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Testimony:

Before the Subcommittee on National Security, Emerging Threats, and 
International Relations, House Committee on Government Reform:

United States General Accounting Office:

GAO:

For Release on Delivery Expected at 1:00 p.m. EDT:

Monday, May 19, 2003:

U.S. POSTAL SERVICE:

Issues Associated with Anthrax Testing at the Wallingford Facility:

Statement of Keith Rhodes, Chief Technologist 
Center for Technology and Engineering, 
Applied Research and Methods:

Bernard Ungar, Director 
Physical Infrastructure Issues:

U.S. Postal Service:

GAO-03-787T:

GAO Highlights:

Highlights of GAO-03-787T, a testimony before the Subcommittee on 
National Security, Emerging Threats, and international Relations, 
House Committee on Government Reform 

Why GAO Did This Study:

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.

What GAO Found:

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 to 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’s 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.

What GAO Recommends:

In addition to its April 2003 recommendations, for those facilities 
that were deemed to be free of anthrax spores based solely on a single 
negative result, GAO recommends that the Postmaster General work with 
CDC, EPA, OSHA, and other relevant agencies, and union representatives 
to (1) reassess the risk level associated with contamination, (2) 
reconsider the advisability of retesting, and (3) communicate any 
relevant health-related information to postal workers and the public.

[End of figure]

May 19, 2003:

Mr. Chairman and Members of the Subcommittee:

We are pleased to be here today to present our findings on anthrax 
testing conducted by the U.S. Postal Service (USPS) and the Centers for 
Disease Control and Prevention (CDC) at the Southern Connecticut 
Processing and Distribution Center in Wallingford, Connecticut (the 
Wallingford facility). As you know, in September and October 2001, four 
letters containing anthrax spores were mailed to news media personnel 
and congressional officials. As a result, the letters contaminated 
numerous postal facilities and exposed several postal workers to 
anthrax.[Footnote 1] Some of the workers became sick, and two died of 
inhalation anthrax. Three others also died from inhalation anthrax, 
including an elderly woman in Connecticut--a postal customer. After 
contamination was found in the Wallingford facility, a union official 
raised concerns regarding how postal managers communicated test results 
to workers. We have issued a report in this regard.[Footnote 2]

Even though our analysis of the Wallingford incident is only one part 
of our larger study, it gives unique insight into the lessons that need 
to be learned from the response of the federal government, state health 
departments, and USPS to the anthrax attacks in the fall of 2001. All 
of these entities served either as direct responders or as advisors, or 
both; and all were creating or adapting guidelines as the crisis 
progressed. The situation was further complicated by an ongoing 
criminal investigation, coupled with a public health emergency.

The Wallingford facility was unique in that it did not directly handle 
the anthrax letters. Rather, it was cross-contaminated by them, with 
the largest number of spores being found in a sample collected from a 
single machine. There was, however, evidence that the spores had become 
airborne (re-aerosolized) since small numbers of spores were found in 
elevated areas--more than 20 feet--above the previously contaminated 
machines. In addition, while other facilities had workers and customers 
who suffered from either cutaneous or inhalation anthrax, the death of 
a postal customer served by the Wallingford facility underlines the 
insidious nature of anthrax and the difficulty in determining a lethal 
dose, since the elderly Connecticut woman died from anthrax when no 
evidence of anthrax could be found in either her home or places she 
frequented. To compound this, a single spore was found on a letter 
received by another postal customer in the community, and yet no other 
illnesses or deaths were reported. Further, the Wallingford facility 
was outside the predictive analysis (a mapping of the facilities 
predicted most likely to be contaminated) that USPS performed to 
determine the impact of the contaminated letters processed through 
facilities in Washington, D.C., and Trenton, New Jersey, on the rest of 
the postal distribution network. The unpredictability of both the 
lethality of anthrax and the route that contaminated mail might take, 
makes it extremely difficult to establish the health risks associated 
with a release of a biological agent inside a facility, such as 
anthrax, that serves the public. This difficulty underscores the need 
for a standardized and aggressive response, as well as forward 
planning, to protect facility workers and the public should an anthrax 
attack occur again.

As you know, determining whether or not a facility is contaminated with 
anthrax is critical. This is dependent upon the effectiveness of the 
methods used to detect anthrax. As a result, at your request, we are 
conducting a study to examine the adequacy of the methods used by 
involved contractors and federal agencies in determining whether postal 
facilities were contaminated. We will report the final results of this 
study at a later date.

In our testimony today, at your request, our remarks will focus on our 
preliminary findings regarding the test results for the Wallingford 
facility. Specifically, we will address the issues that arose 
concerning the following three areas: (1) the collection of 
environmental samples to detect anthrax contamination, (2) the meaning 
of the test[Footnote 3] results from the samples (both qualitative and 
quantitative) with respect to the health risk of the workers, and (3) 
the communication of the test results. Our work thus far has involved 
interviews with officials from USPS, CDC, and experts in this area, 
reviews of relevant documents and literature, and review of the 
documents we were provided by USPS and CDC associated with the sampling 
done at the Wallingford facility during November 2001 through April 
2002. We did not independently assess or verify any of the laboratory 
test results, sampling plans, or sampling methods to determine their 
adequacy or accuracy. Our work has been performed in accordance with 
generally accepted government auditing standards.

