reduced below MCL's by natural attenuation . This is expected t o require approximately 30 years. Monitoring of the off-base plume should be reduced substantially, since there is ample monitoring data to demonstrate that the off-base plume is stable in extent and is slowly decreasing in concentration. Institutional controls iden tified in the ROD can be maintained under the Base Compliance Program. Following site closure, ,Area 1 is considered buildable within the restrictions applied by the institutional

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# 3057 113Ellsworth Air Force Base Final Five
- Year Review controls; in this area, a variety of land uses would be possible since there are no issues of buried waste as in the case of the landfill sites. The Area 2 sites also will be buildable. Off-Base properties have few buildability restrictions related to the presence of the ground water plume, with the exception of the prohibition on water wells construction. County zoning limitations would be more significant than contamination-related constraints. 9.2.9 Flightl ine Refueling Area (S S-08, ST-10, ST-14 ) M anag e m e n t and cl e anup of contaminat e d ground w at er in the F lig htlin e Ref u el ing A re a w a s sh ift e d to Operab l e Unit 11 . Th i s acti o n con s olidat es L T M activi ti es w ith in O U-I 1 . The re maining pu mp h ou ses (No s, l , 2 , and 3) sh oul d be de moli shed whe n n o lon ger n eeded an d the i r US T's r e mov ed. Contamina te d s oil sh ould be re mov ed to the exte nt p ra c ticab l e a t the s am e tim e, s uf fi c ie nt to r e mo ve co ntamination th at c ould c ontaminat e und e r ly in g g round w at e r . A t th at p oint , these si t es can mov e i nto N o Further Action s tatu s. 9.2.10 JP-4 Jet Fuel Release Th i s je t f u el r e l e a se, locat e d s outh of O p erab l e Unit 2, h a s bee n cl e an e d up in acco rd anc e w i th Stat e of South D akota S tandard s. T he r e m e diation s y s t e m i s sh u t do w n . The s it e wi l l be s am p l e d a fi nal tim e during the next five years to ensure that rebound has not occurre d . Then the A ir Force will ini tiate c l osure procedures with the South Dakota DENR. 9.2 . 11 North D ocks Thee free product plume at 80 Row will continue to be monitored and product recovery efforts will continue as long as product is present.

L .", WORK ! ERSLa4 6 10i Wp i E AFB5
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- Y e ar Review 

### 10.0 PR O TE CTI V ENE SS S TA T EMEN TS INT RO DUCTION Based on the current review, the remedial actions at Ellsworth AFB are protective of human health and the environment and are effective in removing immediate risk of exposure to contaminated media. Institutional controls, including restricted access and fencing, prevent access to this area. A continuing order from the installation commander prevents unauthorized actions at the sites (scc Appendix C). Some of the remedial actions will require long-term operation of treatment systems. Compliance with cleanup goals will be evaluated in future reviews. Effective 7 July, 2005, all ground water management was moved to OU-11, but ground water issues are addressed as part of the specific OU descriptions below. 10.1 O U- I The remedy at this site is considered to be protective of human health and the environment and immediate threats have been addressed. The OU-1 remedy consists of SVE and ground water ex traction components which are designed to remediate hotspot contamination in the immediate vicinity of the old fire training pi t area and to contain the plume onsite. A fence has also been instal l ed t o restric t access to the operable unit. A long-term ground water moni t oring program is also in p l ace at this operable unit. Information gathered to d a te at this site indicates a significant amount of cont a minant mass has been removed and continues to be removed from the site and the ground water contaminant plume has been contained. 10 . 2 OU- 2 The remedy at this site is protective of human health and the environment. A landfill cap was installed at this site preventing the infiltration of rainwater as well as direct contact with contaminated soils and a drainage flume was also installed in this area to reroute drainage around the landfill. A fence has also been installed to restrict access to the operable unit. Recently, additional soil cover material has been p l aced t o fil l areas o f se ttl ement in the was t e trenches. Ground water extraction wells have effectively contained TCE contamination moving south from this landfill and have remediated the TCE ground water contamination located to the south. The landfill cap is inspected for integrity on a quarterly basis and a long-term ground water monitoring program is also in place at this operable unit. Information gathered to date at this site indicates that the landfill cap and drainage flume appears to be functioning as designed. 10 . 3 OU
- 3 The remedy at this site is pro tective of human health and the environment. A landfill cap was installed at this site preventing the infiltration of rainwater as well as direct contact with contaminated soils. A fence has also been installed t o restrict access to the operable unit. The landfill cap is inspected for integrity on a quarterly basis. A long-term ground water monitoring program is also in place at this operable unit. Information gathered to date at this site indicates that the landfill cap appears to be functioning as designed. 10.4 O U-4Ellsworth Air Force Base Final Five
- Year Review 

