In 1999, DOE issued a report stating that, based on experience from a decade of planning and conducting cleanup work at the sites for which it is responsible, complete restoration to levels acceptable for unrestricted use could not be accomplished at many of its sites. According to the report, a variety of hazards would remain at many DOE sites after these sites had been cleaned up in accordance with applicable requirements. These hazards include long-lived radionuclides left in place in soils or contained in on-site disposal cells and residual contaminants in surface water and groundwater. The report cited technical challenges—such as lack of existing technology for completely removing some types of waste—and economic limitations—such as prohibitive costs to employ available technology—as reasons why these hazards would remain. As a result, DOE reported that long-term management would be needed at these sites to ensure that the cleanup remedies—i.e., the actions, systems, or other measures put in place to clean up a site—would protect human health and the environment from these hazards into the future. Several DOE organizations, including the Office of Environmental Management (EM), were responsible for long-term management of post- cleanup sites until the department established LM in 2003. As of the end of fiscal year 2019, LM had assumed responsibility for 100 sites across the United States, including sites in Alaska and Puerto Rico (see fig. 1). Several different entities conducted cleanup of sites before LM assumed responsibility for the sites. These different entities conducted cleanup under a variety of authorities: EM. Established in 1989, DOE’s EM is responsible for the cleanup of legacy waste that resulted from the development and production of nuclear weapons and government-sponsored nuclear energy research dating back to World War II and the Cold War. Such waste includes radioactive waste, spent nuclear fuel and nuclear material, and contaminated soil and water, among other things. EM cleaned up 83 of the 100 sites that are now within LM’s portfolio. Key laws that governed EM’s cleanup of these sites include the Comprehensive Environmental Response, Compensation, and Liability Act of 1980 as amended (CERCLA); the Resource Conservation and Recovery Act of 1976 as amended (RCRA); and Title I of the Uranium Mill Tailings Radiation Control Act of 1978 (UMTRCA). Title I of UMTRCA authorizes a cleanup program for uranium mill tailings sites—which produced uranium for nuclear weapons and other defense purposes— that were no longer operational as of 1978, the year of the law’s enactment. DOE is generally responsible for financing the cleanup of these sites. EM also cleaned up sites that are now within LM’s portfolio under the Formerly Utilized Sites Remedial Action Program (FUSRAP). This program was established in 1974 to identify, investigate, and clean up sites where radioactive contamination remained from Manhattan Project and early Atomic Energy Commission operations. EM was responsible for cleaning up FUSRAP sites until 1997, when Congress directed the U.S. Army Corps of Engineers (USACE) to assume responsibility for the cleanup work of the remaining designated FUSRAP sites. USACE. USACE cleaned up 10 FUSRAP sites that are now within LM’s portfolio. Under a memorandum of understanding signed by DOE and USACE in 1999, DOE is responsible for the long-term management of FUSRAP sites after USACE completes cleanup. Key requirements that govern USACE’s cleanup of FUSRAP sites include CERCLA and the National Oil and Hazardous Substances Pollution Contingency Plan. Private licensees. LM’s portfolio includes seven sites cleaned up by private licensees, i.e., commercial operators who were permitted to operate uranium mills or other facilities under a license from the Nuclear Regulatory Commission (NRC). In all except one case, private licensees cleaned up these sites under Title II of UMTRCA, which assigned responsibility to the licensee for reclamation of uranium mill sites operating on or after the law’s enactment in 1978. When a private licensee has completed all cleanup requirements, NRC approves transfer of a site to LM for long-term management. Cleanup activities conducted by these entities included decontaminating, decommissioning, and demolishing buildings; containing and disposing of a variety of hazardous and radioactive wastes; excavating and stabilizing contaminated soil; constructing engineered disposal cells for contaminated materials; containing and treating contaminated surface water and groundwater; and preparing the land for future public, industrial, or commercial use. Depending on the legal and regulatory framework governing cleanup, other agencies or groups may have played a role in setting cleanup standards and helping to select a site’s cleanup remedy. For example, sites cleaned up under Title I of UMTRCA must meet regulatory cleanup standards established by the Environmental Protection Agency (EPA). For certain sites cleaned up under CERCLA and RCRA, DOE has entered into agreements with EPA and the relevant state regulator regarding the necessary cleanup actions, and EPA and the state have provided input in selecting the cleanup remedy. As cleanup of a site nears completion, LM works with the entity responsible for cleanup to prepare the site for transition into LM’s portfolio. The transition process for a given site may take up to 5 years, during which time LM and the cleanup entity develop a long-term surveillance and maintenance plan. Depending on the authority under which a site has undergone cleanup, this plan