Introduction Congress passed the Uranium Mill Tailings Radiation Control Act of 1978 (UMTRCA, P.L. 95-604 ) in the wake of environmental and public health concerns about exposures to radiological and non-radiological waste material originating from Cold Warâera uranium mill tailing sites. Title I of UMTRCA authorized a remedial action program for uranium mill tailing sites that were inactive prior to the law's enactment in 1978. Under Title I of UMTRCA, the federal government was mostly responsible for financing the remediation and decommissioning of Title I sites, most of which produced uranium for nuclear weapons and other defense purposes. Title II of UMTRCA authorized federal agencies to regulate uranium mill tailings produced at commercially licensed facilities still operating on or after 1978. For Title II sites, Congress intended that commercial uranium mill operators, not the federal government, pay for site decommissioning and tailings stabilization activities. The federal government assumes responsibility for both Title I and Title II uranium mill sites transferred to long-term federal management after site decommissioning has been completed. As of FY2019, the Department of Energy Office of Legacy Management (DOE-LM) administers long-term federal management at 31 Title I sites and six Title II sites. DOE-LM manages surface tailings and groundwater monitoring programs at sites under long-term federal management in an effort to minimize any unintended release of potentially radiological or non-radiological material. Long-term monitoring and maintenance activities may include stabilization of the engineered repository of uranium mill tailings and groundwater remediation or monitoring, if necessary. As of FY2019, 23 Title II sites remain owned by commercial operators, who are permitted to operate under the Nuclear Regulatory Commission (NRC) or an NRC agreement state license. When the Title II site operator has completed all site decommissioning requirements, the license is to be transferred to DOE for long-term federal management. This report presents the historical context for the law, the status of implementation since enactment, and selected issues for Congress. UMTRCA does not authorize the regulation of uranium miningâthe process of physically removing uranium ore from the earthâor the disposal of waste material produced by uranium mining. The regulation of uranium mining and the remediation of abandoned uranium mines are not discussed in this report. Uranium Mill Tailings Uranium milling is the process of converting mined uranium ore to uranium concentrate, also known as yellowcake uranium. Milling is common to a number of mineral extraction industries and refers to the physical and chemical processes necessary to concentrate minerals from mined ore. Uranium milling operations use a series of physical (crushing and grinding the mined ore) and chemical processes (acid or alkaline solutions, ion exchange) to concentrate the mineralized uranium ore into yellowcake uranium. Heap leaching, a specific type of uranium milling operation, involves sprinkling sulfuric acid or another solvent directly over the ore in large earthen collection pits. The acidic stream trickles through the ore and dissolves uranium and that stream is collected and processed. Yellowcake uranium produced from the milling process is subsequently converted and enriched for civilian nuclear power production ( Figure 1 ). Tailings are the waste material produced from milling operations. The milling process produces tailings initially as a slurry material, which is disposed of in a settling pond. The slurry tailings material dries, resulting in a sand-like material. Milling operations produce a large quantity of tailings relative to the amount of uranium concentrate produced. NRC estimated that 2.4 pounds of yellowcake uranium oxide is produced from 2,000 pounds of uranium ore. Public health and environmental concerns from uranium milling has been associated with various aspects of historical operations and tailings disposal. The U.S. Environmental Protection Agency (EPA) has identified four health exposure routes from uranium mill tailings: 1. Increased risk of lung cancer from the diffusion of radon gas indoors if tailings material is used for construction material, 2. Inhalation of radon gas or ingestion of small particles directly emitted from the mill piles into the atmosphere, 3. Exposure to gamma radiation produced by radioactive decay products within the tailings, and 4. Wind and water erosion and mobilization of radioactive and other constituents into surface and groundwater. Physical and geochemical mechanisms can liberate trace metals and radionuclides within the tailings into groundwater or surface water. The hazards associated with the release of various radiological and non-radiological constituents from uranium tailings may persist for hundreds or thousands of years. Brief History of Uranium Milling in the United States During the 1950s and 1960s, the U.S. Atomic Energy Commission, a predecessor federal agency to DOE and NRC, procured uranium concentrate by funding domestic uranium ore mining exploration and development, entering into private purchasing contracts with domestic milling companies, and purchasing foreign produced uranium concentrate. The majority of domestic uranium concentrate production prior to 1971 primarily supported the development of nuclear weapons and naval reactors. From 1947 to 1971, annual domestic uranium concentrate production ranged from 20 million pounds to 35 million pounds ( Figure 2 ). After 1971, uranium mill operators produced uranium concentrate primarily for the production of civilian nuclear power. The 1970s were a period of growth for the U.S. nuclear power industry, as 59 nuclear reactors were first connected to the electricity grid between 1970 and 1979. NRC estimated in 1978 that over 109 uranium mills would be required by the year 2000 to support the fuel requirements of the growing reactor fleet. However, domestic uranium concentrate production in the United States decreased by roughly 92% from 1978 to 1993 ( Figure 2 ). By 2000, one active U.S. uranium mill, two partially active U.S. uranium mills, and three in-situ recovery (ISR) facilities combined to produce 4 million pounds of uranium concentrate. Continued growth by the domestic civilian nuclear power industry did not materialize as anticipated in 1978. Numerous factors led to decrease of domestic uranium production. In particular, U.S. nuclear power growth was far less than envisioned by Congress and federal agencies in 1978, as U.S. nuclear plant orders virtually halted after that year and dozens of previous orders were canceled. While the number of operational uranium mills was less than originally envisioned, potential risks from the uranium mills that did operate continue to present technical and regulatory challenges. The awareness of the technical and economic challenges posed during the decommissioning and long-term management of uranium mill tailings have increased since 1978. As of the second quarter of 2018, the U.S. uranium concentrate facilities consisted of one uranium mill and six ISR facilities in operation. Uranium Mill Tailings Radiation Control Act of 1978 The Uranium Mill Tailings Radiation Control Act of 1978 (UMTRCA; P.L. 95-604 ) includes three titles: Title I authorized the remediation of uranium mill tailings inactive prior to the law's enactment in 1978. Title II authorized the regulation of commercial uranium mills operating on or after 1978. Title III directed the NRC to consult with the state of New Mexico to study and designate two mill tailings sites in New Mexico. By 1998, DOE completed site decommissioning for all Title I sites, with the exception of the site located at Moab, UT. Legislation to authorize cleanup at Moab was enacted subsequent to UMTRCA. Title I provisions do not authorize remedial actions for sites in operation on or after 1978, which are addressed under Title II. Provisions under Title III have been resolved. Title IâRemedial Action Program for Inactive Uranium Mill Sites Title I was enacted to address the environmental and public health risks associated with residual radioactive material produced at "inactive" uranium mill sites generated in support of the federal uranium procurement program during the mid-1940s through the 1970s. The majority of the uranium concentrate produced during this time period was for the development of nuclear weapons, nuclear fuel production, and other Atomic Energy Commission programs. After the federal procurement contracts ended in the early 1970s, operations at some uranium mills ceased and licenses were terminated with few environmental remediation requirements. Prior to 1978, federal agencies lacked legal authority to regulate uranium mill tailings. In 1966, federal agencies issued a "Joint Federal Agency Position Regarding Control of Uranium Mill Tailings" urging planning management and stabilization of the mill tailings as the responsibility of the individual owners. Yet without a legally binding