Creosote is derived by distilling tar; the type of creosote most commonly used for wood-treating is manufactured from coal tar. Polycyclic aromatic hydrocarbons—chemicals formed during the incomplete burning of coal, oil, gas, or other organic substances—generally make up 85 percent of the chemical composition of creosote. EPA classifies some of the polycyclic aromatic hydrocarbons in creosote, such as benzo(a)pyrene, as probable human carcinogens. Some polycyclic aromatic hydrocarbons also may have noncarcinogenic health effects, such as decreased liver or kidney weight. From approximately the early 1910s to the mid-1950s, the Federal Creosote site was a wood-treatment facility. Untreated railroad ties were delivered to the site and, to preserve them, coal tar creosote was applied to the railroad ties at a treatment plant located on the western portion of the property (see fig. 1 for an illustration of the site). Residual creosote from the treatment process was discharged into two canals that led to two lagoons on the northern and southern parts of the site, respectively. After treatment, the railroad ties were moved to the central portion of the property, where excess creosote from the treated wood dripped onto the ground. The treatment plant ceased operations in the mid-1950s. During the late 1950s and early 1960s, the area where the treatment plant was formerly located was developed into a 15-acre commercial and retail property known as the Rustic Mall. Through the mid-1960s, other areas of the property, including the former canal, lagoon, and drip areas, were developed into a 35-acre residential neighborhood known as the Claremont Development, which was made up of 137 single-family homes that housed several hundred residents. Issues with creosote contamination at the site became apparent in April 1996, when the New Jersey Department of Environmental Protection (NJDEP) responded to an incident involving the discharge of an unknown thick, tarry substance from a sump located at one of the residences in the Claremont Development. Later, in January 1997, the Borough of Manville responded to complaints that a sinkhole had developed around a sewer pipe in the Claremont Development. Excavation of the soil around the sewer pipe identified a black, tar-like material in the soil. After an initial site investigation, EPA found contamination in both the surface and subsurface soils as well as in the groundwater beneath the site. In 1999, EPA placed the site on the NPL and divided it into three smaller units, called operable units (OU). OU1 consisted of the source contamination (free-product creosote) in the lagoon and canal areas of the Claremont Development. OU2 included other soil contamination in the Claremont Development, such as residually contaminated soil at properties over and near the lagoon and canal areas and the drip area of the former wood- treatment facility. OU2 also included contamination at a nearby day-care facility. OU3 included the Rustic Mall soil contamination as well as groundwater contamination throughout the site. EPA completed all major site cleanup work in November 2007, and the site was declared “construction complete” in March 2008. Ultimately, EPA performed cleanup activities on 93 of the 137 properties in the residential area as well as on the commercial portion of the site. EPA’s ongoing activities at the site include monitoring groundwater contamination, conducting 5-year reviews of contamination levels to ensure that the remedy remains protective of human health and the environment, and selling properties that EPA acquired during the remedial action. According to EPA officials, the agency could remove the site from the NPL as early as 2011; however, this decision will depend on the results of contamination monitoring at the site. Most Superfund sites progress through the cleanup process in roughly the same way, although EPA may take different approaches on the basis of site-specific conditions. After listing a site on the NPL, EPA initiates a process to assess the extent of the contamination, decides on the actions that will be taken to address that contamination, and implements those actions. Figure 2 outlines the process EPA typically follows, from listing a site on the NPL through deletion from the NPL. In the site study phase of the cleanup, EPA or a responsible party conducts a two-part remedial investigation/feasibility study (RI/FS) process. The first part of this process—the remedial investigation— consists of data collection efforts to characterize site conditions, determine the nature of the waste, assess risks to human health and the environment, and conduct treatability testing as necessary to evaluate the potential performance and cost of the treatment technologies that are being considered. During the second part of the RI/FS process—the feasibility study—EPA identifies and evaluates various options to address the problems identified through the remedial investigation. EPA also develops cleanup goals, which include qualitative remedial action objectives that provide a general description of what the action will accomplish (e.g., preventing contamination from reaching groundwater) as well as preliminary quantitative remediation goals that describe the level of cleanup to be achieved. According to EPA guidance, it