Summary:

Three issues emerged with regard to the collection of environmental 
samples at the Wallingford facility: (1) the methods used for 
sampling[Footnote 4], 
(2) the locations from which samples were collected, and (3) how many 
samples were collected. USPS, in response to the anthrax attack of 
2001, developed a plan to test over 280 facilities nationwide, 
including the Wallingford facility. This plan was precautionary and 
assumed that those facilities were probably not contaminated with 
anthrax. Further, this plan specified what sample collection methods to 
use, where to sample, and the number of samples to be collected, among 
other things. At the Wallingford facility, however, it took four 
attempts before contamination was eventually identified. USPS used its 
own contractors to collect a limited number of samples at various 
places in the facility.[Footnote 5] In addition, USPS collected the 
samples using the dry swab method, which is the least effective method 
for collection of samples from surfaces. On November 
9, CDC officials recommended that USPS use moistened swabs; however, 
USPS did not incorporate this recommendation into its sampling 
plan.[Footnote 6] According to USPS officials, in the beginning, they 
mirrored the methods used by CDC in other postal facilities. USPS did 
not find contamination. However, after the death of the elderly 
Connecticut woman on November 21, 2001, CDC and the Agency for Toxic 
Substance and Disease Registry (ATSDR) eventually used targeted 
sampling, focusing on the mail-sorting machines, and different sampling 
methods--wet wipes and high efficiency particulate air (HEPA) vacuum. 
CDC and ATSDR, using a CDC-contracted laboratory, collected more than 
three times the number of samples previously collected by USPS and 
found contamination in some of the samples. Experts we consulted at the 
U.S. Army Medical Research Institute for Infectious Disease told us 
that before October 2001, they had found that dry swabs were 
ineffective at collecting spores and that spores could not be recovered 
efficiently from dry swabs. Finally, even though the contamination 
found at the Wallingford facility was unexpected, according to a USPS 
official, the nationwide plan was not revised because it was 60-days 
removed from the event, well past the perceived incubation period as 
far as health risk was concerned. This approach did not take into 
account the possibility that if spores are present in a facility, re-
aerosolization can occur at any time if the site of contamination is 
disturbed. The USPS official also said that, with a few exceptions, he 
believed, of those facilities that had tested negative during the 
nationwide sampling, none had been retested. Thus, the negative 
findings from the first three sampling attempts at the Wallingford 
facility raise questions about the reliability of a single negative 
sampling result, especially one based upon the use of a method 
considered the least effective, as was the case in Wallingford.

Neither qualitative (positive or negative) nor quantitative test 
results from a qualified laboratory can be used to establish a health 
risk. Concerning qualitative results, positive results only show 
whether contamination is present in the samples collected. However, 
negative results do not necessarily mean that a facility is free from 
contamination. Quantitative test results only show the extent of 
contamination in the specific samples found to be positive--not how 
much anthrax is present in the facility. For example, in the 
Wallingford facility, the level of contamination found in a dust sample 
collected from a mail-sorting machine was about 3-million spores (5.5 
million per gram of dust). However, with regard to the health risk to 
an individual, although this number was significantly higher than what 
was considered historically to be a lethal dose for an individual--
8,000 to 10,000 spores--CDC did not know how to extrapolate the amount 
in a sample to a person's risk for inhalation anthrax.[Footnote 7] EPA 
recently reported that in order to perform credible risk assessments, 
it is essential to identify the minimum number of spores needed to 
cause inhalation and cutaneous anthrax. Nevertheless, there is now a 
consensus among the experts that a few spores could be harmful to a 
susceptible individual, as may have been the case in the death of the 
Connecticut woman.

Three major communication issues arose at the Wallingford facility: 
(1) the timing of the release of the quantitative results; (2) reasons 
for USPS withholding the quantitative results from the workers, such as 
a lack of confirmation and validation of the test results; and (3) the 
terminology used to describe the extent of contamination to the 
workers. First, USPS did not communicate to the workers the 
quantitative test results of the November 28, 2001, test until 9 months 
after it received them, and it did not comply with the Occupational 
Safety and Health Administration (OSHA) regulations, which require the 
release of test results to workers after they are requested. But USPS 
generally communicated to the workers the qualitative test results 
(positive and negative) soon after they became available. Second, USPS 
officials told us that USPS did not release the quantitative test 
results because it could not validate the confirmed results, as 
required by its draft guidelines. However, these guidelines did not 
define either confirmation or validation. The use of the terms 
"confirmation" and "validation" in this context has caused confusion 
both about (1) the status of the methodologies used to detect anthrax 
and 
(2) the communication of test results to workers. The experts we 
consulted told us that, in their view, the terms confirmation and 
validation were not used appropriately in USPS guidelines, and CDC 
concurs with this view. The guidelines do not specify the process and 
methods for confirming test results. Validation is not done after a 
test or a procedure has already been performed, as would have been the 
case with the quantitative test result. Thus, according to the experts 
we consulted, validation, when used in this sense, should not have 
prevented USPS from communicating the quantitative test results. 
According to USPS officials, the term validation, as used in USPS 
guidance, was intended to be used more for quality assurance purposes. 
Finally, the terminology used by USPS after discussion with the chief 
epidemiologist of the Connecticut Health Department was not helpful to 
workers in assessing their risk. USPS communicated the quantitative 
results to workers as "trace" amounts and "a concentration of spores." 
These terms did not provide workers with useful information, when it 
was needed most, which was when they were making decisions regarding 
their health risk. Further, the lack of communication of the test 
results may have contributed to workers' inability to make informed 
decisions, such as whether to continue taking their medication or work 
at another facility. As OSHA noted, "Failure to effectively communicate 
issues, which can have an effect on a worker's health and safety, can 
lead to fear and mistrust.":

Finally, USPS and the other federal agencies involved in the 
communication issues we raised responded positively to the 
recommendations we made in our April 2003 report aimed at enhancing 
communication of test results. However, our preliminary work on testing 
approaches revealed three other issues that we believe need to be 
addressed. These are, for those facilities that were deemed to be free 
of anthrax spores based solely on a single negative sampling result, 
(1) the risk level for postal workers at those facilities and the 
general public served by those facilities, (2) the advisability of 
retesting those facilities--employing the most effective sampling 
methods and procedures, and 
(3) communication to postal workers and the general public of relevant 
information that may be helpful regarding their health. We are making 
recommendations to USPS to address these issues.

