Testimony

Statement by
John Wheeler, Ph.D., D.A.B.T.
Environmental Health Scientist
Senior Toxicologist
Agency for Toxic Substances and Disease Registry
U.S. Department of Health and Human Services
on
ATSDR’s Asbestos-Related Work in El Dorado Hills, California
before
Joint Informational Hearing of the Health Committee and
Environmental Quality Committee
California State Senate

May 11, 2005

Introduction
Good afternoon Madam Chair, Mr. Chairman, and Members of the joint Committees. My name is Dr. John Wheeler. I am a senior toxicologist at the Agency for Toxic Substances and Disease Registry (ATSDR). ATSDR is the principal federal public health agency charged with evaluating the human health effects of exposure to hazardous substances. The agency’s mission is to serve the public by using the best science, taking responsive public health actions, and providing trusted health information to prevent harmful exposures and disease-related exposures to toxic substances.

ATSDR was created by the Comprehensive Environmental Response, Compensation, and Liability Act of 1980, more commonly known as the Superfund law. The Superfund program is responsible for finding and cleaning up the most dangerous hazardous waste sites in the country. Currently, the U.S. Environmental Protection Agency (EPA) lists for cleanup 1244 National Priority List (NPL) sites. ATSDR leads federal public health efforts at these and other sites with actual or potential toxic exposures. In accomplishing this purpose, ATSDR’s priorities include 1) mitigating the risks of health effects at sites with documented exposures, 2) preventing exposures and resulting health effects, and 3) determining health effects associated with exposures.

I have been leading ATSDR’s work in El Dorado Hills, and have significant responsibility in the Agency’s other asbestos-related work. As you may be aware, asbestos is a name given to a group of six different fibrous minerals that occur in the environment. There are two main families of asbestos fibers: the serpentine form, such as crysotile, and the amphiboles, including crocidolite, amosite, and tremolite. Chrysotile is the most common type of fibrous serpentine, with long, flexible fibers, and it is the type most commonly used in commercial products. Amphibole fibers, on the other hand, are brittle, having a rod or needle shape. Although exposure to both types of asbestos increases the likelihood of developing asbestos-related diseases, amphibole fibers tend to stay in the lungs longer and are thought to increase the likelihood of illness, especially mesothelioma, to a greater extent than chrysotile asbestos. The type of asbestos found at El Dorado Hills is primarily amphibole asbestos.

I will begin my testimony with a brief discussion of ATSDR’s involvement with asbestos issues. Our most recent experiences begin in 1999 in the town of Libby, Montana, where vermiculite ore contaminated with amphibole asbestos was mined and processed from the early 1920s until 1990. I will then discuss our work at El Dorado Hills.

ATSDR’s Work In Libby, Montana
Since 1999, ATSDR has been working closely with the EPA, the State of Montana, and other federal, state, and local agencies in evaluating the environmental health impact of asbestos exposure and implementing appropriate public health interventions in the Libby community. ATSDR has completed a public health assessment, a medical screening program, and a review of asbestos-related mortality rates in Libby.

Results of these activities and additional evaluations conducted by ATSDR, EPA, and the State of Montana indicate that people who worked in the Libby mine or processing facilities belonging to W.R. Grace Company and people who lived in the Libby community were exposed to asbestos through contaminated vermiculite, a mineral that was processed into a variety of products, including insulation.

ATSDR undertook medical screening of over 7,300 persons who were potentially exposed to the asbestos in Libby vermiculite. Nearly 18% of medical screening participants had radiographic pleural abnormalities consistent with asbestos exposure. Of the former W.R. Grace employees receiving x-rays, 51% had pleural abnormalities and 3.8% had interstitial lung abnormalities. Mortality due to lung cancer and asbestosis was also found to be elevated in Libby. ATSDR has implemented a Tremolite Asbestos Registry (TAR) of exposed persons (tremolite is one of the amphibole asbestos types found in Libby). The TAR will allow for tracking the health of individuals exposed to tremolite asbestos from the mine in Libby. ATSDR also has funded the State of Montana to conduct additional periodic medical surveillance for eligible persons.

ATSDR’s Work in Addressing Potential Libby Asbestos Exposures Elsewhere in the United States
Records indicate that the vermiculite ore from Libby was shipped to over 200 locations around the United States for handling and/or processing into various commercial and consumer products. In a project called the National Asbestos Exposure Review (NAER), ATSDR is working with other federal, state, and local public health agencies to evaluate past and present exposure pathways at sites that received Libby vermiculite to determine if there was (or is) a hazard to public health at any of these sites.

