Superfund Record of Decision Former Nebraska Ordnance Plant Site OU1 Mead Nebraska


                                   EPA/ROD/R07-95/083
                                   1995
EPA Superfund
     Record of Decision:
     NEBRASKA ORDNANCE PLANT (FORMER)
     EPA ID: NE6211890011
     OU01
     MEAD, NE
     08/29/1995

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      Final Record of Decision
           Operable Unit  1
 Former Nebraska Ordnance Plant  Site
           Mead, Nebraska
U.S. Environmental Protection Agency
             Region VII
         Kansas  City,  Kansas
       Department of the Army
     U.S. Army  Engineer District
   Kansas City Corps of Engineers
        Kansas  City, Missouri
           November  1995

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                                             TABIiE OF CONTENTS


Chapter                                                                           Page

 1. 0    DECLARATION 	 1

 2 . 0    DECISION SUMMARY 	 5
        2.1   SITE NAME, LOCATION, AND DESCRIPTION 	 5
        2.2   SITE HISTORY AND PREVIOUS INVESTIGATIONS 	 6
              2.2.1   Site History 	 6
              2.2.2   Previous Investigations 	 7
              2.2.3   Summary of OU 1 RI Results  	 8
        2.3   COMMUNITY PARTICIPATION 	 9
        2.4   SCOPE AND ROLE OF OPERABLE UNIT 1 REMEDIAL ACTION
              WITHIN SITE STRATEGY 	 11
        2 .5   SUMMARY OF SITE CHARACTERISTICS 	 12
        2 . 6   REMOVAL ACTIONS 	 12
        2 .7   SUMMARY OF SITE RISKS 	 13
              2.7.1   Potential Human Health Risks 	 13
              2.7.2   Potential Environmental Risks  	 18
        2 . 8   SUMMARY OF ALTERNATIVES 	 18
              2.8 1   Alternative 1 - No Action 	 19
              2.8.2   Alternative 2 - Biological Treatment 	 19
              2.8.3   Alternative 3 - Rotary Kiln Incineration 	 20
              2.8.4   Alternative 4 - On-Site Landfill 	 21
              2.8.5   Alternative 5 - Off-Site Landfill 	 21
        2 . 9   TREATABILITY STUDIES 	 22
        2.10  SUMMARY OF COMPARATIVE ANALYSIS OF ALTERNATIVES 	 22
              2.10.1  Introduction 	 22
              2.10.2  Comparison of Alternatives  	 23
              2.10.3  Summary 	 27
        2.11  THE SELECTED REMEDIAL ACTION 	 28
        2.12  STATUTORY DETERMINATIONS 	 28
              2.12.1  Protection of Human Health and the Environment 	 28
              2.12.2  Compliance with ARARs 	 29
              2.12.3  Cost Effectiveness 	 32
              2.12.4  Utilization of Permanent Solutions and Innovative Treatment
                      Technologies to the Maximum Extent Practicable 	 33
              2.12.5  Preference for Treatment Which Reduces Toxicity,
                      Mobility,  or Volume 	 33

 3. 0    RESPONSIVENESS SUMMARY 	 34
        3 .1   OVERVIEW 	 34
        3.2   BACKGROUND ON COMMUNITY INVOLVEMENT 	 34
        3.3   SUMMARY OF PUBLIC COMMENTS AND AGENCY RESPONSES 	 35
              3.3.1   Remedial Alternative Preferences 	 36
              3.3.2   Biological Alternative 	 38
              3.3.3   Air Emission Concerns with Preferred Alternative 	 42
              3.3.4   Preferred Alternative Residuals 	 49
              3.3.5   Risk Assessment 	 51
              3.3.6   Site Characterization 	 54
              3.3.7   Regulatory 	 59
              3.3.8   Other 	 61

SUMMARY OF COMMENTORS 	 65

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                                    LIST OF TABLES

Table                                                                     Follows Page

 1    Range of Explosive Concentrations Detected in Soil 	  9
 2    Summary of Cancer Effects and Slope Factors Used for the Baseline Risk
      Assessment 	  15
 3    Summary of Non-cancer Effects and Toxicity Values Used for
      the Baseline Risk Assessment 	  15
 4    Summary of Lifetime RME Excess Cancer Risk - Soft Pathways 	  16
 5    Summary of RME Noncancer Risk - Soft Pathways 	  16
 6    Risk-Based Remediation Goals 	  18
 7    Estimated Costs for Alternative 2 	  19
 8    Estimated Costs for Alternative 3 	  20
 9    Estimated Costs for Alternative 4 	  21
 10   Estimated Costs for Alternative 5 	  22
 11   Estimated Implementation Times 	  26
 12   Results for the Most Promising Biological Treatability Study Condition 	  39


                                    LIST OF FIGURES

Figure                                                                          Follows Page

  1       Site Location Map 	  5
  2       Site Map 	  5
  3       Contaminated Soil - Leadline 1 	  12
  4       Contaminated Soil - Leadline 2 	  12
  5       Contaminated Soil - Leadline 3 	  12
  6       Contaminated Soil - Leadline 4 	  12
  7       Contaminated Soil - Burning/Proving Grounds 	  12
  8       Contaminated Soil - Bomb Booster Assembly Area 	  12
  9       Contaminated Soil - Administration Area 	  12
  10      Major Components of Alternative 2 	  19
  11      Major Components of Alternative 3 	  20
  12      Major Components of Alternative 4 	  21
  13      Major Components of Alternative 5 	  21

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                                    LIST OF ACRONYMS
ARAR
AT SDR
CERCLA
CFR
CWA
DNB
DNT
FS
HA
HI
HQ
HMX
IAG
NCP
ND
NDEQ
NOP
NPL
NPDES
NRD
NT
O&M
OU
PCBs
RAO
RCRA
ROD
RDX
RfD
RGs
RI
RI/FS
RME
SARA
SWDA
TCLP
tetryl
TNB
TNT
USAGE
USATHAMA
US EPA
UXO
VOCs
Applicable or Relevant and Appropriate Requirement
Agency for Toxic Substances and Disease Registry
Comprehensive Environmental Response, Compensation, and Liability Act
Code of Federal Regulations, latest revision
Clean Water Act
Dinitrobenzene
Dinitrotoluene
Feasibility Study
Health Advisory
Hazard Index
Hazard Quotient
High Melt Explosive or Octahydro-1,3,5,7-tetranitro-l,3,5,7-tetrazocine
Interagency Agreement
National Oil and Hazardous Substances Pollution Contingency Plan
Not Detected
Nebraska Department of Environmental Quality
Nebraska Ordnance Plant
National Priorities List
National Pollutant Discharge Elimination System
Natural Resources District
Nitrotoluene
Operation and Maintenance
Operable Unit
Polychlorinated Biphenyls
Remedial Action Objective
Resource Conservation and Recovery Act
Record of Decision
Research Department Explosive or Hexahydro-1,3,5-trinitro-l,3, 5-triazine
Reference Dose
Remediation Goals
Remedial Investigation
Remedial Investigation/Feasibility Study
Reasonable Maximum Exposure
Superfund Amendments and Reauthorization Act
Solid Waste Disposal Act
Toxicity Characteristic Leaching Procedure
2,4, 6-tetranitro-n-methylaniline
Trinitrobenzene
Trinitrotoluene
U.S. Army Corps of Engineers
U.S. Army Toxic and Hazardous Materials Agency
U.S. Environmental Protection Agency
Unexploded Ordnance
Volatile Organic Compounds

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1.0 DECLARATION
Site Name and Location

Former Nebraska Ordnance Plant
Mead, Nebraska
Operable Unit 1: Upper 4 feet of Soil

Statement of Basis and Purpose

This decision document presents the selected remedial action for the former Nebraska Ordnance Plant (NOP)
site, in Mead, Nebraska, which was chosen in accordance with the Comprehensive Environmental Response,
Compensation, and Liability Act (CERCLA), as amended by the Superfund Amendments and Reauthorization Act
(SARA) and, to the extent practicable, the National Contingency Plan (NCP). This decision is based on
the administrative record file for this site and has been made by the U.S. Environmental Protection
Agency (USEPA) and the U.S. Army Corps of Engineers (USAGE), in consultation with the Nebraska Department
of Environmental Quality (NDEQ). A letter from the NDEQ regarding concurrence with the selected remedial
action for this site is attached.

Assessment of the Site

Actual or threatened releases of contaminants from this site, if not addressed by implementing the
remedial action selected in this Record of Decision (ROD), may present a current or potential threat to
public health, welfare, or the environment.

Description of the Selected Remedial Action

The former NOP site was used as an ordnance loading, assembly, and packing facility. Operations at the
NOP resulted in contamination of soil with explosive compounds. Most of this contamination is confined
to discrete areas associated with drainage ditches. The site has been divided into three operable units.
Operable Unit 1 (OU1) encompasses the upper 4 feet of soil contaminated with explosive compounds. OU2
includes explosives-contaminated soil which could act as a source of groundwater explosives
contamination, soil contaminated with volatile organic compounds (VOCs), and contaminated groundwater. A
former on-site landfill and areas of waste not previously identified are included in OU3.

The remedial action for OU1 addresses one of the principal threats at the site, explosives-contaminated
soil, by thermally treating the contaminated soil on-site. The major components of the selected remedy
include:

• Excavate contaminated soil and debris.

• Sample to verify excavation to cleanup goals.

• Blend soft to reduce any reactive levels of explosives compounds.

• Conduct a risk assessment based on USEPA's combustion strategy.

• Conduct a trial bum to test the performance and emission controls of the incinerator.

• Treat explosives-contaminated soil using on-site rotary kiln incineration and test the
soil to verify the degree of treatment.

• Test treated soft and residuals to verify that they are not hazardous due to the toxicity
characteristic (TCLP) for metals. If treatment residual fails TCLP for metals, it will be
disposed of at an appropriate off-site facility.

• Blend treated soft and solid treatment residuals, backfill on-site in excavations, and
cover with clean soil, as necessary or appropriate, to sustain vegetation.

• Dispose of oversized material and debris in an authorized off-site landfill.

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Statutory Determinations

The selected remedial action is protective of human health and the environment, complies with Federal and
State laws and regulations that are applicable or relevant and appropriate to the remedial action, and is
cost-effective.  This remedial action utilizes permanent solutions and alternative treatment technologies
to the maximum extent practicable, and satisfies the statutory preference for a remedial action that
employs treatment that reduces toxicity,  mobility, or volume as a principal element.  Because this
remedial action will not result in hazardous substances remaining on-site above health-based levels for
direct contact, the 5-year review to ensure that the remedial action continues to provide adeguate
protection from direct contact of explosives-contaminated soil will not be reguired.


                                    LEAD AND SUPPORT AGENCY ACCEPTANCE
                                         OF THE RECORD OF DECISION
                                    FORMER NEBRASKA ORDNANCE PLANT SITE
                                              OPERABLE UNIT 1

Signature sheet for the following Record of Decision for Operable Unit 1; upper 4 feet of
explosives-contaminated soil, final action at the Former Nebraska Ordnance Plant site between
U.S. Army Corps of Engineers and the U.S. Environmental Protection Agency.
  
Regional Administrator                                             Date
EPA Region VII
                            LEAD AND SUPPORT AGENCY ACCEPTANCE
                                OF THE RECORD OF DECISION
                           FORMER NEBRASKA ORDNANCE PLANT SITE
                                    OPERABLE UNIT 1
Signature sheet for the following Record of Decision for Operable Unit 1; upper 4 feet of
explosives-contaminated soil, final action at the Former Nebraska Ordnance Plant site between
U.S. Army Corps of Engineers and the U.S. Environmental Protection Agency.
  
Deputy Assistant Secretary of the Army                            Date
Environment, Safety and Occupational Health

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STATE OF NEBRASKA

DEPARTMENT OF ENVIRONMENTAL QUALITY
Randolph Wood
Director
Suite 400, The Atrium
1200 'N' Street
P.O. Box 98922
JUN 16 1995 Lincoln, Nebraska 68509-8922
Phone (402) 471-2186
E. Benjamin Nelson
Governor
Major Nanci Higginbotham
CEMRK-MDH
U.S. Army Corps of Engineers
Kansas City District
700 Federal Building
Kansas City, Missouri 64106-2896

RE: draft final Record of Decision Operable Unit 1

Dear Major Higginbotham:

The Department has reviewed the draft final Record of Decision Report Operable Unit 1 Former
Nebraska Ordnance Plant Site; Mead, Nebraska. With the understanding of the following notations, the
Department accepts this report as final.

We believe the reference to Chapter 8, Title 118 in the ARAR section is not accurate. In
addition, the contents of Title 118 are extraneous to the selected remedy and therefore Title 118 need
not be cited as an ARAR. Also, the reference to Title 129, "Ch.4.6.002" is not clearly understood by the
Department. The Army should clarify this citation. In the reference to Title 129, Ch. 16, the word
"capacity" is mistakenly used for the word "opacity".

It is the understanding of the NDEQ that a further revision is planned for this document. Part X.
Paragraph J.I. (pg.34) of the IAG has a provision for subsequent modifications of final reports. Any
future revisions to the final ROD should be made in accordance with these provisions.

Should you have any questions regarding our review of the draft final ROD, please contact Ron
Johnsen, Edwin Louis, or me at (402) 471-3388.
Sincerely,

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2.0 DECISION SUMMARY

2.1 SITE NAME, LOCATION, AND DESCRIPTION

The former Nebraska Ordnance Plant (NOP) site occupies approximately 17,250 acres located one-half mile
south of the town of Mead, Saunders County, Nebraska (Figure 1). During World War II and the Korean
Conflict, bombs, shells, and rockets were assembled at the site. The site includes four load lines,
where bombs, shells, and rockets were assembled; the Burning/Proving Grounds, where fuses were tested and
materials were destroyed by burning; a Bomb Booster Assembly Area, where boosters that amplify the effect
of the detonators and assure the complete detonation of the main explosive were assembled; and an
Administrative Area, which included offices, residences, and a laundry (see Figure 2). According to
reports, wastewater from both the load line plant operations and the laundry was washed into a series of
sumps, ditches, and underground pipes.

The former NOP site is situated on unconsolidated deposits that are up to 180 feet thick. Fine grained
materials (silts and clays) comprise the uppermost deposit, which is up to 30 feet thick. Below this fine
grained soil are sand and gravel deposits. The sand and gravel deposits are underlain by shale and
sandstone. The majority of residences, farms, industries, and municipalities in eastern Nebraska derive
water supply from the sand and gravel deposits or from the sandstone. Irrigation consumes the largest
volume of extracted groundwater. The general trend of groundwater flow in the area is southeast, toward
the Platte River.

The site is nearly flat, with a few gentle slopes. Surface water drainage in the eastern portion of the
site is generally to the southeast, toward Johnson Creek and the Natural Resources District (NRD)
Impoundment. In the western portion of the site, surface water drains to the southwest, toward Silver
Creek.

According to the draft National Wetlands Inventory Map for Mead Quadrangle, several wetland types may be
located at or near the site. Based on the Soil Conservation Service (SCS) delineation, on-site wetlands
are not located near areas of contamination at the site and will not be impacted by the OU1 remedial
action. No other sensitive ecosystems or endangered species are known to exist in the area.

Most of the site is owned by the University of Nebraska, which operates an agricultural experiment
station on the premises. Crop, hog, dairy, and cattle research take place on site. Other portions are
owned by the Nebraska National Guard, United States Air Force and Army Reserves. Some private pasture
and crop productions also take place on site, and some private light industry exists near the northern
end of the site. Adjacent land use is primarily agricultural, except for the town of Mead which is
located north of the site.

2.2 SITE HISTORY AND PREVIOUS INVESTIGATIONS

2.2.1 Site History

The former NOP site was a load, assemble, and pack facility which produced bombs, boosters, and shells.
The NOP included four bomb load lines (LL1 through LL4), a Bomb Booster Assembly plant, an ammonium
nitrate plant, two explosives burning areas, a proving range, a landfill, a wastewater treatment plant,
analytical laboratories, and storage and administration facilities. Most of the raw materials used to
manufacture the weapons were produced at other locations and shipped to the NOP facility for assembly.
However, ammonium nitrate was produced at the Ammonium Nitrate Plant during the first months of
operation. Finished munitions, bulk explosives, and related ordnance materials and components were
stored and demilitarized at the site.

Routine plant operations included washout of explosive materials prior to bomb loading and assembly, and
bomb washing following assembly. Wash water was discharged to sumps and in open ditches.

The production facilities were active during both World War II and the Korean Conflict. Nebraska Defense
Corporation operated the NOP site for the Army from 1942 until 1945 and produced boosters and 90-pound to
22,000-pound bombs at the four load lines. These munitions were loaded with trinitrotoluene (TNT),
amatol (TNT and ammonium nitrate), tritonal (TNT and aluminum) , and Composition B
(hexahydro-1,3,5-trinitro-l,3,5-triazine (RDX) and TNT). Tetryl boosters were assembled for bombs in the
Bomb Booster Assembly Area. In 1945, ordnance production operations were terminated, and the facilities
and operations were placed on inactive status.
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During the interim period (1945 through 1949) , the NOP was decontaminated and used primarily for storage
and disposal of bulk explosives and munitions, and production of ammonium nitrate for use as fertilizer.
Decontamination consisted of flushing and sweeping buildings that were not being used for storage.
Explosives processing surfaces were scraped and brushed by hand. Internal roofs and trusses were flushed
with high pressure water, and eguipment was cleaned with steam. After flushing and steaming operations
were completed, explosives residues in the sumps, settling basins, leadoff pipelines leading to the
drainage ditches, and an unspecified guantity of contaminated soil and sludge from the drainage ditches
were removed and reportedly taken to the Burning/Proving Grounds. In some instances, portions of the
tile pipe composing the drainage system from the sump to the open ditches were removed and disposed.
Wooden sidewalks and settling basin covers were also removed and burned in the Burning/Proving Grounds.
The outside roofs of the explosives screening, melt, pour, and cooling buildings on the load lines, and
the Bomb Booster Assembly Area tetryl screening and blending, pelleting, rest house, and magazine
buildings were flushed.

In 1950, the plant was temporarily reactivated and produced an assortment of weapons for use in the
Korean Conflict. Munitions assembled included bombs, shells, rockets, warheads, block cast TNT,
supplementary charges, and boosters. NOP was placed on standby status in 1956, and declared excess to
Army needs in 1959.

Neither the reactivation procedures for the Korean Conflict effort nor the decontamination records after
final plant shutdown could be located, although recommended decontamination procedures were reviewed.
Recommendations included decontamination with hot water and steam. Although recommendations to
decontaminate were made in 1959, later records indicate that at least some of the buildings and lands in
the load lines and Bomb Booster Assembly Area were not decontaminated prior to accessing (McMaster,
1983).

After the NOP was declared excess in 1959, it was transferred to the General Services Administration for
disposition. Approximately 1,000 acres were retained by the Army for National Guard and Army Reserve
training, 12 acres were retained by the Army for use as a Nike Missile maintenance area, 2,000 acres were
transferred to the U.S. Air Force to build the Offutt Air Force Base Atlas Missile Site, and 40 acres
were transferred to the Department of Commerce. Some trichloroethene (TCE) contamination of soil and
groundwater may have resulted from these military activities that followed the excess declaration in
1959. This potential contamination is not located in the areas contaminated with explosives due to
activities prior to 1959 and is being investigated as part of OU2. In 1962, approximately 9,600 acres of
the former NOP site were purchased by the University of Nebraska for use as an agricultural research
farm, and an additional 600 acres were obtained in 1964. The remaining 5,250 acres were eventually
purchased by private individuals and corporations.

Since NOP closure, the property has been used primarily for agricultural production and research. In
addition to these land uses, several commercial operations were conducted on former NOP property. Apollo
Fireworks operated for a period of approximately 20 years in the Bomb Booster Assembly Area. Production
at Apollo was terminated in 1989. At the former administration buildings, two commercial enterprises
were in operation at various times. These included insulation board manufacturing and styrofoam packing
material processing. Property was leased for these purposes by private individuals.

Several environmental investigations (discussed below) resulted in the listing of the former NOP site on
the National Priorities List (NPL) under Section 105 of the Comprehensive Environmental Response,
Compensation, and Liability Act (CERCLA) on August 30, 1990. In September 1991, USAGE, USEPA, and NDEQ
entered into an Interagency Agreement (IAG) under Section 120 of CERCLA to investigate and control
environmental contamination at the former NOP site.

