The Shallow Land Disposal Area (SLDA) site is located in Parks Township, Armstrong County, Pennsylvania, about 23 miles east-northeast of Pittsburgh, Pennsylvania.

The site is 44 acres and contains 10 trenches of contaminated waste and soil.

The U.S. Army Corps of Engineers (USACE) has been directed by Congress to remediate the radiological contaminants at SLDA. During remedial operations USACE is responsible for site security. USACE has hired subcontractors to assist with remediation and site security.

Security will be present year-round, 24-hours a day, 7-days a week.

The Nuclear Regulatory Commission (NRC) is the primary regulator for the SLDA site through the site owner’s license (SNM-2001).  Pursuant to the authority established in Section 8143 of the Fiscal Year 2002 Defense Appropriations Act, Public Law (PL)107-117 Section 8143(a)(2) (Jan. 10, 2002), Congress authorized USACE to “cleanup radioactive waste” at the SLDA, consistent with the Memorandum of Understanding (MOU) between USACE and the Nuclear Regulatory Commission (NRC) dated July 5, 2001, and subject to Public Law 106-60, Section 611, subsections (b) through (e).  Thus, PL 107-117 establishes USACE as the Lead Federal Agency for the remediation project.  USACE will be assisted by the NRC, NNSA, and DOE-EM.  NRC, NNSA, and DOE have invaluable expertise in the handling of nuclear material and environmental remediation.  All are working together to ensure success and to address public concerns regarding the SLDA and surrounding areas. A site-specific MOU with the NRC and Department of Energy’s offices of Environmental Management (EM) and National Nuclear Security Agency (NNSA) detail the relationship between these agencies and USACE regarding the safe completion of the remedial action as specified in the record of decision (ROD).    The Pennsylvania Department of Environmental Protection (PADEP) is the USEPA’s state-level counterpart.  USACE continues to work with PADEP to perform environmental monitoring.

We expect to encounter a wide range of radiological wastes, as well as quantities of non-radiological wastes. The wastes placed in the disposal trenches generally consist of:  process wastes (slag, crucibles, spent solvent, unrecoverable sludge, organic liquids, debris, etc.), laboratory wastes (sample vials, reagent vials, etc.), outdated or broken equipment, building materials, protective clothing, and general maintenance materials (paint, oil, pipe, used lubricants, etc.). The uranium-contaminated materials disposed of at SLDA are present at various levels of enrichment, ranging from depleted to enriched.

Yes. USACE has the necessary experts on staff and is also leveraging expertise from other Federal agencies and the private sector.  NRC, DOE, and NNSA have subject matter experts assigned to assist USACE’s project planning and execution.

Trenches 2 and 3 underwent remediation to approximately 8 feet below ground surface. When operations were ceased on September 30, 2011, the surface at 8 feet below ground surface was covered with an impermeable geo-textile material, backfilled to original grade, and seeded.  Trenches 1, and 4 – 10 remain as found when the USACE took control over the site in 2011.  The USACE has maintained the site through an operations and maintenance (O&M) contract since the original remediation contractor demobilized from the site in March 2013.  Weekly inspections of the grounds are performed, as well as weekly air monitoring (sampling) of the site perimeter. Additionally, USACE has performed annual groundwater sampling since 2013 to monitor groundwater quality near the waste trenches and Kiskimere community.  Sampling results verify that contamination remains within the trenches and site groundwater near Kiskimere reflects background, or natural, conditions.  Results of USACE environmental monitoring are available on this webpage.

No, the mine is not considered part of the site. However, if during the course of remedial activities on the site, USACE identifies contamination on the site that is within the mine below the trenches, then USACE is authorized to address the contamination, if necessary, for the protection of human health and the environment.

USACE is ensuring the safety of the community by maintaining around the clock security and conducting routine air (weekly) and groundwater monitoring (annual).  USACE will continue these actions for the duration of its’ presence on-site.  Two 8-foot fences completely enclose the site and security is maintained 24/7 in order to prevent unauthorized persons from entering the site and disturbing the buried waste or the infrastructure.  USACE performs routine air (weekly) and groundwater environmental monitoring (annual).  Air sampling is conducted by USACE on a continuous basis, and USACE & PADEP conduct radiation dose monitoring of the site perimeter.  These measures will continue during the upcoming remedial actions, and additional monitoring is being planned to ensure that the surrounding community and the environment remains protected.

In order for community members to be exposed to contamination from the site, there must be a complete exposure pathway linking the buried radioactivity at the SLDA to the community outside the site.  No such pathway has been discovered.