### The remedy at this site is protective of human heal th and the environmen t . I m mediate threat s have been addressed. A landfill cap was ins t alled at this site preventing the infiltration of rainwat er as well as direct contact with contaminat ed soils. An off-base prope rty that was impacted by the chlorinated hydrocarbon p l ume originating under the landfill was acquired by the Air Force. Ground water extraction wells were installed on and off base to address the offsite movement of the chlorinat ed hydrocarbon p l ume. These extrac tion wells are reducing the concen tration and extent of the off-base plume. A treatabili ty study is underway to assess the effectiveness of in-situ biodechlorination techniques, which would supplement the pump and treat if they are effective. A fence has also been installed to restrict access to the operable unit. Affected parties have been supplied wi th an alternate source of water via a water main system cons tructed and operated by the Air Force. The landfill cap is inspected for in t egrity on a qua rterly basis. A l ong-term ground water monitoring program is also in place at this operable unit. Information gathered t o date at this site indicates that the landfill cap appears to be functioning as designed. 10.5 O U
- 5 The remedy at this site is protective of human health and the environmen t . A landfill cap was instal l ed at this site, preventing the infil tration of rainwater as well as direc t contact with contaminated soils. The landfill cap in this area has experienced subsidence problems over time and has been repaired several times. In 2001, a system of ground water underdrains was placed in this area to reduce ground water levels and pore pressures near the Pierre Shale surface. The underdrains have been successful in lowering the water table and eliminating the slide movement. A fence has also been installed to restrict access t o the operable unit. The landfill cap is inspected for integrity on a qua rterly basis. Minor grading and re-vegetation is performed as necessary, typically every two or three years, to main t ain the cover. A long-term ground water monitoring program is also in place at this operable uni t . 10.6 O U-6 The remedy at this site is protective of human health and the environmen t . A l andfill cap was installed at this site preventing the infil tration of rainwater as well as direct contac t with contaminated soils. A fence has also been installed to restrict access to the operable unit. The landfill cap is inspected for integri ty on a qua rterly basis. A long-term ground water moni t oring program is also in place at this operable uni t . Information gathered to date at this site indicates that the landfi l l cap appears t o be functioning as designed. 1 0 .7 OU-7 The remedy at this site is protec tive of human health and the environment. The remedy for the OU-7 area is institutional controls and monitored natural attenuation. Semi-annual monitoring is conducted at this si t e to assess natural att enuation and plume movement. A fence restric t s access t o the site. Information gathered to date at this site indicat es that the plume is s t able. 10. 8 OU -8

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# 3057 11 {Ellsworth Air l " orc e Base Final I Q ve - Year Review 

### The remedy at this site is protective of human health and the environment. A soil cover was installed at this site preventing direct contact with dioxin-contaminated soils. A fence has also been installed to restrict access to the operable unit. The soil cover is inspected for integrity on a quarterly basis. A long-term ground water monitoring program is also in place at this operable unit. US Air Force personnel disturbed the soil cover in the fall of 1999 while disposing of some unexploded ordinance. T he soil cover was repaired in the fall of 1999. Recently, prairie dogs have moved toward the debris burial area and threaten to disturb the cover by burrowing in the cover soils. The Air Force is monitoring this situation and is evaluating options that could be implemented in case the cover is affected, lntbnnation gathered to date at this site indicates that the soil cover appears to be functioning as designed. 10.9 OU-9 A no-action ROD was signed for this operable unit. Some of the ground water in this area is being treated and remediated under the OU-I 1 base wide ground water ROD. This action is still protective. 1 0. 1 0 OU- I O A no-action ROD was signed for this operable unit. T his action is still protective. 10.11 OU-I1 The remedy at this site is considered to be protective of human health and the environment and immediate threats have been addressed. The remedy at OU-II consists of eight remedial systems. Five of the remedial systems are connected to a common treatment plant located at FRA-Ptt 1. The remedial systems are located in the South Docks Main area, 30 Row and 50 Row, the Building 102 area and the Pride Hangar area. Ground water collection systems have been added at Pumphouses 4, 5, and 6. The remaining three systems are located in the BG04 west, the BG04 base boundary and the BG05 base boundary areas. A lift station is under construction to address contaminated ground water at the South Flightline Drain. A potential vapor intrusion pathway is being evaluated in on-base buildings. The remedial systems in the OU-I 1 area appear to be functioning as designed, containing the plumes and reducing the mass within the plumes. Monitoring of specific areas continues to address areas where complete containment needs to be confirmed. These include BG-05 and the South Docks Main areas. Parties affected by ground water contamination have been supplied with an alternate source of water via a water main system constructed and operated by the Air Force. 10.12 OU-12 The remedy at this site is protective of human health and the environment. A landfill cap was installed at this site preventing the infiltration of rainwater as well as direct contact with contaminated soils. A fence has also been installed to restrict access to the operable unit. The landfill cap is inspected for integrity on a quarterly basis. A long-term ground water monitoring program is also in place at this operable unit. Information gathered to date at this site indicates that the landfill cap appears to be functioning as designed.