2.2.2. Previous Investigations

Previous investigations include an archives search for the U.S. Army Toxic and Hazardous Materials Agency
(USATHAMA, now called Army Environmental Center) in 1983; Polychlorinated Biphenyl (PCB) investigations
by the University of Nebraska in 1984 and 1985, USEPA in 1988, and USAGE in 1993; a soil, sediment,
surface water, and groundwater investigation by USAGE in 1989; a shallow soil gas investigation in 1990;
a soil investigation by the USAGE in 1991; an unexploded ordnance (UXO) survey and soil investigation by
USAGE in 1991; a preliminary health assessment by the Agency of Toxic Substances and Disease Registry
(ATSDR) in 1991; and a Supplemental Soil Remedial Investigation (RI) for OU1 by USAGE in 1991.

Based on the PCB investigations, PCB-contaminated soil was identified in locations associated with former
transformer pads and subseguently removed by the University in 1985 and USAGE in 1994. Investigation of
remaining PCB-contamination is ongoing and is expected to be completed by the end of 1995.
TCE-contaminated soil gas and groundwater was identified in the north part of Load Line 1 and is being
addressed with explosives-contaminated groundwater under OU2. UXO has not been found on-site, but some
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internal components of ordnance (booster adapters, fuses, propellants, and bulk TNT) were found and
disposed. Investigation of UXO is ongoing at the site and is expected to be completed by the end of
1995. Information from previous investigations pertinent to other operable units and remedial actions is
summarized in the Supplemental RI Report for OU1. All documents related to the site are available for
review in the information repository at the Ashland Public Library. Investigations pertinent to OU1 are
summarized below.

The 1983 archives search was conducted to assess the potential for contamination at the NOP site from
Army operations. Findings of the Archive Search Report were based primarily on the U.S. Army Ordnance
Ammunition Command's 1959 Survey of Explosives Contamination. Areas recognized in the Archives Search
Report as having the greatest potential for explosives-contamination were the four load lines, the Bomb
Booster Assembly Area, and the Burning/Proving Grounds.

In 1989, USAGE conducted a confirmation study to determine if past Army activities at the NOP site
resulted in environmental contamination. A geophysical survey was conducted to screen boring locations
and locate buried materials. The study concluded that explosive residues are present in soil around
three of the load lines.

In 1991, USAGE identified and assessed potential sources of explosives contamination and UXO. USAGE
performed a records review and site inspection which included excavation of two test pits and collection
of 18 soil samples. Locations potentially reguiring remedial action were identified as those where solid
pieces of TNT were visibly present or where TNT was found in soil at greater than 2 percent by weight.
The areas identified based on these criteria were areas of three of the load lines and parts of the
Burning/Proving Grounds.

The Agency for Toxic Substances and Disease Registry (ATSDR) completed its Preliminary Health Assessment
in 1991. ATSDR concluded that potential human exposure to hazardous substances at the former NOP may
result in adverse health effects. It was concluded that the public could be exposed to the explosive
compounds RDX and TNT, via skin contact or soil ingestion.

2.2.3 Summary of OU1 RI Results

In 1991 and 1992, USAGE conducted an OU1 RI to evaluate the extent (area and depth) of explosives-
contaminated soil at the former NOP site. Subsurface borings and surface samples were obtained in the
load lines, the Bomb Booster Assembly Area, the Burning/Proving Grounds, the former Administrative Area,
and the area surrounding the load lines and the Burning/Proving Grounds which is designated as the
Primary Area. Most sampling was based on historical washwater disposal practices during the ordnance
production process. Explosives compounds were detected in soil in all four load lines, the Bomb Booster
Assembly Area, and the Burning/Proving Grounds. No live ordnance was found on-site.

Sampling results indicate that contamination in the load lines is primarily associated with washwater
sumps and drainage ditches from the ordnance production process. The majority of the explosives
contamination was detected in shallow soil. At some locations, however, explosives compounds were
detected at depths of approximately 30 feet below the surface. Explosives contaminant concentrations in
the ditches generally decreased downstream from collection sumps. Concentrations of explosive
contaminants in site investigation soil samples range from not detected (ND) to the maximum shown for
each area in Table 1. There are relatively few areas where contamination detected in the load lines was
not associated with the washwater drainage system.

Explosives contaminants detected include:

2.4,6-Trinitrotoluene (TNT)
• Hexahydro-1,3,5-trinitro-l,3,5-triazine research department explosive (or RDX)
• 1,3-dinitrobenzene (DNB)
2.4- and 2,6-dinitrotoluene (DNT)
1,3,5-trinitrobenzene (TNB)
• Octahydro-1,3,5,7-tetramitro-l, 3, 5, 7-tetrazine (high melt explosive or HMX)
• 2,4,6-tetranitro-n-methylaniline (tetryl)
• o-nitrotoluene (o-NT)
• m-nitrotoluene (m-NT)

TNT, RDX, and TNB were the explosives contaminants most often detected.
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TABIiE 1

RANGE OF EXPLOSIVE CONCENTRATIONS DETECTED IN SOIL

Compound
RDX
HMX
tetryl
TNT
TNB
DNT
DNB
oNT
mNT

Load Line 1
ND-39. 6
ND-0.25
ND-56.7
ND-133,000
ND-338
ND-28.9
ND-4.8
ND
ND

Load Line 2
ND-23,270
ND-2,020
ND-0.84
ND-176,000
ND-430
ND-119.3
ND-1.9
ND
ND

Load Line 3
ND-40.4
ND-2 . 8
ND-1.03
ND-29,700
ND-95.3
ND-14.8
ND-0.57
ND-1.35
ND-0.26

Load Line 4
ND-22.7
ND-4 . 9
ND
ND-131
ND-6.0
ND-17. 6
ND-0.7
ND-7 . 9
ND
Bomb Booster
Assembly
Area
ND
ND
ND-52, 000
ND-7.0
ND-3.6
ND
ND- 1.81
ND-160
ND

Burning/Proving
Grounds
ND-1,700
ND-207
ND-223
ND-313
ND-35.3
ND-1.25
ND-0.87
ND
ND
NOTES:

All units in mg/kg.
ND = Not Detected.
Source: Remedial Investigation Report.
Ac
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2.3 COMMUNITY PARTICIPATION

Community participation activities provide the public with an opportunity to express their views on the
preferred remedial action. USEPA, NDEQ, and USAGE consider public input from the community participation
activities in selecting the remedial alternative to be used for the site.

Community participation was provided in accordance with CERCLA, as amended by SARA. Community
participation highlights include the availability of several key documents in the administrative record,
public comment periods and public sessions.

A Community Relations Plan for the site was prepared by USAGE, and approved by USEPA and NDEQ in May,
1992. This document lists contacts and interested parties throughout government and the local community.
It also establishes communication pathways to ensure timely dissemination of pertinent information.

A Technical Review Committee (TRC) was established to insure that the cleanup of the NOP site would be
carried out in the best interests of the communities involved. The committee reviews and comments on all
official plans and documents, and advises the appropriate agencies before decisions are made regarding
activities at the site. The TRC meets periodically to review issues associated with OU1.

A public meeting was held at the University of Nebraska Field Lab in Mead in July 1989 and in June 1990
to discuss the progress of the ongoing study at the site and to give the community a chance to voice
their concerns and offer comments.

USAGE and USEPA released the Proposed Plan for the site on May 25, 1994, and have made it available for
public review and comment. The information repository for the site has been established at the Ashland
Public Library, 207 North 15th Street, Ashland, Nebraska. The information repository contains the RI
report, Baseline Risk Assessment, Feasibility Study (FS) Report, the Proposed Plan, and other documents
relevant to the site. This information was made available to the public to facilitate public input
concerning the investigation, remediation evaluation process, and preferred alternative identification.

Legal notice of the Proposed Plan and the Public Meeting was included in advertisements in the Wahoo
Newspaper and the Ashland Gazette on June 9, 1994. Press releases announcing the release of the Proposed
Plan and the Public Meeting were provided to the Wahoo Newspaper, the Ashland Gazette, the Lincoln
Journal, and the Omaha World Herald on June 7, 1994. A public comment period on the Proposed Plan was
held from June 14, 1994, to July 14, 1994. As a result of comments received during that period, the
deadline for submitting comments on the Proposed Plan was extended to August 22, 1994. The Proposed Plan
was presented at a Public Meeting held on June 23, 1994, at the University of Nebraska-Lincoln
Agricultural Research and Development Center at the site. At this meeting, representatives of USAGE,
USEPA, and NDEQ answered guestions from the public about the site and the remedial alternatives under
consideration.

Additionally, the USEPA and the USAGE held a Public Availability Session on February 22, 1995 at the Mead
Junior High School. The purpose of the Public Availability Session was to give the public an opportunity
to ask guestions and discuss issues associated with the proposed remedial action on a less formal basis.
Written comments were also accepted from the public between February 22, and March 8, 1995.

All comments received by the USEPA and the USAGE during the public comment periods, including those
expressed at the public meeting, are addressed in the Responsiveness Summary which is attached to this
document.

This decision document presents the selected remedial action for the OU1 at former NOP site in Mead,
Nebraska, chosen in accordance with CERCLA, as amended by SARA, and to the extent practicable, the
National Contingency Plan. The decision for this site is based on the administrative record.

2.4 SCOPE AND ROIiE OF OPERABIiE UNIT 1 REMEDIAL ACTION WITHIN SITE STRATEGY

Early site characterization activities identified some sources of contamination that could be addressed
before full characterization activities were complete for other sources. USAGE, in consultation with
NDEQ and USEPA, organized the remediation into three OUs. These are as follows:

• Operable Unit 1: Control and remediation of the upper 4 feet of soil contaminated with
explosives compounds.

• Operable Unit 2: Control and remediation of contaminated groundwater, soil contaminated
with VOCs, and soil deeper than 4 feet contaminated with explosives.
-------
• Operable Unit 3: Control and remediation of an on-site landfill and other disposal areas
not identified at the signing of the IAG.

Investigations and remediation feasibility evaluations are conducted in accordance with the OU
designations. The objective of the OU1 remediation is to reduce potential risks from direct contact
exposure to explosive compounds in soil to target risk level concentrations which are protective of human
health and the environment.

The selected alternative includes the following processes to meet the objective identified above:

• Excavate contaminated soil and debris.

• Sample to verify excavation to cleanup goals.

• Blend soil to reduce any reactive levels of explosives compounds.

• Conduct a risk assessment based on USEPA's combustion strategy.

• Conduct a trial burn to test the performance and emission controls of the incinerator.

• Treat explosives-contaminated soil using on-site rotary kiln incineration and test the
soil to verify the degree of treatment.

• Test treated soil and treatment residuals using the Toxicity Characteristic Leading
Procedure (TCLP) to verify that they are not hazardous due to the toxicity characteristic
for metals. If treatment residual fails the TCLP for metals, it will be disposed of at an
appropriate off-site facility.

• Blend soil and solid treatment residuals with clean soil, as necessary or appropriate, to
improve its ability to sustain vegetation and backfill treated soil on-site.

• Dispose of oversized material and debris in an authorized off-site landfill.

This alternative will protect both human health and the environment. Thermal treatment of excavated soil
is expected to destroy the explosive compounds, therefore, the risk posed by the upper 4 feet of source
area soil will be eliminated.

2.5 SUMMARY OF SITE CHARACTERISTICS

Results of the OU1 RI indicate that soil in the load lines, Bomb Booster Assembly Area, and
Burning/Proving Grounds are contaminated with explosive compounds. In the four load lines, explosives
contamination in soil is primarily associated with drainage ditches and sumps. In the Burning/Proving
Grounds, contamination appears to have originated from disposal, burning, and testing activities. In the
Bomb Booster Assembly Area contamination appears to be generally limited to isolated areas of high
concentration. In the Administration Area, a sump was found to contain explosives-contaminated sediments
as a part of an unexploded ordnance investigation and the sump and sediment will be treated under OU1.
Estimated areas of soil contamination are shown on Figures 3 through 9.

As described in Section 2.2.3, most of the contaminated soil is found within 4 feet of the ground surface
but the maximum depth of contamination detected is approximately 30 feet. Contaminants detected and their
concentration ranges are shown in Table 1. Of these contaminants, three are classified as possible or
probable human carcinogens, and six may cause noncancer health effects. Potential risk from ingestion of
these compounds in soil at the site is discussed in more detail in Section 2.7, Summary of Site Risks.

The fate and transport of the explosive compounds at the former NOP site are affected primarily by
adsorption, biodegradation, and photodegradation. Some biotransformation of TNT, RDX, DNT, and tetryl
may occur. Biodegradation will probably not be significant, however, unless supplemental nutrients and
adapted microbial populations are available. Photolysis will be potentially significant only in surface
waters. The compounds at the NOP site, therefore, will likely persist in surface soil and slowly leach
into the groundwater. Soil sample results under OU1 and recent groundwater data from OU2 are consistent
with these conclusions.

The estimated soil remediation volume is 8,400 cubic yards based on the remediation goals (RGs) developed
by USEPA. RGs are described further in Section 2.8. The total surface area of contaminated soil is
approximately 56,000 sguare feet. The remediation area and volume will also be defined in more detail
during the remedial design. Additional detail on the procedures used to estimate the remediation area
-------
and volume can be found in the FS Report.

2 . 6 REMOVAL ACTIONS

Three removal actions have been conducted to address potential risk from explosives-contaminated soil
greater than 10 percent explosives, explosives contamination in drinking water, and PCB-contaminated
soil. Two isolated soil areas on the site, in Load Lines 1 and 2, contain explosives concentrations
significantly higher than other areas. The removal action consisted of fencing the two locations to
limit access. Alternate water supplies have been provided to residents with explosives above health
advisories in their drinking water. PCB-contaminated soil surrounding former transformer pads was
excavated and disposed at an off-site facility. Additional investigation of remaining PCB contamination
is ongoing and is expected to be completed by the end of 1995.

2.7 SUMMARY OF SITE RISKS

CERCLA reguires that human health and the environment be protected from risks due to current and
potential future exposure to release of hazardous substances at or from a site. As part of the RI/FS for
OU1, a Baseline Risk Assessment was prepared. The Baseline Risk Assessment evaluates whether potential
unacceptable health or environmental risk is posed in the absence of remedial action. Potential threats
to human health were estimated based on assumptions about the manner, freguency, and concentration to
which a person could be exposed to contaminants at the site. Environmental risk was gualitatively
assessed.

2.7.1 Potential Human Health Risks

A detailed risk assessment was performed to characterize risks to current and hypothetical future
populations. The risk assessment consisted of an exposure assessment, a toxicity assessment, a risk
characterization, and an uncertainty evaluation.

Exposure Assessment

Resident farmers are not currently exposed to explosives-contaminated soil, because they do not reside
within the contaminated areas. Farm workers may be potentially exposed to explosives-contaminated soil
during tilling in the Burning/Proving Grounds. In the future, however, current occupational exposures
on-site could be extended into other contaminated areas and land with explosives-contaminated soil could
be sold to resident farmers. Therefore, the exposure assessment focused on hypothetical future resident
populations. Exposure pathways which were assessed included: ingestion of contaminated soil; ingestion
and dermal contact with contaminated groundwater; ingestion of contaminated home-grown vegetables and
beef; and exposure by inhalation of particulate matter while tilling, planting, or harvesting in the
contaminated areas.

The exposure assessment is based on the chemical dose (concentration per unit time), exposure duration
and freguency, rate of contact, and other specific parameters. For each contaminant, a chemical intake
or dose was calculated for each exposure route. An example of the eguations used for these calculations
is presented below. Other intake eguations are outlined in the Human Health Assessment portion of the
Baseline Risk Assessment.

For the ingestion of chemicals in soil, the following eguation was used:

IRxEFxED
Average Daily Intake = C x
BWxAT
-------
Where C = Average concentration of chemical at the exposure point (mg chemical/unit
environmental medium).
IR = Intake rate (amount ingested/unit time).
EF = Exposure freguency (hr/day, day/yr, etc.).
ED = Exposure duration. This is the total length of time that exposure occurs within the
time period of concern. The product of EF and ED gives the total number
of days or events of exposure.
BW = Body weight of receptor.
AT = Averaging time. This is the time period over which the average dose is
calculated (days).

Intakes were calculated for both expected average exposure conditions and reasonable maximum exposure
(RME) conditions. Average exposure conditions are calculated using average values for the parameters
shown above while RME uses a combination of average and upper bound factors in order to approximate an
intake in the 95th percentile of the intake distribution curve. The NCP reguires that the RME scenario be
used for making risk management decisions.

The risks posed by ingestion of contaminated soil were calculated based on standard body weights,
ingestion rates, and exposure durations. For an adult, a body weight of 70 kg was used to represent an
average adult. An average child's body weight of 15 kg was assumed. Adults' average and RME soil
ingestion rates were assumed to be 50 and 100 mg/day, respectively. Children were assumed to ingest 100
mg/day (average) and 200 mg/day (RME) of soil. Average and RME exposure durations for adult residents
were 30 and 70 years, respectively. Children's exposure duration was assumed to be 6 years under both
the average and RME scenarios. Other exposure assessment assumptions are outlined in Section 3 of the
Baseline Risk Assessment.

Toxicitv Assessment

Under current USEPA guidelines, the likelihood of cancer and noncancer effects due to exposure to site
chemicals are considered separately. Current and potential future uses of the site and its surroundings
were evaluated in order to identify potentially exposed populations and the pathways through which they
could be exposed. Carcinogenic and noncarcinogenic risks posed by contaminants were evaluated for each
potentially exposed population. Criteria for evaluating the potential of site chemicals to cause these
two types of adverse effects are described below.

Criteria for Cancer Effects

USEPA uses a weight-of-evidence system to convey how likely a chemical is to be a human carcinogen based
on epidemiological studies, animal studies, and other supportive data. The classification system for
characterization of the overall weight of evidence for carcinogenicity includes: Group A: human
carcinogen; Group B: probable human carcinogen; Group C: possible human carcinogen; Group D: not
classifiable as to human carcinogenicity; and Group E: evidence of noncarcinogenicity for humans. Group
B is subdivided into two groups: Group Bl: limited human evidence for carcinogenicity and Group B2:
sufficient data in animals but inadeguate or no evidence in humans. The classifications of the
carcinogenic explosive chemicals evaluated during the Baseline Risk Assessment are presented in Table 2.
Some of the explosive compounds detected in OU1 are not carcinogens.

For chemicals with cancer effects, the cancer risk associated with a given dose is calculated by
multiplying the estimated dose from a given route of exposure by a cancer slope factor. Slope factors
are derived from the upper 95 percent confidence limit of the slope of the chemical's extrapolated
dose-response curve. A dose-response curve shows the relationship between a given dose and the
associated tumor incidence. This conservative model assumes no toxicity threshold and, unlike the
noncarcinogens evaluated using the Hazard Index (HI), these risks are assumed to be additive in nature
(i.e., cancer is assumed to be systemic rather than target organ-specific). Slope factors used in the
risk assessment are listed in Table 2.

A cancer risk is expressed as the likelihood for an individual to contract cancer as a result of an
assumed lifetime of exposure to a specific chemical compound. The cancer risks for each compound are
added together to produce the total risk from exposure to multiple compounds.

Criteria for Noncancer Effects

A reference dose (RfD) is the toxicity value used most often in evaluating noncancer health effects
resulting from exposures to site contaminants. The RfDs used in the evaluation of noncancer health
effects depend on the exposure route (oral, inhalation, dermal), the critical effect (developmental or
other) and the length of exposure being evaluated (chronic, subchronic or single event). A chronic RfD
-------
is an estimate of the daily exposure level for the human population, including sensitive populations,
that is likely to be without an appreciable risk of deleterious effects during a lifetime. Chronic RfDs
are developed to be protective for long-term exposure to a compound. Chronic RfDs are generally used to
evaluate the potential noncarcinogenic effects associated with exposure periods between 7 years and
lifetime. Subchronic RfDs are generally used for exposure periods between 2 weeks and 7 years. A summary
of the RfDs used in the Baseline Risk Assessment are presented in Table 3.