regulatory program, DOE subsequently noted that actions resulting from the Joint Position were "far from satisfactory." Multiple communities used uranium mill tailings as construction material for civilian building projects. The characteristically "sandy" uranium tailings were attractive to construct roads, sewers, farmlands, foundations in office buildings, schools, homes, and other structures. These sites became known as vicinity properties . In one instance, DOE reported that a uranium mill operator left a front-end loader on site for members of the public to take as much uranium tailings material as they could handle. NRC stated that 270,000 metric tons of uranium tailings at Grand Junction were used for building materials. In 1972, growing concerns about environmental and public health risks from uranium mill tailings used as construction material led to Congress appropriating funds for remedial action of contaminated sites near Grand Junction, CO. Section 201 of the 1972 Atomic Energy Commission Appropriation Authorization (P.L. 92-314) "assumes the compassionate responsibility of the United States to provide to the state of Colorado financial assistance to undertake remedial action to limit the exposure of individuals to radiation emanating from uranium mill tailings which have been used as a construction related material in the area of Grand Junction, Colorado." The legislation addressing issues at Grand Junction served as the template for the remedial action program authorized under Title I of UMTRCA. Definitions, Scope of Remedial Actions, and Site Inventory Section 101 of UMTRCA defines key terms and identifies federal agencies authorized to implement UMTRCA. A processing site is defined as "(A) any site, including the mill, containing residual radioactive materials at which all or substantially all of the uranium was produced for sale to any Federal agency prior to January 1, 1971 under a contract with any Federal agency â¦ and (B) any other real property or improvement thereon which (i) is in the vicinity of such site, and (ii) is determined by the Secretary [of Energy], in consultation with the [NRC], to be contaminated with residual radioactive materials derived from such site." Vicinity properties are off-site properties where uranium mill tailings were used as construction material prior to the law's enactment. A lesser amount of vicinity properties were adjacent sites contaminated by wind-borne dispersion of mill tailings particles. By 1999, DOE reported that it had remediated 5,300 vicinity properties. DOE's authority to perform surface remedial actions at Title I UMTRCA sites, including vicinity properties, expired on September 30, 1998. Residual radioactive material is defined under Section 101 as "waste (which the Secretary determines to be radioactive) in the form of tailings resulting from the processing of ores for the extraction of uranium and other valuable constituents of the ores; and other waste (which the Secretary determines to be radioactive) at a processing site which relate to such processing, including any residual stock of unprocessed ores or low-grade materials." Tailings are defined as "the remaining portion of a metal-bearing ore after some of all of such metal, such as uranium, has been extracted." DOE's remedial action efforts aimed to permanently isolate the residual radioactive material from the environment. Residual radioactive material was enclosed in engineered repositories consisting of multiple layers of relatively non-permeable materials and capped with rip-rap. These layers are intended to prevent the release of radon gas, limit downward infiltration and water seepage through the tailings piles, and minimize the erosion of repository by natural wind and water. The repository is designed to stabilize residual radioactive material for at least 200 years and up to 1,000 years. A disposal site identifies the location where the engineered tailings repository is sited, which is either at the original processing site or an alternative location. D isposal site is not explicitly defined by statute under Title I. However, EPA regulations define disposal site as "the region within the smallest perimeter of residual radioactive material (excluding cover materials) following completion of control." The distinction between a processing site and disposal site has bearing on long-term federal management obligations. Under UMTRCA, DOE is required to consult with the EPA to prioritize which sites pose a potential health hazard. However, DOE is not bound by EPA's site priority evaluation, and nothing in the statute precludes DOE from proceeding with remedial actions on lower priority sites. UMTRCA instructed DOE to consult with NRC to develop site-specific boundaries. Site designations under this section are not subject to judicial review. Section 102 lists 22 processing sites originally designated under the Title I. The number of Title I and Title II sites has expanded, and a full inventory of UMTRCA sites is presented in Table A-1 and Table A-2 . Cooperative Agreements Section 103 authorized DOE to enter into cooperative agreements with states or tribes to perform remedial actions at inactive uranium mill tailing sites. Cooperative agreements between DOE-LM and states are subject to NRC concurrence. Under Section 103, any cooperative agreement between DOE and states are conditional on the site owner releasing DOE of liability associated with any issues occurring during remedial actions. Section 103 authorizes DOE, NRC, and EPA access to any site for inspection and enforcement subject to the establishment of a cooperative agreement. Section 105 authorizes cooperative agreements between DOE and Indian tribes in consultation with the Department of the Interior's Bureau of Land Management (BLM), similar to provisions in Section 103, when processing sites are located on Indian lands. Land Acquisition and Transfer Generally, DOE remediated the inactive uranium mill tailings and constructed a repository at the original processing site location. However, Congress was aware of instances where inactive uranium mill tailings were located on a floodplain or directly adjacent to a stream or river. In those instances, designing, constructing, and maintaining an engineered repository for the uranium mill tailings located next to a stream may have been technically infeasible. UMTRCA authorizes agencies to determine whether an alternative disposal site was necessary to protect human health and the environment. Section 104 authorizes the state, under a cooperative agreement with DOE, to purchase surface and subsurface rights and transport tailings materials to an alternative disposal site. When NRC and DOE determined that an alternative disposal site was necessary, DOE constructed repositories that were separate from the original inactive uranium mill tailings. The management of the original processing site was returned to the state. Section 104 outlines four options for the state to manage the processing site: (1) sell the land, (2) retain the land, (3) donate the land for public or recreational purposes, or (4) transfer the land to the federal government. The state provides appropriate documentation of remedial actions on the processing site to future purchasers. DOE manages Title I disposal sites under a general NRC license. UMTRCA authorized DOE to obtain the surface and subsurface mineral rights for the disposal site. The acquisition of subsurface interests was required conditional to a cooperative agreement. Congress intended to avoid situations where the extraction of underlying minerals by subsurface mineral rights owners could disrupt the stabilized tailings. Under UMTRCA, inactive uranium mill tailings located on federal public lands are transferred to DOE as a public land withdrawal. Section 104(h) authorizes BLM to sell or lease rights to federal lands located within the disposal site boundary. BLM is required to follow all applicable U.S. laws to sell or lease and provide assurances that the stabilized residual radioactive materials will not be disturbed by mineral development activities. Any prospective mineral developer is subject to licensing. If the stabilized site is disturbed, the private operator must perform site remediation at no cost to the federal government. Section 106 authorizes the purchase of land to develop a consolidated disposal site. The section discourages use of any National Park System, National Wildlife Refuge System, and National Forest System lands. If land is acquired in a state where uranium milling has not occurred, the acquisition is subject to state concurrence. Financial Responsibility During the debate leading to the enactment of UMTRCA, Congress recognized that no clear entity was responsible for the cleanup of inactive uranium mill tailings among the federal government, states, and private site operators. In 1978, the U.S. General Accounting Office (now the Government Accountability Office, GAO) proposed that the federal government was most responsible to fund a cleanup program, as the majority of the uranium