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# 3057 117Ellsworth Air Force Base Final Five
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### 11. 0 NEXT REVIEW The next five year review should be: Initiated By: 1 April 2010. Completed By: September 30, 2010.

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# 3057 118ElL s 'worth ,4 ir Force Base Fmat Five
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### 12.0 M I SC E L L A NEOU S COMM EN TS

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-.... \ L EGEND: _ILMw g solo8 ' , SB 9 30140 ' _, "_ C) I RP P IEZOME TE R \, "'""" CLU S T E R / NES T , '"'" B930124 , \ _ 1993 RI MONITORING WELL \ , 930122 '" "- ..... SOIL BORING LOCATION _It 1 993 R I F I ELD SCRE E NING / . / S O IL BORING LOCATION .. \ /_ IR P, P HAS E II, STA G E 1 &: 2 MONITORING LOC A TION

..... SURFA C E DRA I NA G E

I " I B AS E B O U NDA RY F ENC E \.

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LEGEND: "" MW930108 SB930140 @ IRP PIEZOMETER CLUSTER/ NEST 199 3 RI MONITORING WELL / _22 SOIL BORING LOCATION POND001 (_) 199,3 RI FIELD SCREENING / SOIL BORING LOCATION 

## \ A IRP, PHASE II, STAGE 1 & : 2 MONITORING LOCATION o,so

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# __J OU -3 LANDFILL2 (LF-03) ...... 

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### L T O ILT M APRIL 2000 EV ENT-FLIGHT L IN E

_ IXYL ENE 5 N O E L LSWORTH AFB , SOUT H DAKOTA PREPA R ED FOR U.S. ARMY CORPS OF ENGINEER',APPENDIX A

_ PUBLIC NOTICE OF FI V E-YEAR REVIEW



# - 3057 169

### Ellsworth Ai r Force Base Environmental Restoration Program



# Five Ye ar Revi e w

The EIIsworth Air Force Base environmental team announces the completion of its Five Year Review for the ye a r 2005 . EIIsworth Air Force Base is a Federal " Superfund" site under the Federal Comprehensive Environmental R estoration, C ompensation, and Liability Act ("CERCLA", also known as the "Superfund" Law) . Under this law, the Air Force is requir ed to prepare a "Five Year Review" of the status of the environmental cleanup program. The Five Year Review was first prepared in 2000. It has been updated in 2005 and is available for public review at the locations listed below. Rapid City Public Library Holbrook Library 610 Quincy St. 2650 Doolittle Dr. Rapid City, SD 57701 EIIsworth AFB, SD 57706 394-4171 385-1686 Inv estigation reports of the various EIIsworth cleanup sites ar e availabl e for review at th ese locations, or by appointment at the base environmental office, (605) 385-2680. For more information o r to be added to o ur mailing fist, contact the 2 _ h Bomb Wing Public Affairs office, at (605) 385 - 5056 or e- mail 2 8bw.pa2 @ ellsworth.af.mil.



# 3 0 57 17 0- - AP PEN D I X B COPY OF BASE CONTINUING ORDER



# " 3 0 57 1 7 1

### , ...... " ........_'- DE P AR T M E NT OF THE AIR FORC E
Q HE A DQUARTERS 28TH B O MB W ING (ACC) ELLSWORTH AIR FORCE BASE, SOUTH DAKOTA

' I 8 SE P 2 005 MEMOR A NDUM F O R D I STRIBUTI O N F & T FROM: 28 BW / CC SUBJECT: Land Use Restricti o ns at Enviro nmen t al Restoration Si t es 1. In 1990, Ellsworth AFB was placed on the Environmental Protection Agency's (EPA) National Priority List because of soil and ground water contamination caused by past work practices. In 1992, a Federal Facilities Agreement was signed with the EPA and State Department of Environmental and Natural Resources that divided the base into 12 operable units. 2. The att achmen ts summarize the exis ting restrictions and hazards on each of the 1 2 operable units on base. A copy of the o ri ginal Continuing Order with a map indicating the location of each operable unit on base is at attachment 1. Attachment 2 summarizes the specific restrictions of each operable unit. Attachment 3 delineates the requirement for construction waivers at all restoration program sites. Any violation of these restrictions subjects the base to fines and stipulated penalties. 3. Please be advised that the att ached order continues to be in effect and mus t be s tric tly adhered to by all Ellsworth AFB personnel and contractors. 4 . If there are any questions, please contact Mr. Dell Petersen at extension 5 - 2675.

JE_M_I_olonel , USAF Commander Attachments: 1. 28 BW / CV Memo, 27 Aug 97 2. Operating Unit Restric ti o ns 3. Construction Waiver Memo, 6 Dec 96 4. OU8 Action Plan' " "! DEP A RTMENT OF' TH E AIR F ORCE

_ _ _ F.

