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    Statement by
    Rosemary Sokas, M.D., M.O.H.
    Associate Director for Science, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, U.S. Department of Health and Human Services
    CDC's Participation in Cleanup Activities at the Brentwood Mail Processing and Distribution Center
    before the
    House Committee on Government Reform Subcommittee on the District of Columbia

    July 25, 2002

    Madame Chairwoman and members of the Subcommittee, my name is Dr. Rosemary Sokas, and I am Associate Director for Science with the National Institute for Occupational Safety and Health within the Centers for Disease Control and Prevention (CDC). On behalf of the CDC and the Agency for Toxic Substances and Disease Registry (ATSDR), I am pleased to provide this testimony describing cleanup and safety-related activities involved in reopening the U.S. Postal Services's (USPS) Brentwood Mail Processing and Distribution Center in Washington, D.C. (the "Brentwood facility"), the building that was the most severely affected by the anthrax attacks of last Fall.

    The CDC and ATSDR are part of the Department of Health and Human Services (DHHS). As the nation's disease prevention and control agency, it is CDC's responsibility on behalf of DHHS to provide national leadership in the public health and medical communities in a concerted effort to detect, diagnose, respond to, and prevent illnesses, including those that occur as a result of a deliberate release of biological agents. This task is an integral part of CDC's and ATSDR's overall missions to monitor and protect the health of the U.S. population by preventing and controlling disease, injury, and disability.

    Today I will review CDC and ATSDR's response activities at the Brentwood facility following last year's anthrax attacks, describe our role in the cleanup work being conducted there, and discuss safety issues involved with the decontamination and reopening of the building. The CDC and ATSDR's focus is on protecting the health and safety of the people who work at the Brentwood facility, their families, and the general public. Therefore we continue to work diligently with our federal, state, and local public health partners toward the goal of successfully remediating the Brentwood facility.


    During the anthrax attacks of 2001, CDC assumed a wide range of responsibilities including surveillance to detect new cases of illness; epidemiologic investigations to assess the risks of infection; collection of environmental samples to determine the extent of contamination in affected buildings; analysis of environmental and clinical laboratory specimens; delivery of stockpiled antibiotics and vaccine; follow-up of persons receiving stockpile items; and communication with the public and with public health professionals to provide up-to-date guidance and recommendations.

    One area of CDC and ATSDR focus was the assessment and cleanup of facilities contaminated as a result of the anthrax attacks. We refined methods for environmental testing to determine whether and how extensively anthrax contamination had occurred. This included both air and surface testing. Based on the best available information and ongoing experience, CDC and ATSDR issued and subsequently updated recommendations for conducting environmental sampling and how laboratories should analyze those samples to identify contaminated areas, to characterize the extent of contamination, and to guide cleanup. We also have developed guidelines related to matters of worker safety, such as recommendations for personal protective equipment and medical surveillance for first responders and cleanup workers.

    Throughout these efforts, we have provided technical input to the Environmental Protection Agency (EPA), which is assigned lead responsibility for cleaning up buildings and other sites contaminated by chemical or biological agents as a result of an act of terrorism. These recommendations have been widely disseminated to federal, state, and local health and environmental agencies, and are available at CDC's bioterrorism website ( Our review of the lessons learned from these activities is ongoing and will be used to update our recommendations for responding to anthrax contamination.

    Past CDC and ATSDR Activities at the Brentwood Postal Facility

    During October 19-21, 2001, four postal workers at the Brentwood facility in Washington, D.C., were hospitalized with an illness that was subsequently diagnosed as inhalational anthrax. Two of these employees died as a result of their exposure. Subsequent investigations indicated that the Brentwood facility, the primary mail processing center receiving mail addressed to Zip codes in the Washington, D.C. area, had been contaminated by the letters sent to Senators Daschle and Leahy which were discovered to contain Bacillus anthracis spores and to have contaminated the Hart Senate Office building. These letters passed through the Brentwood facility on the morning of Friday, October 12, 2001.

    The Brentwood facility was closed Sunday, October 21, when the first diagnosis of inhalational anthrax in a Brentwood employee was made. Beginning Monday, October 22, investigators from CDC, the USPS, and a USPS contractor began evaluating the extent of B. anthracis contamination there. This first investigation showed widespread contamination inside the facility, particularly around Delivery Bar Code Sorter machine #17, which had processed the spore-containing letters, and in the Government Mail area, where the letters had been processed for distribution to U.S. government locations.