produced for the generation of uranium mill tailings was purchased at that time under federal supply contracts for the Manhattan Engineering District and other defense programs. In drafting UMTRCA, Congress decided that the federal government should be responsible for most of the remedial action costs at Title I sites and that the states where the Title I sites are located should share a portion of the costs. Section 107 establishes the financial responsibilities for remedial actions for the federal government and the cooperative states. Under Section 107, the federal government is responsible for 90% of the remediation costs, including costs for land acquisition and cleanup of buildings and structures in the vicinity. Under a cooperative agreement, a state commits the remaining 10% share of the remediation costs. The federal government was responsible for all remedial action costs at processing sites located on Indian lands pursuant to a cooperative agreements under Section 105. Development of Remediation Standards Congress authorized EPA to promulgate health and environmental standards for uranium mill tailing sites. Section 108 directed DOE to perform remedial actions in accordance with general health and environmental standards promulgated by the EPA pursuant to Section 275 of the Atomic Energy Act of 1954 (AEA, P.L. 83-703), amended by Section 206 under UMTRCA. EPA finalized standards for Title I sites, under 40 C.F.R. Part 192, Subparts A, B, C, on January 11, 1995. UMTRA Amendments of 1988 DOE identified groundwater contamination at UMTRCA sites during implementation. Groundwater contamination remains an ongoing issue at several sites. In the late 1980s, DOE expressed concern that groundwater contamination issues could not be resolved in a specified period of time. Congress enacted the Uranium Mill Tailings Remedial Action Amendments Act of 1988 (UMTRA, P.L. 100-616 ), which amended Section 112 of UMTRCA to extend indefinitely DOE's authority to perform groundwater remediation. UMTRA provides DOE groundwater remedial authority for Title I sites only. Title IIâRegulation of Uranium Mills, 1978 and After Title II of UMTRCA amended the AEA to authorize the regulation of licensed commercial uranium mills on or after the enactment of UMTRCA. Title II includes provisions authorizing the mechanism for transfer of land and mill tailings to the federal government; establishing regulatory roles of the states and federal agencies; and authorizing agencies to enter into bonding, surety, or other financial arrangements with a licensee to cover the costs of a federal agency administering long-term federal management. Byproduct Material and Site Transfer Section 201 amended Subsection 11e of the AEA to include mill tailings under the definition of byproduct material . Under Section 201, byproduct material is defined as "the tailings or wastes produced by the extraction or concentration of uranium or thorium from any ore processed primarily for its source material content." Section 202 amended the AEA by adding Section 83 authorizing the federal government to retain the byproduct material where the tailings are disposed of for long-term management. UMTRCA allows for the state, at its discretion, to retain the site under long-term management, but no state has elected to do so. Pursuant to Section 202, any license issued that "results in the production of any byproduct material" must comply with NRC decommissioning standards, and byproduct material and the land where it was disposed of must be transferred to long-term federal management. The site is transferred to long-term federal management when NRC, or the state, determines that the site decommissioning has met all applicable requirements. Unlike Title I sites, UMTRCA does not authorize DOE to perform remedial actions at Title II sites under long-term federal management. Section 202 authorizes DOE, as the custodial agency, to "carry out maintenance, monitoring, and emergency measures, but shall take no other action pursuant to such license, rule or order, with respect to such property and materials unless expressly authorized by Congress after the date of the enactment of this Act." NRC may exempt the requirement for long-term federal management prior to the termination of the license if long-term federal management is found "not necessary or desirable to protect the public health, safety, or welfare or to minimize or eliminate danger to life or property." The process to transfer a Title II site from an NRC license to long-term federal management is described in regulation and guidance. For Title II sites transferring federal public lands to long-term federal management under DOE, "DOE must apply to BLM for permanent withdrawal of federal land and minerals from BLM's inventory." Any transfer of BLM lands is subject to National Environmental Policy Act review. The U.S. Army Corps of Engineers, state governments, and local governments may become involved with the land transfer depending on the location of the site and the land ownership. In the majority of UMTRCA public land withdrawals, DOE maintains full regulatory jurisdiction of surface and subsurface interests associated with the disposal site. More recently, there has been interest in alternative uses at federally managed disposal sites. As a result, BLM and DOE have proposed a "partial-jurisdiction" regulatory structure at certain sites. The DOE would regulate the mill tailings repository and ensure that statutory maintenance and monitoring requirements are met. BLM would lease surface and subsurface rights for alternative uses of the land (grazing, recreational, etc.) and mineral development (oil and gas, uranium, etc.). Federal Regulatory Authority Section 205 of UMTRCA amended Section 84 of the AEA authorizing NRC as the principle federal regulator of Title II sites through issuance and enforcement of source and byproduct material licenses. Section 205 directs NRC to manage byproduct materials in manner that protects public health and environment from radiological and non-radiological hazards associated with the processing, possession, and transfer of byproduct materials. In establishing license conditions that would achieve protectiveness, Section 205 also allows NRC to consider costs and other factors. NRC and agreement states are also responsible for ensuring that licensees manage byproduct material in a manner that conforms to generally applicable standards promulgated by EPA. Section 206 of UMTRCA amended Section 275 of the AEA authorizing EPA to set generally applicable environmental and health standards. Congress intended standards to be consistent (to the maximum extent practicable) with the standards required under Subtitle C of the Solid Waste Disposal Act, as amended by the Resource Conservation and Recovery Act of 1976 (RCRA). Congress did not intend EPA standards to be site-specific in order to provide the agencies flexibility to address surface and groundwater issues at a broad range of sites. UMTRCA authorizes EPA to revise these standards periodically. On October 7, 1983, EPA published the final rule for applicable standards for Title II uranium mill tailings sites. The NRC determines whether the licensee has fulfilled all applicable decommissioning standards and license requirements prior to termination of the license and transfer of the site to long-term federal management. The NRC may delegate regulatory authority to an agreement state for issuing and enforcing byproduct material licenses in a manner that conforms to NRC requirements. NRC retains oversight authority over agreement states, and the state ensures that the licensee remains in federal regulatory compliance. Four UMTRCA Title II sites are listed on the National Priorities List under the Comprehensive Environmental Response, Compensation, and Liability Act ( P.L. 96-510 ), which authorizes remediation and enforcement actions against the releases of hazardous substances into the environment. At these four sites, NRC, EPA, and the state regulate remediation efforts by operating under a signed memorandum of agreement, which identifies the various agencies' responsibilities. Congress authorized DOE to implement remedial action programs under Title I and designated DOE as the federal agency responsible for long-term federal management of UMTRCA sites. DOE-LM was established in 2003 and manages environmental contamination at sites associated with legacy activities during World War II and the Cold War. As of FY2019, DOE-LM manages 19 Title I disposal sites, 12 Title I processing sites, and six of 29 Title II disposal sites. DOE-LM anticipates that it will assume custody of 17 additional Title II disposal sites over the next decade. UMTRCA processing and disposal sites are located in 12 states ( Figure 3 ). Site names and title descriptions are presented in the appendix ( Table A-1 ) . State Regulatory Authority Section 204 of UMTRCA amended Section 274b of the AEA authorizing NRC to enter into agreements with states allowing the states to regulate uranium milling operations through the issuance