_ --- _C_JA R TeR J I * 2 1 1 14 g O M III % ' : 1.' _C IA ¢;CI

FROM " 2g B W/ CV SU B J EC T C o nt i n u i ng Or de r, Le n d U s e Res tr ic t i o n.* at

E n v ironm en :zl P . es t o mdonS i te s h On 2 4 Jm - m z ry 1 992 , th e Unit edS _atesA izF or c e , theS tar,e o f So u t hDako t a . end t he EnvL r on - r n - entzlPr ot e c ti o nA

ge n c y(E P A)entere di

nt o a F e d er a lF a cilffie s A g r eem e n ;. gove n d ng a ctiv i ti es zss oc iat e d " , _-iLh the env_ o m ' ne n t_l r e s t ora ti o n o f Ei| s w o rth A i r F or c e Base. As a p art of that agreement , 12 geo_raphic areas o f enviro n men ta l c o n_.mi a afion, "k n o_ as Op erab| e Units , were" i de mif, e d f or remed l a_ o n . C]e_nu p a nd in s t allation of _ 'o u n d water tre z,.m e m sys t ems fo r th o se sites _ / II b e co mp le t e thi s con stru cti on s easo n . Be c au se corre c th_ . g the e nv iromnemal i mpac ts of t he p ast _ill take many ) ,ears , the i n te_uity o f these O p e r able Units mu s t be p ro te c t e d. 2 . The z_ached figure indic a tes are_ where cle_.'mp _ctivi.:ies have taken or are taldng place . SFecific detailed inTorma t ion conc erning the sites is a va. ; l, .ble f rom th e Ellswo_,h I ns tallation Res,' o radon Pro_arn ( / R.P) offi c e. Cle a n u p acdv h 'es an d furore ]and
- u_e pra ctices v .itb.in the Operable Units are stated in e n forceable Records of Decisions _sl d ch IL"ait a nd, in some cases, forbid consu'uc d on activity . . The IR2 o_.]ce must be c onsu!.ed prior to c o ns truction x_iduin an . Ope : zble Unit. The I RP offic e _ill review a ny proposed consu-u c fion _cti_ , i_"and the Record of De o :sion to determine if h_-pact to c!-._nup activities or to exist,.'ng comz

_ , ni6_tcd media _:ill occur. The EPA, the staze, and Ak Comb a t Co m mand m a y be consulted to help dete , - ur_ne the feas lbilky" of projec t s. Pro p osed cons ; r uc ti on a c;iviti e s _ill be accepted, accept e d _i_h mo d . ; ficatio_, or denied.

_ . F d lure to c omply _ith the above r-.stdctions could pl,,c e the Air Force at risk for additional cleanup work _.nd enforcemem actio_ by the StRte o f South Dako t a an d the Environmental Prote c 6on Agenc y . Modifications to this c ontin u ing ord e r c an only be mad e with concu rren c e from the regulator y, agen c { e s. Co d ifica t ion h u toan Ai r Force Instruction is pending. Add_ional information is Rvail_ble from .MrDill Peterseu az 5-2 6 75 .

Att achme nt : Si t e L o cati o n Map



# • 3 0 57 173

# 3 0 57 1 74Ells w orth Op erab l e U n it s O U
- 1 The sel e c t ed altern a tiv e, s o urc e are a s oil a nd gro und-w a ter _eaun e nt , in c l u des the f o ll o wing m a jor c o mp on e n L _: C o n tinued op er ation o /th e in teri m remed i al ac ti o n ( IRA) which co nsis t ed o / con tami nated gr ound-wate r r em o v a l, soll v ap o r ex traction (SVE) , a nd treatme n t Installation of addi 6onal SV E wel l s within the h i sto r ical bum- p it a re a t o b e add ed to t he existi n g IRA SV ' E sy stem ; Re mov a l of contami nat ed grou n d water using addition al ground-water well s and c o llec tio n u_nches to be a dde d t o the IRA ground-water re cove r y system T r e a

_nen t of gro u nd w ater at th e ex is tin g I RA t r e a tm ent p l ant In stitutio na l c o ntro h f o r the are a L on g -term mon i tor i ng Lo n g- te rm o p e ratio na

n d

main te nanceo feq ui pment OU-2 Fo r Landfill No. I , the sele c te d a lte r nati v e, a n e arth c o v e r an d ins ti tutional con tro ls , i ncl u des the fo ll owi ngmaj or compone n ts: Co n s tructing a n earth co v er , cap able o f sus_g peren n i a l veg etation, o v er thos e ar e as of th e l andfi ll that ar e n o t a d equa tel y cov ere d. Fil l ing in low ar e a s an d gra din g the e n ti re landfi ll a rea to pr ov ide for posi tive d ra in a ge of f th e s i t e Insti nmonal co ntrol s for the l a ndfil l are a Long-term ground-w at er monito r ing L o n g -termm a inten a n c e o fs o il c ove r Reali gnm en t a nd l ining of the s torm-wa_e r chan nel For L a nd / i llNo. 6,th e s e le c tedaltern a tive ,i

nstit u tion alc

on t rols,in c lud e sth e fo l l o wingma jo / " con' l p on_nts : Ins_tutional c ontro ls-for-the landfill area L o a g-term gro und-w a ter monito ring L o ng-term m a intenance o f existing c o ver