Background:

On or about October 9, 2001, at least two letters containing anthrax 
spores entered the U.S. mail--one was addressed to Senator Thomas 
Daschle, the other to Senator Patrick Leahy. Before being sent to the 
Brentwood facility in Washington, D.C.--the facility that processed 
mail to the two senators--the letters were processed on high-speed 
mail-sorting machines at a postal facility in Hamilton, New Jersey. The 
Hamilton facility--also known as the Trenton postal facility--processed 
mail that was to be transported to the Wallingford facility for further 
processing.[Footnote 8] A study conducted in Canada in 2001 has shown 
that a contaminated envelope, when opened, may cause a substantial 
primary aerosol event, that is, particles become airborne. Also 
envelopes with the open corners not specifically sealed could also pose 
a threat to individuals in the mail handling system.[Footnote 9]

The letters to the senators contaminated the Brentwood and Hamilton 
postal facilities and, according to USPS, resulted in the cross-
contamination of some mail as it moved between these and other 
facilities in the postal system.[Footnote 10] Cross-contaminated mail 
is believed to have been processed through the Wallingford facility on 
or around October 11, 2001. The possibility of cross-contamination and 
associated potential exposure to anthrax spores, contained in cross-
contaminated mail that was processed at the Wallingford facility, went 
unrecognized until after the death of the Connecticut woman from 
inhalation anthrax on November 21, 2001. Airborne transmission of 
anthrax spores at the Wallingford facility and other facilities is 
believed to have been facilitated by the use of high-speed sorters, as 
well as compressed air, for routine cleaning of the mail-sorting 
machines.[Footnote 11] As a result, USPS terminated the use of 
compressed air at all postal facilities on October 23, 2001.

Environmental testing and remediation for anthrax contamination in a 
facility consists of several steps: sample collection, laboratory 
identification, decontamination, and retesting. To collect samples, a 
sampling plan should be developed, which specifies, among other things, 
number of samples, specific methods to collect the samples, areas in 
which to sample, and instructions for submitting the samples to a 
qualified laboratory for analysis. A variety of sample collection 
methods were used in the Wallingford facility, including dry swabs, wet 
wipes, and HEPA vacuums. Swabs--either wet or dry--have small surface 
areas (similar to Q-tips®). They are typically used to sample small, 
nonporous surface areas (less than 100 sq. cm) that do not have a large 
accumulation of dust. Wet wipes--sterile gauze pads, approximately 3 
inches square--are typically used for sampling larger (more than 100 
sq. cm), nonporous surface areas. HEPA vacuum is a suction device with 
a nozzle--including a cone-shaped filtering trap or sock attached--to 
collect dust samples from a surface or the air. After samples have been 
collected, they are to be transported to a qualified laboratory for 
analyses.

A range of laboratory tests exists for detecting anthrax in a person's 
body and in the environment. However, analysis by the culture method is 
considered to be the gold standard for identifying anthrax. Qualified 
laboratories report anthrax test results either qualitatively (for 
example, as "positive" or "negative") or quantitatively (for example, 
as a specific number of colony-forming units (CFU)), [Footnote 12] that 
is, living cells per gram or square inch of material sampled or in 
milligrams per micro liter.

USPS' Sampling Approach Did Not Identify Anthrax at the Wallingford 
Facility:

USPS's initial sampling approach at the Wallingford facility was 
ineffective in that it did not detect contamination at the Wallingford 
facility as soon as was practically possible. If additional testing had 
not been done to determine the source of contamination for the death of 
the Connecticut woman from inhalation anthrax, it is possible that the 
contamination would have gone undetected. USPS guidelines specified the 
least effective method for sample collection. Assuming that there was 
probably no anthrax contamination, USPS, as part of its nationwide 
testing of over 
280 facilities, initially used a precautionary approach to determine 
whether those facilities, including the Wallingford facility, were 
contaminated.[Footnote 13] This approach included a method--dry swabs-
-considered to be the least effective for sample collection, based on 
comparative studies and the opinions of experts we consulted. This 
approach did not find contamination (negative results) in the 
Wallingford facility. On the other hand, CDC used an approach at the 
Wallingford facility that included a combination of more effective 
methods--wet wipes and HEPA vacuum--with which contamination was found. 
Further, USPS officials told us that based on their mail-tracking 
system, they identified some postal facilities that they considered 
likely to have been contaminated by anthrax letters processed through 
those facilities.[Footnote 14] However, Wallingford was not one of 
these. The negative test results for the sampling at the Wallingford 
facility must, therefore, cast doubt about the true extent of 
contamination in other facilities that tested "negative.":

As part of its approach, USPS used its draft Standard Sampling Plan, 
which specified a minimum number of samples to be collected from 
various areas, using the dry swab method.[Footnote 15] USPS used four 
contractors to sample the Wallingford facility. These contractors were 
previously contracted to conduct routine environmental sampling for 
such substances as air and water, rather than dealing with unusual and 
dangerous bacteria such as anthrax. Before the Wallingford facility was 
tested, USPS and CDC had learned that some of the mail-sorting machines 
in the facilities that processed the letters containing the anthrax 
powder--for example, the Brentwood and Trenton facilities--were found 
to be heavily contaminated. This suggests that mail-sorting machines 
would be a likely starting point for sample collection.