and enforcement of radioactive material licenses. Such agreement states retain the primary regulatory authority over licenses for radioactive materials on the determination that their regulations are as stringent as those of NRC. The agreement state is responsible for issuing and enforcing the license to ensure that the licensee manages byproduct material in a manner that conforms to federal requirements. Section 204 of UMTRCA includes requirements for procedures for rulemaking, environmental analysis, and judicial review. NRC oversees agreement state programs through inspections, training, and varying degrees of participation in rulemakings or other administrative activities. Financial Arrangements Congress intended the NRC to regulate licenses in a manner such that decommissioning requirements would be so stringent as to minimize the need for long-term maintenance and monitoring activities. Section 203 amended Section 161 of the AEA authorizing NRC to enter into short- and long-term bonding, surety, or other financial arrangements with uranium mill licensees. Short-term financial arrangements pay any remaining decommissioning costs if the operator becomes insolvent or otherwise incapable of completing all NRC decommissioning requirements. Long-term financial arrangements pay for the costs for DOE to perform long-term maintenance and monitoring after the license has been transferred to long-term federal management. Status of Implementation The legislative history suggests that public health and environmental concerns at the time were generally focused on preventing exposure to radiological emissions released into the air, such as radon gas. Many in Congress also expressed concern about potential exposure risks associated with the unrestricted use of radioactive tailings material used as fill material for buildings and other construction projects. Less understood at the time of UMTRCA's original enactment was the dispersion and migration of radiological and non-radiological contaminants in groundwater, which has been an issue at some UMTRCA sites. DOE's surface remedial authority expired in 1998 for Title I sites. DOE continues to administer groundwater remediation and monitoring programs at Title I sites under long-term federal management. The Moab processing site in Utah is the only Title I site that has not transferred to long-term federal management. Disposal Site Tailings Stabilization Prior to UMTRCA, federal regulatory agencies had little authority to regulate tailings, and methods were not required under federal law to mitigate the erosion of tailings. Inactive uranium mill tailings piles were often susceptible to natural dispersal by wind, water, and human disturbances associated with unintended access to the tailings material. Under Title I of UMTRCA, state and federal agencies designed disposal sites as engineered repositories, which are intended to stabilize inactive uranium mill tailings for hundreds of years. As of 1994, the GAO reported for Title I remedial actions that "DOE spent $2 billion on surface cleanup activities through fiscal year 1994 and expects to spend about $300 million more through 1998." Since 1998, when DOE's surface remedial authority expired, expenditures at Title I sites have been for groundwater remediation, disposal site stabilization, and monitoring activities. For Title II sites, private licensees are required to fund site decommissioning to all applicable requirements. After decommissioning of the site by the licensee, the disposal site is transferred to DOE-LM for long-term federal management. So far, six Title II sites have transferred to DOE-LM, while the decommissioning of the remaining Title II sites remains ongoing. Given the groundwater, stabilization, and erosion management issues experienced at Title I sites, DOE-LM may encounter similar challenges at Title II disposal sites once they are transferred to long-term federal management. The DOE-LM efforts to stabilize Title I and Title II disposal sites present continuing challenges. Natural factorsâsuch as wind erosion, intense rainfall and precipitation, and droughtsâcan deteriorate the physical integrity of the disposal site and potentially cause the unintended release of contaminants. Vegetation can aid in stabilizing tailings and minimizing erosion. Annual monitoring and maintenance costs may vary from year to year depending on the variability in climatic events. Groundwater Contamination and Monitoring Some uranium mill operations have resulted in groundwater contamination from unlined surface tailings ponds, leach pads, and dissolution of hazardous constituents from water seepage through the tailings piles. Radiological and non-radiological contaminants may migrate if uncontrolled, remain in appreciable quantities, or naturally decrease in the aquifer depending upon site-specific geological characteristics. NRC has characterized groundwater contaminant plumes at some UMTRCA sites as up to three miles long. As such, off-site migration of groundwater contamination has been an issue at some UMTRCA sites. DOE has applied active and passive groundwater remediation strategies at UMTRCA sites. Active groundwater restoration methodsâsuch as pump-and-treatâhave been used with varying results. DOE has implemented natural flushing , a passive treatment method, to manage groundwater contamination. Natural flushing relies upon monitoring to characterize the movement rate and distribution of the contaminant plume. DOE-LM often applies institutional controls at UMTRCA sites in conjunction with groundwater remediation programs. Institutional controlsâwhich include providing alternative water sources, site use restrictions, drilling restrictions, fencing, and signsâare intended to minimize risks associated with exposures to impacted groundwater. For example, issues with persistent groundwater contamination at the Riverton, WY, Title I processing site prompted DOE to develop institutional controls at that site to minimize residents' groundwater use. DOE's institutional controls included certain restrictions and notifications for developing new water wells and arranging alternative sources of water within the control boundary. DOE-LM administers groundwater monitoring programs at several UMTRCA sites. DOE develops a long-term surveillance plan as part of the NRC general license requirements. Included in the long-term surveillance plan are detailed site-specific groundwater monitoring requirements. Groundwater monitoring requirements include the types of groundwater constituents sampled, the frequency of groundwater sampling, and the location and number of monitoring wells necessary to characterize the groundwater contamination. For Title I sites, the 1988 UMTRA amendment authorized DOE to perform groundwater remediation indefinitely. However, DOE is not authorized to perform groundwater remediation at Title II sites under long-term federal management. At Title II sites under long-term federal management, DOE is authorized to perform maintenance and monitoring and to take emergency measures when necessary to protect public health. In the debate leading to the enactment of UMTRCA, some Members expressed the intent to prevent "additional and costly remedial action" unless appropriated by Congress through legislative action. The annual funding needs for UMTRCA sites under long-term federal management are dependent on the degree of site-specific monitoring and maintenance requirements and, for Title I sites, groundwater remediation costs. Moab Processing Site, Utah By the late 1990s, Title I disposal sites were constructed and transferred to long-term federal management, with the exception of the Moab site in Utah. DOE-EM administers the Moab site remediation. The Moab site was originally designated as a Title II site under UMTRCA. The enactment of the Floyd D. Spence National Defense Authorization Act for Fiscal Year 2001 ( P.L. 106-398 ) in October 2000 designated Moab from a Title II site to a Title I site. In designating Moab as a Title I site, Congress terminated the specific license under Title II and transferred the ownership to DOE and the remaining decommissioning costs to the federal government. Uranium mill tailings at the Moab site are located on the north bank of the Colorado River. DOE-EM constructed a railway specifically for this project to transport the tailings to a disposal site, Crescent Junction, located approximately 30 miles to the north. DOE transports tailings and performs groundwater remediation at the site. DOE-EM reports that it had transported 59% of the roughly 16 million tons of uranium mill tailings by the end of December 2018. DOE-EM anticipates project completion by 2034. DOE had incurred costs of $527 million by the end of FY2018 and estimated the total lifecycle costs to range from $1.186 billion to $1.197 billion. Funding for Moab is appropriated annually in the Energy and Water Development and Related Agencies appropriations bill under the Non-Defense Environmental Cleanup account. Selected Issues for Congress Site remediation costs and time frames have