The Rocky Mountain Arsenal, established in 1942, occupies 17,000 acres northeast of Denver, Colorado, and is contaminated from years of chemical and weapons activities. The Army manufactured chemical weapons, such as napalm bombs and mustard gas, and conventional munitions until the 1960s and destroyed weapons at the Arsenal through the early 1980s. In addition, it leased a portion of the Arsenal to Shell Oil Company from 1952 to 1987 to produce herbicides and pesticides. The Arsenal was placed on the Environmental Protection Agency’s (EPA) National Priorities List, the list of the nation’s most heavily contaminated sites, in July 1987. More than 300 species of birds, mammals, amphibians, reptiles, and fish can be found on the installation. Once the EPA certifies the cleanup is complete, the Arsenal is to become a national wildlife refuge managed by the Fish and Wildlife Service. Refuge management activities are already underway. (App. I shows the key physical features of the Arsenal.) Waste disposal practices used by the Army and Shell in the past have resulted in extensive soil and groundwater contamination. Some of the common contaminants include nerve agents, diisopropyl methyl phosphorate (DIMP), and the pesticides dieldrin and aldrin. Other contaminants include heavy metals, such as arsenic, lead, chromium, and mercury, and volatile organic compounds, such as benzene, toluene, and xylene. The 209 contaminated sites on the Arsenal are divided into on-post and off-post segments. The on-post sites include all contaminated structures, water, and soil within the boundaries of the Arsenal. The off-post sites include a region north of the Arsenal requiring cleanup because of migrating groundwater contamination. Cleanup at the Arsenal is subject to the legal requirements of the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) of 1980, as amended (42 U.S.C. 9601); the Resource Conservation and Recovery Act of 1976, as amended (42 U.S.C. 6901); and state laws. (See app. II for a description of the CERCLA process.) The Army is in charge of the cleanup under a Federal Facility Agreement, which was signed in 1989. The signatories include the Army; Shell Oil Company; the EPA; and the Departments of Justice, the Interior, and Health and Human Services. The agreement established a framework for cleanup and a process to resolve formal disputes among the parties. However, the state of Colorado was not a party to the Federal Facility Agreement because of litigation with the Army and Shell. A court-appointed mediator facilitated negotiations between the parties over several years. The recent conceptual agreement for cleaning up Rocky Mountain Arsenal may mark a turning point in years of conflict that has slowed the implementation of permanent cleanup remedies and increased costs. According to Army, EPA, state of Colorado, and Shell officials, long-standing disagreements and extensive studies have diverted key staff and contractors away from the cleanup program and driven costs up. In the 20 years since the installation restoration program began, the Army and Shell have spent about $1 billion to study and control the environmental damage. The majority of the cost has been for studying the site and resolving disagreements. Totaling $354 million as of December 1994, the Arsenal’s study phase is the costliest in the history of DOD’s cleanup program. However, about $316 million was spent on interim remediation projects to cut off contamination pathways. These actions may contribute significantly to permanent solutions. (App. III contains a time line of the Arsenal’s installation restoration program.) The most recent delay in adopting a cleanup plan for the Arsenal was caused by disagreements over cost-effectiveness and alternative cleanup remedies. EPA’s and the state of Colorado’s initial cleanup proposals were estimated to cost about $2.7 billion; Shell Oil Company’s was $1.6 billion; and the Army’s was in the middle, at about $2.1 billion. According to officials from the Army, EPA, and the state of Colorado, the 2-year debate involved how to clean up contaminated soils on the Arsenal and contaminated water off the Arsenal. All parties agreed that soils should remain on-site, because moving them off-site would be prohibitively expensive. However, while the Army and Shell suggested that untreated soils be capped in place to prevent the spread of contaminants, EPA and the state suggested that contaminated soils should be treated to neutralize them, before they are capped or placed in a landfill. The key off-post issue involved groundwater quality standards for water contaminated with DIMP, a by-product of nerve agent production. In 1993, the state promulgated a drinking water standard of 8 parts per billion. The Army and Shell wanted to continue to pump and treat the water to meet EPA’s health advisory of 600 parts per billion, while the state wanted the Army to provide the residents with an alternative water supply. Largely due to the volume of lawsuits, formal disputes, and other disagreements, the Rocky Mountain Arsenal has experienced the costliest study phase in DOD’s