On November 11, 2001, using a contractor, USPS collected 53 samples 
from various sites throughout the facility using dry swabs. The test 
results were negative. Although USPS, as part of its nationwide 
sampling, had only intended to test the facility once, it retested the 
facility on November 21, the day that the elderly Connecticut woman 
died, to determine the possible source of contamination. On November 
21, USPS attempted to identify the path the contaminated letter would 
have taken. USPS collected 64 samples from surfaces where mail was 
processed and from air-circulating units, using dry swabs. Again the 
test results were negative. The November 25, 2001, testing by CDC and 
the ATSDR, while using a different method--wet swab--also collected 60 
samples, of which 8 were from mail-sorting machines. Again, the results 
were negative. Of the 
177 samples collected during the November 11, 21, and 25 samplings, 
15 samples were collected from the facility's 13 mail-sorting machines. 
The Connecticut Public Health Laboratory analyzed all of these samples. 
In addition, according to CDC officials, the numbers of samples 
collected on the above dates were, in part, influenced by the capacity 
of the Connecticut Public Health Laboratory. (See table 1 for sampling 
details.):

Table 1: Summary of Sampling for Anthrax Contamination between November 
2001 and April 2002 and the Associated Test Results for the Wallingford 
Facility:

[See PDF for image]

Source: GAO (summary), USPS, and CDC (data).

[A] The USPS used a contractor; CDC was assisted by the Agency for 
Toxic Substances and Disease Registry.

[B] The sample collected contained 0.55 gram of material (dust) from 
the heavily contaminated machine. The laboratory adjusted its analyses 
to reflect a full gram of sample material and reported the presence of 
5.5 million CFUs per gram, which the chief epidemiologist subsequently 
determined, through extrapolation, to be 2.9 million CFUs--or about 3 
million spores--in the sample. In this testimony, we refer to the 2.9 
CFU for the 0.55 grams of sample material actually collected.

[C] "High-bay" areas refer to elevated areas in the facility such as 
pipes, ducts, joists, beams, and overhead conveyors. Precautionary 
testing was performed to ensure no anthrax was present during annual 
cleaning.

Note: N/A = Quantitative data either not applicable (no anthrax 
present) or not provided.

[End of table]

On November 28, CDC and ATSDR performed what they termed "targeted" 
testing, based upon new information concerning which mail-sorting 
machines were likely to have processed the woman's mail. CDC and ATSDR 
collected 212 samples using a combination of methods: wet wipes and 
HEPA vacuums, rather than the wet swabs CDC had previously used. This 
time, CDC and ATSDR collected 130 samples from the mail-sorting 
machines as opposed to the 15 samples collected during the three prior 
sampling efforts. A CDC-contracted laboratory analyzed the samples and 
found 6 that were positive for anthrax, 2 of which had been collected 
by HEPA vacuum and four by wet wipes. For the November 28 samples, the 
laboratory also provided two quantitative results, one of which, 
according to the Connecticut chief epidemiologist, was about 3 million 
CFUs of anthrax (that is, 5.5 million CFUs per gram of dust) in a 
sample collected from a heavily contaminated mail-sorting machine.

Finally, on December 2, while the contaminated machines were isolated 
and the process of decontamination was beginning, CDC and ATSDR used 
wet wipes alone to collect 200 follow-up samples from the machines to 
determine the extent of contamination on the machines and found 
35 additional positive samples. On April 21, 2002, a USPS contractor, 
in consultation with CDC, OSHA, EPA, and the Connecticut Department of 
Public Health--using HEPA vacuums--tested elevated, or high bay, areas 
above the previously contaminated machines. The sampling was performed 
because of a USPS requirement for testing prior to the routine cleaning 
of elevated areas in facilities that had previously tested positive for 
anthrax. The effort was undertaken to protect workers from the 
possibility of exposure to spores that may have blown into these areas 
as a result of USPS's prior use of compressed air to clean its 
facilities. The results revealed from 1 to 18 CFUs in 3 of 101 samples 
collected from the elevated areas.[Footnote 16] This finding indicates 
that spores had been airborne at some period in the facility.

Based on the testing done at the Wallingford facility by USPS and by 
CDC and ATSDR, neither dry nor wet swabs alone identified anthrax 
contamination in the samples collected. Wet wipes and HEPA vacuums did 
identify anthrax in some samples. Experts we consulted at the U.S. Army 
Medical Research Institute for Infectious Disease told us that before 
October 2001, they had found that dry swabs were ineffective at 
collecting spores. CDC, on November 9, 2001, in commenting on USPS 
draft guidelines, recommended that USPS use sterile swab samples for 
environmental sampling and that these swabs be moistened with sterile 
water. In addition, CDC informed USPS that CDC's own draft procedures, 
that is, "Procedures for Collecting Environmental Sampling for 
Culturing Bacillus anthracis," continued to address bulk and vacuum 
samples. CDC draft guidelines did not, however, address the use of wet 
wipes. CDC also stated that, "some of the state labs may be less 
familiar with the methods needed to perform analyses for vacuum and 
bulk samples." Finally, CDC stated that it understood that USPS' sole 
use of the swab method was related to an accommodation reached with the 
Association of Public Health Laboratories to more effectively use state 
health department laboratories to assist with sample analysis. USPS 
also acknowledged in a subsequent draft of its guidelines that, "the 
Association of Public Health Laboratories does not recognize air, bulk, 
or HEPA vacuum for purposes for Bacillus anthracis identification.":

USPS officials we interviewed said that in the beginning, USPS mirrored 
the methods used by CDC in the Brentwood and Trenton facilities. The 
officials noted that, at one point, "one method was recommended, and 
later, another method was recommended." USPS officials also told us 
that in the absence of any other guidance, they were attempting to use 
pre-existing guidance and extrapolate it to a bio-terrorist attack. In 
December 2001, a study carried out by CDC, ATSDR, and USPS clearly 
showed that sampling methods differed significantly in their ability to 
detect spores, even in a heavily contaminated facility.[Footnote 17] 
According to the study, dry swabs failed to detect spores more than 86 
percent of the time, wet swabs more than 46 percent, HEPA more than 20 
percent, and wipes more than 
13 percent. Based on the study, CDC concluded that dry swabs should not 
be used to sample for anthrax. Finally, a report by the EPA, dated 
February 2003, on environmental sampling for anthrax spores at USPS 
Morgan Postal and Processing facility stated that wipe samples should 
be used for sampling large surface areas, and wet techniques are more 
effective than dry techniques. The report stated that epidemiological 
approaches for different scenarios of environmental sampling should be 
developed.[Footnote 18] These issues raise questions about the 
reliability of a single "negative" sampling result, especially based on 
the least effective method--dry swabs--as was the case initially in 
Wallingford.[Footnote 19]