The projected dose or intake developed in the exposure assessment is divided by the RfD value to compute
the Hazard Quotient (HQ). HQs are additive either across pathways of exposure for single chemical, or
across chemicals for one or more pathways of exposure to determine a HI. The HI was developed by USEPA to
assess the overall potential for noncancer effects posed by chemical exposure. For simultaneous exposure
to several chemicals, the HQs are additive only if the chemicals produce the same effect. The HI is not
designed as a mathematical prediction of the severity of the noncarcinogenic effects, rather it is an
indication of potential adverse effects in view of established RfD criteria for specific chemical
compounds.

Risk Characterization

When the calculated cancer risk from lifetime exposure to site-related chemicals is estimated to be more
than one additional (excess) cancer case in 10,000 people (1 in 10,000 or 1E-04), remedial action is
generally required under the Superfund law. When the cancer risk is between one additional cancer case
in 10,000 and in 1,000,000 people (1 in 1,000,000 or 1E-06), action may or may not be necessary depending
on such site-specific factors as location, environmental impact, and noncancer health effects. Excess
risk from 1E-04 to 1E-06 is termed the target risk range by USEPA. If the risk is less than 1E-06,
action is generally not required unless there are also environmental risks or noncancer health effects.
When the total noncancer HI is equal to or less than one (1), it is assumed that there is no appreciable
risk that noncancer effects may occur. If HI exceeds 1, there is some possibility that noncancer effects
may occur and remedial action may be required.

Results of risks calculated for soil ingestion in the Baseline Risk Assessment are summarized in Tables 4
and 5. Table 4 presents potential cancer risks to adults for 21 exposure areas. These exposure areas
represent an approximately 1-acre area in which a residential receptor could carry out the activities
identified by the exposure assumptions (i.e., ingest soil, plant a garden, pasture a cow, till a field or
install a domestic water supply well). Potential cancer risks above 1E-04 could exist for members of a
future resident farm family. The potential risks to a future farm family are greater than those for the
future worker, therefore, potential risks for the future worker are not included in Table 4. Results of
risk calculations for the future worker are included in the Final OU1 Baseline Risk Assessment.

Although the OU1 Baseline Risk Assessment did include calculations that accounted for exposure to garden
vegetables, risk from exposure to garden vegetables are not presented in this ROD because calculating
risks from garden vegetables has a higher degree of uncertainty. This is because the amount and final
deposition of contaminant uptake by plants, the amount of human home-grown vegetable consumption, and the
final contaminant deposition within humans is not known. Additional evaluation of plant uptake of
explosives will take place under OU3. Potential risks from inhalation while filling and ingestion of
homegrown beef were found to be negligible. The chemicals found to contribute the majority of the cancer
risk were TNT and RDX. Preliminary groundwater risk calculations were performed as part of the FS.
Based on highly conservative assumptions, the calculations indicated risks may exceed 1E-04 for a future
farm family. A more detailed evaluation of potential risks posed by groundwater contamination at the
site was conducted as part of OU2 and presented in the Final OU2 Baseline Risk Assessment (Woodward-Clyde
Consultants, September 1994).

Noncancer His greater than one potentially exist for future resident farm family members. Table 5
presents a summary of potential noncancer effects due to soil ingestion. Noncancer risks due to
ingestion of garden vegetables are not presented because of the increased uncertainty associated with
these calculations. As with cancer risks, potential noncancer effects from inhalation while tilling and
beef consumption were negligible. The majority of the potential noncancer risks are from exposure to
TNT, Tetryl, RDX, and HMX.

Actual or threatened releases of contaminants at or from this site, if not addressed by implementing the
remedial action selected in this ROD, may present an endangerment to the public health, public welfare or
the environment.
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TABIiE 2
SUMMARY OF CANCER EFFECTS AND SLOPE FACTORS
USED FOR THE BASELINE RISK ASSESSMENT
Record of Decision
Former NOP Site
Operable Unit 1
Mead, Nebraska
Chemical Cancer Type/Route(a)

DNT Liver, mammary glands, kidney/Oral

RDX Liver/Oral

TNT Urinary bladder/Oral
Weight-of-Evidence(b)

C
Slope Factor,
Oral

6.8E-01

1.1E-01

3.0E-02
(mg/kg-day)-1(a)
Inhalation
NOTES:

(a)

(b)
Information from the IRIS Database (USEPA 1992) or HEAST Annual 1991 (USEPA 1991) unless otherwise noted. Only chemicals with slope
factors calculated by USEPA are included here.
B2: Probable human carcinogen; sufficient data in animals, but inadeguate or no evidence in humans.
C: Possible human carcinogen.
-------
TABIiE 3
Chemical

DNB

DNT

HMX

RDX

Tetryl

TNB

TNT
SUMMARY OF NON-CANCER EFFECTS AND TOXICITY VALUES
USED FOR THE BASELINE RISK ASSESSMENT
Record of Decision
Former NOP Site
Operable Unit 1
Mead, Nebraska
Effect/Route(a)

Increased spleen weight/Oral

No information available(c)

Liver and kidney effects/Oral

Neurological and liver effects, prostate
inflammation/Oral

Liver, kidney, and spleen effects/Oral

Increased spleen weight, decreased hemoglobin levels,
testicular atrophy/Oral

Liver effects/Oral
Subchronic
RfD(b)

l.OE-03
Oral(a)
Chronic
RfD(b)

l.OE-04
Confidence
Level

Low
5.0E-01(d)
3.0E-03
l.OE-Ol(c)
5.0E-04
5.0E-02
3.0E-03
l.OE-02 (c)
5.0E-05
Low
High
Low
Low
5.0E-04
5.0E-04
Medium
NOTES: (a) Information from the IRIS Database (USEPA 1992) or HEAST Summary Tables (1991b) unless otherwise noted.
(b) Units of the RfD are mg/kg-day.
(c) No information was available at the time the Baseline Risk Assessment was performed and approved. Values have since been
derived by USEPA and are recorded in the HEAST database.
(d) Value calculated from the chronic RfD (without the uncertainty factor of 10 applied in calculating a chronic value from a
subchronic study).
(e) Value from Health and Environmental Effects document for this chemical (USEPA 1990).
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TABLE 4

SUMMARY OF LIFETIME RME EXCESS CANCER RISK - SOIL PATHWAYS
HYPOTHETICAL FUTURE RESIDENT POPULATIONS
Record of Decision
Former NOP Site
Operable Unit 1
Mead, Nebraska

Exposure Area(l) Risk

LL1A 2E-05
LL1B IE-OS
LL1C IE-OS
LL1D 6E-05
LL1E 2E-04
LL1F 6E-06
LL1G 5E-05
LL2A IE-OS
LL2B 2E-03
LL2C 3E-04
LL2D IE-OS
LL3A 8E-06
LL3B 3E-04
LL3C 1E-06
LL3D 2E-05
LL4A 2E-05
LL4B 2E-07
BPGA 1E-04
BPGB 3E-06
BPGC 7E-07
BBA 2E-07
NOTE: (1) Refer to the OU 1 Final Baseline Risk Assessment for
the location of the exposure areas.
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TABIiE 5

SUMMARY OF RME NON-CANCER RISK - SOIL PATHWAYS
HYPOTHETICAL FUTURE RESIDENT POPULATIONS
Record of Decision
Former NOP Site
Operable Unit 1
Mead, Nebraska
Exposure Area(l)
Future Farm Family Adult(2)
Future Farm Family Child(3)
LL1A
LL1B
LL1C
LL1D
LL1E
LL1F
LL1G
LL2A
LL2B
LL2C
LL2D
LL3A
LL3B
LL3C
LL3D
LL4A
LL3B
BPGA
BPGB
BPGC
BBA
2
70
60
4
10
0.4
3
20
100
4
0.06
0.8
20
0.1
2
0.6
0.02
4
0.07
0.005
1
5
400
400
20
70
2
20
100
600
10
0.3
3
100
0.5
8
3
0.07
6
0.4
0.02
0.7
NOTES: (1)Refer to the OU 1 Baseline Risk Assessment for the location of the exposure areas.
(2)Values are chronic hazard quotients.
(3)Values are subchronic hazard quotients.
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Uncertainties

The procedures and inputs used to assess risks in this evaluation, as in all such assessments, are
subject to a wide variety of uncertainties. In general, the main sources of uncertainty include:

• environmental chemical sampling and analysis.
• exposure parameter estimation.
• toxicological data.
• garden vegetable pathway.

Uncertainties in environmental sampling and parameter measurement arise in part from non-uniform
distribution of chemicals in the soil sampled. Conseguently, there is uncertainty as to the actual
guantities of soil containing unacceptable contaminant concentrations. Environmental chemical analysis
errors can stem from several sources including the errors inherent in the analytical methods and
characteristics of the soil being sampled.

Uncertainties in the exposure assessment are related to estimates of how often an individual would
actually come in contact with the chemicals, the period of time over which such exposure would occur, and
in the models used to estimate the concentrations of the chemicals at the exposure point.

Uncertainties in the toxicity assessment are related to extrapolation from animals to humans and from
high to low exposure doses, and from the difficulties in assessing the toxicity of a mixture of
chemicals. There uncertainties are addressed by making conservative assumptions concerning risk and
exposure parameters. As a result, the Baseline Risk Assessment provides upper bound estimates of the
risks to populations near the former NOP site.

Dose estimates for the garden vegetable pathway are relatively uncertain. A very limited amount of
scientific study has been performed on the uptake of explosives by plants. The uncertainty is due
primarily to:

• The amount of explosives uptake by vegetables, represented by the bioaccumulation factor; these
factors are often extrapolated across chemicals, are plant-type specific (garden-fruit, root
vegetables, etc.), plant-part specific, and soil parameter specific.

• The estimated fraction of total vegetable intake that comes from home-grown sources is
conservative.

• Risk calculations that assume the entire garden is planted in contaminated soil, and that the
explosives concentrations are uniform across the garden.

• Metabolism of contaminants by plants is not accounted for in the risk calculations.

USAGE plans to investigate plant uptake of explosives as part of OU3.

2.7.2 Potential Environmental Risks

Potential risks to ecological resources at this site appear to be limited to the terrestrial environment
in the vicinity of soil contaminated with significant levels of explosives. Plant populations exposed to
high levels of TNT and RDX may be subject to growth inhibition and tissue damage. Plant uptake of
explosives compounds will be further evaluated under OU3. Animals that feed in these areas may be exposed
to higher than average intakes from feeding on these plants. Little information exists regarding
exposure through these pathways. Due to the localized nature of contaminated areas, it is unlikely that
population or community effects will occur in the vicinity of elevated soil explosives contamination.

On-site wetlands are not located near areas of contamination at the site and will not be impacted by the
OU1 remedial action. No endangered species or other critical habitat are known to exist in the area.

2.8 SUMMARY OF ALTERNATIVES

Remedial Action Objectives

Remedial action objectives (RAOs) were developed to address the explosives-contaminated soil while
considering the long-term goals of protecting human health and the environment and meeting applicable or
relevant and appropriate reguirements (ARARs) of Federal and State laws and regulations. The RAO for OU1
at the former NOP site is to minimize risk to human health and the environment from direct contact with
soil contaminated with explosives.
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The risk management strategy for OU1 remediation is to address the potential risk to the hypothetical
future adult farm resident from ingestion of explosives-contaminated soil. Risk-based RGs are
environmental concentrations that are protective of public health and meet RAOs. RGs are based on target
risks, risk management strategy, and on assumptions developed by USEPA. RGs were derived using the same
intake eguations used to calculate risk. Rgs governing the excavation and level of soil treatment were
developed for target risks of HI=1 and 3E-06 excess cancer risks. These RGs are shown in Table 6.

TABIiE 6

RISK-BASED REMEDIATION GOALS
Record of Decision
Former NOP Site
Operable Unit 1
Mead, Nebraska
Chemical
HMX
RDX
TNB
DNB
TNT
DNT (2,4- or 2, 6-)
NT
Tetryl
Concentration (mg/kg)
1715.2
5.8
1.7
3.4
17.2
0.9
343.0
343.0
To meet RAOs, remedial action will consist of excavating and remediating contaminated soil in the upper 4
feet that has explosives concentrations greater than RGs. A 4-foot maximum depth was selected by USEPA
as the depth that would prevent direct contact with soil given normal surface activities and conditions.
Remediation of additional soil that acts as a long-term source of explosives contamination to groundwater
is being evaluated further under OU2.

Alternative Descriptions

Seven preliminary remedial action alternatives were developed during the FS. These alternatives
were designed to address the RAOs. Two of the alternatives were eliminated because they were determined
to be ineffective. The remaining five alternatives were evaluated in detail in the FS Report. The
following sections describe these five alternatives. The FS Report provides greater detail for each
alternative.

2.8.1 Alternative 1 - No Action

This alternative was included in the FS Report as a NCP reguirement to provide a baseline against which
other alternatives are compared. The no-action alternative, by definition, involves no remedial action.
Therefore, the potential for ingestion of contaminated soil persists and the potential risks are those
identified in the Baseline Risk Assessment. On-site contaminated soil would continue to contribute a
cancer risk greater than 1E-06 and a noncancer risk greater than HI=1. There are no costs associated
with Alternative 1.

2.8.2 Alternative 2 - Biological Treatment

Alternative 2 included treatment of the explosives-contaminated soil through biological treatment.
Biological treatment is considered an innovative, alternative technology for explosive compounds.
Alternative treatment technologies, as well as cost effective, permanent solutions, are preferred under
SARA to the maximum extent practicable. For the purpose of the FS, composting was evaluated. Composting
involves mixing soil with organic amendments (such as animal manure) and bulking agents (such as wood
chips) to enhance biological activities which reduce the amount of explosives present. Had it been
selected, composting biological treatment could have increased (approximately doubled) the volume of
treated material due to the addition of these materials. Aerobic and/or anaerobic slurry-based
biological treatment could also have been used. Slurry treatment involves mixing water and nutrients
with the contaminated soil in a closed vessel to promote biodegradation.
-------
Figure 10 shows the major components of this alternative. The major components of Alternative 2 included
the following:

• Excavate contaminated soil and debris.

• Sample to verify excavation to cleanup goals.

• Blend soil to reduce any reactive levels of explosives compounds.

• Treat explosives-contaminated soil using biological treatment and test the soil to verify
the degree of treatment.

• Backfill treated soil or compost on-site.

• Dispose oversized material and debris in an authorized off-site landfill.

Table 7 shows estimated costs for this alternative. Capital costs include the direct and indirect costs
associated with construction (or implementation) of the alternative. The annual operation and
maintenance costs (O&M) are the post-construction costs necessary to ensure the continued effectiveness
of the alternative. The present worth cost represents the amount of money that, if invested during the
current year, would be sufficient to cover all expenditures over the life of the alternative. The cost
estimates are conceptual with an estimated +50 percent to - 30 percent level of accuracy.

2.8.3 Alternative 3 - Rotary Kiln Incineration

Alternative 3 would treat explosives-contaminated soil using on-site thermal treatment. Possible
treatment technologies would include on-site incineration, vitrification, or low-temperature thermal
desorption (LTTD). LTTD and vitrification have not been used to treat explosives-contaminated soil at
other sites. Incineration is the only thermal treatment technology previously used successfully at
full-scale for explosives-contaminated soil.

Figure 11 shows the major components of this alternative. The major components of Alternative 3 include
the following:

• Excavate contaminated soil and debris.

• Sample to verify excavation to cleanup goals.

• Blend soil to reduce any reactive levels of explosives compounds.

• Conduct a risk assessment based on USEPA's combustion strategy.

• Conduct a trial burn to test the performance and emission controls of the incinerator.

• Treat explosives-contaminated soil using on-site rotary kiln incineration and test the
soil to verify the degree of treatment.

• Test treated soil and residuals to verify that they are not hazardous due to the toxicity
characteristic (TCLP) for metals. If treatment residual fails TCLP for metals, it will be
disposed of at an appropriate off-site facility.

• Blend treated soil and solid treatment residuals, backfill on-site in excavations, and
cover with clean soil, as necessary or appropriate, to sustain vegetation.

• Dispose of oversized material and debris in an authorized off-site landfill.

Rotary kiln incineration is the selected thermal treatment technology because LTTD has not been proven
for site soil and, although treatability studies indicate vitrification is effective, treatability
studies also indicate that vitrificafion is cost-prohibitive. Thus, rotary kiln incineration is the most
cost-effective, proven thermal treatment for the site.

Estimated costs for implementation of this alternative are shown in Table 8.
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TABIiE 7

ESTIMATED COSTS FOR ALTERNATIVE 2
(BIOLOGICAL TREATMENT)
Record of Decision
Former NOP Site
Operable Unit 1
Mead, Nebraska
CAPITAL COSTS:
Soil Removal
Biological Treatment
Treated Soil Placement
Residuals Management
Groundwater Treatment
Eguipment Salvage

Subtotal Capital Costs

Site PreparationRestoration (5%)
Mobilization/Demobilization (5%)
Health & Safety (8%)
Prime Fixed Fee (5%)

Subtotal

Bonds and Insurance (1%)

Subtotal

Scope Contingency (20%)
Permitting and Legal (5%)
Design Engineering (8%)
Construction-Related Services (8%;

Total Capital Cost

O&M COSTS:
$245,000
$3,555,000
$84,000
$75,000
$57,000
$-124,000

$3,892,000

$195,000
$195,000
$311,000
$195,000

$4,787,000

$48,000

$4,835,000

$967,000
$242,000
$387,000
$387,000

$6,817,000
O&M Annual Costs
O&M Present Worth Cost i

Total Present Worth Cost
discount rate)
$124,000
$1,700,000

$8,517,000
References: Assumptions and calculations for estimated costs are included in the Draft
Final Feasibility Study Report for OU 1.
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TABIiE 8

ESTIMATED COSTS FOR ALTERNATIVE 3
(THERMAL TREATMENT)
Record of Decision
Former NOP Site
Operable Unit 1
Mead, Nebraska
CAPITAL COSTS:
Soil Removal
Thermal Treatment
Treated Soil Placement
Residuals Management
Groundwater Treatment
Equipment Salvage

Subtotal Capital Cost

Site Preparation/Restoration (5%)
Mobilization/Demobilization (5%)
Health & Safety (8%)
Prime Fixed Fee (5%)

Subtotal

Bonds and Insurance (1%)

Subtotal

Permitting and Legal (5%)
Design Engineering (8%)
Construction Services (8%)
Scope Contingency (20%)

Total Capital Cost

O&M COSTS:
$245,000
$7,091,000
$42,000
$98,000
$57,000
$-27,000

$7,464,000

$373,000
$373,000
$597,000
$373,000

$8,808,000

$88,000

$8,896,000

$445,000
$712,000
$712,000
$1,779,000

$12,543,000
Annual O&M Costs
O&M Present Worth Cost i

Total Present Worth Cost
discount rate)
$124,000
$1,700,000

$14,243,000
References: Assumptions and calculations for estimated costs are included in the Draft
Final Feasibility Study Report for OU 1.
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2.8.4 Alternative 4 - On-Site Landfill

Alternative 4 would have minimized the potential for soil exposure pathway completion through containment
of explosives-contaminated soil in an on-site landfill. The landfill would have been designed with
engineering controls meeting the technical reguirements described in Resource Conservation and Recovery
Act (RCRA) Subtitle C landfill regulations. A 5-year review would have been reguired under CERCLA to
assess the long-term effectiveness of this alternative, because soil contaminated above RGs would have
remained on-site.

Figure 12 shows the primary components of this alternative. The primary components of Alternative 4
included the following:

• Clear, grub, and excavate clean soil from the landfill site, and construct the landfill
liner and leachate collection system. The liner would have met Subtitle C design
reguirements or be designed to provide eguivalent performance.

• Excavate contaminated soil and debris.

• Sample to verify excavation to cleanup goals. Backfill excavations with clean fill,
compact backfill, and revegetate the surface.

• Construct the landfill cover over the consolidated soil and debris. The cover would have
met performance reguirements for a Subtitle C landfill.

• Erect a fence around the landfill area and implement deed restrictions.

• Conduct groundwater monitoring.

• Conduct guarterly leachate monitoring and collection. Leachate would have been discharged
under an National Pollutant Discharge Elimination System (NPDES) process or treated and
disposed off-site.

Estimated costs for Alternative 4 are shown in Table 9.