exceeded amounts originally envisioned by Congress, the agencies, and the licensees due to an evolving understanding of the complexities and risks posed by unintended releases of contaminants from uranium mill tailings. In 1995, the GAO reported that DOE's total surface remediation costs were $2.3 billion, exceeding original 1982 estimates by $621 million. Additionally, long-term federal costs to manage disposal sites and persistent groundwater contamination remain uncertain due to unforeseen challenges and site-specific monitoring and maintenance needs. For Title II sites, six sites have been transferred to DOE-LM as of FY2019. Licensees of remaining Title II sites continue to decommission and transfer their sites to DOE-LM. Prior to long-term federal management, UMTRCA directs federal and state regulatory agencies to apply the stringency of decommissioning requirements on a licensee so that the degree of long-term monitoring and maintenance requirements are minimized. DOE-LM manages a Title II site once the NRC or the state transfers the license from the licensee following decommissioning. In certain instances, NRC, DOE-LM, state agencies, and licensees have disagreed about the adequacy of decommissioning, the degree of long-term monitoring, and the amount of funding needed to perform long-term federal management requirements. In some instances, differences in views among the agencies have affected the timing of decommissioning and license transfers to DOE-LM. In other instances, licensees have lacked adequate funding to complete decommissioning. The following sections describe selected issues regarding proposed legislation, site-specific issues decommissioning, and long-term financial assurance. Cheney Disposal Cell Reauthorization DOE and residents continue to discover and excavate contaminated material at vicinity properties (i.e., buildings, roads, and sidewalks) around Grand Junction, CO, where uranium mill tailings were used as construction material prior to the enactment of UMTRCA. Discovered byproduct material from vicinity properties is disposed in the Cheney disposal cell, located 15 miles southeast of the Grand Junction processing site. DOE constructed the Cheney disposal cell in 1990 to accept residual radioactive material from the Title I Grand Junction processing site and vicinity properties contaminated by the use of uranium tailings as building materials. Under Section 112 of UMTRCA, DOE's authority to accept byproduct material at the Cheney disposal cell is scheduled to expire at the end FY2023 or until the cell reaches capacity, whichever comes first. DOE would be prohibited to operate the Cheney disposal cell after FY2023 absent the enactment of reauthorizing legislation. In the 116 th Congress, the House passed H.R. 347 authorizing DOE to dispose of residual radioactive material from processing sites and byproduct material from vicinity sites in the Cheney disposal cell through FY2031. Similar versions of this legislation were introduced in the 115 th Congress. Title II Uranium Reimbursements Thirteen Title II uranium mills produced uranium concentrate under both federal procurement contracts and commercial civilian nuclear power production. Title X of the Energy Policy Act of 1992 ( P.L. 102-486 ) authorized reimbursements to pay Title II licensees for remedial costs proportional to the quantity of byproduct material produced under federal procurement contracts. Reimbursement payments under Title X do not absolve the licensees from completing site decommissioning. DOE-EM administers reimbursement payments to eligible Title II sites with funds appropriated from the Uranium Enrichment Decontamination and Decommissioning Fund, established under Title XI of the Energy Policy Act of 1992, to support remediation of federal uranium enrichment facilities. Title X reimbursements are subject to annual appropriations in the Energy and Water Development and Related Agencies appropriations bill. In 2000, eight years after the authorization of Title X reimbursements, the 106 th Congress recognized that the implementation of decommissioning by licensees was more costly and taking longer than originally envisioned. As of 2019, Title II licensees eligible for Title X continue to face similar decommissioning challenges. For example, committee report language in the FY2019 Energy and Water Development and Related Agencies appropriations bill directs DOE to use funds to "reimburse licensees for approved claim balances in a timely manner and to avoid accumulating balances and liabilities." From FY1994 to FY2018, DOE reported that $355 million was reimbursed to 13 licensees. According to DOE, there were $26 million in approved but unpaid claims as of FY2018, and estimated remaining program liability was $99 million for the remaining sites eligible for reimbursements. Transfer Status and Funding Various technical, financial, and regulatory issues have affected the timing of the transfer of Title II sites to long-term federal management. NRC's statutory responsibility is to regulate uranium mills and tailings for Title II sites in a manner that allows a licensee to complete site decommissioning in manner so stringent that little long-term maintenance and monitoring would be required. Congress intended NRC to mitigate financial burdens to the licensees while requiring that all decommissioning requirements be fully met. The transfer of the remaining Title II sites to DOE-LM for long-term federal management would remain pending until NRC determines that the licensee has completed all decommissioning requirements. NRC estimates specific dates for some Title II sites, while others are listed as "to be determined." Table A-1 identifies Title I and Title II sites that have transferred to long-term federal management, and Table A-2 identifies Title I and Title II sites that have not yet transferred to long-term federal management. DOE-LM would become responsible for long-term federal management of Title II sites currently licensed by NRC or an NRC agreement state upon the completion of decommissioning and site transfer. For some Title II sites, DOE-LM and NRC have reached differing conclusions regarding the adequacy of decommissioning, the degree and type of long-term monitoring requirements, and the funds needed to pay for long-term monitoring and maintenance costs. Section 203 of UMTRCA authorized NRC to collect a bond or other financial arrangement to pay for the costs in the event that a licensee was unable to fulfill all of their decommissioning requirements. UMTRCA does not authorize the use of federal funding to pay for the decommissioning of Title II sites. In the event that the bond were insufficient to pay for the full decommissioning costs, UMTRCA provides no additional mechanism for funding to complete decommissioning. In some instances, Title II licensees have lacked adequate financial resources to complete NRC's decommissioning requirements. If left unreclaimed, exposure risks from releases of radiological and non-radiological contaminants may present issues to affected communities. The magnitude of public health and environmental risks posed by unreclaimed tailings may vary among individual sites. Long-Term Financial Assurance For sites that have transferred to long-term federal management, DOE-LM administers Title I and Title II sites under an NRC general license. UMTRCA authorized long-term monitoring and maintenance costs at Title I sites to be paid by the federal government. For Title II sites, Congress intended that the licensee would pay for any necessary long-term monitoring and maintenance costs using a one-time long-time surveillance charge (LTSC). Annual costs are largely dependent on the extent of site-specific groundwater monitoring and intermittent maintenance activities on the repository. Under current federal law there are different statutory authorities for DOE-LM to perform remediation at Title I sites and Title II sites under long-term federal management. For Title I sites, Congress authorized DOE-LM to implement groundwater remediation indefinitely, recognizing the ongoing remediation challenges at some Title I sites after decommissioning. UMTRCA does not provide DOE-LM remedial authority for Title II sites under long-term federal management. At Title II sites under long-term federal management, DOE-LM is authorized to perform monitoring, maintenance, and emergency measures. Emergency measures is not explicitly defined by statute, potentially raising issues of interpretation in the event of future remedial action needs. Selected issues with Title I and Title II long-term financial assurance are discussed in the following sections. Title I Sites Congress provides funding for the long-term federal management of Title I sites through DOE annual appropriations. For Title I sites under long-term federal management, program funding for DOE-LM is funded under Environmental and Other Defense Activities account in the Energy and Water Development and Related Agencies appropriations bill. DOE-EM continues to administer remediation at the Moab site in