When construction of the Iowa Army Ammunition Plant was completed in 1942, it was known as the Iowa Ordnance Plant (IOP). IAAAP produced munitions for World War II from the plant's inception in September 1941 until August 1945.

Production resumed in 1949 and has continued to the present. The ammunition items that are loaded, assembled and packed at IAAAP include projectiles, mortar rounds, warheads, demolition charges and the components of those munitions, including primers, detonators, fuses and boosters. The load, assemble and pack (LAP) operations use explosive material and lead-based initiating compounds.

In 1947, the IOP was selected as the first production facility for the manufacture of high- explosives components for weapons under the AEC. From 1947 to 1975, portions of the IAAAP facility were under AEC control for research, development and production of materials and components as part of America’s early atomic program. The AEC-operated portions of the plant were commonly known as the Burlington Atomic Energy Commission Plant (BAECP).

Between 1965 and 1973, a series of specialized tests were conducted exclusively at the Firing Site (FS) 12 Area. Some of the tests used depleted uranium (DU). Some of these tests consisted of conventional munitions surrounded by a large ring of DU that was broken, partially dissipated and scattered upon detonation. Approximately 4 tons of DU were associated with the testing at the FS-12 Area, according to the Agency for Toxic Substances and Disease Registry, 2003.

In the late 1960s, it was determined that AEC operations at BAECP would be phased out. BAECP closed in July 1975, and control of the areas reverted to the Army.

In 1989, IAAAP was proposed for inclusion on the National Priority List (NPL) pursuant to Section 105 of the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) and the Superfund Amendments and Reauthorization Act of 1986 (SARA); it was added in August 1990 (EPA ID #IA7213820445). In September 1990, the Army and U.S. Environmental Protection Agency (EPA) Region VII entered into a Federal Facility Agreement (FFA, also called “Army FFA”) to define the roles and responsibilities for the Army’s CERCLA activities at IAAAP and the process for interagency coordination.

IAAAP was placed under the U.S. Department of Defense (DOD) Defense Environmental Restoration Program (DERP), which manages CERCLA activities to identify, investigate and mitigate past hazardous-waste disposal practices that may have contributed to the release of pollutants into the environment at U.S. Army installations/facilities. Past munitions production has resulted in contamination of soil and groundwater as well as discharges of waste water containing explosives to surface water. Numerous environmental investigations have been conducted at IAAAP under DERP. Investigation and remediation of contamination under DERP has been ongoing since the early 1990s. The Army has conducted remedial actions at the Explosive Disposal Area (EDA) East Burn Pads area, West Burn Pads area, North Burn Pads area and the North Burn Pads landfill. The Army has also performed soil cleanups at the Former Line 1 Impoundment, the Line 800 Pinkwater Lagoon, the Fire Training Pit, the Pesticide Pit and other areas at IAAAP.

The Administrative Record for IAAAP DERP CERCLA actions is maintained by the Army and includes information and documentation that support remedy decisions at the site, including Preliminary Assessments (PA), Site Inspections (SI), Remedial Investigations (RI), Feasibility Studies (FS), Proposed Plans (PP), Records of Decision (RODs), Engineering Evaluation/Cost Analyses (EE/CAs), Action Memorandums, Remedial Action (RA) Reports and other documents.

In 1974, the Department of Energy (DOE) created the Formerly Utilized Sites Remedial Action Program (FUSRAP) to address sites used during the nation’s early atomic energy program that had residual contamination exceeding current regulatory limits.

In 1997, a congressional action transferred FUSRAP responsibility from the DOE to the U.S. Army Corps of Engineers (USACE) under the Energy and Water Development Appropriations Act of 1998.

In general, the objective of the CERCLA process is to evaluate the nature and extent of contamination at a site, and to identify, develop and implement appropriate remedial actions in order to protect human health and the environment. The typical process consists of a Preliminary Assessment (PA), Site Inspection (SI), Remedial Investigation (RI), development of a Feasibility Study (FS) report/Proposed Plan (PP) and a Record of Decision (ROD). The ROD, which establishes the selected remedy to address excess risks, is followed by Remedial Design (RD), Remedial Action (RA) and Closeout.

FUSRAP began applying the CERCLA remedial process to IAAAP in 2001, but the investigation into possible radiological contamination at IAAAP began much earlier.