Test Results Cannot Be Used to Determine Health Risk for Workers:

Neither qualitative (negative or positive) nor quantitative tests 
results can be used to definitively establish the risk to an 
individual's health. Interpreting positive test results from a sample 
as a health risk would require a real understanding of the physical 
behavior of airborne anthrax spores as well as factors that may 
influence their behavior. Thus, while both qualitative and quantitative 
test results from a qualified laboratory can show that a facility is 
contaminated, they do not show the actual extent of contamination in 
the facility or the health risk for workers. In particular, qualitative 
test results show if a facility is contaminated or not. Further, while 
quantitative test results show the number of CFUs in a sample, such 
results can be difficult to interpret and, possibly misleading, 
depending upon the relative distribution of surface dust versus spores 
and the effectiveness of the sampling methods. Nevertheless, because of 
factors affecting how well a sample method picks up anthrax and 
limitations affecting the amount of anthrax that can be extracted from 
that sample, experts agree that there would be more anthrax in the 
facility than can be picked up by a sample. However, according to 
officials from the U.S. Army Medical Research Institute for Infectious 
Disease, what is most important is not the number of spores in a sample 
but whether or not any spores exist. On the other hand, EPA recently 
reported that in order to perform credible risk assessments, it is 
essential to identify the minimum number of spores needed to cause 
inhalation and cutaneous anthrax.

Negative test results, as shown at the Wallingford facility, do not 
necessarily mean that a facility is free from contamination. Test 
results at a contaminated facility could be negative if (1) the 
sampling method used was not sufficiently effective; (2) samples were 
not collected from places where contamination was actually present; and 
(3) an insufficient number of samples were collected. Concerning the 
sampling methods used in the Wallingford facility, for example, the 
samplings conducted on 3 different days, which involved collecting a 
limited number of samples from various places in the facility, using 
either dry or wet swabs, came out negative, while a subsequent 
sampling--which used (1) a combination of sampling methods, (2) a 
different sampling approach, and (3) an increased number of samples--
came out positive. It is, therefore, essential to have a sound sampling 
plan that includes effective methods and do repeat testing if it is 
considered necessary.

Once contamination is confirmed, actions must be taken to protect the 
workers and decontaminate the facility. Interpretation of the positive 
test results requires a real understanding of the physical processes 
involved in generating airborne particles, such as anthrax; the 
behavior of such particles; and the factors that influence their 
behavior. Evaluation of the health risks involves the assessment of 
components that govern the particle-size profile, stability, and 
biological impact. The greatest risk to a worker's health in the 
Wallingford facility appears to have come from the particles that 
became airborne as mail that had been cross-contaminated passed through 
the sorting machines. In the case of the Wallingford facility, postal 
officials suspect that contamination of the facility may have occurred 
a few days after October 9, when the second set of letters, those 
addressed to the two senators, passed through the Trenton facility. It 
is likely that this high-risk period would have been no more than a few 
hours, while spores were still airborne. Nevertheless, once spores have 
settled, a risk can arise if spores again become airborne, thus making 
it possible for workers to inhale them.

Investigations of anthrax contamination in the U.S. Senate Office 
building found that simulated day-to-day office activities (that is, 
paper handling, foot traffic, mail sorting, trash container movement, 
patting chairs) resulted in spores again becoming airborne. Eighty 
percent of these airborne particles were in the size range 0.9 to 3.5 
microns and, thus, would be capable of causing inhalation 
anthrax.[Footnote 20] It was noted that even minimal movement caused 
viable spores to become airborne. It is therefore very likely that 
compressed air, used for machine cleaning, could provide sufficient 
energy to cause particles to become airborne, particularly from areas 
where there are high local concentrations of spores, as was the case in 
Wallingford. Similarly, the processing of a cross-contaminated letter 
through a sorting machine may also provide sufficient energy to cause 
spores to again become airborne. Based on these findings, it is 
important to recognize that in a mail-processing facility that has 
tested positive for anthrax, there is a risk to the health of workers 
because spores may become airborne again after the primary event--the 
passage of the contaminated letters--has occurred. In addition, these 
spores could then create a risk of cross-contamination of mail.

USPS asked CDC whether it should conduct additional testing of postal 
facilities to assure workers safety. On February 25, 2002, in its 
response, CDC stated that additional testing was not warranted at that 
time. CDC noted several reasons for not retesting those facilities 
including, 
(1) qualitative or quantitative testing for anthrax does not accurately 
correlate with exposure threshold or predictors of disease at these 
work sites; (2) since the initial contamination, there has been no 
report indicating increased risk for disease among the workers at these 
sites; and (3) there is a good reason to believe that the risk for 
workers has decreased since the initial attack as a result of USPS's 
newly adopted prevention and control measures, such as repetitive 
machine decontamination, medical monitoring, and revised operating and 
maintenance procedures.

According to the experts, the level of contamination found at the 
Wallingford facility was significantly higher than the level--8,000 to 
10,000 spores--historically considered likely to cause disease in the 
individual when inhaled in a fine powder form. However, there is now a 
consensus among the experts that even a few spores could be harmful to 
a susceptible individual, as may have been the case in the death of the 
Connecticut woman. According to officials from the U.S. Army Medical 
Research Institute of Infectious Disease, what is most important is not 
the number of spores in a facility but whether or not any spores are 
found.