Utah. Funding for the Moab site is appropriated annually in the Energy and Water Development and Related Agencies appropriations bill under the Non-Defense Environmental Cleanup account. DOE annual expenditures can vary from site to site depending on costs related to many factors, including the degree of groundwater remediation or monitoring and disposal site maintenance. For example, from 2008 and 2012, an interagency report from January 2013 noted that total DOE expenditures at the Tuba City disposal site were $13.96 million (approximately $2.8 million per year), while total expenditures at the Mexican Hat disposal site were $110,000 (approximately $22,000 per year). Neither DOE-LM annual budget justifications nor annual appropriations bills specify funding for annual long-term federal management costs by site or for the site inventory as a whole. Annual funding for DOE-LM is presented in annual budget requests and appropriations as a single line-item. In all, DOE-LM oversees over 100 sites contaminated by radiological, chemical, and hazardous wastes associated with the legacy of nuclear weapons production during World War II and the Cold War. UMTRCA processing and disposal sites constitute 37 of those sites. Congress appropriated $159 million to DOE-LM in the Energy and Water Development and Related Agencies Appropriations Act, 2019 ( P.L. 115-244 ), the same amount as requested. Title II Sites For Title II sites, Congress intended that commercial uranium mill operators will pay for site decommissioning and the costs for a federal agency to perform long-term federal management. To cover these long-term federal management costs, NRC requires licensees to pay an LTSC upon the transfer of the site to DOE. Section 203 of UMTRCA provides NRC authority to collect this LTSC from the licensee to pay for DOE's costs to perform long-term maintenance, monitoring, and emergency measures. This one-time LTSC fee is deposited as a miscellaneous receipt into the General Fund of the U.S. Treasury when each site license is transferred to DOE. In the 1980 Final Generic Environmental Impact Statement for uranium milling, NRC described the justification for the minimum LTSC fee based on the assumption that average long-term monitoring at UMTRCA Title II sites would cost $2,500 per year. NRC assumed an average annual real rate of return, and each licensee is required to pay the minimum one-time L TSC of $ 250,000 (in 1978 dollars, adjusted for inflation). NRC has not revised the minimum LTSC since regulations were promulgated in 1985. NRC allows for the minimum LTSC fee to be increased based on expected site-specific surveillance or controls requirements if needed. UMTRCA does not authorize a mechanism to recover additional fees from licensees once the license has been transferred to DOE-LM. The adequacy of the LTSC to cover DOE's costs to perform long-term maintenance and monitoring has been an issue. In 1995, the GAO recommended that NRC improve "the accuracy of the one-time charge made to owner/operators to ensure that this charge fully covers future costs at their sites." In 2014, the DOE Office of Inspector General (IG) found that DOE-LM had spent $4.25 million at six Title II sites under long-term management. During the same three-year period, the IG report found that the available funds from the LTSC fees were $0.148 million. To the extent that the LTSC fees are insufficient to cover annual monitoring and maintenance costs, DOE-LM would be responsible to carry out long-term management responsibilities, subject to availability of annual appropriations. DOE-LM has discretion to allocate appropriated funding among eligible sites under long-term federal management. If the current minimum LTSC do not fully cover annual long-term federal management costs for the remaining Title II sites when they transfer to DOE-LM, the IG report states "the total cost to the American taxpayers could be significant." Yet, there is a limited availability of information by site and by year for DOE-LM's monitoring and maintenance costs at UMTRCA sites under long-term management. DOE-EM has provided life-cycle cost ranges and completion date estimates for Environmental Management sites, including the Moab site, in annual budget justifications. CRS was unable to identify DOE cost estimates for any other UMTRCA site. The federal government will be responsible for the long-term management costs for all UMTRCA sites once transferred to DOE-LM. Potential issues for Congress may include the decommissioning and transfer status of the remaining Title II sites, the adequacy of funding to complete decommissioning at certain sites if the licensee is unable to fulfill its obligations, and the adequacy of the long-term surveillance charges to meet future long-term management needs. Appendix. Appendix


Introduction Congress plays an overarching role in shaping outdoor recreation throughout the nation through legislation and oversight. Congress's role in outdoor recreation resources, policies, and programs often involves the agencies that manage recreation resources on federal lands and waters. However, Congress also has supported crosscutting legislative, analytic, and planning efforts dedicated to outdoor recreation broadly, and it has established programs that facilitate recreation on nonfederal lands. Legislation, hearings, and congressional reports have indicated the significance of outdoor recreation economic activity as a decisionmaking consideration in many contexts, not just those involving federal lands. As Congress continues to debate outdoor recreation issuesâincluding provision of federal resources, planning efforts, and fundingâdata on the size, distribution, and relative importance of the outdoor recreation economy may inform these debates. Outdoor Recreation Jobs and Economic Impact Act In April 2016, the Secretary of the Interior announced that the Department of the Interior would sign a memorandum of understanding with the Department of Commerce to undertake a feasibility study to analyze outdoor recreation's impact on the U.S. economy. The Secretary noted that "credible data on the tangible economic benefits of public lands" would be a valuable resource for stakeholders, including Congress, and that the study would count the contributions of the outdoor recreation economy in a "comprehensive and impartial" way. Later that year, Congress explicitly authorized these efforts through passage of the Outdoor Recreation Jobs and Economic Impact Act. In addition to ensuring the availability of economic data on outdoor recreation, the act ensured methodological uniformity with other statistical activities of the Bureau of Economic Analysis (BEA) that analyze the economic impact of private industries. The act directed the Secretary of Commerce, acting through BEA, to assess and analyze the outdoor recreation economy of the United States and its contributions to the economy generally. The act required the Secretary to consider employment, sales, and contributions to travel and tourism, in addition to any other items the Secretary considered appropriate. Consequently, BEA developed the Outdoor Recreation Satellite Account (ORSA), an account using the same data and methods as BEA's gross domestic product (GDP) statistics. BEA released the first ORSA prototype statistics for comment in February 2018, and it released the first official ORSA statistics in September 2018. BEA released the most recent ORSA statistics on September 20, 2019. Congress has indicated general approval of the ORSA and directed BEA to develop regional statistics in future years; BEA included state-level prototype statistics in the 2019 release. The House Appropriations Committee also directed the Department of Commerce, in coordination with the agencies of the Federal Recreation Council, to continue to refine the account and to report on the feasibility of identifying amounts allocated by the federal government to outdoor recreation efforts. The National Outdoor Recreation Economy About the Outdoor Recreation Satellite Account BEA prepares the ORSA statistics as required by the Outdoor Recreation Jobs and Impact Act. The most recent ORSA statistics, released in September 2019, measured the period from 2012 to 2017. The ORSA "measures the size of the outdoor recreation economy and the link between outdoor recreation and the broader U.S. economy." BEA constructed the ORSA by isolating outdoor recreation spending and production from the broader industries and categories that BEA already tracked. BEA compiles data into industry accounts (e.g., retail trade, manufacturing, construction, and others) and uses all this data to calculate gross domestic product (GDP). The ORSA is a satellite account in that it isolates and combines the parts of many individual industries that are related to outdoor recreation. For example, as described by BEA, existing industry accounts show "the production of all apparel, whereas the ORSA shows the production of apparel used specifically for outdoor recreation activities, such as wetsuits and hiking boots." The ORSA divides