# 305 7 1 7 5T h e s el ec ted alter nativ e, c ap ping, i nc l u de s _ e f ol l o_dng m a j or com po nen t s: Placing a so i l c ov er cap able of sustaining perennial vegezafi on, o ve r t he lan d fi ll ar ea A p r e-des i gn stud y to e x amine the need f o r lsndRU gas'cont r ol measu r es / ns ti mtin na l conU rol s f o r the lan dfi l l ar e a L o ng- te r m gro und - wate r mo n i to ri n g, and l on g -term ma_t enance o f s o ft c o ver OU - 4 Th e s el ecte d altern ati ve f o r the l a nd fall , s oi l cover, in c ludes the following m a j or co mpon e nts : I nstitution a l c on trols f o r th e land t-tllare a P la cing a s o il co ve r c apab le ofsusta t u i n g pere n ni a l v eget a ti o n o v er the lan dfi]I area Landfill gasm onR o ring a ndp a s si ve co ll ec tion s yst em , a sn e ce s s a ry Long - termmonitorin ga

nd

ma intenan c e Th e s ele c te d ah crn a n ve for th e g round w ater, pun_ a nd treat , include s the foll o wing majo r c ompon en ts C o n t inu edo pera,on ofth ei nt m 'iml_me d i_ac t ion ( IRA)which c onsist s ofremov a land uce amac n to f c ontamin at ed gro u n d water InstaJ ladon of re c ove ry trench e s and / or additional ext r action wells to be a dded t o the existing IRA gzound - wa rc rr

e covery s yst e m T_atmen t of r emov e d g r ound wat_ at th e t re atmen t p l a n t buil t fo r the IRA Discha r g e o f treated ground wate r t o a s urf a c e w ater dra ina g e, t o th e B a_e w astewat cr t re a tment plant, o r b y tmde r g_ound injec tion OU-5 Th e s e lected alternative, Co v ering. includes th e fo ll owing m a j or c ompon e nts: •P la c ing t s o il co ve rc apable ofs usuiningpe re nni a l ve get a ti o nove r thel a ndfillm-c a ins ti tution a lcont r olsfo r thel a ndfill ar ea

' Lo ng- termground-w a t er moni t o r ing;and ,l ong-te r mma / nt c n a n cc ofs o ft c over OU- 6 The s el ec ted ah er nadve , c apping, includ e s th e foll o w i ng m aj or C Omp On En ts : Pla c ing a so ilc o v erca pableof s u sta ining pe r e nn_ l vegetation over thel a ndfilla re a Mod i fi c ati on o f s to rm-w a ter di s= lur xe point and d rain a ge


# 3057 176h x s ti ru

_ion al c on trol s for the l a n dfilJ ar e a L o ng- te r m ground- w at e r, s u r f a ce -w ater , and s edim en t mo n h o z- i n g L o ng- term m ai nte na n c e o f s o il cov er OU- 7 Th e s e l e ct ed al tern a ti v e f or s oi l s, tnc timr3onal c o n tro ls , i nc l u d e s the f ollo w ing major cor apone ats : I n sti tu tiona l control s for fu tur e land use .A J a exte n s i v e re cords s e arch w i ll b e perform e d th a t m ay pro vid e a d di ti ona l i nforma ti on re la ti ng to the b oria ] u enc h e s . A r emo va l ac ti o n m i ght b e us e d to a d d r e ss w ast e with i n the t r e nch e s if the w e i g h t o f e vi d en ce f rom thi s r e co rd se arch c o m b ine d with p r e v io u s i n fo nmti o n ide nt_es an d w ar ra n ts

_ ty pe o f remedi al acti vi_,. 

