The vermiculite ore mined at Libby, Montana, between 1923 and the early 1990s contained high concentrations of naturally occurring asbestos minerals, including tremolite, winchite, richterite, and others (see fig. 1). As the ore was mined and processed, dust containing asbestos fibers was released into the air, which workers then inhaled. By the early 1900s, asbestos was recognized as a cause of occupational disease. Initially, the disease associated with asbestos was asbestosis, a nonmalignant respiratory disease characterized by scarring of the lung tissue that may progress to significant impairment and death. During the 1930s and 1940s, the connection between asbestos exposure and lung cancer emerged. By 1960, the connection between asbestos and mesothelioma—a cancer of the mesothelial lining of the lungs—was established. Diseases stemming from exposure to asbestos may not be apparent for decades after the initial exposure. Thus, even though the Libby mine closed around 1990, many residents, former workers, and others who were exposed to the asbestos-contaminated ore, recently have been diagnosed with asbestos- related diseases and many more may become ill in the future. EPA’s involvement with Libby’s asbestos-contaminated vermiculite ore dates back to the late 1970s and continued intermittently until 1999, when the agency initiated an investigation that led to ongoing cleanup activities in the Libby area. In 1978, EPA learned that workers at a vermiculite processing plant in Marysville, Ohio—one of hundreds of sites across the United States where Libby vermiculite ore was sent—were exhibiting symptoms of asbestos-related diseases. Between 1980 and 1982, EPA issued a series of reports related to asbestos-contaminated vermiculite. Most of these reports indicated that there was a lack of data on both exposure to asbestos-contaminated vermiculite and its adverse health effects. Further, the reports identified problems in sampling, analysis, and reproducibility of data regarding low levels of asbestos in vermiculite, which made it difficult to acquire data on exposure and health effects. One of the studies also noted that EPA needed to develop more information identifying, among other things, the vermiculite-mine sites, the processors of vermiculite, and the potential number of employees exposed to asbestos-contaminated vermiculite. In a February 1985 report, EPA estimated the levels and ranges of exposure to asbestos-contaminated vermiculite for workers and the general public and indicated that, with further study, this information could be used for regulatory decision making. This report contained a list of the locations of 52 exfoliation plants in the United States that had received vermiculite ore from the Libby mine. Even so, EPA did not initiate any action at the time and, until 1999, did little to address concerns about the health risks associated with exposure to asbestos-contaminated vermiculite ore. In 1999—after a series of newspaper articles reporting that miners and their families in the area of Libby, Montana, had died or were ill from exposure to the asbestos-contaminated vermiculite ore—EPA began investigating the contamination in the Libby area and began cleaning up the contamination in 2000. Subsequently, concerns were raised about why EPA had not taken action much earlier in Libby, which resulted in investigations by both the EPA Office of Inspector General and GAO. The subsequent reports concluded that, due to various challenges, EPA missed past opportunities to take steps that might have protected the citizens of Libby. These challenges included (1) fragmented regulatory authority and jurisdiction with other federal agencies and within EPA, along with ineffective communication, which made it difficult for EPA to take action; (2) limitations of science, technology, and health-effects data that made it difficult for EPA to determine the degree of health risk at Libby; and (3) funding constraints and competing priorities, which led EPA to de- emphasize dealing with asbestos-contaminated vermiculite. Since these reports were issued, as part of an ongoing criminal case against W.R. Grace, the government has alleged that Grace engaged in a conspiracy to defraud EPA and the National Institute for Occupational Safety and Health by concealing and misrepresenting the nature of the asbestos-containing vermiculite produced at the mine. Grace has denied the allegations. When EPA began cleaning up contamination in the Libby area in 2000, it also took steps to identify and evaluate sites that may have received shipments of Libby ore for asbestos contamination according to CERCLA. Under NCP regulations that implement CERCLA, a removal site evaluation involves, among other things, identifying the source and nature of any hazardous-substance release, analyzing the magnitude of the potential threat to human health and the environment, and evaluating factors necessary to make the determination of whether a removal is necessary. According to NCP regulations, when EPA is the lead agency for a cleanup, an EPA region must take certain actions, as appropriate, to notify