The risk is low. Once remediation starts, several measures will be in place to further reduce risk.  1) Airborne contamination will be controlled by wetting work surfaces to ensure that contaminated particles do not pose a threat.  2) The pace of excavation was and will continue to be slow, thorough and deliberate. The amount of radiological contamination will be measured before it is excavated and while it is being processed onsite.  3) The air concentration around the excavation will be measured and monitored for worker and community safety.  4) Air inside the material processing building is controlled and treated before it is emitted.  5) During trench excavation, groundwater will be monitored continuously with in-situ sensors and sampled no less than monthly.  6) Storm water and groundwater that come into contact with exposed trench surfaces/contents will be routed to the on-site wastewater treatment plant.  After water is treated, USACE will sample all treated water in approximately 20,000gallon batches and verify that the criteria established with PADEP have been achieved and coordinate with PADEP prior to discharge to the Kiskiminetas River.

The 8 on-site and 1 off-site perimeter air monitors are set at the average breathing zone height of the average person. These air monitoring stations have been strategically placed around the perimeter of the site to provide weekly samples of any upwind, crosswind and downwind particles containing radiological contaminants. The air monitors run continuously (24/7/365) collecting air, and the filters are analyzed weekly.  There are also radiation monitors in these locations that monitor gamma radiation.  These are checked (analyzed) monthly.  Airborne radiation doses have always been well below the dose limits in the Nuclear Regulatory Commission’s criteria for licensed sites undergoing decommissioning.

Radioactive material is not leaving the site via surface water drainages.  Dry Run surface water and sediments were sampled by USACE during the Remedial Investigation (2003 – 2004) (RI) and in 2013 and this sampling indicated that the surface water was well below Federal and state regulatory limits for water.  Sampling of Dry Run as it exits the site (at the fence line) will continue to be monitored by USACE annually.  The current USACE site operations & maintenance contractor performs weekly erosion prevention and sediment control inspections across the site.  Carnahan Run and mine outfalls adjacent to Carnahan Run were sampled by USACE during the RI (2003 – 2004) and this sampling indicated that Carnahan Run is not impacted by radioactivity from the SLDA site.  In 2012 and 2013, USEPA sampled surface water and sediment from groundwater seeps, springs, and/or outfalls in the watersheds of Dry Run, Carnahan Run, and Kiskiminetas River near the SLDA and confirmed that the surface water drainages were not conveying radioactive material off-site.  USACE has robust erosion control measures and a storm water collection system in place to contain sediment and water from exiting the excavation sites.

No.  Federal, State, and local permits are not required at sites undergoing a CERCLA remedial action (See Section 121(e)(1) of CERCLA).  However, USACE and PADEP have developed and applied substantive standards to any effluent discharges at the site.

There is no evidence that any groundwater wells in the nearby community are contaminated.  USACE conducts annual monitoring of the groundwater on-site confirm that radionuclides are not migrating off the site in the groundwater. These reports are available on the project website.

Yes, there are wells on all sides of Trench 10.

No additional wells are planned.

Yes. Sampling data of on-site soil and ground water testing is contained in the Remedial Investigation (RI) documentation, which is available on our website, and also at the Apollo Library and the USACE district office in Pittsburgh.  Please call 412-395-7500 if interested in viewing these files and data at the USACE district office.  In addition, reports explaining the results of recent environmental monitoring (air and radiation monitoring, groundwater monitoring) are available on the USACE website.

USACE will evaluate the location of fencing to ensure property rights are respected, and site security is maintained.

No. The extent of contamination associated with SLDA is delineated in the RI.

The Formerly Utilized Sites Remedial Action Program (FUSRAP) was established in 1974 by the Atomic Energy Commission to identify, evaluate, and remediate sites with contamination resulting from activities of the former Manhattan Engineer District and Atomic Energy Commission, or similar sites (such as SLDA) added by Congress. In 1997, Congress transferred authority for executing and administering the FUSRAP from the DOE to USACE.  Additional information on FUSRAP is available at the website,

Congress annually appropriates funding for the FUSRAP.  The Government may seek to recover costs from potentially responsible entities, and the money recovered may be used to fund FUSRAP.

Radiation is a naturally occurring type of energy. It can be released by unstable forms of atoms, the basic units of matter, as they change into more stable forms. The energy released is emitted as either waves (such as X-rays or gamma rays) or particles (for example alpha and beta radiation). The three most common types of radiation are: 

- Alpha particles, which are the largest and slowest atomic particles. They can travel only a few inches through air. They can be stopped by a sheet of paper or the outer layers of skin.

- Beta particles are smaller and faster than alpha particles and can travel further in air. They can easily be stopped by a thin shield such as a sheet of aluminum foil.

- Gamma radiation, which consists of gamma rays rather than atomic particles. Gamma rays are a type of electromagnetic wave, much like X- rays, and move at the speed of light.  They travel farther through air than alpha or beta particles and can be stopped by a thick shield of lead, steel, or concrete.

