U.S. Postal Service:

Issues Associated with Anthrax Testing at the Wallingford Facility

GAO-03-787T: Published: May 19, 2003. Publicly Released: May 19, 2003.

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The anthrax attacks of 2001 resulted in 23 cases of the disease, 5 deaths, and the contamination of numerous U.S. Postal Service facilities, including the Southern Connecticut Processing and Distribution Center in Wallingford, Connecticut (the Wallingford facility). But none of the workers at the Wallingford facility contracted the disease from the anthrax contamination. As a result, GAO was asked to examine the adequacy of methods used to determine whether the Wallingford facility and other postal facilities were contaminated. In this testimony, GAO presents its preliminary findings concerning the test results for the Wallingford facility: (1) the collection of samples to detect anthrax, (2) the meaning of the test results, and (3) the communication of the test results to workers.

At the Wallingford facility, it took four attempts before anthrax contamination was eventually identified. The first two attempts by U.S. Postal Service contractors collected samples at various places in the facility, using dry swabs, the least effective method for sample collection. The Postal Service nationwide sampling plan required that contractors use dry swabs to collect anthrax samples at more than 280 facilities, including Wallingford. But the Centers for Disease Control and Prevention (CDC), in commenting on the plan, had recommended that the Postal Service use other sampling methods. Nevertheless, the Postal Service did not revise its sampling plan, and, with a few exceptions, has not retested the other facilities that had negative test results. In the third attempt, CDC and the Agency for Toxic Substance and Disease Registry also found no contamination using wet swabs, but in the fourth attempt--using wet wipes and HEPA vacuums to collect the samples--they found contamination in samples from mail-sorting machines. Anthrax test results, whether qualitative (positive or negative) or quantitative, cannot be interpreted as a health risk, based on current scientific knowledge. Positive test results establish the presence of contamination, but only in the samples collected. Quantitative test results, although more definitive, only indicate the extent of contamination in the samples collected, not the amount present in the whole facility. Negative results, as the initial tests at the Wallingford facility demonstrated, do not necessarily mean that a facility is free from contamination. As EPA recently reported, knowledge of the "lethal dose" (the number of spores required to kill 50 percent of people exposed to airborne anthrax) is necessary for a credible health risk assessment. Although previous estimates of a lethal dose--8,000 t o 10,000 spores--are being reconsidered, there is still no agreement on the lethal dose. However, some experts now agree that only a few spores could be harmful to a susceptible individual. As CDC also concluded, even with numbers of spores as high as those found in one sample from one mail-sorting machine at Wallingford--about 3 million spores--CDC did not know how to extrapolate the quantitative test results to an individual's risk for inhalation anthrax. In an April 2003 report, GAO found that the Postal Service's communication of test results to workers at the Wallingford facility generally appears consistent with its guidelines. But the decision not to release the first positive quantitative test results, after a worker' union requested them, was not consistent with OSHA's requirement to disclose requested results. The Postal Service said it did not release the December 2001 quantitative results because it could not validate them, as required by its guidelines, which, however, do not define validation or use it appropriately. The Postal Service communicated the results to workers as "trace" and "a concentration of spores"--terms that did not provide workers with useful information needed to make health-related decisions. It has agreed to revise the guidelines as GAO recommended. Further communications appear warranted based on GAO's ongoing work.

Recommendations for Executive Action

  1. Status: Closed - Implemented

    Comments: The Postal Service set up a working group composed of CDC, EPA, postal, and other agency officials to reassess the risk level and reconsider whether additional facility testing is needed. The resulting report, dated August 2004, provides the results of the working group's assessment. According to the report, the working group concluded that the risk to postal workers and the public is negligible, in part because continued epidemiological tracking has not revealed additional cases of anthrax disease.

    Recommendation: The impact of additional anthrax cases could result in illness or loss of life as well as loss of confidence in the nation's postal system. Further, even though the health risk is probably low, it is uncertain; therefore, the Postmaster General should, in consultation with CDC, the Environmental Protection Agency (EPA), the Occupational Safety and Health Administration (OSHA), as well as any other relevant agencies and postal unions, for those facilities that were deemed to free of anthrax spores based solely on a single negative sampling result, reassess the risk level for postal workers at those facilities and the general public served by those facilities.

    Agency Affected: United States Postal Service

  2. Status: Closed - Implemented

    Comments: The Postal Service set up a working group composed of CDC, EPA, postal, and other agency officials to reassess the risk level and reconsider whether additional facility testing is needed. The resulting report, dated August 2004, provides the results of the working group's assessment. According to the report, the working group concluded that the risk to postal workers and the public is negligible, in part because continued epidemiological tracking has not revealed additional cases of anthrax disease. Thus, according to the working group, there is no need to conduct additional testing.

    Recommendation: The impact of additional anthrax cases could result in illness or loss of life as well as loss of confidence in the nation's postal system. Further, even though the health risk is probably low, it is uncertain; therefore, the Postmaster General should , in consultation with CDC, EPA, OSHA, as well as any other relevant agencies and postal unions, for those facilities that were deemed to free of anthrax spores based solely on a single negative sampling result, reconsider the advisability of retesting those facilities and employing the most effective sampling methods and procedures.

    Agency Affected: United States Postal Service

  3. Status: Closed - Implemented

    Comments: The Postal Service set up a working group composed of CDC, EPA, postal, and other agency officials to reassess the risk level and reconsider whether additional facility testing is needed. The resulting report, dated August 2004, provides the results of the working group's assessment. According to the report, the working group concluded that the risk to postal workers and the public is negligible, in part because continued epidemiological tracking has not revealed additional cases of anthrax disease. Thus, according to the working group, there is no need to conduct additional testing. The Postal Service communicated the working group's results to postal workers and the public, including the rationale for the group's decisions.

    Recommendation: The impact of additional anthrax cases could result in illness or loss of life as well as loss of confidence in the nation's postal system. Further, even though the health risk is probably low, it is uncertain; therefore, the Postmaster General should, in consultation with CDC, EPA, OSHA, as well as any other relevant agencies and postal unions, for those facilities that were deemed to free of anthrax spores based solely on a single negative sampling result, communicate to the postal workers and the general public the results of the reassessment of health risk, the advisability of retesting, the rationale for these decisions, and other relevant information that may be helpful regarding the health of the postal workers and the general public.

    Agency Affected: United States Postal Service

 

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