Prior to departure from IAAAP in 1975, the AEC performed a cleanup at Firing Site (FS)-12, by excavating soils at the testing area, known as “ground zero,” and by scraping a few inches of topsoil off an area of several hundred square meters surrounding ground zero. In the cleanup, approximately 31,000 cubic feet (1,200 barrels) of soil contaminated with DU metal pieces were temporarily stored in Building 1-11. These materials were subsequently disposed of at a waste-disposal facility. After the AEC turned over operations of FS-12 to the Army in 1975, the FS-12 area was used for testing conventional weapons not containing DU until November 2000.

In 1975, the AEC also conducted a radiological survey of the Line 1 areas. The AEC determined that no real property contained residual radioactive contamination above standard. However, the “standard” for comparison was not specified.

In 2000, the DOE performed an indoor survey of selected Line 1 buildings used by the AEC. Levels of residual DU was found in some buildings. The DU found in one of the buildings was found in a plastic pan, which was removed and disposed of as radioactive waste.

In a report written in November 2000 by the DOE’s Oak Ridge National Laboratory titled “Results of the Indoor Radiological Survey of the Iowa Army Ammunition Plant, Middletown, Iowa” (DOE, July 2001), the DOE concluded that contamination in a building in Line 1 and at Firing Site 12 was likely attributable to AEC activities. This report also stated that contamination in the Line 1 building could have been the result of either AEC or Army activities.

In April 2001, a gamma walkover survey and soil-sampling survey were performed by FUSRAP at the Firing Sites 6 and 12 Areas, finding non-uniform dispersion primarily located on or near chunks identified as DU throughout Firing Site 12, with two spots located at Firing Site 6.

The Preliminary Assessment (PA) Report of IAAAP was completed in December of 2001 and identified 13 areas for further investigation for potential radiological contamination under FUSRAP.

In October 2002, the Army Field Support Command/Joint Munitions Command (Provisional), a JMC predecessor, conducted an Aerial Radiometric Survey, with the results published in August 2003. The survey concluded that there was no anthropogenic radioactive contamination (arising from human activity) on the majority of the plant; however, indications of anthropogenic sources were observed over the bunkers in Yard E, the Coal Pile at the heating plant, and at the Firing Site 12 Area.

Inspections of the gamma-ray spectra over Yard E sites showed that depleted uranium is the major anthropogenic radioisotope present. The net spectrum over the Coal Pile indicated an excess of natural uranium compared to the land surrounding the heating plant. This is attributed to the licensed activities that were ongoing at the plant under Iowa radioactive materials license, #0290-1-29-SM1. The low activity and relatively small area of the Firing Site 12 source area resulted in poor statistics for the net spectrum; however, the spectrum was consistent with depleted uranium. No off-post radioactive contamination was found.

In 2003, a Site Reconnaissance Survey of Buildings L-37-1, L-37-2 and L-37-3 performed under FUSRAP found no radiological contamination and concluded that the buildings could be released for unrestricted use free of radiological restrictions.

In 2004, FUSRAP conducted a radiological screening survey of the Explosive Disposal Area, Inert Disposal Area, Demolition Area/Deactivation Furnace and the Line 1 Former Waste Water Impoundment Area. The survey identified a small area at the Inert Disposal Area that contained a cesium-137 object. The object was removed. The U.S. Army Environmental Command’s Installation Restoration Program (IRP) has assumed responsibility for actions required to remediate the surrounding soils that were left in place and covered. The site screening survey of the four identified areas was completed in autumn 2004. The report “Final Summary of the Radiological Survey Findings for the Iowa Army Ammunition Plant Explosive Disposal Area, Inert Disposal Area, Demolition Area/Deactivation Furnace, and Line 1 Former Waste Water Impoundment Area” was finalized in 2005 and reported that these areas are free from radiological contamination. The report recommended the elimination of these sites from further FUSRAP action. These four areas would continue to be under the control of the IRP remediation program.

Soils/structures consisting of seven geographically separate sites were recommended for further FUSRAP investigation and remediation, where required. These sites include Line 1, the FSA, Yard C, Yard G, Yard L (soils surrounding Warehouses L-37-1,-2 and -3), Warehouse 3-01 (building interior) and the West Burn Pads Area south of the road (WBPS).

In May 2006, a draft RI sampling work plan for these seven sites was developed and submitted to the state of Iowa and the EPA for review. Although the EPA had difficulty in meeting the review time frame, the EPA did encourage USACE to proceed with the RI fieldwork in the absence of a final work plan.