the public about a removal action. These actions include (1) designating a spokesperson to notify immediately affected citizens and state and local officials about the cleanup; (2) creating a record documenting the basis for the cleanup action and making the record publicly available; (3) publishing a notice that the record is available for review in a major local newspaper; and (4) providing an opportunity for the public to comment on the record. When EPA expects the cleanup action to last more than 120 days, the regional office must also conduct interviews with interested or affected parties, prepare a formal community response plan, and establish at least one local information repository at or near the cleanup location, such as at a public library. EPA has also issued numerous policy directives and guidance documents over the years establishing additional public notification procedures that EPA regions should follow. For example, EPA guidance issued in July 1992 directed regions to interact closely with and reach out to communities. This guidance specifies that one of the goals of public participation is to inform the public about the risks associated with a site and any cleanup actions. The guidance also states that it is imperative for EPA to give the public prompt, accurate information about the nature of threats to public health and the environment, and the removal action necessary to mitigate the threats. In its April 2002 guidance, EPA stated that just complying with NCP provisions is often insufficient for informing the media, the public, and interested stakeholders. This guidance strongly suggested the regions use other options for meeting community needs, such as scheduling press briefings; establishing a local or toll-free telephone hotline; and canvassing neighborhoods to identify residents’ needs, fears, and concerns. ATSDR has provided information to EPA to help assess the risks posed by potential asbestos contamination at selected sites that received Libby ore. Specifically, in 2002, ATSDR launched the first phase of its National Asbestos Exposure Review. Under this phase of the project, ATSDR evaluated human health effects that may be associated with past or current exposure to asbestos at 28 of the sites that had received and processed the vermiculite ore mined in Libby, Montana. These sites were selected because they received a high-volume of Libby ore (greater than 100,000 tons) or EPA identified them as needing further investigation. These 28 sites together received about 80 percent of the vermiculite ore shipped from the Libby mine between 1964 and 1980. EPA, with assistance from other federal and state agencies, has assessed 271 sites that were thought to have received asbestos-contaminated ore from Libby, Montana, to determine if the sites are contaminated with asbestos and if they need cleanup. As a result of these investigations, 19 sites were identified as requiring cleanup. As a part of ATSDR’s effort to evaluate public-health risks posed by past and current exposures to asbestos contamination in the Libby area and at some of the sites that received the Libby ore, ATSDR has noted there is an absence of key information on the toxicity of the asbestos found in the Libby ore. ATSDR also noted that the methods EPA used to sample and analyze the air and soil at most of the 28 sites it reviewed have since been improved and now better quantify asbestos levels. After the EPA Office of Inspector General recommended in December 2006 that EPA perform a toxicity assessment to determine safe levels of exposure for humans, EPA agreed to do so. EPA has taken a number of actions to identify and evaluate sites that may have received Libby ore and, when needed, has conducted removal actions. In early 2000, EPA began compiling a list of facilities that might have received asbestos-contaminated vermiculite ore from the Libby mine. To compile the list, it used shipping records and other information obtained from W.R. Grace as well as historical information about vermiculite processing facilities from the Bureau of Mines and the U.S. Geological Survey. Initially, EPA identified over 500 sites, but after coordinating with the U.S. Geological Survey to update and revise the list of facilities and eliminate duplicate entries, EPA narrowed the list to less than 300 potential sites. The data that EPA collected on the sites believed to have received Libby ore paint a picture of the distribution of Libby ore across the United States. Figure 2 illustrates the nationwide distribution based on 195 sites for which data on the amount of ore shipped were available. These 195 sites are believed to have received a combined total of at least 6 million tons of ore from the Libby, Montana, mine and ore processing operations. The 271 sites were located in 39 states, the District of Columbia, and Puerto Rico. The most sites were in California (28) and Texas (26). EPA has continued to identify sites and will investigate them as it deems necessary. For example, in 2006, EPA identified additional sites (included in the 271) that it needed to assess for asbestos contamination.