- Natural radiation is found in soil and in the food we eat.  Radiation also reaches us as cosmic radiation from outer space. Finally, many common medical procedures, such as chest or dental X-rays, expose us to radiation.  Further information regarding radiation may be found in the brochure.

Exposure to radiation can occur in many ways. For those radioactive elements that decay via release of gamma rays, one can be exposed simply by being near the radiation. This is because the external gamma rays can travel through air. However, not all radioactive elements release gamma rays. For those other radioactive elements that decay via release of alpha or beta particles, one has to inhale or ingest the radioactive substance in order to be exposed. For that type of radiation, exposure could occur only via inhalation of vapors or of small soil particles containing radioactive material, incidental ingestion of soil contaminated with radioactive material, and ingestion of water contaminated with radioactive material.  Further information regarding exposure and risk may be found in this fact sheet.

The curie is a measure for the amount of radioactive material. It was named after French scientists Marie and Pierre Curie for their landmark research into the nature of radioactivity. The basis for the curie is the radioactivity of one gram of radium.   A picocurie is one trillionth of a curie.  Radium decays at a rate of about 2.2 trillion disintegrations per minute. Thus, a picocurie (abbreviated as pCi) represents 2.2 disintegrations per minute.  More information on this topic may be found here.

Previously excavated material included nuclides (Am-241, Pu-239, Pu-241, Ra-228, Th-232, U-234, U-235, and U-238) listed in the Record of Decision document, as amended.   Per DoD policy, in order to ensure the safety and security of public and workers, the Corps cannot discuss the quantities or enrichments of the materials found at site.  

All exhumed waste from the remediation activities in 2011 have been disposed at licensed waste facilities.

During the initial phase of remediation, a breach of a safety procedure occurred requiring the work to be stopped. The contract period of performance expired before work could be resumed.

The gas line was moved because of the excavation.

Our investigation of the site indicated that isolated areas over and around the trenches had levels that are slightly above the natural background. These isolated areas will be remediated.  These levels, while elevated above background, do not pose a risk to human health or the environment.

None of the waste excavated at the site contained Uranium-233. The materials in question were very difficult to characterize, severely degraded and of concern; however, once the full characterization of the material was complete, no U-233 was detected.

USACE’s selected remedy is Excavation and Off-site Disposal.  This approach involves the excavation of the radiologically contaminated soil and debris, off-site transportation, and disposal at an appropriate permitted/licensed disposal facility in order to comply with the selected applicable or relevant and appropriate requirements (ARARs).  The site owner, not USACE, has the sole responsibility to remediate other site contaminants. 

No. Under the law, USACE is only authorized to remove radioactive waste and other chemical material comingled with radioactive waste above a certain threshold.  The site owner is responsible for any chemical materials found and has agreed to work with the USACE, NRC & PADEP to dispose of such material accordingly.

None of the USACE-approved disposal facilities authorized for FUSRAP reside in PA, so currently, all waste disposal actions will be out of PA.

While the risk from the radioactive waste in the trenches is below the CERCLA minimum threshold, there is possibility of future risk due to potential geologic shifting of the material and the potential for future agricultural use of the site. Under current conditions the SLDA site presents very little risk to human health.  The site is currently vacant and surrounded by a fence that is actively maintained.  There is very little radioactive contamination outside the footprints of the 10 trenches, and the contamination that is present at those isolated areas poses very little current and future risk.  However, reasonable assurance cannot be made that these conditions will remain, and the radionuclides in the trenches could be gradually released into the environment over time. The existence of room and pillar mine works below the site and the potential for subsidence are also long-term considerations.

Knowledge gained during the initial remediation fundamentally changed our approach to the site and our estimate of the remediation cost.  CERCLA requires that when a fundamental change is made to the basic features of the Selected Remedy with respect to scope, performance, or cost, the lead agency is required to develop a ROD Amendment.  

The current estimate-to-completion is $430M-500M and 10 years to complete excavation of the trenches and return the site to NRC control.

Our current estimate is 10 years, but many things can affect the schedule including weather, funding and the complexity of work.

The cost estimates were updated to reflect knowledge gained during the initial remediation phase, current pricing levels, and risk-based contingencies. These contingencies take into account risk associated with all aspects of the project.  Risk-based contingencies are determined through the Cost Schedule Risk Analysis (CSRA) process.  The process includes a software-based statistical analysis of project risks to identify, analyze, and account for a wide range of uncertainties including disposal cost, transportation, weather and labor.  The CSRA results in a range of estimated project costs and durations associated with varying confidence levels. The 80% confidence level estimate of cost and schedule for budget development was selected based on Corps guidelines. The CSRA estimates are updated annually to reflect the most current information available from actual field experience during the prior year’s activities.