In an attempt to lessen the risk that spores might become airborne, 
USPS stopped the use of compressed air for cleaning mail-sorting 
machines and also revised its cleaning methods to include those less 
likely to cause spores to be blown about the facility, for example, wet 
mopping instead of dry brushing.

USPS'S Failure to Release Quantitative Results Caused Communication 
Problems at the Wallingford Facility:

USPS generally provided the Wallingford facility's test results to 
workers at the facility within 1 day of receiving the results, 
consistent with USPS guidelines requiring that workers be notified "as 
soon as possible." However, USPS did not inform the workers as promptly 
after contamination was identified in the facility in December 2001, 
and it also did not promptly provide information to workers on the 
quantitative test results after a union official requested them.

On December 2, 2001--when anthrax contamination was first identified in 
the facility--USPS met with workers to inform them that "trace" amounts 
of anthrax had been found in samples collected on November 28. Knowing 
that the laboratory initially identified a small number (one or two 
CFUs) of anthrax spores, the chief epidemiologist for Connecticut--who 
helped lead the investigation--told district postal managers that it 
would be accurate to use the term "trace" to describe the extent of 
contamination. On December 12, 2001--2 days after district postal 
managers said they received written confirmation of the presence of 
about 3 million spores in one of the samples collected on November 28 
and, possibly, 4 days after headquarters postal managers received the 
results--district postal managers told us that they informed workers of 
the following: While trace amounts of anthrax existed on three mail-
sorting machines, a "concentration" of spores had been identified in a 
sample collected from a fourth machine. But it was not until 9 months 
after USPS had received the quantitative results of the November 28, 
2001, testing that it provided the information to the workers.

According to USPS, it did not release the quantitative test results to 
workers because it could not validate the confirmed results, as 
required by its guidelines, which state that results cannot be released 
until confirmed data are received from CDC or a state public health 
laboratory. However, the guidelines do not define the meaning of either 
"confirmation" or "validation," nor do they specify the steps that must 
be taken to validate test results. According to USPS managers, USPS 
could not ensure that the sampling had been done in accordance with 
procedures specified in the guidelines and, thus, could not validate 
the results, as required by the guidelines. [Footnote 21] A USPS 
headquarters' manager told us that the term validation was intended to 
describe a method for ensuring that work had been done in accordance 
with USPS' sampling and testing procedures and for coordinating the 
release of validated results. A USPS official also told us that the 
term validation, as used in USPS guidance, was intended to be used more 
for quality assurance purposes. The guidelines do not specify who is to 
do the validation or how it is to be done, particularly when the 
testing is not done or sponsored by USPS. Thus, the use of the terms 
confirmation and validation in the context of USPS guidelines has 
caused confusion about (1) the status of the methods used to detect 
anthrax (e.g., were the methods appropriately used) and (2) whether and 
when test results were to be communicated to workers.

The experts we consulted told us that, in their view, the terms 
confirmation and validation were not used appropriately in USPS 
guidelines. Confirmation is a process in which a qualified laboratory, 
using specific tests, determines the presence of anthrax in a sample. 
Normally, validation is a process that is carried out before a test or 
procedure is used for a specific purpose to ensure that such a test or 
procedure is effective. Thus, according to these experts, validation is 
not usually done after a test or a procedure has already been 
performed, as would have been the case had the results been validated 
in the manner described by USPS officials. Thus, according to the 
experts we consulted, validation, when done appropriately, should not 
have prevented USPS from communicating the quantitative test result.

These experts also (1) told us that the sampling method (HEPA vacuums) 
used to collect the samples that were quantified was appropriate and 
(2) agreed that the lack of documentation about the extent of surface 
area sampled, especially given the complexity of the facility's mail-
sorting machines, could have made interpretations of the results 
difficult.[Footnote 22] They explained that the method of counting CFUs 
is a long-standing, definitive, and universally accepted 
microbiological technique for determining the amount of bacteria in a 
given sample, including anthrax. The results show how many spores have 
replicated to form colonies, which can then be seen by the naked eye. 
Thus, regardless of the sampling issues at Wallingford, none of the 
agencies involved provided any evidence indicating that the number of 
CFUs identified by the laboratory was incorrect.

USPS communicated the quantitative results to workers as "trace" 
amounts and "a concentration of spores," based on discussions with the 
chief epidemiologist of the Connecticut Health Department. However, 
according to the experts we consulted, use of the terms trace amounts 
or concentration of spores did not provide workers with useful 
information, when it was needed most, which was when they were making 
decisions regarding their health risk.

According to experts we consulted, the use of the term "concentration" 
to convey the finding of about 3 million spores in one sample may have 
been misleading because it did not adequately convey the potential 
health risk associated with the sample, along with any limitation 
associated with the results. The experts also said that providing 
information about the actual test results to workers would have given 
them better information for making informed medical decisions. In this 
case, according to the experts we consulted, an appropriate way to 
communicate the results to workers would have been to indicate that 2.9 
million CFUs (from 0.55 grams of dust) were found in a sample from one 
machine, along with appropriate limitations regarding the sampling 
procedures used.