2.8.5 Alternative 5 - Off-site Landfill

Alternative 5 would have included removal of explosives-contaminated soil from the site for disposal in
an off-site landfill with engineering controls meeting the technical reguirements described in RCRA
Subtitle C. Off-site disposal is the least preferred alternative under SARA.

Figure 13 shows the major components of this alternative. The primary components of Alternative 5
included the following:

• Excavate contaminated soil and debris.

• Sample to verify excavation to cleanup goals. Backfill excavations with clean fill,
compact backfill as needed, and revegetate the surface.

• Haul excavated soil and debris to an off-site landfill with engineering controls meeting
the reguirements described in RCRA in Subtitle C.

Estimated costs for Alternative 5 are shown in Table 10.

2.9 TREATABILITY STUDIES

Treatability studies were performed to assess the feasibility of rotary kiln incineration, vitrification,
and slurry-based biological treatment.

The incineration study consisted of bench-scale treatability tests. The results of the study indicate
that explosives-contaminated soil from the former NOP site can be treated to meet Rgs and that the
treated soil would not be classified as RCRA hazardous by toxicity characteristic testing.

The vitrification study consisted of a bench-scale test. Results of this bench-scale test indicate that
explosives-contaminated soil from the former NOP site can be treated to meet RGs. The treated vitrified
product was not classified as RCRA hazardous by toxicity characteristic testing, and air emissions did
not contain detectable levels of explosive compounds.
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TABIiE 9
ESTIMATED COSTS FOR ALTERNATIVE 4
(ON-SITE LANDFILL)
Record of Decision
Former NOP Site
Operable Unit 1
Mead, Nebraska
CAPITAL COSTS:

Soil Removal
Landfill Construction
Groundwater Treatment
Monitoring Wells

Subtotal Capital Cost

Site Preparation/Restoration (5%)
Mobilization/Demobilization (5%)
Health and Safety (8%)
Prime Fixed Fee (5%)

Subtotal

Bonds and Insurance (1%)

Subtotal

Scope Contingency (20%)
Permitting and Legal (5%)
Design Engineering (8%)
Construction-Related Services (8%)

Total Capital Cost

O&M COSTS:

Annual O&M Cost (years 1 through 5)
Annual O&M Cost (years 5 through 30)
Annual O&M Cost (after year 30)
O&M Present Worth Cost (6%)*

Total Present Worth Cost (6%)*
$304,000
$404,000
$57,000
$50,000

$815,000

$41,000
$41,000
$65,000
$41,000

$1,012,000

$10,000

$1,022,000

$202,000
$51,000
$152,000
$81,000

$1,498,000
$166,000
$148,000
$26,000
$2,200,000

$3,698,000
*Assumes guarterly monitoring for years 1 through 5 and annual monitoring thereafter.

References: Assumptions and calculations for estimated costs are included in the Draft Final Feasibility
Study Report for OU 1.

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TABIiE 10
ESTIMATED COSTS FOR ALTERNATIVE 5
(OFF-SITE LANDFILL)
Record of Decision
Former NOP Site
Operable Unit 1
Mead, Nebraska
CAPITAL COSTS:

Soil Removal and Backfill
Soil Disposal
Groundwater Treatment

Subtotal Capital Cost

Site Preparation/Restoration (5%)
Mobilization/Demobilization (2%)
Health & Safety (8%)
Prime Fixed Fee (5%)

Subtotal

Bonds and Insurance (1%)

Subtotal

Scope Contingency (20%)
Permitting and Legal (5%)
Design Engineering (2%)
Construction-Related Services (3%'.

Total Capital Cost

O&M COSTS:
$304,000
$1,680,000
$57,000

$2,041,000

$102,000
$41,000
$163,000
$102,000

$2,449,000

$24,000

$2,473,000

$495,000
$124,000
$49,000
$74,000

$3,215,000
Annual O&M Costs
O&M Present Worth Cost (6% discount rate)

Total Present Worth Cost
$124,000
$1,700,000

$4,915,000
References: Assumptions and calculations for estimated costs are included in the Draft
Final Feasibility Study Report for OU 1.
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The slurry-based biological study consisted of simultaneous laboratory-scale and bench-scale testing.
The goals of biological treatability testing were to assess the biodegradability and fate of the
explosive compounds. Treatability studies included aerobic, anaerobic, and seguential anaerobic/aerobic
treatments. The studies used shake flasks to simulate batch and continuous flow slurry-phase
bioreactors. The results of these tests indicate that, under the conditions evaluated, limited treatment
of explosives-contaminated soil from the site could occur. Rgs were not met during the slurry-based
biological study performed for the former NOP site. Further testing and optimization would be reguire to
determine if slurry-based biological treatment or composting would be able to meet RGs.

2.10 SUMMARY OF COMPARATIVE ANALYSIS OF ALTERNATIVES

2.10.1 Introduction

USEPA has established nine criteria that balance health, technical, and cost considerations to
determine the most appropriate remedial action alternative. These criteria are used to select a
remedial action that is protective of human health and the environment, attains ARARs, is cost
effective, and utilizes permanent solutions and treatment technologies to the maximum extent
practicable. The remedial action alternatives developed in the FS have been evaluated and
compared using the nine criteria set forth under NCP 300.430(e)(9)(iii). These nine criteria are
summarized as follows:

1. OVERALL PROTECTION OF PUBLIC HEALTH AND THE ENVIRONMENT addresses whether a remedial action provides
protection of human health and the environment and describes how risks which are posed through each
exposure pathway are eliminated, reduced, or controlled through treatment, engineering controls, or
institutional controls.

2. COMPLIANCE WITH APPLICABLE OR RELEVANT AND APPROPRIATE REQUIREMENTS (ARARs) addresses whether a
remedial action will meet all applicable or relevant and appropriate reguirements of Federal and
State laws and regulations and/or provides grounds for invoking a waiver.

3. LONG-TERM EFFECTIVENESS AND PERMANENCE refers to the ability of a remedial action to maintain
reliable protection of human health and the environment over time, after RAOs have been met.

4. REDUCTION OF CONTAMINANT TOXICITY, MOBILITY, OR VOLUME THROUGH TREATMENT addresses the anticipated
performance of the treatment technologies a remedial action employs.

5. SHORT-TERM EFFECTIVENESS addresses the period of time needed to achieve protection from adverse
impacts on human health and the environment that may be posed during the construction and
implementation period, until RAOs are achieved.

6. IMPLEMENTABILITY is the technical and administrative feasibility of a remedial action, including the
availability of materials and services needed to implement a particular option.

7. COST includes estimated initial capital, O&M costs, and present worth costs.

8. STATE ACCEPTANCE indicates whether the state agency concurs with, opposes, or has no comment on the
preferred remedial action alternative at the present time.

9. COMMUNITY ACCEPTANCE is based on comments received from the public during the public comment period.
These comments are assessed in the Responsiveness Summary attached to this ROD.

2.10.2 Comparison of Alternatives

Alternatives were compared in the FS with respect to the nine evaluation criteria. This comparison is
discussed below. For the purpose of this discussion, the evaluation criteria have been divided into
three groups (threshold, balancing, and modifying criteria) based on the function of each criterion
during remedial action evaluation and selection.

A. Threshold Criteria

Threshold criteria are statutory reguirements that must be satisfied by a remedial action alternative in
order for it to be eligible for further detailed evaluation in the FS and subseguent selection. These
two criteria are discussed below.
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Overall Protection of Human Health and the Environment

Alternative 1 (no action) would not have satisfied the requirement for overall protection of human health
and the environment. Estimated risks remaining under the no action alterative would have been the same
as those identified in the Baseline Risk Assessment. Alternatives 2 and 3 are the most protective of
human health and the environment because they include treatment. The goal of biological treatment is to
transform contaminants to less toxic products, therefore, successful application of biological treatment
would have permanently reduced the potential for exposure to explosives compounds. Thermal treatment
(Alternative 3) is expected to permanently eliminate the potential for exposure by any exposure route
through destruction of the contaminants. Alternative 4 would have been protective because it included
on-site containment of contaminated soil, thereby interrupting the potential soil exposure pathways.
Alternative 5 would have provided protection through containment at an off-site location.

Compliance with ARARs

All alternatives except Alternative 1 would comply with the ARARs which have been identified for the
site.

B. Balancing Criteria

Five balancing criteria are used to identify major trade-offs between the remedial action alternatives
which satisfy the two threshold criteria. These tradeoffs are ultimately used to identify the preferred
alternative and to select the final remedy. Because Alternative 1 does not meet the threshold criteria,
it is not evaluated under the balancing criteria.

Long-Term Effectiveness and Permanence

Had they been selected and effectively implemented, all of the action alternatives would have resulted in
risks at or below the target level (cancer risk = 3E-06 and noncancer HI=1) either by interrupting
exposure pathway completion or by treating the exposure source (contaminated soil). Alternatives 2 and 3
reduce risks by treating the potential exposure source (contaminated soil). Thermal treatment
(Alternative 3) may be more protective than biological treatment (Alternative 2) because it has been
proven on a full-scale basis for explosives and has achieved the RGs for explosives compounds during
site-specific treatability studies. Alternatives 4 and 5 would have provided long-term effectiveness by
interrupting the soil exposure pathways. However, alternative 4 would have required significant
long-term maintenance and management and a five-year review. A five-year review is required for those
remedial actions that result in hazardous substances remaining on-site above health-based levels. No
five-year review would be required for the off-site landfill alternative or the treatment alternatives as
long as the treatment alternatives met the RGs. If Alternative 2 had been selected and did not achieve
the RGs, a five-year review would have been required.

Long-term controls for the on-site containment alternative (Alternative 4) consisted primarily of cover
and leachate control maintenance, groundwater monitoring, and deed restrictions. Maintenance and
monitoring are reliable and should have been adequate to detect failure. Deed restrictions would have
been reliable only if they had been effectively enforced. Long-term controls at the off-site landfill
(Alternative 5) would have been the responsibility of the receiving facility.

Reduction of Toxicitv, Mobility, or Volume through Treatment

If effectively implemented, alternatives 2 and 3 are the only alternatives which would satisfy the
preference for remedial actions that employ treatment technologies that significantly reduce toxicity,
mobility, or volume of the untreated waste. These alternatives would use treatment to destroy or degrade
the explosive compounds in the former NOP site soil, thereby significantly reducing the toxicity and
mobility of these compounds. Alternative 3 is expected to provide a greater reduction of toxicity and
mobility than Alternative 2 because greater contaminant destruction is expected, and because biological
treatment (Alternative 2) may produce unknown breakdown products. In addition, it is uncertain whether
biological treatment would have achieved the RGs for the site. Thermal treatment is not expected to
significantly reduce the volume of soil. Biological treatment would have increased the volume of
material if composting had been used. However, the contaminants in the soil would be reduced and,
therefore, the volume of contaminated soil should have been eliminated or significantly reduced by both
Alternative 2 and 3.

Alternatives 4 and 5 would not have included treatment of contaminated soil. They would not have reduced
the toxicity or volume of contaminated soil. Both alternatives, however, would have reduced the mobility
of contaminants by containment. Leachate from the on-site landfill would have been collected and treated
under Alternative 4, minimizing potential migration to groundwater.
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Alternatives 4 and 5 would not have satisfied the statutory preference for treatment under CERCLA Section
121(b). In addition, off-site disposal (Alternative 5) is the least preferred remediation option as
noted under CERCLA. Additionally, containment on-site would have been potentially reversible; if
containment structures had been breached, exposure pathways would have potential to be completed again.

Short-Term Effectiveness

All action alternatives would have had the potential to generate dust, noise, and increased traffic
during excavation activities. Alternative 4 would have provided the most short-term effectiveness
because only excavation, on-site hauling, and routine construction activities were involved. Short-term
risks to workers, the community (including University of Nebraska personnel), and the local environment
from these activities are easily controlled. Short-term risks for Alternative 2 were expected to be
similar to those for Alternative 4 because biological treatment was not expected to pose significant
short-term risks beyond those associated with excavation. Alternative 5 (off-site landfilling) would
have posed additional potential short-term risks to both workers and the community because contaminated
material would have been transported off-site. Thermal treatment (Alternative 3) may potentially pose
some short-term risk to on-site workers through operations of the treatment facility, and to the
community through possible fugitive emissions. A risk assessment will be conducted for the incineration
alternative in accordance with USEPA's combustion strategy. The incineration facility will include
emissions control eguipment, such as a baghouse to remove particulates and afterburners to destroy
remaining contaminants or combustion products, to minimize these short-term risks.

TABIiE 11

ESTIMATED IMPIiEMENTATION TIMES
Record of Decision
Former NOP Site
Operable Unit 1
Mead, Nebraska

Alternative Implementation Time
2 32 months
3 15 months
4 8 months
5 4 months

NOTE: Implementation times have an +50/-30 percent level of accuracy.

An alternative's implementation time is the time it takes from mobilization of facilities and eguipment
to demobilization. Table 11 lists implementation times that were estimated for each alternative, based
on the +50 percent to -30 percent FS level of accuracy.

Implementability

Alternative 5 would have been the most implementable because the construction or process activities
involved (landfills and hauling firms) are available. Construction, maintenance, and monitoring included
in Alternative 4 would have been implementable, and specialists are readily available. Alternative 3
(incineration) specialists and eguipment are also readily available. Alternative 2, biological treatment,
would have been the least implementable alternative because it has not been used full-scale on
explosives, it is available from only a limited number of vendors, there was uncertainty associated with
performance, and it may have been difficult to monitor due to unknown intermediate compounds. Composting
reguires conventional technology and can be readily implemented using commercially available eguipment
and materials; however, its application to explosives-contaminated soil is innovative.

Costs

Alternatives were evaluated in terms of estimated capital, O&M, and present worth cost. Estimated costs
based on a +50 percent to -30 percent level of accuracy are provided in Tables 7 through 10. These costs
were based on a remediation volume of 8,400 cubic yards.

C. Modifying Criteria

The two modifying criteria were evaluated following comment on the proposed plan and are addressed as the
final decision is made and the ROD is prepared. The results of the modifying criteria are summarized
below.
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State Acceptance

This assessment evaluates technical and administrative issues and concerns NDEQ may have regarding each
of the alternatives. NDEQ has been actively involved in the entire RI/FS process leading to the
development of this ROD, including being party to the Interagency Agreement, participating in all
technical review and public meetings, oversight of field work, and review and comment on all draft
project documents. A letter from the NDEQ regarding concurrence with the selected remedial action for
this site is attached.

Community Acceptance

Public comments on the selected remedial action were presented at the public meeting on June 23, 1994.
Twenty-eight written comments were received during the comment period which extended from June 14, 1994,
to August 22, 1994. An additional ten comments were received during the public comment period from
February 22, 1995 to March 8, 1995.

In general, the public had differing opinions regarding the use of incineration as the preferred
alternative. Nine comment letters fully supported the use of incineration. Nineteen comment letters
were received that neither supported nor opposed the use of incineration. Ten comment letters, including
one submitted by a public interest group, opposed the use of incineration. A summary of public comments
and USEPA/USACE responses are provided in the Responsiveness Summary, Section 3.0 of this document.

2.10.3 Summary

Based on the nine evaluation criteria, Alternative 1 would not have provided protection from the
potential site risks and would not have complied with the ARARs. Therefore, it does not meet the
threshold criteria for selection of a remedial action alternative for the site.

If it had been selected Alternative 2 may have reduced contaminant mobility and toxicity through
biological transformation of explosive compounds to other organic compounds, but final transformation
products may have been unknown. Slurry-based biological treatment has not shown the ability to achieve
the RGs. Additional studies would be reguired to determine the effectiveness and implementability of
biological treatment.

Alternative 3 will be protective of human health and the environment and will attain the ARARs. Thermal
treatment (incineration) has been proven for explosives-contaminated soil, and will achieve RGs. Thermal
treatment provides a greater degree of long-term effectiveness and permanence because it consists of a
proven treatment method, and does not rely upon containment of contaminants. Because incineration
results in complete destruction of contaminants, no long-term management and maintenance will be
reguired.

If Alternative 4 had been selected, it would have been protective for soil exposure risks, but
containment would have been reversible. Alternative 5 would have provided protection, but transferred
untreated contaminants to another location. Off-site disposal is the least preferred alternative under
SARA.

Implementation for on-site rotary kiln incineration should not pose technical problems, because similar
remedies have been implemented at other sites. Had the containment alternatives (4 and 5) been selected,
this would have been true for those alternatives also. Biological treatment, however, is a relatively
new technology for explosives-contaminated soil and, therefore, may have been difficult to implement.

2.11 THE SELECTED REMEDIAL ACTION

Alternative 3 was selected because it will be protective of human health and the environment, will comply
with ARARs, will utilize permanent solutions to the maximum extent practicable, will significantly reduce
the toxicity, mobility, and volume of contaminants through treatment, and is implementable. This
alternative satisfies the RAOs for this remedial action discussed in Section 2.8.

The major components of the selected remedial action for OU1 include:

• Excavate contaminated soil and debris.

• Sample to verify excavation to cleanup goals.

• Blend soil to reduce any reactive levels of explosives compounds.
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• Conduct a risk assessment based on USEPA's combustion strategy.

• Conduct a trial burn to test the performance and emission controls of the incinerator.

• Treat explosives-contaminated soil using on-site rotary kiln incineration and test the
soil to verify the degree of treatment.

• Blend treated soil and solid treatment residuals, backfill on-site in excavations, cover
with clean soil, as necessary or appropriate, to sustain vegetation.

• Dispose of oversized material and debris in an authorized off-site landfill.

2.12 STATUTORY DETERMINATIONS

CERCIA Section 121(d) reguires that the selected remedy comply with all federal and state environmental
laws that are applicable or relevant and appropriate to the hazardous substances, pollutants, or
contaminants at the site or to the activities to be performed at the site. Therefore, to be selected as
the remedy, an alternative must meet all applicable or relevant and appropriate reguirements (ARARs) or a
waiver must be obtained. A discussion of how each ARAR applies to OU1 is provided below.

2.12.1 Protection of Human Health and the Environment

The selected remedial action will protect human health and the environment through thermal treatment of
soil at a depth of 4 feet or less posing risk greater than the target risk. This will eliminate the soil
ingestion pathway through which contaminants pose risk.

2.12.2 Conpliance with ARARs

The selected remedy will be designed to comply with all ARARs of Federal and State laws. A list of ARARs
pertinent to the site is contained in the detailed analysis section of the FS Report. The ARARs that
will be achieved by the selected alternative are:

FEDERAL

Clean Air Act of 1963, as amended:

40 CFR 50.1-6, 8, 9, 11, 12, and Appendices A-H, J, K; 40 CFR 60.50-54; and 40 CFR 61.01, 5, 6,
10-15, 19

This regulation is pertinent to excavation and materials handling activities which may cause particulate
emission concerns. Control measures, including water or other dust suppressants, truck tarpaulins,
covers for soil stockpiles, and temporary structure for the treatment process train, will be used to
mitigate particulate values to the atmosphere. Thermal treatment emissions of particulate matter and
nitrogen dioxide are also of concern. The air pollution control system for the rotary kiln incinerator
will be designed to meet appropriate Clean Air Act reguirements.

Clean Water Act of 1977, as amended:

40 CFR 122.1-7, 21, 22, 28, 29, 41-48, 49, 61-64; 40 CFR 125.1-3; 40 CFR 136.1-5 and Appendices A-C;
40 CFR 403.5-7, 13, 15

Fluids from eguipment decontamination will be discharged, if needed, to the surface, surface water, or an
on-site treatment facility, or will be disposed, if needed, by an off-site facility. Surface or surface
water discharge is acceptable for liguid residuals that meet substantive reguirements of the NPDES.
These regulations are also pertinent to the discharge of process water. Process water may be recycled to
guench the ash, sprayed back on-site for dust control, discharged to the surface or surface water, or
treated off-site. Discharge limits will be established during the design phase.

40 CFR 125.30-32

This regulation is applicable if effluent discharge factors are fundamentally different from the factors
considered by USEPA in the development of the national limits. Under CWA301 and 304, USEPA may reguire
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that the effluent be analyzed for explosives, which are not on the analytical list of compounds.

40 CFR 125.70-73

This regulation is applicable if the thermal treatment residual water (if any) discharge limit to surface
water is "more stringent than necessary." This regulation specifies reguirements for obtaining approval
of an alternate effluent limit.