may require approval by regulators such as EPA or NRC. Other transition responsibilities include identifying and preserving records and checking that administrative institutional controls and other real property instruments are in place. DOE considers site cleanup to be complete when, among other things, short-term cleanup activities have been completed and long-term cleanup measures, such as groundwater treatment, are in place. According to a DOE document, ongoing groundwater remediation continues at many sites after the official completion of cleanup because of the long timeframes required to capture and remediate contaminated groundwater. Once LM acquires a site, it places each site into one of three categories based on the actual or anticipated long-term surveillance and maintenance activities associated with the site. LM has nine “category 3” sites, which require the most intensive surveillance and maintenance due to the extent of residual contamination, according to LM officials. These sites typically have an ongoing remediation system—such as a groundwater treatment system, according to officials—that LM must monitor and maintain. LM has 49 “category 2” sites, which require routine inspection, monitoring, and maintenance. LM has 42 “category 1” sites, which require management of records or stakeholder requests for information. LM also maintains a list of 52 sites that, as of September 2019, are expected to transition into its portfolio over the next three decades. Figure 2 illustrates sites’ transition from cleanup entities and their categorization. Appendix II provides additional details about the current sites in LM’s portfolio as of fiscal year 2019, and appendix III provides details about sites that, as of September 2019, are scheduled to transition to LM by 2050. According to LM officials, LM does not have a schedule or process for retiring sites from its portfolio. Depending on the sites’ clean- up standards and intended reuse, LM will likely be managing some sites for centuries. LM’s budget includes funding for other activities that are not directly associated with its 100 sites. These activities include conducting an inventory of abandoned defense-related uranium mines, overseeing pensions and post-retirement benefits for former contractor workers at closed DOE sites, and leading and coordinating DOE’s environmental justice activities. As of fiscal year 2019, LM’s overall budget was about $159 million. Federal accounting standards require agencies that are responsible for cleaning up contamination to estimate future cleanup and waste disposal costs and to report such costs in their annual financial statements as environmental liabilities. According to these standards, environmental liability estimates are to include probable and reasonably estimable costs of cleanup work. Environmental liability estimates do not include cost estimates for work for which reasonable estimates cannot currently be generated, such as cleanup costs at sites where no feasible remedy exists, according to the standards. In fiscal year 2019, DOE reported $505 billion in environmental cleanup and disposal liabilities, of which about $64 billion are categorized by DOE as “other legacy environment” costs. LM’s environmental liability is part of this category, along with several other types of environmental liability costs. LM estimated its environmental liability in fiscal year 2019 at $7.35 billion, an amount that has been relatively stable over the last 5 years. However, LM expects its environmental liability to increase as it acquires additional sites, according to LM officials. According to LM financial data, LM’s environmental liability estimate in fiscal year 2019 was $7.35 billion. LM’s guidance defines its environmental liability as an estimate of life-cycle costs associated with five main activities—determined by DOE—occurring over 75 years (see fig. 3). LM develops guidance on how its site managers should estimate their sites’ environmental liability. In accordance with this guidance, site managers are to develop estimates of the direct costs over the upcoming 75-year period. They are also to determine a certain amount of contingency to account for potential changes in LM’s project scope because of unknown and unpredictable events over the upcoming 75- year period. As shown in figure 4, LM activities related to long-term surveillance and maintenance of its sites accounted for about $3 billion—or 40 percent—of its fiscal year 2019 environmental liability. LM activities related to program direction and to archives and information management each accounted for about 23 percent and 22 percent, respectively, of LM’s fiscal year 2019 environmental liability, and activities related to asset management and to communication, education, and outreach combined for about 15 percent. Of LM’s approximately $3 billion in costs for long-term surveillance and maintenance, LM’s category 3 sites—the nine sites that require the most intensive level of management—accounted for almost half of these estimated costs (see fig. 5). The Rocky Flats site in Colorado accounted for the largest share of this portion of the liability (about $452 million), and the Fernald Preserve site in Ohio accounted for the second-largest share (about $308 million). Long-term surveillance and maintenance responsibilities for category 1 and category 2 sites, transition costs associated with sites that LM will acquire in future years, and other program-wide activities—such as exploring new technologies and operating a laboratory—accounted for the remaining share (about $1.5 billion) of LM’s