    From December 17 through 20, 2001, investigators from CDC, ATSDR, the USPS, and a USPS contractor conducted an additional investigation at the Brentwood facility. This investigation had both an immediate health and safety purpose with respect to Brentwood and broader applied research goals regarding how to assess and clean up anthrax contamination. The immediate objective was to conduct additional surface sampling at the Brentwood facility to more thoroughly characterize the distribution of B. anthracis spores throughout the facility, including areas where workers did not become ill, and within the building ventilation system. The broader goals were to compare the effectiveness of different methods for collecting the samples used to detect anthrax spores on surfaces, to compare the results of different methods for analyzing those samples, and to evaluate the effectiveness of cleanup efforts to remove spores from known contaminated surfaces.

    The results of this two-pronged investigation were shared with staff at the Brentwood facility, USPS management, the postal workers unions, and the District of Columbia Department of Health. This information has been presented in scientific conferences and incorporated into our recommendations, improving our national capacity for present and future responses to anthrax.

    Current and Future CDC and ATSDR Role at Brentwood Postal Facility

    Since the completion of that investigation, CDC and ATSDR scientific staff have been working with experts from EPA, D.C. Department of Health, USPS, Department of Defense, and the Occupational Safety and Health Administration to review and provide input into the draft cleanup plans. The goal is to provide the USPS and the Brentwood Incident Commander and his team of consultants with the advice they need to ensure that these plans incorporate the best available protection for workers and the community. These plans address issues such as the strategies for environmental remediation of the facility, the type of environmental sampling needed to evaluate the effectiveness of remediation, and measures to ensure that workers and the general public are protected during cleanup operations. In addition, we currently are in discussion with the USPS about the specific role that CDC and ATSDR might play in conducting laboratory analysis of environmental samples collected from the Brentwood facility.

    The D.C. Department of Health and the EPA are leading a multi-agency panel that will review the post-cleanup sampling data from Brentwood and advise when it is appropriate to re-occupy the building and return it to normal service. CDC representatives are participating in this panel.

    To best protect the workers who will re-occupy the Brentwood facility, decisions about re-occupancy should be based on data that are the highest quality available. CDC believes data should appropriately reflect site-specific contamination, past epidemiology findings, and remediation factors, using the best and most current science and sampling methods. That sampling must be thoroughly and rigorously conducted, and techniques used for sample collection and for cleanup should be those shown to be valid and effective. As with the Hart Building cleanup, the standard for determining that the building is clean should be that samples collected after cleanup show zero detectable spores.

    As with any other public health problem, it is the goal of the CDC to use the best science and technology available to minimize the risk of illness and disease to the greatest extent possible. It is not possible to eliminate risk entirely or guarantee that a building is absolutely free of risk. But as with the successful re-occupancy of the Hart building, we believe that a science-based process can allow a determination that the remediation was successful, that rigorous sampling was unable to find any residual viable spores, that workers can safely return, and that normal service to the public can safely resume.

    CDC is working with local health departments to take other steps at the Brentwood facility, such as investigating deaths that have occurred over the past nine months among Postal Service employees to determine if there have been more deaths than usual or any suspicious deaths that might be related to anthrax. Our investigations have not found any factors different from what would be expected during a typical year. We plan to issue an updated report from this investigation in the next several weeks.


    In summary, since shortly after the anthrax attacks of last year, CDC and ATSDR have been involved in assisting with response efforts at the buildings contaminated by anthrax spores. At the Brentwood postal facility, we helped to determine the extent and distribution of contamination, assessed the effectiveness of sampling methods, and evaluated cleanup methods. We continue to assist the USPS, EPA, and others responsible for decontamination of the Brentwood facility by providing statistical, methodological, technical, and risk assessment consultation regarding sampling to assess whether anthrax spores remain after decontamination efforts are carried out. We are developing approaches and procedures based on the knowledge we have gained to date. These approaches may continue to evolve as we learn more. CDC and ATSDR remain committed to the goal of protecting the health and safety of postal workers returning to the Brentwood facility, the public that uses the facility, and the neighboring community.

    Thank you. I will be glad to answer any questions you may have.

Last Updated: May 13, 2003