40 CFR 125.100-104

This regulation provides guidelines for preventing discharge of toxic pollutants from material handling
and storage areas to waters of the United States.

Public Health Service Act: Title XIV, as amended by the Safe Drinking Water Act of 1986, as amended:

40 CFR 141,11-12; 40 CFR 141,50; 40 CFR 141,60-63; 40 CFR 143.03

Residual water from thermal treatment (if any) and fluids from eguipment decontamination will be
discharged to the surface, surface water, an on-site treatment facility, or an off-site treatment
facility. If it is discharged at the surface, it can percolate into groundwater. This regulation is not
applicable to explosive compounds. However, due to the chemical composition of explosives, there is a
potential for nitrate in the discharge. Surface or surface water discharge is acceptable for liguid
residuals that meet substantive reguirements; however, if treatment is reguired prior to surface
discharge, it may be more cost-effective to treat and dispose residual water at an off-site facility.
Private use of groundwater is not precluded, therefore these reguirements are relevant and appropriate.

Solid Waste Disposal Act (SWDA) as amended by Resource Conservation and Recovery Act (RCRA) of 1976:

40 CFR 261.1-7

This regulation applies to OU1 in determining the classification of soil and debris as nonhazardous.

40 CFR 261.10, 11, 20-24, 30-33, 268.30.40

Residuals produced through thermal treatment must be tested to determine if they exceed the TCLP.

40 CFR 262.11

This regulation provides the procedure for determining whether any solid waste produced at the site is
hazardous based upon 40 CFR 261. This regulation is applicable to the use of the TCLP test for metals in
the ash after treatment by the incinerator.

40 CFR 262.34

This regulation defines the time periods and conditions for accumulation of hazardous waste on-site and
limits the accumulation time to less than 90 days without reguiring compliance with 40 CFR 264. This
regulation will be an ARAR only for the ash that fails the TCLP test for metals.

40 CFR 264,30-56

These regulations are for the preparedness, prevention and contingency planning for operators of waste
treatment facilities that store hazardous waste for more than 90 days. Although these regulations are
applicable for this site only if the ash that fails the TCLP test is stored for more than 90 days, which
is not anticipated, the majority of the reguirements of these regulations will be complied with to ensure
the safety of the incinerator unit.

40 CFR 264.340-351

These technical reguirements for incinerators are relevant and appropriate to thermal treatment of soil.
Substantive reguirements of these regulations will be met.

40 CFR 266, Subpart H

These regulations are for hazardous waste when treated in boilers and industrial furnaces. The metals
emissions criteria from these regulations is applicable for this site.
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STATE

Nebraska Surface Water Quality Standards - Title 117:

Ch. 2-4

Residual water from thermal treatment (if any) and fluids from equipment decontamination may be
discharged to surface water or an on-site treatment facility in accordance with the substantive
requirements of the NPDES permit process. Surface or surface water discharge is acceptable for liquid
residuals that meet substantive requirements; however, if treatment is required prior to surface
discharge, it may be more cost-effective to treat and dispose liquid residuals at an off-site facility.

Rules and Regulations Pertaining to the Issuance of Permits Under the National Pollutant Discharge
Elimination System - Title 119:

Ch. 2-66

Residual water from thermal treatment (if any) and fluids from equipment decontamination may be
discharged in accordance with the substantive requirements of the NPDES permit process.

Rules and Regulations Governing the Nebraska Pretreatment Program - Title 127:

Ch. 2-38

Nebraska Air Pollution Control Regulations - Title 129:

Ch. 2,5

These chapters are used to evaluate whether the incinerator will be a major source, and if so, whether a
permit (or equivalency) is required. It is assumed that the incinerator will not meet the criteria of a
major source.

Ch. 16

This regulation is applicable to the design of the incinerator stack height.

Ch. 32

This regulation is applicable because of the potential for dust emissions during excavation, handling,
transportation, and construction.

Ch. 34

This regulation includes requirements that NDEQ may impose for testing emission sources to determine the
rate of contaminant emissions.

Ch. 39

This regulation is applicable to the selected remedial action because it incorporates the use of
diesel-powered equipment for excavation, handling, transportation and construction.

2.12.3 Cost Effectiveness

The selected remedial action is cost-effective because it provides overall effectiveness proportional to
its costs. The estimated costs of the selected remedy are somewhat greater than the other alternatives,
yet provides a much higher degree of overall protection than the less costly alternatives by utilizing a
proven treatment method to address the potential risks of the explosives-contaminated soil rather than an
unproven treatment method or a containment method.
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The selected remedy will be effective in the long-term due to the significant and permanent reduction of
the toxicity, mobility, and volume of explosives-contaminated soil.

2.12.4 Utilization of Permanent Solutions and Innovative Treatment Technologies to the Maximum Extent
Practicable

SARA specifies a preference for utilization of permanent solutions and innovative treatment technologies
or resource recovery technologies to the maximum extent practicable. The selected remedial action
utilizes a permanent solution but not an innovative treatment technology. Of those alternatives that
comply with the threshold criteria, USAGE, USEPA, and NDEQ have determined that the selected alternative
provides the best balance in terms of long-term effectiveness and permanence, reduction of toxicity,
mobility, and volume through treatment, short-term effectiveness, and cost.

2.12.5 Preference for Treatment Which Reduces Toxicity, Mobility, or Volume

By treating soil containing explosives greater than excavation RGs, the selected remedial action
addresses one of the principal threats posed by the former NOP site and satisfies the statutory
preference for remedial actions that employ treatment to significantly reduce toxicity, mobility, or
volume of contaminants in soil. Thermal treatment using rotary kiln (based on the treatability study)
will irreversibly reduce the toxicity and mobility of the explosive contaminants.
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3.0 RESPONSIVENESS SUMMARY

In June 1994, the U.S. Environmental Protection Agency (USEPA) and the U.S. Army Corps of Engineers
(USAGE) released the Proposed Plan for the Former Nebraska Ordnance Plant (NOP) , Operable Unit 1 (OU1),
i.e., soil contacted by explosives. A public comment period for the Proposed Plan, originally scheduled
for June 14, 1994, to July 14, 1994, was extended to August 22, 1994, as a result of reguests from the
public. During this period, 28 comment letters were received. The USEPA and the USAGE sponsored a
public availability session on June 15, 1994, and a public meeting on June 23, 1994, during which the
preferred alternative was presented and explained to the public and guestions and comments were taken for
the record.

A second public availability session was held on February 22, 1995, and a second public comment period
ran from February 22 to March 8, 1995, to answer additional guestions and take additional public comment.
During this second comment period 10 comment letters were received.

This Responsiveness Summary serves two functions. First, it summarizes the comments of the public.
Second, it provides responses to the comments on the Proposed Plan that were made at the public meeting
and that were submitted in writing during the public comment periods.

3.1 OVERVIEW

The preferred alternative for OU1 at the former NOP that was proposed by the USEPA and the USAGE in the
Proposed Plan, and presented during related public sessions, was on-site rotary kiln incineration of the
explosives contaminated surface soils. Contaminated surface soils are those soils which contain
explosives above the cleanup goals established by the USEPA, and which are present within 4 feet of the
ground surface.

Verbal public comments on the preferred alternative were documented at the public meeting on June 23,
1994. A total of thirty-eight written comment letters were received during the two public comment
periods.

In general, the public was divided over the use of incineration as the preferred alternative. Nine
comment letters fully supported the use of incineration. Nineteen comment letters were received that
neither supported nor opposed incineration. Ten comment letters, including one submitted by a public
interest group, opposed the use of incineration.

3.2 BACKGROUND ON COMMUNITY INVOLVEMENT

Even before the public availability session and public meeting in June, efforts were undertaken
to inform the public of steps toward remedial action at the site, and to involve the public in the
decision-making process. Community relations activities increased in 1994 with the culmination of the
investigation activities for explosives contaminated soils and the necessity for decision-making
regarding cleanup of soil at the site. Some of the major activities aimed at involving the community and
obtaining their feedback have been:

1. A community survey of residents and local officials via on-site interviews, as well as telephone
interviews, was conducted in January 1992.

2. A Community Relations Plan dated May 28, 1992, was prepared that outlines the approach to be taken
toward community relations and public participation.

3. Periodic fact sheets were mailed to the public in May 1992, June 1994, August 1994, and February 1995
to provide updates and additional information as necessary.

4. Public meetings were held in May 1989, June 1990, and June 1994 to report on project progress and to
solicit comments. Notices of these meetings were provided to the Ashland, Wahoo, Lincoln and Omaha
newspapers.

5. Two availability sessions were held at the site in June 1994 and February 1995 to discuss progress,
answer guestions and discuss concerns.

6. Technical Review Committee meetings are held periodically with representation by the USEPA, NDEQ,
USAGE, Lincoln Water System, Natural Resources District, Nebraska Department of Health, the
University of Nebraska - Lincoln and the Saunders County Board of Supervisors.
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7. An information repository was established at the Ashland Public Library, in Ashland, Nebraska. Site
information is also available at the USEPA office in Kansas City, Kansas, and the Nebraska Department
of Environmental Quality office in Lincoln, Nebraska.

8. A collect telephone line to the USAGE was established so that the public can call to get questions
answered without charge.

3.3 SUMMARY OF PUBLIC COMMENTS AND AGENCY RESPONSES

This responsiveness summary includes statements made at the June 23, 1994, public meeting and comments
submitted in writing to the USAGE during the public comment periods from June 14 to August 22, 1994, and
from February 22 to March 8, 1995. It also includes USEPA and USAGE responses to those comments and
guestions.

Comments and guestions have been paraphrased or guoted in italic text. Every attempt has been made to
accurately preserve the intent of the comment and to include all issues raised. The letters in
parentheses following the comments represent the commentors; a commentor key is included on the page
following the responsiveness summary. All commentors who raised similar or related comments are
referenced.

The official public meeting transcript and written comments on file in the Administrative Record at the
Ashland Public Library in Ashland, Nebraska contain the verbatim comments from all commentors. The
comments have been grouped according to common issues in order to avoid repetition in the responses, and
the issues have been grouped into the following categories for ease of reference:

• Remedial Alternative Preferences
• Biological Alternative
• Air Emission Concerns with Preferred Alternative
• Preferred Alternative Residues
• Risk Assessment
• Site Characterization
• Regulatory
Other

3.3.1 Remedial Alternative Preferences

ISSUE 1. The identification of incineration as the preferred alternative was supported by the Chairman
of the Mead Village Board, the University of Nebraska, the Lower Platte North Natural Resource District,
and several residents living at or near the site. (A, F, J, N, 0, U, X, AK, AD, AL, AN).

Rotary kiln incineration is a proven technology that has been successfully used at similarly contaminated
sites in the country. The USEPA and the USAGE agree that based on the Remedial Investigation (RI),
Feasibility Study (FS) , and experience with explosives-contaminated soil incineration at other sites,
rotary kiln incineration is the most appropriate method for addressing explosives-contaminated soil at
the former NOP site.

ISSUE 2. The contamination has been in the dirt for at least 40 years and nobody has died yet, so leave
it alone. It will do more harm to put it into the air than leave it alone. (Z, AA)

A Baseline Risk Assessment (BLRA) evaluates potential carcinogenic and non-carcinogenic health risks to
determine if action needs to be taken at a site. A BLRA was conducted to evaluate what potential
ecological and human health risks could exist on-site due to the explosives- contaminated soil.
According to the National Contingency Plan (NCP), if the results of a BLRA exceed a carcinogenic risk of
greater than 1 in 10,000 or a non-carcinogenic hazard index of greater than 1, then cleanup is required.
For the former NOP site, the calculated risk exceeded these NCP criteria, therefore, cleanup is required.

Additionally, results of the Remedial Investigation indicate that the explosives contaminated soils have
contributed to groundwater contamination in the past, and are a continuing source of contamination to
groundwater. Removal of the explosives contaminated soil is necessary to stop further movement of
explosives contaminants from the soil to the groundwater.

ISSUE 3. Using an off-site landfill or an on-site landfill would be a lot cheaper than incineration and
quicker in some ways. Full consideration needs to be given to the risks and benefits of landfilling, and
it should not be essentially discounted because of its low ranking in the NCP's political hierarchy.
Licensed off-site landfilling is the answer (M, AA, AF, AH, AI).
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The identification of a preferred alternative and selection of a final alternative are based on the best
balance of nine criteria used to evaluate remedial action options. The nine criteria are:

• Overall protection of human health and the environment.
• Compliance with applicable or relevant and appropriate federal and state requirements.
• Long-term effectiveness and permanence.
• Reduction of contaminant toxicity, mobility, and volume through treatment.
• Short-term effectiveness.
• Implementability.
Cost.
• State acceptance.
• Community acceptance.

As stated in the comment, an off-site or on-site landfill would be cheaper and could be constructed in a
short period of time. However, two of the other criteria used to evaluate remedial action options are
long-term effectiveness and permanence, and reduction of contaminant toxicity, mobility, or volume by
using treatment. Because long-term maintenance and management would be required for the landfill to
prevent the potential for leaks and failure in the future, the landfill alternatives would not have been
as effective or permanent in the long-term. Furthermore, the soil would not be treated prior to
landfilling, so there would be no reduction of contaminant toxicity, mobility, or volume.

By destroying contaminants in the soil, incineration does reduce the toxicity and mobility of the
contaminants. Because of this contaminant destruction, no long-term maintenance or management are
required. Therefore, incineration rates more favorably than either on-site or off-site landfilling when
evaluated based upon the long-term effectiveness and permanence criterion, and the contaminant reduction
criterion.

In addition to these evaluation criteria, the Superfund law includes a statutory preference for
treatment, rather than containment and/or disposal. Also, according to the Superfund law, off-site
disposal without treatment is the least favored remedial action where practicable treatment technologies
are available. Incineration meets both of these statutory preferences; landfilling does not. Reference
"Comprehensive Environmental Response, Compensation and Liabilities Act (CERCLA) Section 121 (b) ."

ISSUE 4. The University of Nebraska strongly suggests that soil remediation for both Operable Unit 1 and
Operable Unit 2 occur concurrently. (F)

The USEPA and the USAGE agree that if OU1 and OU2 soil both require treatment, it would be most efficient
to incinerate all soils from both OUs concurrently. Whether or not this is possible will depend on the
results of the OU2 Feasibility Study, the timing of the OU2 remedy selection, and public comments on a
proposed OU2 remedy.

ISSUE 5. I do not believe the public has enough information to make an informed decision about this
incineration option. (B, C, H, I, J, N, 0, P, and Q)

The USAGE has followed the relevant guidance and regulations concerning the selection of a preferred
alternative. The information generated consists of several documents, the most important being the
Remedial Investigation, the Baseline Risk Assessment, and the Feasibility Study. All of these documents,
along with other relevant information concerning this site, are located in the Administrative Record.
The USEPA and the USAGE believe that the information presented in the documents located in the
Administrative Record provide sufficient information on this site and the alternatives considered. In
addition, numerous public meetings, Technical Review Committee meetings and fact sheets have provided a
substantial amount of information about the site to members of the public.

ISSUE 6. I think that we are getting hung up on little things here tonight. We've been having a lot of
hearings, and now we are trying to get some action and we'd like to keep it going. (J, N, 0, P)

The USEPA and the USAGE agree that site cleanup should be conducted as expeditiously as possible.

3.3.2 Biological Alternative

ISSUE 7. If biological remediation is cheaper and takes less time, why isn't it as effective? Would it
get rid of as much or more of the contaminants as incineration? I have found literature on biological
treatments to be rather optimistic and hope it will be seriously considered for the Mead plant. (D, R,
V, AN)
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The literature referred to was for a biological treatment process called composting. Composting was
initially shown to be promising by the United States Army Environmental Center (AEC) in 1982. Since
1982, AEC has conducted extensive studies at the Umatilla Army Depot Activity (UMDA) in Hermiston,
Oregon. Composting was chosen to remediate explosives contaminated soils at the UMDA site. However, the
UMDA site differs greatly from the former NOP site. For example, the former NOP has eleven contaminants
of concern, UMDA has only two. Composting studies have been conducted for TNT and RDX. No composting
studies involving all of the contaminants of concern found at the former NOP have been completed.
Despite all of the studies that have been conducted, the final products of composting of TNT and RDX are
unknown. In other words, these contaminants are chemically transformed in the compost pile, but no one
knows exactly what happens to them or what chemicals are formed in the process. As a result, a landfill
may have to be constructed to contain the composted material because there may be some hazardous
materials that remain in the treated soil. Furthermore, the final treated material volume will be
approximately twice the original soil volume due to the addition of amendments. Composting is an
innovative technology that is promising; however, at this time it has not been completed successfully at
a full scale site.

Treatment of the soil via composting would take more time than incineration. The proposed plan estimates
that composting would take approximately 32 months to remediate the site. Incineration is estimated to
take approximately 15 months and the actual operating time of the incinerator is estimated to be less
than half that.

The Feasibility Study cost estimate did indicate that composting was less expensive than incineration;
however, the USAGE has a database of incineration of explosives for past sites to examine, whereas
composting has no such history. Although the USAGE used the most current, best available information to
prepare the composting cost estimate, there is a much greater potential for actual costs to differ from
estimated costs for composting (for the above reasons) than there is for incineration because of the
unknowns associated with composting.

Additionally, the UMDA treatment goals for composting are 30 ppm for RDX and TNT. At the former NOP, the
cleanup goals are 5.8 ppm for RDX and 17.2 ppm for TNT. Additionally, the former NOP has requirements
less than 5 ppm for TNB, DNB, and DNT. The treatment goals for the former NOP are much lower than those
for the UMDA because of the greater potential for future residential development. Therefore, the
alternative proposed for remediating the explosives contaminated soils at the former NOP site must be
able to achieve substantially lower goals than those set for the UMDA site. The bio-treatability tests
conducted during the FS did not meet the clean-up goals for the former NOP site. Incineration
treatability testing showed that incineration destroyed all detectable quantities of the contaminants.

ISSUE 8. How long were biological treatability tests conducted? How close to the target concentrations
did the biological treatability studies come? (C)

The actual time that the soils were treated during the biological treatability study ranged from 8 to 60
days. The length of treatment time was one of the parameters studied in 36 different experiments
conducted during the study. The planning, implementation, analysis and reporting for the entire study
took over nine months.

Of all the treatment conditions evaluated in the biological treatability studies, none reached the
remediation goals for all of the contaminants. Some treatment conditions resulted in better treatment
for some of the contaminants than it did for others. The most promising biotreatment results showed
significant TNT degradation but very little or no degradation of RDX and 2,4-DNT. In the case of
2,6-DNT, the biotreatment process actually increased the concentration of the contaminant. The following
Table shows the concentration of explosives in the treated soils and the remediation goals. The
remediation goals were reached for only 6 of the 11 contaminants.
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TABIiE 12
RESULTS FOR THE MOST PROMISING
BIOLOGICAL TREATABILITY STUDY CONDITION
Explosives
Compound

DNT
DNT

•yi
Contaminated Soil
Concentration
(mg/kg)
1730
53.1
1.59
0.331 U
1.51
0.452 U
0.409 U
0.433 U
539
80.3
72.4
Soil Concentration
After Treatment
(mg/kg)
116
6.46
1.57
6.48
1.38
0.608 U
0.760 U
0.618 U
451
85.7
0.273 U
Remedial
Goal
(mg/kg)
17.2
1.7
0.9
0.9
3.4
343.0
343.0
343.0
5.8
1715.2
343.0
TNT

TNB

2,4-

2,6-

DNB

o-NT

m-NT

p-NT

RDX

HMX

Teti

NOTES:

U - No contamination detected. Number represents detection limit.
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ISSUE 9. Composting and aerobic and anaerobic slurry treatments have few similarities, and the
advantages and disadvantages of composting should not be used to judge the merits of other remediation
treatments. Biological treatability studies should be continued and expanded in order to be given a more
appropriate opportunity to show clear success or failure.(E, T, AI, AN)

Biological treatment (biodegradation) uses microorganisms to mineralize and/or transform the explosives
contaminants into other compounds that may be less toxic. Slurry-based and composting biological
treatment were both evaluated during the FS. In slurry-based treatment, water and nutrients are mixed
with contaminated soil in a reactor to promote biodegradation. Slurry-based biological treatment may
occur under either aerobic (with oxygen) or anaerobic (without oxygen) conditions. Composting involves
mixing soil with organic amendments (such as animal manure) and bulking agents (such as wood chips) to
enhance biological activity.