environmental liability related to long-term surveillance and maintenance. LM’s total environmental liability has generally remained stable in recent years, although there have been some notable fluctuations at individual sites. In fiscal years 2015 through 2018, LM’s total environmental liability remained between $6 billion and $7 billion per year, and increased to slightly over $7 billion in fiscal year 2019 (see fig. 6). Most notably, LM’s total environmental liability increased by about $2 billion (about 41 percent) between fiscal years 2014 and 2015. LM officials attributed this increase to adopting a more thorough approach for estimating future costs associated with sites scheduled to be transferred from USACE under FUSRAP. LM officials said that, before fiscal year 2015, LM had used a standard cost estimate for all of USACE’s sites, which resulted in an underestimate of the associated liability. According to LM officials, in fiscal year 2015 LM began estimating costs based on individual sites’ specific conditions, which allowed LM to capture more potential costs. Similar to LM’s overall environmental liability, the long-term surveillance and maintenance portion of LM’s environmental liability has generally remained stable in recent years, though individual sites have seen some notable changes. From fiscal year 2015 through 2018, LM’s environmental liability related to long-term surveillance and maintenance remained between about $3 billion and $3.5 billion. Similar to LM’s overall environmental liability, the long-term surveillance and maintenance portion of LM’s liability saw a more significant increase between fiscal years 2014 and 2015, from about $2.2 billion to about $3.4 billion. At the site level, of LM’s nine category 3 sites, the Fernald Preserve and Mound sites in Ohio are examples of sites that have had mostly steady decreases from fiscal year 2014 to 2019, which LM officials attributed in part to adjustments to groundwater treatment strategies at Fernald Preserve as well as transferring ownership of most of the Mound site to another party. In contrast, several other sites (including Rocky Flats and Grand Junction in Colorado and Weldon Spring in Missouri) saw overall decreases from fiscal year 2014 to 2016 followed by steady increases from fiscal year 2016 to 2019, which LM officials generally attributed to costs of site maintenance at Rocky Flats, construction at Weldon Spring, and planning activities for the potential closure of the disposal cell at Grand Junction. LM officials provided additional details on specific factors driving sites’ changes in environmental liability. For example: At the Fernald Preserve site, the long-term surveillance and maintenance liability has decreased overall from about $367 million in fiscal year 2014 to about $308 million in fiscal year 2019 (about a 16 percent decrease). The site manager for Fernald attributed this decrease to improvements in the site’s groundwater treatment strategy. In 2014, LM made changes to optimize the site’s “pump-and- treat” system (which brings contaminated water above ground so that it can be treated and contaminants removed) by increasing pumping from the wells in the portion of the site with the most contamination, according to the site manager. Further, the site manager said that this change increased the amount of water coming from the more contaminated areas, making the water treatment more efficient and cost-effective in the long-term. At the Mound site, the long-term surveillance and maintenance liability has decreased from about $124 million in fiscal year 2014 to about $68 million in fiscal year 2019 (about a 45 percent decrease). According to LM officials, this decrease is in part due to a transfer in ownership. Specifically, LM transferred ownership of the majority of the site to the Mound Development Corporation to sell or lease parcels of the land to third parties for commercial use. Transferring ownership meant that LM gave up some of its responsibilities and their associated costs (such as maintenance and repairs at buildings that are now privately owned), although it continues to fulfill ongoing groundwater treatment and records management responsibilities. At the Rocky Flats site, the long-term surveillance and maintenance liability has increased substantially since fiscal year 2016, from about $269 million to about $452 million in fiscal year 2019 (about a 68 percent increase). According to the site manager for Rocky Flats, this increase can be attributed to additional costs needed to repair aging infrastructure. Specifically, a landfill on the site, which was constructed in the 1950s, has been damaged by erosion in recent years, and LM is currently undertaking a large-scale project to repair and stabilize it after previous repairs failed to provide a long-term fix. This project, which is due to be completed in the summer of 2020, includes installing about 260 steel anchors of up to 95 feet in length into the soil around the landfill. These anchors are intended to keep the soil intact while drains route groundwater away from the areas of the landfill that are particularly vulnerable to erosion. LM’s environmental liability is likely to grow as it acquires more sites in future years, even as LM takes steps to reduce the environmental liability associated with its current sites, according to LM officials. According to an LM document, as of September 2019, LM is scheduled to acquire 52 additional sites by 2050, including six category 3 sites, 45 category 2 sites, and one category 1 site. Since LM does not account for the environmental liability