### T h e sele ct ed _ten -
_tive f or 8
- m_md wat er , in s ti t utiona l c ontrols wi th addie ona] mun it oring , i ncl u de s the f o ll o win g m a j or c o mp onen_: - Imtimtiona l cunt :r ol s fo r g r ou n d w a t er use I mp [ememin g a l ong - t e r m groun d-w a te r m ord to r / n g and m a int ena nce pro g_m OU- 8 O U-8 is d i vi de d into tw o d isti nc_ areas o f i n v e s tig a ti o n. A r ea I and Are a 2 . A rea I is the area s urrounding th e ac tu al ]EODAr e a ks etf. A r e a 2 cons i s

_ of th e Debr i s B ur i al A r e a w h e r e wa st e f rom d_e EO D Ar ea w as bur i e d . Alter mtive s f or re med ia l a cti on w ere evalua te d se para tely f o r e ach e xeL Th e s elec te d a l t

_nzti ve for Area 1

_ OD A r e a ), v ege tati v e u 3_ cov e r and in s t / m d o na l ccm t mh,incl

_]es the follo wi ng m a j or co mp one n ts : C o

_ucun g a n

_ c o ver o ve r a portion oft_u: E O D A re a I ns ti tution al contro

_ for the EOD Are a Lo ng- te rm se di me n t s a mpl ing Lon g -t e rm m aintena n c e o f e_, h cov er T h e s ele c t e d al tern a t i ve fo r Area 2 (D e br i s B uri a l A re a), vege t a t i v

e so ft cov eta nd iz_ fi tutionalcontro l s, i nc lude s t he fo l / o wia g majo r c o r c z pon e a zt s : Co nsu

_tctin g an e ar t h co v er ov e r th e Debri s B uria l A r e a I v_titulional con t z o l s for the D e b t -_ Bu ri al Ar ea an d l ong- t er m mai n t enanc e of e a rth cov e r OU- 9 B a se d on the f ind in g s o f the ris k a ssessrn ent , unacc ept able r isk to h u m an he al th an d th e e n vi ron m ent d oe s not e x ist and reme di ation is not warrante d for OU-9. Pre s e n tly , a corr e ctiv e ac ti on plan (und e r . t

_ e State p etro le um re l e a s epr o gram) isunde r w a yt oad d r es s fu e l comp o n e nt s int he g roundw at er i nthe southern

3

_ tC_ _ 

# 3 0 57 1 77p o r tion ofO U
- 9 . Re med_ti on of other ar e as w her e s o il Jmd / or g rou nd w at er is c o ntz mL n a t e d b y p el r o l eu m wil l bepe r f or m ed in

co mp l ia n c e w it h S tat e o f South Dak ot a re g ul at io n s. O U-I O B ase do u the finding 5o

fnoun accep t ab leri

s kto h uma n h e a l t h a ndth e envi r onment , rem e dia t io n is

no t w ar r ran t e dforOU-10. R e m e di a fi ono f s o i ls a nd / o rgrou ndw a te z c on ta min ate dby petrole u mwillbe pe rf o r me dund e rtheSt a teof So uth Da k ota reg u l a t i on s . O UOU- I l h a sbeendivid edinto t wo a

_ e

_ , A r e a i sth eS o ut hDo c ksS t ud y Ar ea,a ndAr e a 2 is t he BG 04 a nd BG0 5 S tudy A r e as. The se l ected akern a ti vc f o r Ar e a I , Grou nd-W a te r Ex_ c6 on an d T r ot with Co n t a inme n t , i n c ludes the f ollowing ma jo r component: G rou n d - w ater remo v al an d

_ eau n c n t i n t he 5 outh Docks Study Area On - b_ e co nt_nm c n t o f g r ound w

_ r co nt_R_ co n tamin an ts at c on ce n tra tion s abo ve F e deral Ma ximu m Co n t am in an t L evels ( M C L s) md State of So uth D ako t a Grou nd - W at e r Q uality Sta nd ar ds Imt im t i on a l c ontrols a ndl o ng-t e r mmo nitor i n g T

h e se l ec_ .e d alt ern a ti v e f o r Are a 2 . Gr ound-Wate r Co n_n a n d Treatme n t. , inc ludes the f oll o wing maj or c, o mpoa ent s: G r ound- w zz er rem o va l a ndu _u r . cut al o ng th e north ea

__ b_e bou n d a ry and a t are_ o f .high c on ta minant conc emr4fions on -b a s e Na tu r ala u en ua tion o flo w co _t c onc e nt ra tion a re a s , p r im arily off-b as e Alt e rn a ti ve w a ter s u pp ly t ore s id e n t s a ff

c_e d byco nt ami n a ti o n c o m ing fr omthe b ase A dditi on z l in v es tig a ti on to d etermi n e the east ern exte nzo f o ff - b a se ground- wa ter c on ta min ati on h_fi mt ion a l c ont r ols a nd l ong . mrmm o nkoring O U -1 2 The s e l ec te d _te mati ve, capp i ng , i nclude s the f oll o wing ma jo r compo n e n t s : Pl a cing a s oil co v erca p abl e o f s u_alning p ere n n ia l v e se t a ti o n over th e h a r dfill area P r e- d esig n s tud y lo id e nti fy the sou rc e of r neth an e and e xam ine the ne ed fo r h ard .fill ga s con tro l me a .su_ c s ,a

ndev aluateth e nee d f o rerosio n co n trol m ea sures a l on g t h e str ea m a dj ace n tto th e i_ r dfill e_ a