The treatability studies conducted for the former NOP site were slurry-based to offer a greater chance of
achieving treatment (by enhancing contact). The studies were conducted under aerobic and anaerobic
conditions, and alternating aerobic and anaerobic conditions. All conditions evaluated in the
treatability studies are reported in the Treatability Study Report.

Composting was selected as the representative process option for the biological treatment technology
because it is the most widely studied and easiest to physically implement. The FS used the
characteristics of composting in evaluating the nine criteria and comparing biological treatment with
other technologies. However, in selecting composting as the representative process option, the
advantages and disadvantages of both composting and slurry-based biological treatments were considered.

The advantage of composting is that the eguipment required is simple; therefore, the associated cost is
lower. The disadvantages with composting are that the amendments significantly increase the volume of
material resulting from treatment, and the soil/amendment mixture limits the physical contact between the
contaminants, organisms, and nutrients required for treatment to occur.

The contact limitations encountered in composting are overcome by using slurry treatment. Because a large
volume of water is added to the soil, and the slurry (water and soil mix) can be mixed more readily than
a compost mix, there is a much greater chance of achieving the necessary contact among contaminants,
organisms and nutrients required for treatment. The disadvantage is that the equipment is much more
complicated and expensive, and significant dewatering (drying) is required following treatment.

The USEPA and the USAGE believe, based upon the biological treatability studies that were conducted
during the Feasibility Study process, that biological treatment was given an appropriate opportunity to
succeed.

ISSUE 10. The variable nature and extent of munitions contamination at the [former] NOP site presents an
excellent opportunity to investigate several remediation strategies. Would USAGE consider a dual
approach in remediating the [former] NOP site, with incineration being the primary remedial treatment
performed in conjunction with other pilot-scale projects that involve alternative remediation
technologies? (E, F, T)

The variable nature and extent of munitions contamination at the former NOP site does present an
opportunity to investigate several remediation strategies; however, USAGE'S main objective is to clean up
the site in the fastest, most economical way while meeting all clean-up goals and remedial objectives.
In the opinion of the USEPA and the USAGE, the suggested dual approach would not be conducive to
achieving this objective.

3.3.3 Air Emission Concerns with Preferred Alternative

ISSUE 11. The full range of chemicals emitted in stack gases whenever you incinerate hazardous materials
has not yet been identified either by type or by volume. Uncontrolled release of gas emissions can occur
during the incinerator startup or shutdown or when the waste is fed too fast into the incinerator. (C,
P)

All combustion processes (e.g., gas stoves, automobiles, furnaces, candles, forest fires, camp fires,
incinerators) emit a number of chemicals. Some are hazardous, others are not. Many compounds are
present at concentrations below that which can be detected, and health effects for all such substances
have not been determined. Complete identification, in any controlled combustion system, is not possible
due to the high number of compounds and the minute concentrations that can be formed in combustion
reactions. The bulk of total unburned hydrocarbons that are produced in combustion processes is usually
methane (natural gas, on a weight basis). For incineration, a majority of the contamination will be
converted to carbon dioxide and water.
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While the specific compounds which may be emitted have not been completely identified, the risks from
unknown compounds may be estimated. For conservative estimates a high toxicity value may be chosen and
applied to the total quantity of unburned hydrocarbons. Alternate estimates could be made using a
weighted average of toxicity values for organic compounds known to be present in the emissions. The risk
from such estimates may be added to the risk from compounds with known quantities and toxicities (e.g.,
Principal Organic Hazardous Constituents measured during the trial burn) to determine total risk. Risk
estimates determined by using total unburned hydrocarbons and the weighted average approach have been
reported to be small.

The incinerator to be used at the site will be a state-of-the-art unit. During regularly scheduled
startup and shutdowns, the system will not feed explosives contaminated material to the incinerator;
therefore, no uncontrolled releases to the atmosphere will occur during these periods. During emergency
shutdowns, as opposed to routine wastefeed shutoffs, the thermal relief valve will be opened and process
gases will be released to the atmosphere. The duration of such events are typically very short (on the
order of minutes) and all contaminants and gases released will have already passed through the rotary
kiln which will operate at temperatures greater than 1500°F. Because the gases exiting the system during
a thermal relief venting will have been exposed to high temperatures in the rotary kiln, explosives
contaminants will have been predominantly destroyed prior to being released.

As will be discussed in the responses below, the feed rate into the incinerator is set during the trial
burn. The feed rate will be continuously monitored during operations. If this feed rate ever exceeds
the operating conditions found during the trial burn, the waste feed system will be shutdown.

ISSUE 12. Virgin fuel oil, rather than waste fuel oil, should be used to fire the incinerator. (AI)

The fuel used for the incinerator is a function of the unit design and the availability of local fuels.
Potential fuels include propane, natural gas, and fuel oil. Waste fuel oil could be used as a fuel for
the proposed incinerator, however, it cannot be a hazardous waste.

ISSUE 13. Attainment by an incinerator of the current destruction and removal efficiency (ORE) standard
does not assure protection of human health and the environment. What mechanisms do you use to assure
that emissions standards set in the trial burn are always being met? If you cannot continuously monitor
emissions and you do not have a technological instrument available to measure them, how are you going to
know whether or not they meet criteria? (C, D, M, P, AH, AI)

The DRE is a measure of the effectiveness of the combustion process in an incinerator. A trial burn will
be performed to establish the operating parameters that must be maintained during normal operation of the
incinerator, and adherence to these parameters, once established, will assure that the DRE is attained.
A trial burn contains three separate emissions tests run under the same incinerator conditions. The
incinerator must pass all three emissions tests to be considered to have passed the trial burn. The
trial burn will include many different phases of testing and the incinerator will be operated under more
stressful conditions than will be encountered during normal operation, i.e., more contaminated soil than
is expected will be used, soil will be burned for a shorter than optimal durations, etc. Also, only
clean soil will be fed to the incinerator until various operating conditions are met. During the trial
burn the exhaust stack will be sampled for metals, dioxins, POHCs, PICs (organics), oxygen, carbon
monoxide, total hydrocarbons, particulates, and carbon dioxide.

During the trial burn, the operating conditions of the incinerator will be monitored via a computerized
control system. The control system will record all readings from the incinerator for evaluation. The
record will include the continuous real time readings from the stack gas analyzers (carbon monoxide,
oxygen, carbon dioxide and total hydrocarbons) as well as continuous readings of incinerator operating
parameters (soil feed rate, temperature of rotary kiln, temperature of the secondary combustion chamber,
pressure in the rotary kiln, pressure drop through the air pollution control system, water flow rate in
air pollution control system, temperature entering and exiting the air pollution control equipment,
induced draft fan speed, flow rate of fuel and air to the burners in the rotary kiln and in the secondary
combustion chamber, exhaust gas flowrate and temperature, and other items specific to the incinerator
that the regulators require). This computerized record will be reviewed along with the analytical
results from the exhaust stack sampling, feed and treated soils sampling, discharge water sampling, and
fly ash sampling (solids from the air pollution control system) and a decision will be made regarding the
operating parameters of the incinerator (all continuous measurement, as listed above for stack gas
analyzers, temperatures, etc.). If the incinerator passes all emission requirements, the incineration of
contaminated soils will be allowed to proceed.

The incinerator operating conditions monitored during the trial burn, together with continuous monitoring
of stack gas carbon monoxide, oxygen, and opacity will become operating limits. As described above, the
operating conditions that will be set as limits depends on the final design of the incinerator, but
typically between 15 and 20 separate operating conditions are established. The incinerator will only be
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allowed to burn contaminated soils as long as all incinerator operating conditions and emission monitors
are within the established limits. As during the trial burn, these operating conditions will be
continuously monitored and recorded to create a permanent record. If any one operating condition
deviates from the limits, then the conveyor feeding contaminated soils into the incinerator will be
instantaneously shut down. This is known as the "automatic waste feed cut-off system." This automatic
waste feed cut-off system must be regularly tested by the operators to ensure it continues to function,
and records of the tests must be maintained.

By conducting the trial burn testing at maximum contaminated soil feed rates, maximum metal content of
the soils, and exaggerated or "worst case" operating conditions, and then ensuring that during normal
operation the incinerator is always operated at better conditions while burning hazardous wastes,
incinerator emissions during normal operations are assured to be better than those measured during the
trial burn. Operation of the incinerator in this manner assures that emissions are always within the
allowable limits.

ISSUE 14. EPA's own document stated that there is no way an incinerator can meet its 99.99% DRE goal.
(D)

EPA is aware that information in certain EPA documents has been misinterpreted to suggest that the 99.99%
DRE reguirement cannot be met. EPA disagrees. Achievement of the 99.99% DRE will be a reguirement.
Trial burn data will be available for public review for verification that the reguirement has been met.

ISSUE 15. The hysteresis effect in incinerators means that automatic shutoff devices cannot guarantee
immediate cessation of toxic emissions and that actual DREs are depressed. (D, AI)

The study cited by the commentor states that tests to identify the hysteresis effect have been carried
out only on industrial boilers and not on rotary kiln incinerators. USEPA is familiar with the
theoretical existence of the hysteresis effect in industrial boilers. However, the modes of operation of
industrial boilers and rotary kiln incinerators are very different. The hysteresis effect is the theory
that after the waste has stopped being fed to the incinerator, that hazardous emissions may continue for
sometime. In a rotary kiln incinerator, even after the automatic shutoff devices stop additional wastes
from being fed into the incinerator, the incinerator continues to burn the wastes already in the rotary
kiln, and the air pollution control system will continue to remove harmful constituents from the air
emissions.

ISSUE 16. When hazardous materials are incinerated, new products, called products of incomplete
combustion (PICs), can be created. Only a fraction of PICs that are emitted in incinerator gases have
been identified and few PICs have been fully evaluated for toxicity. Of those that have been identified,
some have been determined to be highly toxic. A USEPA 1990 report indicates that combustion systems
always produce PICs. Burning explosives-contaminated materials causes the formation of PICs which have a
high nitrogen content, including nitrogenated polycyclic aromatic hydrocarbons (PAHs) which are highly
carcinogenic. (C, D, AI)

See response to ISSUE 11 for chemicals emitted. Incineration is not 100% efficient. Performance
standards for incinerators reguire that at least 99.99% of the principle contaminant, or the Principal
Organic Hazardous Constituent (POHC), be destroyed by the incinerator. When combustion fails to
completely destroy the contaminants, Products of Incomplete Combustion (PICs) are formed. The formation
of PICs can be minimized by maintaining the initial combustion products under high temperature (1600 -
1800°F) and oxidizing conditions for an extended time (0.5 - 2 seconds). In an incinerator, this is
accomplished by using more than one combustion chamber and specially engineered turbulent mixing.
Confirmatory monitoring of parameters such as carbon monoxide (the most prevalent PIC) and temperature is
used to evaluate whether the incinerator is operating at the conditions found acceptable during the trial
burn.

Testing has shown that PIC and POHC concentrations being emitted from the stack during trial burns for
state-of-the-art incinerators were about the same, i.e., PIC emissions were very low. Air pollution
control devices also remove PICs with the same efficiency as they remove POHCs. In addition, there is no
evidence that PICs are necessarily more toxic than POHCs. In fact, data from incinerators have shown
that some PICs are non-hazardous.

In response to concerns raised in an EPA Science Advisory Board Report released in 1985 concerning PIC
emissions, EPA developed specific PIC control reguirements for hazardous waste incinerators. There are
maintaining carbon monoxide emissions below 100 parts per million or maintaining total hydrocarbon
emissions below 20 parts per million as indicators of complete combustion. In addition, emissions PICs
will be measured during the trial burn. Based on research done to date, EPA has concluded that a large
percentage of PIC emissions are non-chlorinated low molecular weight compounds, such as methane and
ethane. Low molecular weight organic compounds tend to be less toxic and less carcinogenic. For
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example, methane and ethane, which can be produced naturally by many biological processes, are not known
to be carcinogenic and have low toxicity.

The PICs to be analyzed during the trial burn will include 17 chlorinated dioxin and furan compounds as
well as organic compounds that will be selected based on their toxicity and potential to be emitted,
given the nature of the contamination present in the soil. This PIC emission data will be evaluated in a
risk assessment to evaluate whether emission of organic compounds, as well as metals, are at safe levels.

The design of an incinerator has a major impact on the formation of PICs. The incinerators used for soil
cleanup projects are designed to ensure thorough mixing of combustion gases with oxygen. The operating
reguirements will specify that temperatures, combustion gas residence times, and excess oxygen levels are
maintained at levels necessary for good combustion. Further, the post-combustion section of these
incinerators are designed to minimize the low temperature formation of PICs like dioxins and furans.
Based on combustion research conducted by EPA, low temperature formation of dioxins and furans can be
controlled by maintaining air pollution control temperatures below 450°F or above 750°F (Combustion
Science and Technology, 1990, Vol. 74, pp. 223-244). These incinerators rapidly guench combustion gases
to less than 400°F, thereby minimizing the potential for formation of these compounds as PICs.

The potential emissions of the most significant PICs from a health impact standpoint, chlorinated dioxins
and furans, as well as other PICs that may be emitted from the contaminated soils will be controlled at
safe levels. The design and operation of the incinerator will ensure that PIC emissions will be low.

ISSUE 17. Incineration redistributes metals rather than destroying them. Incineration of metals renders
them more toxic because their surface-to-volume ratio is increased, thereby becoming more easily inhaled
or ingested by living organisms, or more easily leached from incinerator ashes buried in trenches or
landfills. Metal emissions have not been fully evaluated for toxicity. (C, AI)

At the former NOP site, soils with elevated metals concentrations are generally not collocated with soils
contaminated with explosives. Metals associated with airborne particulates will be removed by the Air
Pollution Control System (APCS). At other sites where incineration is being used to burn explosives
contaminated soils, all metals criteria have been attained. Samples of the incinerator residuals (soils
and fly ash) will be tested for metals following treatment using the Toxicity Characteristic Leaching
Procedure (TCLP) to determine whether metals will leach from the residuals above regulatory levels. The
TCLP test is intended to simulate the amount of contaminants that will leach from the soils when placed
in the environment. If the TCLP standard is exceeded, then the soil will be stabilized prior to disposal
in an off-site landfill.

ISSUE 18. When heat and pressure build up in an incineration process such that injury to personnel or
damage to eguipment could occur, an emergency relief valve is opened to relieve the heat or pressure.
When the TRV opens, emissions go directly into the atmosphere bypassing the pollution control eguipment.
When the emergency relief valve is opened, there is no way that 99.99 percent destruction and removal
efficiency can be met. How much (and what) is going to come out of the emergency dump stack? (B, C, D,
Y)

The Thermal Relief Valve (TRV) is used as a safeguard to prevent injury to personnel or damage to
eguipment. The TRV is not used to circumvent the Air Pollution Control System (APCS). Temperature,
pressure and other parameters are monitored in the incinerator system, and the TRV is opened only if the
integrity of the incinerator or APCS is threatened. When the TRV opens, the material feed system shuts
down and no more material can be processed through the rotary kiln. When this happens, the incinerator
must be brought back on line by an operator, not automatically, and only after a determination is made
regarding the cause of the TRV opening and corrective actions to be taken in the future.

The TRV is not used by the operators, it is only used during an emergency. If the TRV is opened, there
will be a short-term release of gases that have not passed completely through the air pollution control
system. Past EPA evaluations of commercial incinerators have shown that the average length of time the
TRV is open during an emergency situation is about 20 minutes.

However, because the TRV follows the primary combustion chamber (rotary kiln or the burning chamber),
much of the removal and destruction occurs prior to the TRV. Any risks from TRV openings are associated
only with short-term exposures.

The exact type and amount of emissions which may result from opening of the TRV would depend on the
design of the particular incinerator unit. The risk assessment to be prepared for the incinerator will
take into account emergency TRV openings by estimating actual emissions.

ISSUE 19. I understand it's possible to design an incinerator system that would not need an emergency
relief valve. (D)
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As noted above, the purpose of the TRV on a rotary kiln incinerator is to prevent injury to personnel or
damage to equipment during an emergency shut down. USEPA and USAGE are not aware of any transportable
rotary kiln incinerator designs which do not incorporate a TRV.

ISSUE 20. The TRV should include mechanisms to monitor emissions quantitatively and qualitatively and
the data should be disclosed publicly in writing indicating the quantity and type of materials released
in addition to the reasons for the dump stack use within 2 weeks. (AI)

See Issue 18 for more discussion on releases from Thermal Relief Valves (TRVs). Due to the short
duration of these events there is no method to quantify or qualify emissions from an emergency relief.
Reports on the duration and reason for opening the TRV, as well as what efforts will be conducted to
prevent the situation from occurring again, are required by USEPA. This information will be made
available to the public in the information repository at the Ashland Public Library.

ISSUE 21. Will there be stack monitors and who, besides USAGE, would be monitoring the system for
particulates and other emissions? (B, H, M)

The stack has continuous monitors for several parameters: oxygen, opacity, carbon monoxide, and total
hydrocarbons. These systems are operated and maintained in accordance with federal and state
regulations. The actual sampling of the system will be completed by the contractor under close
supervision of the USAGE with USEPA overseeing the operation. Results of the trial burn and monitoring
will be made available to the public in the information repository.

ISSUE 22. Stack tests of incinerator emissions should be conducted weekly during the operational phase.
These tests should sample for the fullest range of compounds, including dioxins. Results should be
publicly available in writing within two weeks of the test. I am concerned about the lack of periodic
testing of stack emissions, and potential health threats from those emissions. (D, M, Z, AA, AI, AM)

Analysis of stack emissions is not cost-effective and would provide no additional protection of public
health and the environment. The performance of weekly stack emissions testing throughout the period of
incineration operation as the commentor suggested would not be cost-effective. Preliminary estimates
indicate the cost of such a testing effort could be $100,000 per sampling event, which would equate to $2
million over a five month incineration operation period.

Perhaps even more importantly, the value of such testing with respect to protection of health and the
environment is minimal. Given the state of today's technology, sampling and real time analysis of stack
emissions in the field is technically impossible. Following the collection of emission samples, each
sample would have to be sent to an off-site independent analytical laboratory for analysis. Analysis of
the samples and reporting of the results would take approximately 30 days under normal circumstances.
Thus the results of the stack testing would be for emissions that had taken place about 30 days
previously. Such a delay would allow no opportunity to evaluate the results and take any corrective
measures in the operation of the incinerator.

Of greater value than this type of emissions testing is the continuous monitoring of incinerator
operation parameters established in the trial burn. If any one of the established parameters is exceeded
during incinerator operations, the incinerator operator has the opportunity and responsibility to take
immediate corrective measures to ensure that the incinerator is either brought back into compliance with
the established parameters or, if necessary, shut down. Thus while weekly stack emissions for
site-specific parameters sounds attractive, given the state of today's analytical capabilities, public
health and the environment are better protected by the continuous monitoring of incinerator operation
parameters established in the trial burn.

Results of the trial burn and incinerator monitoring will be made available to the public in the
information repository in the Ashland Public Library.

ISSUE 23. Is the methodology used to test the air quality documented in a report which the USEPA
oversees? Are there penalties for failure to meet the quality standards of the USEPA? At other sites
where explosives-contaminated soil has been incinerated, have there been explosions, and have penalties
ever been assessed? At the Cornhusker Army Ammunition Plant (CAAP), significant amounts of solid
materials accumulated in the secondary combustion chamber (SCC) (which was supposed to be burning gases
only). Two employees were severely burned when attempting to clean out solid materials from the SCC that
had clogged the quench vessel located immediately below the SCC. (C, G, M, AA, AI)

The methodology used to test stack gases during the trial burn will be specified in the trial burn plan
and will be approved by the USEPA and the NDEQ before beginning the trial burn. The test methods to be
used are governed by federal regulations. These methods have been extensively studied and rigorously
evaluated in the field. If standards are not met during the trial burn, the incinerator will not be
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allowed to operate, and if the incinerator is not operating the incineration contractor will not be paid.
The USAGE will have staff on-site to monitor the operation of the incinerator and any other activities
being performed on site. If operating parameters set as a result of the trial burn are not met during
operation, the soils will not be fed to the incinerator.