related to long-term surveillance and maintenance for a portion of its sites until it acquires them, LM officials could not tell us by how much its total environmental liability will increase as a result of acquiring these sites. However, officials said that some sites transitioning to LM in the future will be increasingly complex, which will likely mean increased long-term surveillance and maintenance costs. In particular, one official told us that the FUSRAP sites LM is set to acquire from USACE will be larger and have more extensive residual contamination than FUSRAP sites that LM had previously acquired. As a result, these sites will likely require LM to undertake more extensive and costly long-term surveillance and maintenance activities, according to this official. At the same time, LM officials said they are taking steps to help reduce the environmental liability at LM’s current sites, such as exploring ways to improve the cost-effectiveness of managing residual groundwater contamination. For example: At the Shiprock site in New Mexico, LM has initiated an environmental assessment to evaluate the impacts of removing an evaporation pond into which contaminated groundwater is being pumped, according to the site manager. The site manager also told us that removing this pond could mean reducing the scope of the site’s water pumping activities and ultimately adopting a different groundwater treatment strategy that could prove to be more efficient. Further, the site manager said that this removal would result in reduced long-term surveillance and maintenance costs associated with ongoing repairs to the pond. At the Tuba City site in Arizona, LM is conducting an environmental assessment to weigh options for a new groundwater treatment strategy. According to the site manager, the current strategy, which involves injecting clean water into the site’s contaminated aquifer to flush out contamination, does not cost-effectively address the root cause of the groundwater contamination. Among other options, LM may use its assessment to seek alternate concentration limits accompanied by restrictions to grazing and water use, which LM officials said could be a cost-effective way to manage residual contamination. LM officials we interviewed identified a number of challenges that LM faces in providing long-term surveillance and maintenance of sites. In particular, officials identified challenges related to three main areas: (1) the performance of remedies on its sites, (2) environmental conditions, and (3) new requirements and regulations. LM is taking some actions to address the challenges that officials identified. However, it has not planned for how to address challenges with remedies at some sites that may require additional cleanup work outside the scope of its expertise and resources, and it has not developed plans to assess and mitigate challenging environmental conditions that may become more frequent or intense because of climate change. According to LM officials, LM faces challenges with cleanup remedies not performing as predicted or intended at some sites. For example: At the L-Bar site in New Mexico, officials told us that the disposal cell, which was constructed by a private licensee under UMTRCA Title II and holds about 2.1 million tons of radioactive mill tailings, began experiencing erosion problems shortly after NRC transferred the site to LM in 2004. This erosion is threatening to undermine the disposal cell, according to LM officials (see fig. 7). At the Monticello site in Utah, monitored natural attenuation—the groundwater treatment remedy originally agreed to by DOE, EPA, and the Utah state regulator—proved ineffective in meeting cleanup goals within a few years of being implemented and of the site being transferred to LM. As a result, in 2015, LM implemented a pump-and- treat approach that reduced contamination; however, officials told us that the efficacy of this approach has declined over time, and LM is again seeking to change the remedy. To address challenges related to the performance of remedies, LM is currently undertaking a risk analysis effort to rank sites according to several types of risks, including the risk that a site will not attain compliance with cleanup goals or that compliance will not be maintained into the future. According to LM officials, LM plans to use the results of the risk analysis to inform decisions about where to focus resources, to identify systemic technical challenges, and to identify possible opportunities for reducing LM’s environmental liability, such as through technology development. LM is also addressing challenges related to remedy performance by updating some sites’ remedies. For example, LM has implemented an erosion monitoring program for the L-Bar site and, at the Monticello site, is collecting data that could allow it to seek regulatory approval for a new groundwater compliance strategy, according to LM officials. LM officials said that, in general, they consider such updates to be routine and to fall within LM’s mission to provide long-term surveillance and maintenance of these sites. Nonetheless, LM officials told us that as LM acquires additional sites and as remedies age, future challenges related to remedy performance could result in the need for more extensive work, including active cleanup work that is outside the scope of LM’s mission, capabilities, and resources. We found that LM has developed agreements and procedures for addressing such challenges at sites cleaned up by USACE, but has not developed such agreements and procedures for sites cleaned up by EM or by private