In August 2006, an FFA to address FUSRAP at IAAAP was executed among USACE, the DOE, the EPA and the state of Iowa.

The RI fieldwork began in October 2006. As a result of EPA comments, a final RI work plan “update package” was issued in June 2007 and fieldwork was completed at the end of June 2007. The RI evaluated all releases and threats of releases of hazardous substances, pollutants or contaminants, except for groundwater contamination (which was addressed by another Army environmental program). Sampling was conducted in such a manner that the data collected could be used to aid in the future design of remedial action (if RA were warranted). The RI Report documented the results. In February 2008, USACE, St. Louis District, issued a draft RI report and baseline risk assessment. In October 2008, USACE, St. Louis District, issued a Final RI report.

Because the RI sampling did not indicate radiological soil contamination at Line 1 and the West Burn Pads (Area South of the Road) and because two Army soils RODs addressing the chemical contamination at these areas already existed and were deemed valid, FUSRAP proceeded with Remedial Design and RA for the Line 1 soils and WBPS soils areas under the existing Army RODs. The soils at these sites were not addressed in the October 2008 Final RI report.

The RI identified six areas for further evaluation in the Feasibility Study (FS). FUSRAP prepared the FS following CERCLA/EPA guidance. The FS evaluated possible remedial actions to address contamination at the FSA; Yards C, G, and L; Warehouse 3-01; and Line 1 structures.

In September 2009, a draft Feasibility Study (FS) report was issued to FFA parties for review. A significant number of comments -- and the surfacing of additional information regarding operations at the plant -- resulted in a second draft FS report (referred to as Revision B1) being issued Feb. 18, 2011. A draft Proposed Plan (PP) was also issued at that time. A PP summarizes the findings of the FS and identifies the preferred alternative for remedial action.

A significant difference between the initial draft report and the Revision B1 draft report is the consideration of the December 2006 Dispute Resolution Agreement between the Army and the EPA for the Installation Restoration Program (IRP) work completed at Iowa. The agreement reflects the application of the Military Munitions Rule (40 CFR 266.200 et. seq.) to the determination of the scope of FUSRAP authority on the FSA. It resulted in limiting the FUSRAP response at the FSA to the removal of source material containing DU.

Regulator review of the draft FS report and draft PP ended March 10, 2011. USACE resolved the comments and reissued a draft final FS report and PP March 31, 2011. With the concurrence of the FFA parties, these documents became final April 22, 2011, and the 30-day public review period began. A notice was placed in the local newspaper – The Burlington Hawkeye – announcing the availability of the PP, requesting public input and identifying the date, time and location of the public hearing. A public hearing was held in Burlington, Iowa, May 17, 2011, at the Comfort Suites Hotel and Conference Center in Burlington, Iowa, to present the PP to members of the community. Oral comments were received at the hearing.

No written comments were furnished. None of the comments necessitated a change in the PP; thus, National Oil and Hazardous Substances Pollution Contingency Plan (NCP) requirements regarding public participation were met.

In the PP, USACE recommended Alternative 4 which consists of excavation of DU exceeding remediation goals (based on a future industrial land use), sorting of the soil to remove DU fragments (physical treatment) and disposal of the DU off-site at an approved, licensed disposal facility. MARSSIM-based Final Status Survey evaluations were to be completed to determine residual levels of contamination, risk and long-term management requirements. In the PP, USACE also recommended Alternative S3, decontamination/replacement of structures.

The FUSRAP Record of Decision (OU-8 ROD, or FUSRAP ROD) specifying the selected remedy for the remediation of soil and structures was executed Sept. 2, 2011. This ROD outlines the remedial activities that will be undertaken to address radiological contamination resulting from AEC activities conducted previously at IAAAP. The OU-8 ROD selected remedy included Alternative 4, Excavation of DU-Contaminated Soil with Physical Treatment and Off-Site Disposal, along with Alternative S3, Decontamination/Replacement of Structures.

The main components of the remedy include:

• Excavation of DU-contaminated soil at Firing Sites 1 and 2; Firing Sites 3, 4 and 5; the Firing Site 6 Area; and the Firing Site 12 Area;
• Physical treatment of DU-contaminated soil excavated via soil sorting;
• Decontamination of structural surfaces and/or replacement of structural components ( effected structures in Line 1);
• Disposal of DU-contaminated materials at a properly permitted off-site facility.