outdoor recreation activity into core activities and supporting activities. Core activities include the production and purchase of goods and services used directly for outdoor recreation, such as equipment, fuel, concessions, and fees. Supporting activities are defined as goods and services that facilitate access to outdoor recreation activities, such as travel and tourism expenses, local trips, construction, and government expenditures that support outdoor recreation (including local, state, and federal spending). BEA also organizes its statistics using conventional and broad views of outdoor recreation. The conventional activities include "all recreational activities undertaken for pleasure that generally involve some level of intentional physical exertion and occur in nature-based environments outdoors," such as camping, fishing, hiking, and hunting. Other activities include additional activities undertaken for pleasure that occur outdoors that may not meet the conventional definition (i.e., do not require intentional physical exertion or occur in a nature-based setting), such as outdoor concerts and festivals and games and sports fields. The two categories of activities can be combined to generate a broad view of the outdoor recreation economy. BEA calculates the ORSA from the same data used to calculate GDP broadly. Â As such, the ORSA is directly comparable to other BEA products, including other satellite accounts, like those for arts and cultural production. In addition, the estimates used to create the ORSA follow internationally recognized standards for national accounting, including creating GDP, value added, and other measures. Thus, in theory, the ORSA results can be compared to other measures of GDP, gross output, and value added, although differing assumptions, data, and methods may influence to what degree other measures are equivalent to ORSA statistics. As described above, the ORSA combines data from many different BEA industries; thus, although very general comparisons can be made, direct comparisons risk double-counting. For example, comparing the size of the ORSA to the size of the apparel industry would be inaccurate, because some value added from the apparel industry is included in the ORSA. Outdoor Recreation Satellite Account Estimates According to the ORSA statistics, in 2017, the current-dollar value added of the outdoor recreation economy was $427 billion. The outdoor recreation economy accounted for 2.2% of GDP. As shown in Figure 1 , supporting activities, such as construction and travel and tourism expenses, accounted for approximately half of outdoor recreation value added in 2017, approximately $213.9 million current dollars. Conventional outdoor recreation accounted for 30.7% of value added. Other recreation accounted for 19.3%. BEA organizes its accounts by industry. BEA reports that the arts, entertainment, recreation, accommodation, and food services industry was the largest contributor to the outdoor recreation economy in 2017, accounting for $112.9 billion of current-dollar outdoor recreation value added. The second-largest industry in 2017 was retail trade, accounting for $95.7 billion of current-dollar value added. Figure 2 provides a full breakdown of contribution to value added by industry. BEA reported that the outdoor recreation economy generated approximately 5.1 million jobs in 2017. The arts, entertainment, recreation, accommodation, and food services industry was the largest industry included in the ORSA for both compensation ($67.3 billion current dollars) and employment (2.1 million) in 2017. Retail trade was the second-largest industry for both compensation ($49.8 billion current dollars) and employment (1.6 million) in 2017. The largest amount of value added in 2017 from an individual conventional outdoor recreation activity (as defined by BEA) came from boating/fishing, accounting for approximately $21Â billion in current-value dollars, or approximately 5% of value added from outdoor recreation (see Figure 3 ). The activities that generated the most value added are not necessarily the most popular, according to an FS participation survey. For example, although equestrian activities were among the six largest activities in terms of value added, an FS survey found that equestrian activities were among the three smallest activities for number of participants (see " National Outdoor Recreation Participation " for more information). Although much of the economic activity tracked by BEA to calculate value added can be linked to a specific activity (see " About the Outdoor Recreation Satellite Account "), some economic activity cannot. For example, multiuse apparel and accessories (such as backpacks, bug spray, and other items) that can be used for many activities accounted for approximately $48.6 billion in current dollars, or over 11% of value added. In real terms, the outdoor recreation economy grew 3.9% between 2016 and 2017, faster than the 2.4% growth for the overall U.S. economy. Real gross output, compensation, and employment all grew faster in the outdoor recreation economy than in the overall economy in 2017. Between 2012 and 2017, the outdoor recreation economy grew by approximately 9.9%. In 2017, BEA released prototype statistics on the percentage of each state's GDP from outdoor recreation (see Figure 4 ). BEA's preliminary results found that Hawaii, Montana, Maine, Vermont, and Wyoming had the five highest proportions of state GDP from outdoor recreation. However, other measures of economic importance vary considerably by state. For example, California, Florida, and Texas had the highest total outdoor recreation value added. Wyoming, Hawaii, and Alaska and Maine (tied) had the highest percentage of state employment from outdoor recreation. The relative importance of recreation in individual states depends on the size of the outdoor recreation economy, the state's economy generally, and the state's employment and compensation patterns. It is unclear to what extent these estimates may change if BEA adjusts its methods for calculating state statistics. Official state statistics are scheduled for release in fall 2020. Other Estimates of Economic Activity In addition to the estimates created by BEA, researchers, advocacy groups, and industry associations create estimates of the outdoor recreation economy. Many groups estimate impacts of individual activities, sectors, geographic areas, or outdoor recreation areas (e.g., angling, winter snow sports, a given watershed, or a given state). The broadest of these is the Outdoor Industry Association's (OIA's) Outdoor Recreation Economy report, which has been produced annually since 2006. Prior to publication of the ORSA, OIA estimates were sometimes cited to gauge the size of the outdoor recreation economy as a whole. According to OIA's 2017 report, the outdoor recreation economy generated $887 billion in consumer spending, the majority of which ($702 billion) was trip and travel spending, including airfare, lodging, fuel, groceries, tickets, lessons, guides, and other unspecified expenses spent anywhere away from home. OIA estimates that the outdoor recreation economy directly supports 7.6 million jobs. OIA also estimates that the outdoor recreation economy generates $65.3 billion in federal tax revenue and $59.2 billion in state and local tax revenue. OIA's estimates of the size of the outdoor recreation economy, and other estimation efforts, cannot be directly compared to the ORSA. This may be due to differences in method, assumptions, measurement, or statistics reported. Specifically, the OIA reports measure consumer spending and tax revenue, which are not part of the ORSA and are not directly comparable to any statistic reported in the ORSA. OIA's estimate of jobs (7.6 million) is higher than BEA's estimate of jobs (5.2 million), but it is unclear to what extent the data reported are similar in measurement or whether they represent the same year. BEA excluded exports and imports in its calculation, and these figures may be captured in OIA's statistics. BEA states that external reports on the outdoor recreation economy that include "activities with a high share of spending on imported goods and services (such as apparel) will likely have higher estimates than the ORSA." BEA also states that other reports may include spending on items not used for outdoor recreation (for example, bicycles used for commuting). In general, because other reports do not give the same statistics as the ORSA, and due to methodological differences, it is unclear whether (and to what degree) the ORSA and other reports may or may not be in disagreement, despite apparent large differences in results. The results of the ORSA and OIA reports have certain broad commonalities. For example, both reports find that large amounts of economic activity are driven by activities requiring relatively expensive purchases, such as vehicles (for example, boating or off-highway vehicle activities). Both reports also find that expenses related to travel, such as lodging, airfare, and food away from home, constitute