_ Institutional co n trols for the hardfill area s Long-term monitoring


# 3057 1 78Imp le m e nta tionofthere m edi e s w

/ ll re duceth e fum_v risk tohuma n heakhtnd th e e nvironment to zcceptabl el evel s . CHECKL I ST Ac c e s s E x cavation Con t s n d nation Re mark s 

### A l l o wed A l l o wed O U- I No N o No No Groundw._er / So_] 

### No Ground w ate r / S oi l



## - -- . .--

_ • No _c

_ .__5 -2 6 80_ f==

=

_ Soil 

## C_undwa terP So /

i C ,_l 5 -2 6_f o

_ c c_ s Yes Gr o undwater l So il Yes OU-12 No $o i .ll

_ _ Ca l l.__ 5 - 2 6

_. .

80

f or access



# 305 7 179

### •_.,._7:_'_._ DEPARTMENT OF THE AIR FORCE AIR C O M B AT C O MM A N D CI V I L E N G IN E E R SQUADRON '_. _ _ 'S . =

_ /

_ L A N GL E Y A' R FORC E BA S

_ . V I RG INIA 

### o 6 DE C '_ H EMO RAN D U H FOR D IS TR IBU T I O N F ROM : HQ ACC / C E V 129 An d r ews St r eet S_e 1 02 L an g ley AFB VA 23 665 SUBJ E CT: Constr u c t ion Wai v er Req u ests for Znstallation Restorat i on P rogram ( I RP) si t es i . Ref e rence: Air Force I nstr u c t ion (AFI] 32 -10 2 1 , 12 Hay 94, Pl a nning and P ro qramming of Facility Co ns t r u c t ion Proje c ts. 2 . This letter is t o pro vi de clarifica t ion of the AC C p ol icy regardin g cons t r u c t ion on I RP'sit e s. E ven though AF I 32-1021 prir_ a ril y addresses HI L C O N pro j ec t s, the wai v er des crib e d be l o w s ho u ld be us e d f or any type of cons t ruction activity on or ne a r s i t e s. The w ai v er process is d esigned to ens u re risks to human health a nd the en vi ro nment are co n si d ered before the start of constru c tion projects. 3. A problem developed recen t ly when a r e quest for waiver was appro v e d for an FY96 HIL C ON project based o n the ass umption the site should'be remediated b e fore the actual start of c onstr u ction. This c o n d i t ional approval gav e the const r u cti o n agen cy the go- a he ad to contin u e design and contr a cting a c t i ons. U nfortuna t e ly, the M!LC O N proj e ct was mov e d forwar d to FY95, while the I RP p roject slipped a year. Th e r e sult was t he H I L CON was re a d y to go out on the street f o r bids and th e I RP cl e anup was not u nder contr a ct (in fact, the R emedial Investigation / Feasibility S tudy [RI / FS) had not star t ed). 4. In _noth e r recen t instance, a chain link fen c e w as constructed across" an IR P site. The fence must now be rem o ved to accomp l ish an I R P remedial action. The pro j ect was not coordinated t hrough the environmental flight. 5 . Written waiver for construction r e quests on an I R P site sho u ld be s e nt from the _a s e Civil E ngine e r to HQ ACC / C E V, c o py AC C C E5 / E S. Waiver requests should be submitted for closed IRP si t es as w ell as a c ti v e si t e s . Th e waiver reque s t sh o ul d incl ud e £he following . informa t ion:
a . A d escription o f the proposed c o nstruction b The IRP site numb er c The exoected impact o f the p r o p o sed construction o n th e site d . Information regarding whether or not regula t or y agencies have been co ntacte d regar d ing the pr o pos e d c o nstruc t ion.


# 3057e. A descr i p t i on of t he plan to d isp o se of so il o r gr ou n d w a te r which' is to be re mo v e d f r om the site d uring cons t r u c t ion. f. A d_script i on of potentia l con f li c t s between th e pr o ject an d o ngoing o r plann e d IR P pro j ec t s at the s i te . The req u est sho u l d e x