may be necessary to screen out certain options to reduce the number of technologies that will be analyzed in detail to minimize the resources dedicated to evaluating less promising options. EPA screens technologies on the basis of the following three criteria: effectiveness: the potential effectiveness of technologies in meeting the cleanup goals, the potential impacts on human health and the environment during implementation, and how proven and reliable the technology is with respect to the contaminants and conditions at the site; implementability: the technical and administrative feasibility of the technology, including the evaluation of treatment requirements and the relative ease or difficulty in achieving operation and maintenance requirements; and cost: the capital and operation and maintenance costs of a technology (i.e., each technology is evaluated to determine whether its costs are high, moderate, or low relative to other options within the same category). After screening the technologies that it has identified, EPA combines selected technologies into remedial alternatives. EPA may develop alternatives to address a contaminated medium (e.g., groundwater), a specific area of the site (e.g., a waste lagoon or contaminated hot spot), or the entire site. EPA guidance states that a range of alternatives should be developed, varying primarily in the extent to which they rely on the long- term management of contamination and untreated wastes. In addition, containment options involving little or no treatment, as well as a no-action alternative, should be developed. EPA then evaluates alternatives using the nine evaluation criteria shown in table 1 and documents its selected alternative in a record of decision (ROD). Next, either EPA or a responsible party may initiate the remedial action that was documented in the ROD. Like the RI/FS, implementation of the remedial action is divided into two phases. The first phase is the remedial design, which involves a series of engineering reports, documents, and specifications that detail the steps to be taken during the remedial action to meet the cleanup goals established for the site. For EPA-led remedial actions, EPA may either select a private contractor to perform the remedial design or, under a 1984 interagency agreement with the Corps, assign responsibility for designing the remedial action to the Corps, which may select and oversee a private contractor to perform the design work. The second phase is the remedial action phase, where the selected remedy, as defined by the remedial design, is implemented. Similar to the design phase, for EPA-led remedial actions, EPA may either select a private contractor to perform the remedial action or assign the remedial action to the Corps, which would be responsible for contractor selection and oversight during the remedial construction. When physical construction of all remedial actions is complete and other criteria are met, EPA deems the site to be “construction complete.” Most sites then enter into an operation and maintenance phase, when the responsible party or the state maintains the remedy while EPA conducts periodic reviews to ensure that the remedy continues to protect human health and the environment. For example, at a site with soil contamination, the remedial action could be to build a cap over the contamination, while the operation and maintenance phase would consist of monitoring and maintaining the cap. Eventually, when EPA determines, with state concurrence, that no further remedial activities at the site are appropriate, EPA may delete the site from the NPL. The extent of the contamination in a residential area at the Federal Creosote site was the primary factor that influenced EPA’s risk assessment conclusions, remedy selection decisions, and site work priorities. EPA determined that risk levels were unacceptable given the site’s residential use. EPA then selected remedies for the site, taking into account space constraints and other challenges associated with a residential cleanup. Finally, EPA placed a high priority on scheduling and funding site work because the contaminated area was residential, thereby reaching key cleanup milestones relatively quickly. From the spring of 1997 to the summer of 2001, EPA conducted multiple rounds of sampling and risk assessment at the Federal Creosote site and concluded that human health risks exceeded acceptable levels. Specifically, EPA assessed the air, groundwater, surface soil, and subsurface soil as part of an initial site investigation and an RI/FS process. See appendix III for a timeline of EPA’s risk assessment activities. EPA’s initial investigation of site contamination, which began in 1997, included such efforts as assessing whether contamination was affecting public drinking water supplies; investigating the nature of the bedrock and the aquifer underlying the site; collecting soil samples from 30 properties selected on the basis of their proximity to the lagoons, canals, and drip area of the former wood-treatment facility; and collecting approximately 1,350 surface soil samples (up to 3 inches below the ground surface) from 133 properties in and near the residential development. From this initial investigation, EPA concluded that site contamination posed unacceptable human health risks.