large shares of the economic activity generated by outdoor recreation. National Outdoor Recreation Participation According to one source, measures of national trends in outdoor recreation participation are based primarily on the National Survey on Recreation and the Environment (NSRE), a population-based survey conducted by the U.S. Forest Service (FS), sampling all areas of the country and participation in 17 outdoor activities. The NSRE measures both participation (the number of respondents who report engaging in the activity at least once over the course of a year) and consumption (the number of times the respondent indicates engaging in the activity). The survey does not estimate the total number of participants in outdoor recreation generally, only participation rates in the 17 activities studied. The most recent NSRE was completed for the period 1999-2009, and an update is ongoing. The NSRE estimated that, for the activities considered, a maximum of 194 million people (visiting developed sites) and a minimum of 8 million people (primitive skiing) participated every year (see Table 1 for additional details). FS estimated that approximately 82% of NSRE respondents participated in visiting developed sites, the activity with the highest participation rate. In terms of the frequency with which participants engaged in each activity (shown as "Activity Days" in Table 1 ), FS estimated that participants engaged in the most popular activity (viewing nature) over 32.4 billion times; this activity, however, is a major outlier, and participants engaged in the next several most popular activities between 8.3 billion and 1.8 billion times. Between 1999 and 2009, FS estimated that participation in nature-based outdoor recreation generally increased. The number of U.S. participants in the surveyed activities increased by 7.1% over this period. Certain activities, such as those oriented toward viewing and photographing nature, off-highway vehicle activities, and several physically challenging activities (e.g., kayaking, snowboarding, surfing) had relatively large increases in participation compared to the average over this period. More people overall participate in outdoor recreation in the eastern United States than in the western United States, in large part because most of the U.S. population resides in the East. However, participation rates (measured as the number of participants per hundred people) are higher in the West for all activities except hunting and fishing. In addition to this broad trend, demographic factors, such as population size, age, gender, race, ethnicity, education, and income, are correlated with the rate of outdoor recreation. For example, relative to the general population, people engaging in hunting and fishing are more likely to be rural residents, and people engaging in skiing and snowboarding are more likely to be urban residents. Availability of and proximity to recreation settings also are highly correlated with the rate of outdoor recreation participation. The amount of recreation that occurs on lands of differing ownershipâfor example, federal, state, local, and privateâlikely varies widely by activity and location (see section on " Recreation Visits to Federal Lands " for further discussion of recreation on federal lands). Approximately 60% of lands in the United States are privately owned, and approximately 28% of the total land area is federally owned; the remainder is in a mix of state, local, tribal, and other ownerships. Over 92% of federal land is located in 11 western states and Alaska. The uneven distribution of federal land between the eastern and western United States influences what lands provide outdoor recreation opportunities in different regions of the United States, particularly given that, for some federal land management agencies, at least half of visits to the properties they administer come from people who live within 50 miles. FS found that private lands were a more important recreation setting in the East, with the total number of recreation visits on private lands in the East nearly four times the number in the West. In the West, respondents reported that they spent the majority of activity days in all surveyed activities on publicly owned lands of any kind. In contrast, respondents in the East spent the majority of activity days in some surveyed activities on private lands and some on publicly owned lands. Outdoor Recreation on Federal Lands The ORSA statistics measures the state of the outdoor recreation economy generally. From the standpoint of public lands management, there is often congressional interest in how the government's provision of recreational opportunities translates into economic activity in communities around federal recreation resources. Legislation, hearings, and congressional reports have indicated the significance of this economic activity as a policy consideration in contexts involving federal lands. In the past decade, federal agencies and interagency groups have conducted studies measuring economic contributions specific to federal lands. Because these studies examine multiple agencies under a single framework, and because they report value added, the results are comparable to one another. In the sense that value added is a consistent concept, they also may be generally comparable to other measures of value added, such as the ORSA results, although differences in methods, data, and assumptions mean any comparison can be, at best, highly general. According to these studies, in FY2017 dollars, visitors spent approximately $54 billion in the local economies of federal recreation areas in FY2012 and $49.8 billion in FY2016, generating $55 billion in value added in FY2012 and $53.9 billion in value added in FY2016 (see Table 2 ). The studies indicate that outdoor recreation on federal lands directly supported 880,000 jobs in FY2012 and 826,000 jobs in FY2016. The authors of the studies in Table 2 limited their studies of visitor spending to areas within 50 miles of the federal recreation site. The authors state that this limitation provides a conservative estimate. Although research suggests that many visits to federal recreation sites do indeed originate from nearby, the nationwide estimates discussed above (see " The National Outdoor Recreation Economy ") indicate that a large proportion of economic activity derives from travel-related expenses. If the travel-related portion of economic activity related to federal sites is not being captured in these results because that activity occurs more than 50 miles from the federal recreation site, these studies may undercount the true value. Similarly, results of national studies indicate that activities requiring major purchases (e.g., vehicles) account for a large proportion of the outdoor recreation economy. If visitors do not report such expenditures, it also may result in undercounting. The agencies used different methods to measure visitation and economic activity; thus, estimates may be only generally comparable. Federal Lands' Recreation Resources and Uses Federal lands comprise approximately 640 million acres in the United States, about 28% of the total land area. Approximately 92% (573 million acres) of federal lands are located in 11 western states and Alaska, with over one-third (224 million acres) of all federal land in Alaska alone. The Forest Service (FS) and the Bureau of Land Management (BLM) manage the majority of federal land. Nearly all federal land is open and available to the public for recreation. Although there is considerable overlap in the recreation opportunities across agencies, some agencies could be considered to have dominant niches. FS and BLM offer a range of opportunities, from camping, picnicking, and birdwatching in developed settings to activities in undeveloped backcountry, motorized recreation, and others. Opportunities on Fish and Wildlife Service land emphasize wildlife, fish, and birds. The National Park Service (NPS) is associated with "iconic natural and cultural resources." Opportunities on land owned by the Bureau of Reclamation, National Oceanic and Atmospheric Administration, and U.S. Army Corps of Engineers (USACE) tend to center on water and underwater resources. Although some agencies' resources are used mostly by locals, all agencies have resources with regional, national, or international markets. Recreation Visits to Federal Lands Table 3 presents information from various sources on recreation visits to federal lands from FY2012 to FY2017. In general, these statistics are not comparable to the NSRE estimates given above due to differences in measurement. The statistics indicate that, in general over this period for agencies with complete data, FS and NPS had the most visits. These statistics underscore that size and location are imperfect predictors of recreation resource use; USACE, for example, has higher visitation than several agencies that manage more federal land area. These differences may be due to proximity to population centers, the types of resources available on different lands, and other factors.