licensees under Title II of UMTRCA. Specifically, regarding sites cleaned up by USACE under FUSRAP, under the 1999 memorandum of understanding between DOE and USACE, USACE is responsible for carrying out additional cleanup actions when it determines such actions are necessary. In addition, LM guidance related to transition and transfer of FUSRAP sites includes examples of situations in which LM would return a site to USACE for additional cleanup, such as situations in which routine monitoring identifies new areas of contamination. Conversely, for sites where EM was responsible for active cleanup, a 2005 memorandum co-signed by the leadership of LM and EM includes a brief statement about the need for LM and EM to coordinate in instances of “significant remedy failures.” LM officials told us that structural or engineering damage could signify evidence of a “significant remedy failure,” but said that such criteria have not been documented. They also said that LM has not defined a process by which such failures would be addressed. Finally, LM officials said that there is no mechanism in place under UMTRCA for LM to return a site to NRC or to seek recovery of costs from a private licensee for any additional cleanup that needs to be done. According to agency officials, LM has not developed agreements or procedures for addressing challenges that require active cleanup work at sites cleaned up by EM because LM has not yet encountered such instances at any of its sites. They also noted that LM has been more focused on long-term surveillance and maintenance and the process of transitioning sites into its portfolio from EM and private licensees, rather than a process for moving sites back to these entities if a cleanup remedy fails. However, under federal internal control standards, management is to design control activities to achieve objectives and respond to risks, such as by clearly documenting internal control in management directives, administrative policies, or operating manuals. By working with EM and NRC to develop agreements and procedures for identifying and addressing circumstances at LM sites that require new cleanup work beyond the scope of LM’s mission, capabilities, and resources, LM can help ensure mitigation by the most appropriate entity of the risks to human health and the environment that such instances would present. LM faces challenges with environmental conditions at the sites—some of which may become more frequent or intense—and, according to its mission, LM must react to these challenges to ensure the sites remain protective of human health and the environment. For example: At the Rocky Flats site in Colorado, officials told us that extreme rainfall events over the past few years have caused soils covering an on-site landfill to “slump,” or slip downhill. In particular, rainfall during 2015—the site’s wettest year on record, according to LM officials— caused a 20-foot slump in the landfill. The Boiling Nuclear Superheater site in Puerto Rico and the Pinellas County site in Florida were both in the path of Hurricane Irma in 2017, though neither site sustained substantial damage. At the Weldon Spring site in Missouri, the site manager said that tornadoes pose a risk to the site’s infrastructure, and that a strong tornado in 2013 damaged the site’s interpretive center. To address challenges related to environmental conditions, LM has been repairing damages caused by extreme weather events. For example, at the Rocky Flats site, LM is undertaking a major project to repair and stabilize its aging landfill, as discussed earlier. At the Weldon Spring site, LM installed a tornado shelter in 2014 and is currently building a new interpretive center. In addition, according to the 2020 LM Site Sustainability Plan, LM has taken a number of steps to implement emergency and security measures, such as completing emergency drills and tabletop exercises. The U.S. Global Change Research Program—which coordinates and integrates the activities of 13 federal agencies that research changes in the global environment and their implications for society—reported in its November 2018 Fourth National Climate Assessment that climate change is playing a role in the increasing frequency of some types of extreme weather, such as extremely heavy rainfall and hurricanes; these are environmental conditions that have presented challenges at LM sites. The assessment reported that climate models are consistent with temperature and precipitation extremes becoming more frequent, more intense, or longer in duration, which may make certain natural disasters more frequent or more intense. As a result of the significant risks posed by climate change and the nation’s fiscal condition, in February 2013, we added Limiting the Federal Government’s Fiscal Exposure by Better Managing Climate Change Risks to our list of areas at high risk for fraud, waste, abuse, and mismanagement, or most in need of transformation. In our March 2019 update to this high-risk area, we reported that the federal government needs to improve the resilience of facilities it owns and operates, and land it manages, against the effects of climate change. In addition, in October 2019, we found that EPA needs to improve management of risks from climate change at Superfund sites where remedies may need to be operational indefinitely (see sidebar). We Found That EPA Should Take Additional Actions to Manage Risks from Climate Change Superfund is the federal government’s principal program to address sites with hazardous substances. It was established by the Comprehensive Environmental Response, Compensation, and