These exposure pathway investigations are initially being conducted at 28 “Phase One Sites” that have been identified for evaluation on the basis of the nature of processing performed, tonnage received, and current site conditions. The findings for these Phase One sites will guide our future actions with regard to other sites that received and processed vermiculite ore from Libby. Health statistics reviews (to evaluate mortality and/or cancer registry data) are currently under way in 25 states, and pilot mesothelioma surveillance has been initiated in three states (New York, Wisconsin and New Jersey). In addition, ATSDR has funded a comprehensive community exposure assessment project in a community in Minnesota where neighborhoods may have been exposed to particulate air emissions and/or waste dumping from a plant that received asbestos-containing vermiculite ore from Libby, Montana. ATSDR is also funding a study to evaluate the progression of asbestos-related pulmonary abnormalities among a group of workers in Ohio who had past exposure to Libby vermiculite.

Although these methodologies have certain limitations, for the five health statistics reviews completed to-date, ATSDR did not find any significant excess of asbestos related mortality or asbestos related malignancies in communities near the sites. For the twelve health consultations completed to-date, ATSDR has determined that former workers and household contacts were likely to have been exposed to asbestos released during vermiculite processing and that further public health intervention is warranted for these groups.

What Has ATSDR Done in El Dorado Hills, California?
ATSDR’s work in El Dorado Hills, addressed in the Health Consultation released last week for public comment, concerns public health implications of asbestos exposure at the Oak Ridge High School. ATSDR concludes that, because exposures have been minimized, the school currently poses no apparent public health hazard. However, those likely to have experienced the greatest exposures to asbestos in the past, through outdoor activities around the athletic fields and tracks – coaches, student athletes, and outdoor maintenance staff – may be at increased risk of developing asbestos-related disease.

As you are aware, Oak Ridge High School is located in El Dorado Hills, California, about 30 miles northeast of Sacramento in El Dorado County. Naturally occurring asbestos (NOA)—as opposed to asbestos encountered through mining or processing—has been identified in rocks and soils on and around school property. ATSDR became involved through our petition process, by which a community member requested that the Agency evaluate the public health implications of current and past asbestos exposures to students and staff at the high school. ATSDR has investigated the asbestos exposures at the school, prepared a public health consultation, and released the findings of the health consultation to the public on May 6, 2005.

Sampling by the school district and the EPA showed that asbestos, of the amphibole variety, is in soil and in air near disturbed soil on the school grounds. ATSDR is concerned with the health implications of breathing in asbestos fibers because exposure can be associated with pleural disease, asbestosis, lung cancer, and mesothelioma. ATSDR is well aware that many issues in asbestos science are currently debated among scientists, including the role of mineralogy and fiber size in toxicity, the best means of assessing exposure, and methods for measuring disease within an exposed population.

To this end, ATSDR has used its experience at numerous sites across the nation, combined with the best science possible, to determine the impact of asbestos exposure on students, faculty, and staff at Oak Ridge High School. To assess the impact of asbestos exposures on the Oak Ridge High School community, ATSDR used information from several agency public health activities. These activities include use of an expert panel on the role of fiber size in asbestos toxicity following the World Trade Center disaster; experience in testing asbestos-exposed populations in Libby Montana; agency work to improve asbestos toxicity assessment; and experiences throughout the agency’s years in educating the public, training health care workers, and mitigating exposures.

To provide the best science possible, ATSDR has participated in and hosted a number of workshops in asbestos exposure and toxicity assessment. To ensure scientific integrity, ATSDR asked three asbestos science experts who have no affiliation with ATSDR to peer-review the public health consultation. The purpose of the peer review was to ensure that the evaluation performed in the document used the best science, given the nature of the available information. ATSDR released the public health consultation (including peer review comments and our responses) to the public for comment on May 6, 2005.

ATSDR has provided an active federal presence in the El Dorado community by participating in a public meeting organized by EPA in February 2004; by distribution of a newsletter to the community on agency activities in June 2004; by a presentation on the agency's experience and knowledge about health effects of amphibole asbestos at a science seminar organized by EPA in August 2004; by responding to numerous phone calls and emails from community members; and by conducting teleconferences with community organizations, among other activities. The agency plans to continue its involvement with the El Dorado community and provide another health consultation that will discuss the broader community-wide data recently collected by EPA.