During the incineration of soils, the dust caused by drying the soils will be carried with the gases into
the secondary combustion chamber. It is for this reason that incinerators include particulate control
systems (if no solids are carried over then there would be no need for particulate standards on
incinerators). At Cornhusker Army Ammunition Plant (CAAP), a steam explosion did occur as a result of
this solids carry-over issue. The solids that carried over from the CAAP incinerator into the secondary
chamber caused a significant amount of material to collect in the secondary chamber, creating a slag of
material in this chamber. A steam explosion occurred when a portion of the hot slag fell into water in
the quench tank causing a steam explosion. This was an industrial accident caused by equipment design
and was not related to the contaminants at the site. The design problem that caused this accident has
been corrected and will not be present in the incinerator for this site.

ISSUE 24. There should be an independent person or group monitoring the [trial burn] test. (D)

EPA representatives will provide continuous oversight evaluations during the trial burn. EPA
representatives will also provide periodic oversight evaluations throughout the period of incinerator
operations to ensure that all sampling activities are in accordance with established protocols. Also,
all samples collected will be analyzed by independent laboratories. Finally, the trial burn report and
all subsequent reports will be reviewed by EPA and will be made available to the public in the
information repository in the Ashland Public Library.

ISSUE 25. There have been problems with every rotary kiln-type of mobile incinerator put into use to
cleanup Superfund sites which would all be considered dangerous to the general populace, on record by the
EPA. (M)

EPA disagrees with the allegation of serious problems with all mobile rotary kiln incinerators, and is
unaware of any such EPA record which would support the commentor's allegations. EPA is aware of several
sites where rotary kiln incineration has been successfully used to treat explosives contaminated soils
similar to those found at the Former NOP site. A discussion of the cleanup efforts at these sites can be
found in the EPA publication "Handbook: Approaches for the Remediation of Federal Facility Sites
Contaminated with Explosive or Radioactive Wastes", EPA/625/R-93/013, September 1993.

3.3.4 Preferred Alternative Residuals

ISSUE 26. Will the highly contaminated soil, which is considered an explosive by itself, be diluted
before it is put into the incinerator? How would you determine the pretreatment soil concentrations
before the soil is fed into the reactor? It is not clear that sufficient characterization has been done
to identify areas of high explosives concentrations which could be reactive and cause an explosion simply
through handling if enough friction is created. (C, E, AI)

Field screening analytical techniques will be used to ensure that soil is handled appropriately based
upon the concentration of explosives in the soil, and to ensure that soil with contamination above
cleanup goals will be incinerated. Soils considered to be an explosion hazard will be hand excavated
with non-sparking tools (in accordance with the Army Explosives Center requirements) and mixed with
lesser contaminated soils to ensure that no explosion hazard exists during treatment. The Remedial
Investigation sampling did characterize soils with high enough concentrations of explosives to be
considered an explosion hazard and found that only two areas (one location in Load Line 1 and one
location in Load Line 2) contain high enough concentrations of explosives to be a potential explosion
hazard. It is estimated that approximately 12.5 cubic yards of soil contain such high concentrations.
These areas have been addressed in a removal action that involved fencing the areas to prevent access
until the soil can be cleaned up under the OU1 remedy.

ISSUE 27. In some cases, an incinerator may produce a larger volume of hazardous waste than it destroys.
Incineration creates ash and other residues whose toxins are more highly concentrated and which must be
disposed at a hazardous waste landfill. It is difficult to understand how soil is going to be
non-hazardous enough to return to the place from which it was originally taken. Returning incinerated
soil directly to the site may be detrimental to the environment. (C, M, Y, AI)

This incinerator will not create a larger volume of soils and fly ash than entered the system. Based on
the incineration treatability study conducted for the former NOP site, all organic compounds were below
detection limits and the metals did not leach out in excess of regulatory standards. The returning of
incinerated soils that have met the remediation goals for the site will not be detrimental to the
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environment because they will no longer be considered contaminated. Incinerator residues will be tested
for explosives and metals. Any residues that still contain explosives will be incinerated until the
explosives are destroyed; any residues that contain elevated amounts of metals will be disposed of
off-site in accordance with State and Federal regulations.

ISSUE 28. Is water used in the incinerator process? How much? What is done with the water following
treatment? What are the costs associated with wastewater treatment? (D, M, Y, AI)

Water is used as a part of the Air Pollution Control System (APCS). The amount of water used is a
function of the type of APCS used. Any water from the APCS will be tested, treated, and disposed of
following treatment in an appropriate manner based on the type and amount of contaminants, if any, that
the water contains, and their concentrations. The testing, treatment and disposal of the water will be
conducted in accordance with appropriate State and Federal regulations. The cost associated with
treatment or disposal of APCS water is a function of the volume and concentrations of contaminants in the
water. The cost for water consumption, treatment, and disposal is a very small portion of the total
project cost.

ISSUE 29. What are the expected volumes and costs of disposal for fly ash from the incinerator's APCS?
(AI)

The volume of fly ash is a function of the Air Pollution Control System (APCS) used. It is anticipated
that up to 10% of the dry soils will be captured as flyash, i.e., 840 cubic yards if 8,400 cubic yards of
soil are treated. These materials will be tested following the trial burn to ensure acceptability to be
combined with the other treated soils and returned to the excavations.

ISSUE 30. What constituents (organics and/or metals) will be tested for in the ash when you run a TCLP
test? (H)

The eight RCRA metals (arsenic, barium, chromium, cadmium, lead, mercury, silver, selenium) will be
tested for in the ash using the Toxicity Characteristic Leaching Procedure (TCLP) test (see Issue 16 for
more on TCLP). Organics will be tested using EPA method 8330 for explosives.

3.3.5 Risk Assessment

ISSUE 31. There needs to be some explanation of why the Final Baseline Risk Assessment, October 12,
1992, Table 2-5, showing a list of chemicals of potential concern at Nebraska Ordnance Plant, OU1,
indicates that some of those difficult materials which incineration can't handle well are included. (C)

Table 2-5 identifies all of the potentially harmful chemicals detected in OU1. But the Table does not
address how high the concentrations of these chemicals are, where they are located, or any other relevant
factors. The two types of chemicals listed in Table 2-5 that warrant detailed consideration when an
incinerator is the chosen remedy for the contamination are PCBs and metals. The Remedial Investigation
showed that PCBs were present in soils at the site, but only at locations separate from the explosives
contamination. These PCB-contaminated areas are being dealt with by other means than incineration (see
Issue 42 for more on PCB remediation).

Metals were found in OU1 soil samples. Metals are natural components of soil and all soil samples will
contain metals at some concentration. Except for a small number of localized areas, elevated
concentrations of metals resulting from former NOP operations are not present in the areas of explosives
contamination being addressed under OU1. To account for few localized soils areas where metals are
elevated, an Air Pollution Control System will be utilized on the incinerator to minimize metals
emissions from the incinerator. The potential for metals emissions and the risk posed to human health
will be taken into consideration in the incinerator risk assessment.

ISSUE 32. How are cleanup level concentrations determined? What is the specific test that determines
toxicity? (E)

Cleanup goals for the site were calculated on the basis of the results of the Baseline Risk Assessment
(BLRA). In the BLRA, the potential ways that people might take in doses of chemicals were identified and
likely exposure scenarios developed. The BLRA for the former NOP site showed that the "Adult-resident"
and "Child-resident" scenarios yielded unacceptable total risks. It was for this reason that cleanup was
determined to be reguired. The USEPA then calculated how much the chemical concentrations in soil would
have to be reduced to be protective of human health, i.e., determined cleanup level concentrations, by
preventing risk to humans above an acceptable level.
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The tests that are used to determine the toxicity of chemicals are based on estimating human effects from
animal data. If animal data was not used, it would be necessary to rely on data solely from humans.
While there is some data from human exposure to certain contaminants, the data is frequently based upon
inappropriate exposure conditions or based upon exposure conditions sufficiently rare enough that solid
conclusions about the data cannot be made.

For cancer, toxicity tests usually are performed by giving rats or mice varying doses of a chemical to
determine the highest dose that the animal can take before showing distinct poisoning symptoms.
Statistical calculations are then performed to determine an upper bound estimate of the probability for
the animal of developing cancer. A safety margin is then applied to the data to develop conservative
conclusions for translation of the data to human exposure. For noncancer risks, animals are also used to
determine the lowest and highest dose of a chemical that causes identifiable toxic effects. Safety
factors are then applied to this dosage information to translate the data to human exposure with
conservatism.

Both the cancer and non-cancer toxicity values contain very conservative assumptions designed to protect
humans from harm even though the original data is taken from animal studies.

ISSUE 33. Who decides what risk will be used or what risk the public will accept? The risk factor used
should be one in a million or less. (H, Y)

Currently, the U.S. EPA defines acceptable cancer risk as one in a million for an individual chemical and
non-cancer risk as a hazard quotient of 1 or less. This means that for carcinogenic concerns, an
individual should not be exposed to more than a one in a million chance of developing cancer from being
exposed to a toxic chemical. For non-cancer risks, this means that the daily amount of a chemical taken
in by a person should not exceed the dose that should not have any adverse health effects. These levels
of cancer and non-cancer risks have parallels in safety standards set by other Federal agencies, such as
the Food and Drug Administration.

ISSUE 34. Because explosives are not naturally occurring compounds, the remediation goals should be set
at background levels, or zero. Remediation goals for organics and metals should be set to background.
(M, Y, AI)

The purpose of the Baseline Risk Assessment (BLRA) was to identify the risks and the chemicals causing
the risks. Based on the results of the Remedial Investigation and the BLRA, cleanup levels for the
explosives were established by the USEPA in accordance with the National Contingency Plan. These cleanup
levels ensure that all soils within four feet of the ground surface which could pose a cancer risk
greater than one in a million, or a non-cancer hazard index greater than 1, will be excavated and
incinerated.

The ideal solution for explosive contaminants at the former NOP would be their total destruction.
Because no currently available remediation technology can assure 100 percent destruction of these
contaminants, cleanup to zero concentrations cannot be achieved. However, the State and Federal
regulations governing incinerator operation do require that explosives contaminants at the site be
destructed sufficiently to remove 99.99% of the contamination.

In general, explosives contaminated soils at the site are not co-located with elevated metals
concentrations. This means that in most locations being addressed by OU1, metals concentrations are at
or near background levels. Thus, no metals remediation goals are being established as part of OU1.
Rather, areas of suspected metals contamination will be addressed under OU3.

ISSUE 35. What is the cumulative effect on humans and the environment when combining pathways of
exposure to explosives-contaminated materials, heavy metals, and explosives? (AI)

The Baseline Risk Assessment concluded that cancer risks, if cleanup of the site is not conducted, to
potential future farm residents in the most contaminated areas might be as high as two in a thousand and
that the dose received by these residents might be one hundred times the Reference Dose. Most of this
risk was considered to be due to the explosives RDX and TNT. Eating vegetables grown in these areas was
considered to be the major route of exposure. These risks exceeded the risks considered acceptable by the
USEPA and NDEQ, necessitating cleanup.

ISSUE 36. Request that full risk assessments be completed for the chosen remedy, incineration, and for
the other identified alternatives: biological treatment, containment in an on-site landfill and
containment in an off-site landfill. How can the public or USAGE move forward until that is done? (C,
H, I, N, 0, P, Q, Y)
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In selecting the preferred alternative, each of the FS alternatives was compared to nine criteria listed
in the National Contingency Plan (see Issue 3 for the criteria). Although not a full risk assessment,
many of the nine criteria do in fact take risk into account. For example, the concept of risk is
inherent in the criteria "Overall Protection of Health and the Environment", "Reduction of Contaminant
Toxicity, Mobility and Volume", and "Long-Term Protectiveness and Permanence." Thus, risk related issues
associated with each of the alternatives were evaluated as part of the Feasibility Study evaluation of
the nine EPA criteria. Any alternative that fails to meet the reguirements of the nine criteria cannot
be implemented regardless of the risk associated with it. For example, the USAGE conducted a substantial
study of biological treatment for OU1 soils. None of the methods studied reduced explosives
concentrations to the levels reguired to reduce health risks to acceptable levels, which is one of the
nine criteria. Since the USAGE has been unable to make biological treatment meet the cleanup goals,
biological treatment cannot be selected as the preferred remedy and a risk assessment of biological
treatment is not necessary.

The USAGE identified incineration as the preferred alternative because it is the alternative that best
meets the reguirements of the nine criteria. In accordance with EPA policy, a detailed risk assessment
will be performed to evaluate the potential risks associated with incineration of the soil at this site.

ISSUE 37. The baseline risk assessment should be redone to account for compounds other than explosives
and PCBs, to conduct an analysis beyond the screening level done for metals, to assess non-PCB
chlorinated compounds, and to account for the sampling deficiencies identified. The baseline risk
assessment should take into account key pathways of exposure such as inhalation of vapors, dermal contact
with soil, ingestion of milk, garden vegetables, crops and the full food chain. In addition, risk to
nursing or pregnant women must be considered as well as effects on wildlife and migratory waterfowl,
herbivorous mammals, and seed-eating birds. (AI)

The Baseline Risk Assessment (BLRA) considered all the potentially harmful chemicals which were detected
at the site, not just explosives and PCBs. Key pathways for human exposure were also considered. The
BLRA considered soil ingestion, dermal contact with soil, inhalation of dust (PCBs and explosives
generate very little, if any, vapors), and vegetable and beef consumption. The BLRA has been reviewed
for adeguacy and approved by EPA Region VII, NDEQ, and the Army Environmental Hygiene Agency.

ISSUE 38. All risk assessments should guantify every conceivable concern identified on-site. (AI)

The Baseline Risk Assessment (BLRA) did guantify risks for all the potentially harmful chemicals detected
at the site by all of the significant exposure pathways, as detailed in the response to Issue 36. What
the BLRA showed was that not every potentially harmful chemical was present in sufficient concentration
in all complete pathways to pose a significant health risk. All significant exposure pathways were
addressed, and the results showed that unacceptable risks potentially exist. Addressing "every
conceivable complete pathway of exposure" would not increase the total risk relative to the risk already
identified, and would have no effect at all on the decision that remediation of OU1 is needed.

3.3.6 Site Characterization

ISSUE 39. The full extent and nature of the problems and contamination on-site have not yet been
determined. Therefore, sufficient and reliable testing has not been conducted to assure that explosives
are not co-located with a wide variety of additional contaminants, including metals and PCBs. USAGE is
attempting to evade significant problems resulting from inadeguate and incompetent site characterization
by testing to ensure that only explosives-contaminated soil is being fed into the incinerator. (C, M, Y,
AI)

We disagree that sufficient and reliable testing has not been conducted. The USAGE has taken 1,560
samples for explosives, 488 samples for metals, 172 samples for volatile and semi-volatile organic
compounds, and 530 samples for PCBs at transformer areas. The scope of OU1 was developed specifically to
address the areas where explosives contamination in the soil presents a health risk. The sampling has
shown that sources of soils contaminants other than explosives are not co-located and, therefore, will
not be incinerated. These other areas are being addressed in other actions or OUs. For example, 1,446
tons of PCB contaminated soil was removed from the site in the summer of 1994, and metals contaminated
soils are being addressed under OU3. See Issue 40 for further discussion regarding sampling during
incinerator operation.

ISSUE 40. Waste should be routinely fingerprinted for metals and chlorinated compounds (including PCBs)
prior to incineration. (AI)

Based on the historical process used at the site, and the extensive testing done on OU1 soils, no PCBs,
chlorinated compounds or significant concentrations of metals are expected in the explosives contaminated
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soil. However, testing during the trial burn for the full range of contaminants will be conducted and,
due to public concern for PCB contaminated soil being fed into the incinerator, periodic testing for PCBs
will be conducted during incineration operation.

As was determined during the RI, the metals concentrations are not significantly above natural levels.
An incinerator risk assessment will be developed to determine the risk resulting from incineration
operations and will include assessment of all emissions combined, including the contributions from
metals. Additionally, the APCS will be designed to remove metals before being emitted from the stack of
the incinerator.

ISSUE 41. Discrepancies exist within the RI Report regarding the detection of explosives in the
Burning/Proving Grounds where a wide variety of metals and chlorinated compounds have been found. (AI)

Table 1-2 of the Remedial Investigation (RI) report states that no explosives compounds were detected in
the Burning/Proving Grounds in initial sampling events. However, Section 4 of the RI correctly indicates
that, based on additional sampling conducted as part of a supplemental investigation, explosives
compounds were found in the soil at the Burning/Proving Grounds. Metals were also detected in the
Burning/Proving Grounds but not at significant levels, and the Air Pollution Control System on the
incinerator will be designed to account for the metals concentrations that were found. Additionally, no
chlorinated compounds have been found to be co-located with the explosives contaminated soils.

ISSUE 42. Sampling and analysis of PCBs were conducted only around locations that housed electrical
transformers and pads. (AI)

Because PCB contamination is a result of leaking electrical transformers, PCB contamination is expected
to be found only around transformers and concrete transformer pads. PCBs were investigated in the
Remedial Investigation and were found only in areas where transformers exist(ed) and not in locations
where explosives contamination existed. A removal action was initiated in the summer of 1994 that has
already removed 1,446 tons of PCB contaminated soil and debris and will be completed by the end of 1995.
Testing during the trial burn, and periodic testing during operation of the incinerator will be conducted
to ensure no PCBs will be fed into the incinerator.

ISSUE 43. Standard qualitative analytical procedures were not used in the PCB analysis: samples were not
reanalyzed at lower dilutions when PCBs were not detected or were detected at levels much less than the
detection limit; 28 percent of surrogates were omitted during sample extraction - therefore results were
biased high or low; it was difficult to correlate field screening results with laboratory analytical
results. (AI)

Standard qualitative analytical procedures were used in the PCB analysis. Surrogates are compounds
similar to the contaminant of interest which are added in the laboratory to samples to check the results
of the analysis for the contaminant. Based upon the information gained from samples where surrogates
were added, the PCB results tended to be biased high even though surrogates were not used for all of the
samples analyzed. This means that the analysis may have indicated the presence of PCBs in a sample even
though PCBs actually may not have existed in the sample. The results, therefore, are conservative since
they tend to overestimate the amount of PCB contamination in the soil.

ISSUE 44. Based on the 1990 soil gas survey, Remedial Investigation, the Baseline Risk Assessment, the
Feasibility Study, and the Treatability Study, TCE and other chlorinated compounds are present in the
explosives-contaminated soil on-site. Therefore, chlorinated compounds will be burned and dioxins will
be formed and spewed into the atmosphere. (M, Y, AF, AH, AI)

TCE and other chlorinated organic analytes were detected in soil gas, ground water, and soil in the Atlas
and Nike Missile Areas. These areas are discrete, are not contaminated with explosives, and are not
included in the soil to be cleaned-up under OU1. The USAGE is currently evaluating whether contaminated
soils in the missile areas have the potential to act as a continuing source of VOC contamination for
groundwater. However, such soils, if they exist, will be addressed as part of another operable unit.

ISSUE 45. Certify that detection limits for all measurements were properly set at background levels for
all chemicals of concern in the soils and, where applicable, ground and surface water. The background
levels should be representative of uncontaminated areas in eastern Nebraska. (AI)

A detection limit is a level of contamination below which an analytical instrument using a given
analytical method will not be able to detect contamination. By contrast, background levels are levels
that are believed to represent the levels that result from naturally occurring local geological
conditions rather than man-made contamination. Background levels for naturally occurring compounds, such
as metals, are often much higher than detection limits, while the background levels for man-made
compounds are effectively zero. Therefore, arbitrarily setting detection limits equal to background is
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neither appropriate nor technically feasible. Rather, detection limits are established at the lowest
levels possible given the limits of technology and the analytical methods employed. The reguired
detection levels used here were established by the protocols reguired under the Interagency Agreement
between EPA and the Army as levels that will protect human health and the environment. The OU1 Remedial
Investigation determined that the analytical detection limits were adeguate to measure background
concentrations of analytes at levels which could adversely affect human health or the environment. Also
see Issues 48 and 49 for more information.