Liability Act of 1980 and is administered by the Environmental Protection Agency (EPA). EPA lists some of the most seriously contaminated sites on the National Priorities List (NPL) and has recorded over 500 contaminants at those sites. Some NPL sites are located at federal facilities, where departments such as the Department of Energy are responsible for cleanup. However, most NPL sites are nonfederal, where EPA generally carries out or oversees the cleanup conducted by one or more potentially responsible parties. In October 2019, we reported that available federal data on flooding, storm surge, wildfires, and sea level rise suggest that about 60 percent of all nonfederal NPL sites are located in areas that may be impacted by these potential climate change effects. According to EPA officials, remedies at nonfederal NPL sites may have to be operational indefinitely, during which time the potential effects of climate change may become more extreme. We found that EPA has taken some actions to manage risks from the potential impacts of climate change effects at nonfederal NPL sites, but that its actions did not fully align with essential elements of enterprise risk management. For example, we found that EPA officials do not always have direction to ensure that they consistently integrate climate change information into site-level risk assessments and risk response decisions, according to EPA officials. Without providing such direction, EPA cannot ensure that remedies at nonfederal NPL sites will protect human health and the environment in the long-term. We made four recommendations to EPA, including that it provide direction on how to integrate information on the potential impacts of climate change effects into risk assessments and risk response decisions at nonfederal NPL sites. EPA agreed with one recommendation and disagreed with the other three. We continue to believe that all four are warranted. LM’s 2016-2025 Strategic Plan acknowledges the challenges posed by climate change. To support the objective of improving the long-term sustainability of environmental remedies, the plan includes a strategy to “assess the effect of climate change on environmental remedies and develop plans to mitigate significant impacts.” However, LM provided minimal information about ongoing or planned efforts to carry out this strategy. Specifically, the 2020 LM Site Sustainability Plan, which officials said provides information about LM’s future plans to adapt to changing climate conditions, includes the term “climate change” one time, in reference to sustainable buildings—not to remedies. The plan describes one pilot project conducted at the Monticello site to evaluate the site’s main climate stressors and capacity to adapt to those stressors, but it does not describe whether or how LM intends to use the results of the pilot project, such as any specific plans to roll out the project to other sites. Aside from the 2020 LM Site Sustainability Plan, LM officials said they have a goal to review sites’ conceptual models, which predict how remedies should perform under different conditions, with the aim of updating the assumptions in the models to better account for real-world conditions. However, LM did not provide details about how it intends to meet this goal, such as a schedule for implementing this review across its sites. According to LM officials, LM has not developed a plan or schedule for reviewing sites’ conceptual models because of competing priorities. In addition, LM officials told us they have not assessed the effects of climate change or developed plans to mitigate those effects because of a lack of concern about the risks posed by climate change. Specifically, site managers in charge of several of LM’s category 3 sites—including Rocky Flats, which has the highest environmental liability of LM’s 100 sites and is currently implementing the large-scale project described above to address erosion caused by extreme precipitation—told us that they have not assessed the potential effects of climate change on their sites because they do not believe climate change is a concern. Recognizing the federal government’s significant role in managing climate-related disaster impacts, GAO’s Disaster Resilience Framework provides three broad principles that those who oversee or manage federal efforts can consider when analyzing opportunities to enhance their contribution to national disaster resilience. For instance, under the information principle, the framework states that accessing authoritative, understandable information can help decision makers to identify current and future risk and the impact of risk-reduction strategies. In addition, the integration principle states that integrated analysis and planning can help decision makers take coherent and coordinated resilience actions. By developing plans to assess the effect of climate change on LM’s sites and to mitigate any significant impacts and, as part of these plans, incorporating principles from GAO’s Disaster Resilience Framework, as appropriate, LM could better ensure that its remedies will protect human health and the environment in the long term. According to LM officials, LM faces challenges when regulators update or adopt new requirements and regulations for contaminants, meaning that remedies in place when LM received a site may no longer meet standards. For example: At several sites, such as the Fernald Preserve and Mound sites in Ohio and the Rocky Flats site in Colorado, LM officials told us they are investigating for per- and polyfluoroalkyl substances (PFAS) or vapor-forming chemicals, which are