The soil-sorting process system is used to separate soils that are contaminated with DU from soils that aren't. This process reduces the amount of material that must be shipped to an off-site, licensed disposal facility. On-site soil with DU concentrations less than the ROD RG is used as backfill material, which reduces overall project cost. The construction season at IAAAP is approximately eight months from April to November.

Currently, the Army and USACE are performing cleanup simultaneously on IAAAP, with the Army remediating contaminants resulting from munitions production under the Defense Environmental Restoration Program (DERP) and USACE remediating contaminants resulting from the nation’s early atomic energy program under FUSRAP.

For Remedial Design/Remedial Action, separate Operable Units and Records of Decision are involved:

- The Army Interim Soils (OU-1) ROD, dated March 1998, and the Army Final Soils ROD, dated August 1998, which identify the remedy for contamination in soils at Line 1 and the West Burn Pads South of the Road (WBPS); and

- The FUSRAP (OU-8) ROD, dated September 2011, which identifies the final remedy for soils and structures that are radiologically contaminated as a result of AEC operations previously conducted at IAAAP.

OU-1

Areas within the Explosive Disposal Area (EDA) were investigated in the RI (1996). The North Burn Pads, North Burn Pads Landfill, East Burn Pads and West Burn Pads area are addressed in the 1998 Interim soil ROD.

Follow-on sampling at Line 1 to support the Army ROD, more commonly referred to as Pre-Design Investigation (PDI), was conducted by the Army in the form of a Supplemental RI (TN & Associates), dated August 2002. The Supplemental RI evaluated only non-radiological contaminants and concluded that additional data was necessary to define the nature and extent of contamination associated with the contaminants of concern (COCs).

In the interim remedial action, soil from these areas with contaminants at levels exceeding ROD-specified remediation goals was disposed at the Inert Disposal Area. No radioactive materials were discovered during gross radiological screening.

This entailed excavation of soils at the area of concern and management/disposal of those soils at the Inert Disposal Area or off-site if the IDA was unavailable. Some soils at the Inert Disposal Area would require treatment (following processes previously employed in Army remedial actions).

After the Line 1 and WBPS soils were removed from consideration as part of the FUSRAP RI report, USACE began developing a design for the RA at the two areas and the process of acquiring a contractor. A draft Remedial Design/Remedial Action Work Description document was prepared and submitted to the EPA, the state of Iowa and the DOE April 25, 2008, for a 45-day review. Comments were received and addressed and a Draft Final Remedial Design/Remedial Action Work Description (dated July 30, 2008) was issued to the FFA parties Aug. 1, 2008.

USACE contractor Safety and Ecology Corporation (SEC) mobilized to the site in October 2008. Area preparations began at both Line 1 and WBPS. Excavations were very slow because of several logistical challenges, such as muddy conditions, the need for unexploded ordnance (UXO) support, the presence of utilities that required hand digging, and the need to access excavations beneath building walkways. Some of the excavations were not accessible to large equipment and trucks so excavated soil and backfill material had to be hauled to open areas by compact excavator or conveyor belt. In addition, there were numerous occasions when SEC had limited access to Line 1 because of production work being done by American Ordnance (AO) at the site. Excavated material was disposed of at the on-site Inert Disposal Area (IDA) with the exception of PCB-contaminated and SVOC-contaminated material, which was disposed of off-site. Work proceeded until the week before Christmas 2008 when harsh weather required demobilization.

When remedial action resumed in June of 2009, it was determined that for some Line 1 locations, remediation would not be possible because of recontamination from residual materials in abandoned waste lines, run-off from buildings/roofs and contaminated groundwater. These locations at Line 1 were restored temporarily to allow time for further characterization.

Backfilling of some open excavations from fall/winter 2008 were performed as well. By the end of June 2009, the primary focus was at WBPS. The excavation process was slow because of required UXO oversight and because excavations were being expanded slowly when samples failed to meet remediation goals (RGs). Also, disposal was halted because the IDA was shut down because of a UXO sighting that was not resolved for more than a month. Meanwhile, it became clear that the volume of contaminated material at WBPS would grow well beyond the design.