Following a request for test results by a union leader and an 
investigation by OSHA, USPS eventually released the quantitative 
results 9 months later. The delay was not consistent with OSHA 
regulations. OSHA did not cite USPS for failure to disclose the 
quantitative test results within 15 working days of the union leader's 
January and February 2002 requests; however, in an October 7, 2002, 
letter to USPS, OSHA noted that a "failure to effectively communicate 
issues which can have an effect on a worker's health and safety, can 
lead to fear and mistrust.":

In addition, two federal guidelines, developed in 2002 by GSA and the 
National Response Team, suggest that more--rather than less--
information should be disclosed. For example, GSA's guidelines 
emphasize the need for "timely, clear, consistent, and factual" 
information, including any limitations associated with the information, 
so that people can make informed decisions. The other set of 
guidelines, developed by the National Response Team, warns agencies not 
to withhold information because it could affect the agency's 
credibility. However, neither USPS's guidance nor the more recent 
federal guidelines fully address the communication-related issues 
concerning anthrax that developed at the Wallingford facility. For 
example, none of the guidelines specifically require the full 
disclosure of all test results, including quantitative test results. 
Likewise, OSHA regulations for communicating test results to workers do 
not address the need for full, immediate, and proactive disclosure. 
Thus, we made several recommendations to minimize the likelihood that 
the communication-related problems at the Wallingford facility will 
recur elsewhere (see appendix I). USPS, EPA, and GSA generally agreed 
with our recommendations affecting them, but OSHA did not comment on 
our recommendation to it.

Our work to date on this study has revealed three other issues that we 
believe need to be addressed. These are, for those facilities that were 
deemed to free of anthrax spores based solely on a single negative 
sampling result, (1) reassessing the risk level for postal workers at 
those facilities and the general public served by those facilities, 
(2) reconsidering the advisability of retesting those facilities--
employing the most effective sampling methods and procedures, and 
(3) communicating 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.

Conclusions:

The Wallingford incident gives unique insight into the lessons that 
need to be learned from the response of the federal government, state 
health departments, and USPS to the anthrax attacks in the fall of 
2001. The unpredictability of the lethality of anthrax; the broad 
spectrum of the population at risk of exposure, including postal 
workers, postal customers and others; and the inability to determine 
the route that contaminated mail might take as well as the extent of 
cross-contamination, are all factors that make it extremely difficult 
to establish the health risks associated with a release of a biological 
agent, such as anthrax, inside a facility that serves the public. This 
difficulty underscores the need for a standardized and aggressive 
response as well as forward planning to protect both the workers and 
the public should this happen again.

When considering the testing approach taken, and the methods used, to 
detect anthrax in postal facilities in the fall of 2001, it is 
important to recognize that the knowledge and experience of public 
health officials and others in this area were continually evolving. 
Experts we consulted and studies we reviewed indicated that the use of 
dry swabs alone were the least effective method of detecting anthrax. 
In addition, CDC recommended that dry swabs should not be used for 
anthrax detection. Initial sampling of the Wallingford facility, using 
USPS nationwide sampling guidelines (which provided for the use of dry 
swabs), did not find contamination. Also, use of the same guidelines to 
conduct nationwide testing may not have identified anthrax 
contamination that could have existed in some of those facilities that 
tested negative using dry swabs alone.

In February 2002, CDC advised USPS, that to ensure worker safety, there 
was no need to retest postal facilities for a variety of reasons. 
Accordingly, USPS followed CDC's advice and did not retest any of those 
facilities. However, in our discussion with CDC officials, they agreed 
that there are many uncertainties associated with anthrax risk 
assessment. For example, we do not know the lethal dose for an 
individual, how to extrapolate contamination in a facility to a health 
risk for an individual, and whether postal facilities still contain 
spores, and the reliability of the methods used to rule out anthrax 
contamination. CDC also agreed that there could still be spores in some 
facilities. Consequently, there remains a risk, albeit probably low, of 
further infection. While CDC judges the risk to be low, we believe that 
it is important that this judgment of the risk be communicated to 
workers and the general public so that they are in a position to make 
informed decisions about their health and safety.

Public health response is most effective and efficient when it is 
proactive, when it focuses on prevention, rather than on consequent 
management. Thus, the Wallingford incident illustrates the challenges 
facing the federal government, the state health departments, the 
network of diagnostic laboratories and those companies that serve the 
general public, including USPS. The challenge can be summed up in one 
question, "Is it safe?" This is what everyone asked during the fall of 
2001, and this is what everyone is trying to answer to this day. 
Unfortunately, the best answer anyone can give is, "It is probably 
safe." Once a building has been contaminated, one can never say there 
is no risk, but there can be a low risk. What all those who are trying 
to protect the public health must realize is that they are defining the 
risk level for others: in this case, the postal workers as well as the 
general public.

Recommendations:

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; 
we therefore recommend that the Postmaster General, 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, (1) reassess the 
risk level for postal workers at those facilities and the general 
public served by those facilities, (2) reconsider the advisability of 
retesting those facilities and employing the most effective sampling 
methods and procedures, and 
(3) 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.

Mr. Chairman, this concludes our statement. We will be happy to answer 
any questions you or members of the Subcommittee may have.

Contacts and Acknowledgments:

Should you or your offices have any questions concerning this report, 
please contact me at (202) 512-6412 or Bernie Ungar at (202) 512-2834. 
We can also be reached by e-mail at rhodesk@gao.gov and ungarb@gao.gov. 
Individuals making key contributors to this testimony were Don Allison, 
Hazel Bailey, Latesha Love, Laurel Rabin, Cady Summers, and Kathleen 
Turner. Drs. Jack Melling and Sushil Sharma provided technical 
expertise.

[End of section]

Appendix I: Recommendations Contained in Our April 2003 Report on the 
Wallingford Facility:

To help prevent the recurrence of the communication problems that 
occurred at the Wallingford facility, we recommended that the 
Postmaster General; the Administrator of the General Services 
Administration; and the Administrator of the Environmental Protection 
Agency, as Chairperson of the National Response Team, work together to, 
where applicable, revise guidelines to:

* require prompt communication of test results, including quantified 
results when available, to workers and others;

* specify the terminology that should be used to communicate 
quantitative test results to workers and others (e.g., the number of 
colony-forming units per gram or square inch of material sampled) and 
any limitations associated with the test results;

* define what is meant by the validation of test results and explain 
the steps that must be taken to validate sampling or testing methods 
that are undertaken by the agency itself or by another organization;

* specify the actions that should be taken if test results cannot be 
validated, including a strategy for communicating unvalidated results;

* specify the agencies that should be involved in deciding what to 
communicate to workers and others, as appropriate;

* require documentation of the basis for decisions made, including the 
(1) advice the organization receives from public health officials and 
others about the communication of health-related information to workers 
and others, as appropriate, and (2) specific content of what agencies 
and other organizations communicate to workers and others; and:

* reflect the Occupational Safety and Health Administration's 
regulations for disclosing test results requested by workers or their 
designated representatives.