history. According to DOD reports, the Arsenal’s study costs represent at least 16 percent of the Army’s total study costs for about 1,200 installations. The Arsenal’s study phase began more than 20 years ago and was completed recently, in October 1995, when the Army requested public comment on its preferred remedy. As of December 1994, Shell and the Army had spent approximately $354 million on studies, which represents about 37 percent of the total costs incurred by Shell and the Army at the Arsenal. Figure 1 shows shared cleanup costs by category. Historical cost (1975-87) Shell contribution remaining in special account Total: $961 million Over 400 studies have been conducted at the Arsenal since 1983. Approximately 14,000 samples were taken and 230 reports were produced during the study phase. Although the complexity of the site warranted study, according to Army, EPA, and state officials, the litigation and other disputes encouraged excessive and duplicative studies. For example, had the parties come to an earlier agreement on the installation’s future use and on levels of ecological standards, some of the studies might have been avoided. Relationships among the key parties have been strained by differences throughout the history of the cleanup program, but particularly since 1983 when two major lawsuits were filed. The Army sued Shell, and the state of Colorado sued the Army and Shell to recover compensation for natural resource damages and cleanup costs. The state sued the Army again in 1986 to enforce regulatory authority over parts of the cleanup. Although the Army and Shell settled their suit in 1988, the first Colorado case has not yet been resolved and the second case went to the U.S. Supreme Court. In January 1994, the Supreme Court refused to hear the case, letting stand the lower court’s decision in favor of Colorado’s jurisdiction. The key parties’ exhaustive efforts to resolve their legal disputes involved 7 years of assistance from a court-appointed mediator. (See app. IV for a detailed chronology of major legal actions involving Rocky Mountain Arsenal.) In addition to the lawsuits, more than 140 issues have been taken to formal dispute since 1987 under the Federal Facility Agreement, which allows the parties to dispute Army decisions. Disputes have been triggered by a variety of technical issues, often requiring further studies to resolve the controversy. For example, the parties disagreed about what level of dieldrin is considered safe in soil. The Army, EPA, and Shell have all conducted and evaluated studies on this issue, yielding different results and reaching different conclusions. This dispute was invoked in December 1987 and is still not resolved. According to Army, EPA, and state officials, study results are particularly sensitive because precedents set at the Arsenal could potentially have ramifications for Shell Oil Company at its other locations. Although final cleanup has not begun, the Army and Shell have made efforts to mitigate the most critical threats at the Arsenal. As of December 1994, they had spent about $316 million on source control and interim actions designed to provide immediate containment or treatment of some of the more highly contaminated areas. Early assessments, conducted between 1975 and 1985, identified ways to minimize the potential for exposure to and migration of contaminants. Resulting projects included the installation of three groundwater treatment systems at the Arsenal’s boundary, the closure of an abandoned well, and the removal of sewer lines known to be a source of soil and groundwater contamination. Building on earlier source control efforts, the Army began its interim actions in 1986 to control immediate problems while the final cleanup solutions were being determined. The resulting 14 interim actions were designed to be consistent with long-term comprehensive cleanup on and off the Arsenal. Two of these, the incineration of liquid waste from the Arsenal’s major disposal basin and the removal of asbestos, have permanently removed the hazardous materials. Table 1 shows, for each of the 14 actions, the start date, actual or estimated completion date, and the actual or estimated cost as of December 1994. If the parties are successful in adopting the on- and off-post cleanup plans as expected in 1996, the final cleanup can begin. The conceptual agreement reached in June 1995 resolved the major disputes and outlined a $2.1-billion cleanup to be completed in 2012. However, the current cost and completion targets may be overly optimistic given remaining uncertainties about the final details. In addition, costs have significantly increased over time at the Arsenal. According to the conceptual agreement, the parties are expected in 1996 to adopt a final cleanup plan or record of decision for a $2.1-billion cleanup effort. Although most of the cleanup is expected to be accomplished by 2012, groundwater treatment and monitoring will continue for at least 30 years. The conceptual agreement resolves the two most significant disputes among the parties, regarding contaminated soils on site and contaminated groundwater off site.