What Were ATSDR’s Findings?
In general, ATSDR has found that past exposures at the high school were high enough to warrant health concern within certain groups. These groups include coaches, outdoor maintenance workers, and student athletes, because they are most likely to have had greater exposure to asbestos through outdoor activities at school locations where asbestos was found. ATSDR also found that, as a result of the remedial actions taken by EPA, there is no health concern related to current exposure. However, ATSDR recommends that appropriate operations and maintenance be carried out to ensure against recontamination.

ATSDR concludes that EPA and the school district personnel have removed the potential for exposure to asbestos on the school campus. Specifically, the classrooms have been cleaned and tested for asbestos, and all bare areas and soils containing asbestos have been either covered with clean fill or landscaped to prevent the release of asbestos fibers. ATSDR determined that current asbestos exposures at the school have been minimized and are not likely to increase the risk of disease.

The available data about past exposures and amphibole toxicity are insufficient to permit an accurate estimation of the risk from past exposures. However, ATSDR used the available data to reach general conclusions about likely exposures and to obtain a general sense of the health effects that could result from exposure. This evaluation of the data indicates that potential exposures to amphibole asbestos in the past were high enough to increase the risk of adverse health effects for highly exposed groups. These potentially highly exposed groups include coaches, outdoor maintenance workers, and student athletes, because they are most likely to have been exposed during the time they spent at the school fields and tracks.

This does not mean that people in these groups who were exposed in the past will develop asbestos-related disease. It means that potential exposures were high enough to increase risk and that it was necessary to take action to prevent further exposure by cleaning classrooms and covering soils or landscaping.

In summary, ATSDR finds:

  1. Current exposures to asbestos at Oak Ridge High School have been minimized by cleaning classrooms and covering or landscaping bare areas of soil throughout the campus.

  2. Exposures to amphibole asbestos probably occurred in the past. The greatest exposures were likely experienced by coaches who spent substantial time on athletic fields and tracks, by outdoor maintenance staff, and by student athletes.

  3. Past exposure to amphibole asbestos increases the risk of developing mesothelioma and other lung diseases. Not enough information exists to permit an accurate estimation of this risk. Groups who had the highest exposures would have more risk of developing asbestos-related disease. However, the increased level of risk does not necessarily mean that disease will result.

  4. Studies on the prevalence and magnitude of amphibole asbestos exposures outside Oak Ridge High School will provide information essential for determining the risk of developing asbestos-related disease in community members as a whole.

The recommendations of the health consultation are the following:

  1. The school district should carry out the operations and maintenance plan to ensure that cleaned classrooms and campus areas remain free of asbestos over time.

  2. Because some increased risk of developing asbestos-related disease is possible, people in the most highly exposed groups (coaches, outdoor maintenance staff, and student athletes) should inform their physicians about their potential asbestos exposure. Their physicians can offer appropriate preventive care and watch for early signs of disease. If the time since a person was first exposed is greater than 10 years (the minimum time for asbestos-related lung changes to occur) or if a person has symptoms of respiratory disease, the physician may recommend consultation with a specialist who has expertise in asbestos-related disease. ATSDR physicians are available to provide advice to private physicians, if requested, and are developing outreach programs to educate local healthcare providers about asbestos-related disease.

  3. The state should continue to monitor health outcome data for asbestos-related disease.

  4. ATSDR should investigate the potential for amphibole asbestos exposure in the community as a whole and use this information to study the link between low-level environmental exposures and resulting health effects in communities.

  5. The El Dorado County Air Quality Management District should ensure full enforcement of state and county air toxics regulations to minimize potential asbestos exposures in the community.

  6. Homeowners should follow local and state recommendations for minimizing asbestos exposure around the home.

What Are the Next Steps for ATSDR in El Dorado Hills?

  1. ATSDR will evaluate additional EPA data collected in other areas of the county to assess risks of amphibole exposure at Oak Ridge High School and other nearby areas with naturally occurring asbestos.

  2. ATSDR will use this information to evaluate the necessity and feasibility of conducting appropriate health studies for Oak Ridge High School and the community.

  3. ATSDR will also evaluate the necessity and feasibility of maintaining a registry to track potentially exposed people in the area.

  4. ATSDR will provide information and recommendations to the community and health care providers on asbestos-related disease.

  5. ATSDR will collect and analyze community-level data (i.e., individual concerns, questions, and news media content) and provide community education as indicated.

Madame Chair, this completes my testimony, and I am pleased to answer your questions at this time.

Last Revised: May 17, 2005