ISSUE 46. The entire site has not been screened for volatile and semi-volatile organic compounds. (M,
AI)

Volatile and semi-volatile organic compounds (VOCs and SVOCs) were investigated in the site-wide Remedial
Investigation (RI) and in the Confirmation Study. Based on the results of these studies, VOC and SVOC
contamination has been found to be limited to the Atlas and Nike missile areas. The presence of this
contamination in these areas is a result of the degreasing operations (cleaning of the missile parts) and
consists of limited amounts of TCE. The highest concentration of TCE in soils was 99 parts per billion
(ppb) found in one sample in the Nike area. Soil samples were taken in areas where soil gas
investigation indicated high concentrations of TCE in soil gas, yet TCE was identified in few soil
samples above detection limits. Soil from these areas is not part of OU1 and the soil will not be
incinerated under OU1.

ISSUE 47. The RI Report indicates that soil metal contamination has been identified in the drainage
ditch systems; explosives contamination exceeding Preliminary Remediation Goals is located primarily in
drainage ditches. Therefore, metals are probably co-located with explosives. There is no reliable and
convincing evidence to show that metals and explosives are not co-located. (AI)

As discussed in Issue 45, metals occur naturally and are ubiguitous in the environment. Therefore, some
metals will be present in the explosives contaminated soil. However, metals concentrations in the
explosives contaminated areas are, in general, not significantly elevated above background levels. The
Air Pollution Control System (APSC) will be designed to remove most metals that may exist in the soil and
an incinerator risk assessment will be conducted to evaluate the overall risk that results from all
emissions from the incinerator.

ISSUE 48. Establishment of background levels for metals is inadeguate because sampling at five on-site
locations was used to establish background levels rather than sampling off-site. Was the background site
for metals far enough away from where previous burning occurred? (D, AI)

It is important to take background samples in locations geologically similar to the site so that
representative background levels can be established. Because the site is very large (17,253 acres) and
most of the site is unaffected by contamination from the production process, background metal samples
were taken on the former NOP site but in areas removed from where the explosives were handled, stored or
burned.

ISSUE 49. The determination that metals must be elevated to five times their background level in order
to constitute a level of concern is inappropriate. Because metals uptake can cause bioconcentration of
metals in plants, no metal level above background is acceptable. (AI)

Action levels for metals are commonly set at five times the background level, in lieu of a more
sophisticated statistical difference test, in order to determine if metal levels are elevated and action
is needed. Metals are generally not co-located with explosives contaminated soils. However, the Air
Pollution Control System on the incinerator will be designed to minimize metals emissions and an
incinerator risk assessment will be conducted to determine the risk from all incinerator emissions.

ISSUE 50. Three unidentified detonation pits have not been located. (Y)

Based upon historical aerial photographs and site surveys, a demolition area was located south of Highway
63. Samples were taken of this area under two previous investigations and no contamination was found.
However, under OU3, five suspected detonation craters were identified within the demolition area and
samples will be taken during upcoming OU3 field work. These areas are not included in OU1.

ISSUE 51. The ammonium nitrate, high explosives and finished ammunition storage areas have not been
characterized. (AI)

OU1 addresses explosives contaminated soils which pose a direct contact risk only. The groundwater under
the former ammonium nitrate plant area will be investigated for nitrates, nitrites and total nitrates as
a part of OU3. Additionally, screening for explosives will be conducted at the high explosives storage
area (also known as the raw product storage areas) in OU3 to determine if further investigation is
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needed. Based upon historical information regarding use of the finished ammunition storage areas, and
the fact that finished ammunition was stored in these areas, there is no reason to believe that
contamination exists in these areas and no further investigation is anticipated at this time.

ISSUE 52. The entire site has not been screened for asbestos. Asbestos-contaminated soil is present
throughout the load line areas. This must be addressed prior to selecting a final remediation strategy
for OU1. (AI)

The surface soils around the load lines were not analyzed for asbestos because asbestos was only used at
the site in building materials (for construction of the buildings) and the soil is not expected to
contain asbestos.

ISSUE 53. The entire site has not been screened for unexploded ordnance. Despite what the Proposed Plan
and Fact Sheet say, unexploded ordnance has been found on-site. Unexploded ordnance could be encountered
during remediation. (AI)

A removal action was initiated in October 1994, to investigate for, and remove, any unexploded ordnance
or related items that may exist on the site. This removal action is expected to be completed this year.

Components of ordnance have been found at the site and there is potential for unexploded ordnance (UXO)
or ordnance and explosive waste (OEW) to be encountered during the remediation effort. The Department of
Defense has developed criteria which reguires that an explosive safety hazard analysis be performed for
proposed remediation efforts prior to initiation of remedial activities. The remedial action contractor
will be reguired to perform this analysis prior to initiation of the remediation effort and the Army will
oversee the field activities to ensure compliance with these reguirements.

ISSUE 54. Wooden sewer pipes used at the former Weldon Spring Ordnance Works are being remediated
because they were found to be contaminated with explosives. Sewer pipes and surrounding soil at the
former NOP may also be laden with explosives residue that are sources of contamination. The site sewer
system should be investigated to determine what materials were used to construct the pipes, the pipes'
location, and whether they contain explosives residue and have leached into the surrounding soil.
Consultation of drawings is not sufficient. (AI)

The former Weldon Spring Ordnance Works (WSOW) plant produced raw materials (TNT) that was shipped to
other facilities for loading into ordnance. Wooden sewer pipes were used for discharge of the large
guantities of water that was used in the TNT production process. At the former NOP site, the raw product
produced at facilities like the WSOW was loaded into ordnance and water was used primarily to washdown
relatively minor amounts of residue from the loading process to prevent a buildup of explosive materials
in the facilities. Because of the relatively small guantity of water used at the former NOP, as opposed
to a raw production facility like the WSOW, process water was discharged directly to drainage ditches
rather than to a piped sewer system.

However, because explosives contaminated clothing was laundered in the Administration Area, explosives
contamination was found in a culvert pipe near the former laundry facility and this pipe will be removed
under this operable unit.

ISSUE 55. Sampling was conducted mainly in areas suspected to be contaminated. Given approximately 40
years of erosion and tilling, open burning activities in the burning/proving ground, and the lack of
information regarding activities conducted during operation, contaminants can be expected to have
dispersed very long distances across the site and off-site. (M, AI)

The Remedial Investigation (RI) was conducted to identify the extent of contamination for the entire
former NOP site. During the RI, grid sampling was conducted to determine if dispersion of contaminants
over a wide area was a concern. The grid sampling indicated that dispersion is not a concern, and that
the contamination existed primarily in the drainage ditches as a result of washdown from the historical
production processes. In addition, sampling was conducted in the deeper subsurface soils in all
locations where there was a potential, based upon historical aerial photographs, for soils to have been
disturbed due to tilling, grading, backfilling, etc.

3.3.7 Regulatory

ISSUE 56. Based upon our review of the record, there is no guestion that the explosives-contaminated
soil at the [former] NOP site must be managed as RCRA wastes. Immediate and forceful enforcement actions
[should] be taken against USAGE if it fails to adhere to this regulatory mandate. (AI)
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The USEPA, the NDEQ and the USAGE agree that the Resource Conservation and Recovery Act (RCRA)
requirements are relevant and appropriate to the remediation efforts to be conducted under OU1 and that
the remediation efforts will comply with the substantive requirements of RCRA.

ISSUE 57. EPA Reqion 7 and [N]DEQ should acquire the assistance of persons with demonstrated expertise
in the manufacturinq, detonation, disposal, and incineration of military explosives for requlatory
oversiqht of this project and that his or her credentials be made publicly available upon hirinq or
execution of a contract. (AI)

Paraqraph 300.120 of the National Oil and Hazardous Substances Pollution Continqency Plan states that:
"DOD will be the removal response authority with respect to incidents involvinq DOD military weapons and
munitions, or weapons and munitions under the jurisdiction, custody, and control of the DOD." Althouqh
the former NOP is not currently under the jurisdiction, custody and control of the DOD, the Army has
expertise in the manufacture, detonation and disposal of unexploded ordnance or ordnance and explosive
waste (UXO/OEW) and all remedial activities conducted at this site will include prior clearance of
UXO/OEW or activity oversiqht by UXO/OEW experts within the Army.

ISSUE 58. Has an incinerator contractor been identified? To what extent does the Army indemnify the
incineration contractor and any other contractors who work for the Army? (C, G,M)

An incinerator contractor has been identified for cleanup of the soils under this operable unit. The
USAGE will not indemnify the contractor for the incinerator.

ISSUE 59. Given that the City of Omaha has a much more strinqent standard for particulate matter, why
was 0.08 per dry standard cubic foot selected as the standard for particulate matter? (H)

No particulate matter standard has been selected for the site. The value of 0.08 qrains per dry standard
cubic foot was referenced in the public meetinq as the standard because it is the federal standard for
incinerators burninq hazardous waste (40 CFR 264.343 (c)) . The standard for the former NOP site will be
set durinq the desiqn in accordance with the substantive requirements of State and Federal requlations.

ISSUE 60. Nebraska Department of Environmental Quality (NDEQ) offices in Lincoln should have
continuously-connected communication to the incinerator operation which will notify the office when the
dump stack is in use. (AI)

EPA has requested that the Army provide immediate phone notification followed by a written explanation
for the event if the TRV is used, and the Army has aqreed to provide this. Given the anticipated short
duration of burninq at the site, we believe a continuously-connected communication link would not provide
additional protection of public health.

ISSUE 61. A memorandum of aqreement between NDE[Q] and USAGE [concerninq Cornhusker Army Ammunition
Plant] waived the application of enforcement actions and penalties provided in Nebraska requlations.
This waiver must not be applied to the Mead site. (AI)

No such waiver will be applied to this site.

ISSUE 62. It is imperative that this incinerator be permitted just like the commercial incinerator
operatinq permanently in the State. (C)

Accordinq to the Superfund law, incinerators used for remedies at Superfund sites do not have to be
permitted like commercial units. However, the incinerator to be used at the former NOP site will be
required to meet all the substantive, as opposed to administrative, requirements of a RCRA permit.

ISSUE 63. If the Interaqency Aqreement (IAG) is reqarded as an impediment to thorouqh characterization
of the site with respect to chlorinated and other orqanic compounds prior to remediation of OU1 because
of the desiqnation of Operable Units specified in the Interaqency Aqreement, the aqreement should be
amended. (AI)

Given the size of the site, the OUs were created to prioritize investiqative and cleanup action at this
site and to ensure that the project was divided up into manaqeable units. This is common at larqe
Superfund sites. Explosives contaminated soils, under OU1, were qiven the hiqhest priority for cleanup
because of their potential to act as a continuinq source of contamination to qroundwater. Dividinq the
project into manaqeable units and prioritizinq was helpful in completinq this work.

The Interaqency Aqreement was siqned pursuant to Section 120 of CERCLA. The IAG is not an impediment to
thorouqh site characterization.
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ISSUE 64. A federal judge ordered an incinerator shut down because it was violating the law and
threatened the public's health. However, the judge's decision was overturned by the Circuit Court of
Appeals who ruled that because the cleanup of the Superfund site had already begun, the federal courts
had no jurisdiction. The affected community had no opportunity to seek recourse for the problems,
malfunctions, violations, and lack of enforcement by the government once the cleanup began. (C)

The U.S. Court of Appeals for the Eighth Circuit held in Arkansas Peace Center v. Arkansas Department of
Pollution Control and Ecology that under Section 113(h) of CERCLA a citizen suit cannot be brought to
challenge a Superfund removal action until that action is completed. To expedite Superfund cleanups,
Congress made them immune from several different kinds of court challenges. The commentor is correct
that options for a suit challenging an ongoing remedy are limited under existing law unless the lawsuit
falls within one of the exceptions given in the Superfund law. In response to the underlying concern
that the comment appears to convey, the USEPA and the USAGE intend to insure that the incinerator is
operated in a safe and lawful manner, and to be responsive to community concerns in the event that there
are any problems that need to be addressed.

3.3.8 Other

ISSUE 65. We would appreciate further public notice and input opportunity. (B, I, P, Q)

As a result of reguests from members of the public, the 1994 30-day public comment period was extended
from June 14 - July 14, 1994 to end on August 22, 1994 to provide additional time for public comments to
be submitted. In addition, a second public availability session was held on February 22, 1995 and a
second public comment period running from February 22 to March 8, 1995, were held to provide another
opportunity for public input. The Superfund law reguires public participation efforts (i.e., proposed
plans, public meetings, public comment periods, and responsiveness summaries) in order to provide the
public with information regarding the investigations and decisions regarding Superfund sites and to seek
public input for those decisions. Documents for the site have been placed in the information repository
at the Ashland Public Library for public review. USEPA and USAGE have attempted to provide the public
with additional information by holding additional meetings, preparing fact sheets, holding Technical
Review Committee meetings, and holding public availability sessions at the site.

ISSUE 66. A shotgun or other firearm should not be used to remove slag stuck to the incinerator. (AI)

A shotgun will not be allowed to be used in this project. See also Issue 23 for more discussion
relating to this issue.

ISSUE 67. Information reguests were made regarding indemnification agreements and the liabilities for
current non-DOD landowners and taxpayers should any problems arise at the site
during remediation. (AI)

There are no indemnification agreements between non-DOD landowners and the Army at this site.

ISSUE 68. I am concerned with solvent [VOC] contamination in the groundwater spreading southeast. Will
there be free water testing for area residents? If the affected ground is not removed, how much water
over time will be affected? (L, R, S)

Private well testing is being conducted on a guarterly basis for those wells in or near the groundwater
contamination plume. Bottled water or water treatment has been provided for residents when sampling has
indicated that the groundwater is contaminated with concentrations of site-related contaminants above
federal standards or health advisories, as applicable. Additionally, water will continue to be provided
for affected (current and future) residents.

This responsiveness summary addresses OU1, but we agree that the excavation of explosives contaminated
soil is an important factor in alleviating future groundwater contamination. OU2 addresses existing
groundwater contamination and additional soil below a depth of 4 feet that is a continuing source of
contamination to groundwater. The removal of explosives contaminated soil by OU1 will significantly
reduce the source of explosives contamination to groundwater.

The USAGE is currently evaluating whether contaminated soils in the missile areas have the potential to
act as a continuing source of VOC contamination for groundwater. However, such soils, if they exist,
will be addressed as a part of another operable unit.

ISSUE 69. There is a rumor that some of the contaminated soil is being transported to a location down
south. Is this true? (L)
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Neither the USEPA, nor the USAGE, have arranged for soil to be transported off-site with the exception of
small quantities of soil that were taken to a laboratory to be used in treatability studies conducted for
the USAGE by its' contractor as well as approximately 1,100 cubic yards of PCB-contaminated soil which
was removed as part of a 1994 removal action. EPA will attempt to determine whether excavation is taking
place on behalf of third parties.

ISSUE 70. The Corps needs to begin at once the cleanup of contaminated groundwater. (M)

At the time of negotiation of the Interagency Agreement, the parties agreed to organize the site into
three operable units in order to address the multiple site issues in an efficient manner. Operable Unit
1, the explosives contaminated soils, was designated for investigation and cleanup first in order to
remove those soils which were a direct contact threat to on-site workers, students and other members of
the general public, and which were also acting as a continuing source to the groundwater contamination.
However, work on Operable Unit 2, the contaminated groundwater, is also a high priority for action. The
USAGE is developing plans for containing the portion of the groundwater plume contaminated with TCE as a
removal action. This removal action will stop the further migration of the TCE contaminated groundwater.
The public will have the opportunity to review and comment on the Engineering Evaluation/Cost Analysis
(EE/CA) for the containment project very soon. Although containment of the TCE plume does not complete
all the action that will be required for the contaminated groundwater, the Superfund law requires that
the removal action will be consistent with the final groundwater cleanup plan. The investigation of
groundwater contamination, and the analysis of final cleanup alternatives, has been undertaken
concurrently with the soils cleanup analysis process, and is nearing completion. As with Operable Unit
1, a Proposed Plan for cleanup of the contaminated groundwater will be issued for public review and
comment prior to a final decision being made.

ISSUE 71. It does not appear that the full costs associated with incineration have been calculated.
(AI)

The FS costs for all alternatives are calculated to be a -30/+50% estimate used for the purpose of
comparing alternatives (cost is one of the nine criteria). This means that the actual cost could range
from 30% below to 50% above the estimate if all criteria, components or conditions remain the same. Cost
estimates for the selected remediation will be refined during the remedial design phase.

ISSUE 72. Can those who have made comments or questions identify their affiliation, if any, or their
place of residence? Maybe the people living in this area should have a little more to say in the cleanup
situation than people or groups that are representing others. (J, K, X)

Most commentors did identify their address and affiliation in their comment. The record reflects this
information. USEPA and USAGE have attempted to address all public comments regardless of the residency
of the commentor.

ISSUE 73. I would like to see the Corps of Engineers use skilled local craftsmen in the site cleanup
efforts. (AL)

The cleanup contract will be performed by a contractor selected in accord with the Federal Acquisition
Regulations and the contractor will be required to comply with the laws, regulations and executive orders
applicable to such contracts. While the Corps of Engineers cannot mandate the hiring of local craftsmen,
contractors generally hire local workers to the extent a local work force exists with the necessary
skills because cost savings can be realized by such hiring practices.

ISSUE 74. We would like to express our concern with the amount of time it is taking to begin cleanup.
We would like to see the contaminated soil cleaned up as soon as possible. (L, Y, AJ)

The USEPA and the USAGE also want to see the contaminated soil cleaned up as soon as possible. Rotary
kiln incineration will result in the explosives contaminated soils being cleaned up sooner than
biological treatment for two reasons. First, rotary kiln incineration is a proven treatment technology
for explosives contaminated soils, therefore, no lengthy treatability studies to determine whether it
will effectively treat such soils will be required. Because biotreatment of explosives contaminated
soils is not a proven technology, additional treatability studies would be required before soil cleanup
could begin. Second, rotary kiln incineration requires the shortest time to treat site soils to the
required cleanup levels of the treatment options considered.

The landfilling alternatives would result in the removal of contaminated soil more quickly than treatment
by incineration. However, landfilling simply moves the contaminated soils from one location to another,
whereas, rotary kiln incineration would result in actual destruction of contaminants. See Issue 3 for a
more complete discussion of the landfilling alternatives as compared with incineration.
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ISSUE 75. Will there be testing for radioactive materials that were buried in the Mead area? (S)

The USAGE has analyzed a limited number of samples for radioactivity near the burning/proving grounds,
and has not identified any elevated levels of radioactivity in the samples analyzed. Those results can be
found in the April 1989 Confirmation Study Final Report.

The University of Nebraska has been issued a permit by the Nebraska Department of Environmental Quality
for the burial of radioactive materials on-site. The buried materials are associated with University
research efforts and consist of such items as paper, glass, liguid scintillation vials, etc. The
University of Nebraska has installed groundwater monitoring wells downgradient of the burial areas, and
is responsible for monitoring those wells in accordance with the conditions of the burial permit.
Further information can be obtained from the University of Nebraska Agricultural Research and Development
Center at (402) 624-8000.
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SUMMARY OF COMMENTORS
Public Meeting, June 23, 1994

The following people made oral comments:

A Douglas Gustafson
B Pat Sheele
C Lynn Moorer
D Melissa Konecky
E Steve Comfort
F Richard McManaman for Dan Duncan
G Mark Hutcherson
H Dorothy Lanphier
I Lori Moseman
J John Kirchmann
K Karen Johnson
L Viola Irvin
M Denise Meyer
N Richard McManaman
0 Larry Heldt

The following people made written comments at or outside of the public meeting:

A Douglas Gustafson
D Melissa Konecky
E Steve Comfort
F Dan Duncan
I Lori Moseman
J John Kirchmann
L Viola Irvin
M Denise Meyer
N Richard McManaman
P Harland and Judy Schauer
Q lone Hall
R James Morgan
S Mary Eggeling
T Patrick Shea
U John Miyoshi and Larry Angle
V Wendy Hall
X Tricia Kirchmann
Y Larry Meyer
Z Mr. and Mrs. Robert Drews and Family
AA Lester and Evelyn Drews
AB Joe Francis (NDEQ)
AC Doris Karloff
AD Saunders County Board of Supervisors
AE Victor Sedlacek
AF Stephen Exon
AG Jacgueline Eihausen
AH Heather Exon
AI Michael Ryan and Lynn Moorer
AJ Doug and Viola Irvin
AK Gene Lewis
AL Tom Banks
AM Dorothy and D. Konecky
AN Larry Erickson
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