USACE currently expects to begin trench excavation in Fall 2024.

Safety is our main concern.  Due to the presence of Special Nuclear Material and Beryllium, the work will be tightly controlled by processes unique to this site. Approximately 30,000 tons of material from a variety of different waste streams must be excavated and processed for disposal.  Each type will require different removal, handling and disposal procedures.

If unexpected materials are detected at levels that are considered a threat to workers or community safety, work will stop, and engineering safety controls will be implemented.  The material will be characterized and disposed of in a safe manner.

Yes. Safety is paramount. We will take our time and remove the material in a safe manner.  If unexpected material is discovered that may pose a risk, excavation will stop until the material is characterized and appropriate safety controls are in place.

USACE is currently evaluating methods for excavating the trenches.

The Administrative Record, which includes the RI, Feasibility Study (FS), Proposed Plan (PP), and ROD, outlines the areas of the site that require remediation.  If during excavation, we discover evidence that the contamination extends beyond the original trench boundaries or the fence line, USACE has the authority to “chase” contiguous areas of contamination as they lead away from the site. We have no evidence now of contamination extending off-site.  The RI, FS, PP, and ROD are available on this webpage.

A geophysical survey was conducted on the site in 2006 which verified the location of the 10 trenches as identified in historical information. The geophysical survey was supplemented with sampling to verify its results. This geophysical survey also verified no other anomalies on or leaving the project site.

Trucks transporting wastes from the site will travel on local roads rated for commercial truck traffic to the extent necessary to access approved routes leading to the disposal facility. All shipments arriving and departing the site will comply with US DOT regulations and undergo extensive cleaning, radiological surveys, and physical inspection prior to being dispatched.

USACE will follow the Multi-Agency Radiation Survey and Site Investigation Manual (MARSSIM) approved by the EPA, DOD, DOE, and NRC that details protocols in performing a Final Status Survey of the entire site to ensure that radiological cleanup goals have been met. Additionally, the NRC and PADEP will review the data report packages and have the right to perform their own verification surveys and sampling prior to concurring that the USACE has met the cleanup goal.

The Remediation Contractor, Jacobs Technologies Inc, is responsible for hiring site labor.  Currently, the hiring process for site labor has not started.  Once specific information is available, it will be included on the SLDA website.

Yes. Through our coordination with local partners and first responders, we will be prepared for contingencies that we may encounter at the site.

The local responders will inform residents of any necessary actions. USACE and our contractors will work with the local communities’ first responders (police, EMS, fire and rescue), Armstrong County Emergency Management officials, Region 13 Emergency Management Team and the Pennsylvania Emergency Management Agency (PEMA) to develop an Incident Response Plan. The plan will be rehearsed and exercised with each of our response team partners listed above in addition to associated contracted response resources. We have also gathered first responders onsite to provide awareness and preparedness training.

No. However, USACE and our contract partners, in coordination with local EMS and county HAZMAT responders, will include addressing this type of response within our Incident Response Plan. We will meet with local responders to provide specific site awareness and preparedness training if a response is required. On-site drills with local & state emergency managers are in the planning stages currently.

Work plans created for the 2011 remediation did not include a Criticality Accident Alarm System (CAAS), with concurrence of NRC. USACE will evaluate the use of a CAAS during remedial design planning.

USACE and our contractors will perform hazards assessments and continue to monitor all hazards to workers and the environment prior to performing any tasks, as well as monitoring during work activities.  Hazards will be continuously monitored for changes in conditions. Careful and thorough procedures are created on a task-by-task basis and for overall site operations. A hierarchy of controls are used to ensure that the controls are appropriate and effective, beginning with administrative controls, then followed by engineering controls, and then lastly personal protective equipment.  Personnel work and general area monitors are used to track conditions and verify that the controls used to minimize hazards are effective and provide evidence of the effectiveness.  All applicable safety procedures will be followed, such as requiring workers to wear personal protective equipment and personal radiation monitors (badges). Air monitoring devices will also be placed around the trenches.

The stability of the mines has been evaluated by professional geologists who determined that the mines will not be compromised by excavation and on-site activities.

Mine water is not contaminated with radiological constituents from the site.  Wastewater generated during the remediation and storm water within the contaminated areas will be collected and will not flow through the underground mines.

Covering the trenches during excavation may be evaluated during development of the work plans to determine the need for and feasibility of this approach. Air monitoring and sampling units will be placed on individual workers, around the trench areas, and around the perimeter of the site to monitor for potential emissions. Airborne emissions may be controlled by wetting the work areas to prevent wind-blown particles. This is the preferred and effective technique used at other USACE clean-up sites.

There will be noise associated with work activities equivalent to what is typically experienced in association with construction activity.  Additionally, residents might expect an increase in road traffic as a result of site work.