In light of new concerns about the possibility and impact of future 
terrorist actions using unforeseen hazardous substances, we also 
recommend that the Assistant Secretary for Occupational Safety and 
Health consider whether the Occupational and Health Administration 
regulations should require--in emergency situations--full and 
immediate disclosure of test results to workers, regardless of whether 
the information is requested by a worker or his or her designated 
representative.

FOOTNOTES

[1] Technically, the term "anthrax" refers to the disease caused by 
Bacillus anthracis and not the bacterium or its spores. In this 
testimony, we use the term "anthrax" for ease of reading and to reflect 
terminology commonly used in the media and by the general public.

[2] U.S. General Accounting Office, U.S. Postal Service: Better 
Guidance Is Needed to Improve Communication Should Anthrax 
Contamination Occur in the Future, GAO-03-316 (Washington, D.C.: April 
7, 2003).

[3] The terms "test" or "testing" refer to the laboratory analysis of 
the samples collected.

[4] Technically, the term "sampling" refers to a strategy to extract 
organisms that might be present in the environment. In this testimony, 
however, sampling refers to the number of samples collected, as well as 
other associated events, on a given day.

[5] CDC officials told us that the number of samples collected on a 
given day was, in part, governed by the capacity of the state 
laboratories to process the samples. 

[6] USPS Draft Standard Sampling Plan dated November 9, 2001. USPS's 
Draft Interim Guidelines replaced this plan in late November 2001.

[7] It is important to note that the range of spores (8,000 to 10,000) 
for the human lethal dose was extrapolated from animal studies. This 
range of spores refers to a dose that will kill
 50 percent of individuals exposed to airborne anthrax. However, the 
lethal dose for a person could be a few spores, as may have been the 
case with the Connecticut woman.

[8] Two other contaminated letters were sent to a television news 
anchor and the editor of The New York Post in New York City on or 
around September 18, 2001. Although the letters were processed through 
the Hamilton (Trenton facility), it is not known whether these letters 
contaminated the Wallingford facility.

[9] B. Kournikakis, and others, Risk Assessment of Anthrax Threat 
Letters. Suffield: DRES Technical Report TR 2001-048, September 2001.

[10] USPS officials suspect that the source of the contamination that 
caused the elderly woman to contract anthrax was the October 9th set of 
letters processed at the Hamilton facility in New Jersey. 

[11] Centers for Disease Control and Prevention, "Evaluation of 
Bacillus anthracis Contamination Inside the Brentwood Mail Processing 
and Distribution Center--District of Columbia; Mortality and Morbidity 
Weekly Report (2001), vol. 50, pp. 1129-1133. 

[12] The term "colony-forming units" refers to the number of living 
cells in a sample and is typically reported per gram of material 
sampled for HEPA vacuum samples and per square inch for samples 
collected using wipes.

[13] Facilities in Florida, New Jersey, New York, and Washington, D.C., 
had already been tested and found contaminated.

[14] According to USPS, to determine the condition of sites of possible 
contamination and to evaluate specific downstream sites throughout the 
country, USPS obtained test equipment, systems, and contract services. 
When testing was completed in late November 2001, 
284 facilities were tested, with 23 positive and 261 negative results.

[15] USPS contractors used the USPS Draft Standard Sampling Plan, dated 
November 2 and 9, 2001. The draft USPS interim guidelines, dated 
November 16, 2001, replaced this plan, and a subsequent version of the 
guidelines was issued December 4, 2001.

[16] Specifically, the test results indicated (1) 1 CFU from 7.50 grams 
of material sampled, 
(2) 10 CFU and 11 CFU from 7.69 grams of material sampled, and (3) 13 
CFU and 18 CFU from 5.67 grams of material sampled.

[17] See CDC, "Surface Sampling Methods for Bacillus anthracis Spore 
Contamination," Emerging Infectious Diseases Journal, Vol. 8, No. 10 
(October 2002).

[18] U.S. Environmental Protection Agency: Summary Report: Peer Review 
Workshop on Environmental Sampling for Anthrax Spores at Morgan Postal 
Processing and Distribution Center, May 30, 2002, New York City, New 
York. (EPA 500-R-03-001, Washington, D.C., February 2003).

[19] USPS officials told us that they are in the process of revising 
their interim guidelines, however, we have not yet reviewed these 
revised guidelines.

[20] C.P. Weiss and others, "Secondary Aerosolization of Viable 
Bacillus anthracis Spores in a Contaminated U.S. Senate Office," 
Journal of American Medical Association, vol. 288 (2002), pp. 2853-
2858.

[21] U.S. Postal Service, Interim Guidelines for Sampling, Analysis, 
Decontamination, and Disposal of Anthrax for U.S. Postal Service 
Facilities (Dec. 4, 2001). These guidelines were developed as the 
anthrax crisis unfolded, with input and guidance from several federal 
agencies, including CDC and OSHA, and the national unions that 
represent postal workers.

[22] We consulted with numerous experts in the field of microbiology, 
including Dr. Jack Melling, former Director and Chief Executive Officer 
of the British Center for Applied Microbiology Research, Porton Down; 
Dr. Paul Keim, Professor in Microbiology, Northern Arizona University; 
Col. Eric Henchal, Department of the Army; and Dr. Barbara Johnson, 
former Safety Officer at the Dugway Proving Grounds, Department of the 
Army.