p l ain what w i ll b e d one if unexpec t e d c o nt a mination i s f ou nd. 6 . O nce t he request f o r waiver is revie w ed_by HQ AC C/C E V , it will be e ither approved, d isapproved or returne d for addi tio nal inf o rmatio n . T h e HQ A C C/ C EV r esponse will includ e an e xpl a n a tion of th e a c t i on taken. I f add i tional informat i on is requ i r e d , a reques t w il l be i s s u ed f rom ACC CES / E S V . Most w a i ver, req u e st s are a p proved and sho u ld be s ubmi t t ed early enough i n the pr o grammi n g p ro c ess t o avoid de l ays in construction ac t ivities. C oordination w i t h the Restorat i o n E lement at th e installation sho u l d help avoid this t y pe of s i ting i s s u e . 7. I ns t all a tions shoul d use discretion in t h eir ap pl i c ation for w a iv e rs b y k eepi ng i_ _in d t h a t th e g o al o f th e waiver pr o c e ss is t o " control rea so nabl[fore s ee a ble impa c ts to'human health or t h e env i ronm e nt. C ons_:ruc t ion a c ti v ities o n a n _R P si t e whi c h implement the si t e remediatlon a s part of the IR_ do not req u i r e a waiver (e.g. installation o f wells, pipin g, pum p-houses , etc.) In addition, mino_ ac t iv i t ies on IRP s i t es wh ic h can be _emonst r ate d _o h a ve ne gl i g i b le ri s k a n d w ill not ot h e r w i s e int e rf er e w it h Z Rp ac tivi tie s a t t h e s i t e ma

y n ot ne e d a. w aiv e r. So u n d _ec hn i c al judg m e n t s hould he ex er c i sed by t h e insta l latio n i n id ent ify i ng s u ch ca ses . 8. Plea se dir e c t questions to ygur A C C i KP Prosr a m M ana ger or M r N orm i n G u e nther, A C C C E S / E SV E a t DSN 5 74- 36 80.

A t ta ch m ent : D i s t ribu ti o n li s t c c: HQ ACC / C KPD / CE PH / CEPR ACC CE S / E SP E / E SP W '



# 3057 181O U-8 ACTION PLAN 1 . S tra teg y: T o restore the O p = abl e U n it ( OU) g s i t e q ui ckl y t o its or igin a l co nfi g ura tion un derth e approval o f South D ak ota Dcp_l m c n t of Env i ro nm e nt a nd N atu ral R e s ou rces a nd t he E n vir onme n tal Protec tion A ge nc y ( E PA). e n s u r i ng s a fe ty to th e si te an d pers onnel. To i mple m e nta p rogr a mth at w i ll e nsur e all R estorationsites o n b a s ec o mp l y withth eReco r d o f D ec i s ion(ROD ) a ssign e dby theWing Co mma nd e r. 2 . S tatus:On 26 August99 , l 6 pie ce sofdyr u t m R e

th a t w e xc exuding mtro gl_e_-in w e r e destr o yedon t heold E x p losiv e sO

r d n a n c eDi s po s a l pOD) R an ge , crea t i n g 2 pitsapprox i m a t e ly 8 fe et indi a m e t e r , a n d 3 fe et d e ep.L a t e r , tw o m or e e m e rg e n cy d e to n a t ion s o cc urr e d , on 2 5 Aug 9 9 tod e s t r o y a ddi ti on a lle ak ingdyn a mite , a ndon 28 S o p9 9 ,a groundburstproj e c ti l e simulator an d a n M - I 8 smok e gr e nadethatd u dfiredurin g a tr a inin ge

x e r c is e . T he deton a tions d a m a g e d thel a ndfill c a pt h a tis pa rtofOUS . L a teon 5 O c t99 , C_V id e n t ifi e dthe c r a t e rs a nd / m m edia ze lyb e g a nnotifi ca tionsup th ec h a inof c ommmd. ACC , EPA a ndst a teo f fi c i a lsw

e re no t ifiedon 6 O c t9 9 . 3 A ct ionItems: Re vair Site 3.1 Obtain funding and c o ntract to re s tore s ite 3. 2 D ev e lo p s amp lin g plan and repair plan 3.3 Coll e ct s a mples o f site and re s tore to original design condition Ir_provem cnt Process 3.4 Con s truct f e n ce around O U -g bound ary, limiting all future ac c ess 3.4.1 Survey fenc e lo ca tion 3.4.2 Obtain diggdng p ermit 3.4.3 Sub m it work re qu e st 3.4.4 Install f e nc e 3.5 / nstall signs on O U8 f e nc e s imilar to tho se on o ther O U ' s that s tate, "Closed, No Acc e ss, Conta c t 385-26 8 0 " 3.6 Pre id c ntify a lo c ation on bas e for e mer g en c y dispo s al of ordnan ce 3.7 Update EOD Tea m Chi e f C he ckli s t to in c lude notifi c ation require m e nts and a map of approved dispo s al area 3.g Update CEV S p ill Bil_der to in c lud e ch e cklist that id e ntifi e s notifi ca tion mquirern e nt s and a map of approved dispo s al area 3.9 R e distribute c opy of s tanding ord e r 3.9.1 R e distribute original copy o f s tanding order w ith cov er l e tter by Col P. 3.9.2 R e di s tribute s tanding order with updated poli c y l e tters with e very n e w WG / CC 3 .10Provid e lraining to all 28 CES Flight Chiefs , 28 CES/ CEO Sup erintendents, and 2 8 CES heavy equi p ment operators 3.11 Provid e awaren ess training to all "On-S c ene Commanders"



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