emerging contaminants that EM was not required to address when cleaning up these sites. EPA has published information regarding potential impacts to human health and the environment from these and other emerging contaminants. Federal regulatory standards issued by EPA in the future could affect LM sites. At the Bluewater site in New Mexico, LM officials said that the state recently adopted an updated, more stringent uranium drinking water standard. Under the new standard, the area of groundwater that is considered contaminated is much larger than the area of groundwater considered contaminated under the standard in place when NRC approved transfer of the site to LM, according to officials. To address challenges related to new requirements and regulations, LM is monitoring changes to federal and state standards. For example, LM participates in interagency working groups, such as a PFAS working group led by DOE’s Office of Environment, Health, Safety, and Security. Participation in the working groups helps LM monitor the evolution of a federal PFAS regulatory standard, according to LM officials. In addition, LM officials told us that they routinely review state and federal regulatory changes, with the aim of providing sites time to prepare for any changes. LM also evaluates its surveillance and maintenance practices against current regulatory and best management requirements to identify any gaps. For instance, in 2018, the contractor that provides support services to LM reviewed site management practices listed in UMTRCA Title I and II sites’ site management plans against current regulatory requirements. The review identified a number of discrepancies between practices and requirements. For example, the review found that some site management plans were developed many years ago and had not been updated to reflect changes in remedy requirements. LM indicated it planned to take steps to address the discrepancies identified by this review. For example, LM is planning to update its site management plans to include the most current remedy requirements for each site. At many sites contaminated from nuclear weapons production and nuclear energy research dating back to World War II and the Cold War, completely eliminating risks to human health and the environment is unlikely. LM is responsible for protecting human health and the environment from the risks that remain after other entities have cleaned up these sites, and its mission is long-term—LM sites will require surveillance and maintenance for hundreds or even thousands of years. Over this period, the likelihood that cleanup remedies will experience performance challenges is high, and these challenges may exceed the scope of LM’s mission, capabilities, and resources. LM acquires sites from several cleanup entities, but has not developed agreements or procedures with EM or NRC for addressing challenges that require new, active cleanup work. By working with EM and NRC to develop agreements and procedures for identifying and addressing circumstances at LM sites that require new cleanup work beyond the scope of LM’s mission, capabilities, and resources, LM can help ensure mitigation by the most appropriate entity of the risks to human health and the environment that such instances would present. Environmental conditions also present challenges to LM’s sites, and some of these conditions may become more frequent or intense in the future, according to the 13-agency U.S. Global Change Research Program. To ensure the long-term protectiveness of remedies, it is important for LM to understand how climate change may affect its sites. LM’s strategic plan includes a strategy to assess the effects of climate change on its sites, but the agency provided minimal information about how it plans to carry out this strategy. GAO’s Disaster Resilience Framework outlines a set of principles that those who oversee or manage federal efforts can consider when analyzing opportunities to enhance their contribution to national disaster resilience. By developing plans to assess the effect of climate change on LM’s sites and to mitigate any significant impacts, and, as part of these plans, incorporating principles from GAO’s Disaster Resilience Framework, as appropriate, LM could better ensure that its remedies will protect human health and the environment in the long term. We are making three recommendations to DOE: The Secretary of Energy should direct the Director of LM and the Assistant Secretary of the Office of Environmental Management to develop agreements and procedures for identifying and addressing circumstances at LM sites that require new cleanup work beyond the scope of LM’s mission, capabilities, and resources. (Recommendation 1) The Secretary of Energy should direct the Director of LM to work with the Nuclear Regulatory Commission to develop agreements and procedures for identifying and addressing circumstances at LM sites that require new cleanup work beyond the scope of LM’s mission, capabilities, and resources. (Recommendation 2) The Secretary of Energy should direct the Director of LM to, as called for in LM’s strategic plan, develop plans to assess the effect of climate change on LM’s sites and to mitigate any significant impacts. These plans should incorporate principles from GAO’s Disaster Resilience Framework, as appropriate. (Recommendation 3) We provided a draft of this report to DOE for comment. In its comments, reproduced in appendix IV, DOE agreed with our three recommendations. In its letter, DOE officials stated that in response to our first two recommendations, it plans to work with DOE’s Office