WBPS areas D, E, and F merged to form one large excavation. Before the excavation could expand southward, there was another delay. Trees located in potential excavation areas needed to be inspected for Indiana bats (an endangered species). The inspection by an Army biologist required three consecutive nights of observation with no high winds or rain. No bats were observed so the trees were felled. In the summer of 2009, it was discovered that, in addition to the explosives contamination at WBPS, there was barium-only contaminated soil that exceeded the land disposal restriction (LDR) and, in some locations, met the definition of hazardous waste. With the unexpected volume of material and contaminants, it became necessary to pursue off-site disposal for which an Explanation of Significant Difference (ESD) to the Army ROD had to be developed. At the EPA’s request, FUSRAP developed a draft ESD addressing the barium issue. This ESD was finalized in March 2011. Further driving the need for off-site disposal was the notification that the IDA would have less capacity than previously indicated and would soon be closed. Research was conducted, and a couple of suitable off-site disposal facilities were identified. EPA approval of their use was requested and later received.

In the winter of 2010, the tree line was removed after it became clear that remedial action would be necessary eastward to the Spring Creek tributary. In spring and summer 2010, the WBPS excavation was completed with more than 25,000 tons of soil removed.

USACE is in process of issuing a Remedial Action Closeout Report (RACR) for FUSRAP activities at the WBPS under the Army Soils RODs.

After backfill and restoration of WBPS was completed, SEC resumed remedial action at Line 1. Remedial action was performed at five locations previously excavated in 2008. Clean backfill material was removed and set aside to be analyzed for re-use. Further excavation was performed to remove previous failed samples and to attempt to identify the source of contamination. As in 2008, the weather conditions became too cold for productivity by the beginning of December, forcing SEC to demobilize until spring 2011.

In April 2011, FUSRAP mobilized its Engineering contractor – SAIC – to the Line 1 site to collect additional data to better delineate contamination associated with the recently discovered leaks at the waste line. An Addendum to the RD was issued to address seven additional areas requiring excavation of explosives-contaminated soil at Line 1. On June 13, 2011, SEC mobilized back to the Line 1 site and a water-treatment system was established. Two conveyors were brought on-site to transport excavated material out of EU-6A (one of the most confined excavation areas.) EU-6A and another excavation unit were excavated. In 2012, SEC collected additional samples to delineate contamination associated with clarifiers, sumps and water troughs. The sampling results indicated the presence of explosives in concentrations exceeding the RGs at six new areas at Line 1.

Remedial action at Line 1 continued until March 2013 when the remediation contractor encountered inaccessible soils at excavation EU9B-B in the vicinity of Building 1-70. As a result, it was determined to suspend further work at Line 1, pending the planned demolition of the Building 1-70 structure.

An American Ordnance subcontractor completed the demolition and removal of Building 1-70 in August 2018. Other buildings where potential contamination may exist – such as 1-05-1, 1-05- 2 and 1-155-1 – were also demolished between September 2018 and June 2019. Soil samples were collected, and they indicate that in addition to Building 1-70, a relatively small amount of remediation is necessary at each of the other buildings.

Additional remedial action by FUSRAP is planned for Line 1. A RACR will be issued once all FUSRAP remediation activities at Line 1 have been completed.

OU-8

The PDI (Supplemental RI (TN & Associates, 2002)), conducted by the Army, also included sampling at the Firing Sites Area. The Supplemental RI evaluated only non-radiological COCs and concluded that additional data was required to define the nature and extent of contamination.

At the time of execution of the FFA in November 2006, additional data was needed at the Firing Sites Area to evaluate potential radiological contamination, and to define the extent of contamination. DU had been detected in previous sampling at the FS-6 and at FS-12 Areas.

In June 2011, FUSRAP supplied technical support to American Ordnance in preparation for parking-lot construction at the Firing Sites 1 and 2 areas.

A draft Remedial Design/Remedial Action Work Plan (RD/RAWP) was prepared and submitted to the FFA agencies in 2012. The Final RD/RA Work Plan was approved Feb. 6, 2013. The RD/RAWP outlines a comprehensive process that follows the governing CERCLA and FFA requirements for implementing the selected remedy in the OU-8 ROD.

With approval of the RD/RAWP document, remedial action could begin. At that time, it was anticipated that excavation and backfilling would take two years.

At the Firing Sites Area, a pilot study was conducted in June 2013 to identify site-specific soil and fragment characterization, DU and radiological measurements needed to determine separation equipment settings, and demonstration of excavation and DU removal techniques.

After the pilot study was deemed a success, remedial action started in July 2013 and is ongoing. A load-out pad was constructed at M-Yard in August 2015 so that soil above the remediation goal (RG) can be shipped out of IAAAP.