of Environmental Management and the Nuclear Regulatory Commission to develop agreements and procedures for identifying and addressing new cleanup work beyond LM’s mission scope of long-term stewardship. DOE officials also stated that in response to our third recommendation, LM will develop site assessment and mitigation plans, taking into account any significant effects of climate change and incorporating principles from GAO’s Disaster Resilience Framework, as appropriate. DOE also provided technical comments, which we incorporated as appropriate. We are sending copies of this report to the appropriate congressional committee, the Secretary of Energy, and other interested parties. In addition, the report is available at no charge on the GAO website at https://www.gao.gov. If you or your staff have any questions about this report, please contact me at (202) 512-3841 or trimbled@gao.gov. Contact points for our Offices of Congressional Relations and Public Affairs may be found on the last page of this report. GAO staff who made key contributions to this report are listed in appendix V. Rocky Flats site (Colorado) Shiprock Disposal site (New Mexico) Tuba City Disposal site (Arizona) Weldon Spring site (Missouri) DOE considers site cleanup to be complete when, among other things, short-term cleanup activities have been completed and long-term cleanup measures, such and groundwater treatment, are in place. DOE Office of Environmental Management (EM) Planned transfer in FY 2022 Durita Disposal site East Tennessee Technology Park site Gas Hills East Disposal site Gas Hills North Disposal site Ray Point Disposal site Split Rock Disposal site Planned transfer in FY 2023 Bear Creek Disposal site Hazelwood site private licensee U.S. Army Corps of Engineers (USACE) David C. Trimble, (202) 512-3841 or trimbled@gao.gov. In addition to the contact named above, Amanda K. Kolling (Assistant Director), Katherine Killebrew (Analyst in Charge), and Rachel Pittenger made key contributions to this report. Also contributing to this report were Mark Braza, Ellen Fried, Susan J. Irving, Richard Johnson, Keegan Maguigan, Katrina Pekar-Carpenter, Dan Royer, and Doris Yanger.

Summary: After over 70 years of nuclear weapons production and energy research at hundreds of sites across the country, DOE faces over $500 billion in environmental liabilities associated with cleanup of hazardous contamination and long-term management of these sites. LM is responsible for the portion of these liabilities associated with long-term management of sites after active cleanup has been completed. LM oversees 100 sites across the country. Depending on the sites' clean-up standards and intended reuse, LM will likely be managing some sites for centuries. Senate Report 116-48 accompanying the National Defense Authorization Act for fiscal year 2020 includes a provision for GAO to review LM's operations, including the nature of its environmental liability. This report examines (1) LM's environmental liability, and (2) any challenges LM faces in managing its sites and how it is addressing those challenges. GAO analyzed data on LM's environmental liability; interviewed officials at LM headquarters and those responsible for the nine sites requiring the most intensive level of management; and reviewed relevant policies, procedures, and guidance. The environmental liability of the Department of Energy's (DOE) Office of Legacy Management (LM) was estimated at $7.35 billion in fiscal year 2019 and, according to LM officials, is expected to grow as LM acquires more sites (see figure for LM's current sites). Long-term surveillance and maintenance activities associated with radioactive and hazardous waste, such as treating residual groundwater contamination, account for about 40 percent of the costs. LM's environmental liability has generally remained stable over the past 5 years. As of September 2019, LM is scheduled to receive 52 additional sites by 2050, and officials expect LM's environmental liability to grow as a result. Officials said LM is taking steps to reduce its environmental liability at its current sites, such as exploring alternative approaches for reducing residual contamination. LM officials identified challenges in providing long-term surveillance and maintenance of sites related to: (1) the performance of remedies that contain or reduce contamination, (2) environmental conditions, and (3) new regulatory requirements. LM is taking some actions to address these challenges. For example, at its Rocky Flats, Colorado, site, LM is repairing an aging landfill that was damaged by extreme rainfall events. However, LM has not yet planned for how to address challenges at some sites that may require new cleanup work that is not in the scope of LM's expertise and resources. By developing agreements and procedures with the entities that would be responsible for conducting this new cleanup work, LM can help mitigate risks to human health and the environment. In addition, LM has not made plans to assess the effects of climate change on its sites or to mitigate those effects, as called for in its strategic plan. By developing plans to assess the effect of climate change on its sites and to mitigate any significant impacts, LM could better ensure that its remedies will protect human health and the environment in the long term. GAO is making three recommendations, including that DOE develop agreements and procedures for circumstances that require new cleanup work and that it develop plans to assess and to mitigate the effects of climate change on its sites. DOE agreed with all three recommendations.