Order Code RL31280
CRS Report for Congress
Received through the CRS Web
The U.S. Postal Service Response to the Threat
of Bioterrorism Through the Mail
February 11, 2002
Frank Gottron
Science and Technology Analyst
Resources, Science & Industry Division
Congressional Research Service ˜ The Library of Congress

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The U.S. Postal Service Response to the Threat
of Bioterrorism Through the Mail
Summary
The deliberate mailing of Bacillus anthracis spores through the U.S. Postal
Service (USPS) has caused five deaths, twenty-two cases of anthrax, and massive
disruptions to Congress and the USPS.
Both the public and private sector are examining an array of methods to limit the
risk of future attacks. The array of potential solutions include improving mail
handling procedures, changing the USPS anonymous mailing policy, installing
bio/chem agent detectors, and sterilizing the mail.
For the USPS these decisions are complicated by its precarious financial state.
Some proposed solutions may require an increase in postage rates and/or decreased
levels of service. Each of these may further depress postal revenues and threaten the
continued existence of the USPS as an independent, self-supporting entity.
Policymakers will need to decide if the USPS must ensure the safety of mail
recipients. At this point it is not clear if this is practical or even possible with existing
technology. It may be that it is practical to protect only the mail addressed to the
most likely targets of future attacks.
Some of the measures that the USPS has taken or is planning to take to protect
postal workers and mail recipients are common sense alterations to the mail
processing procedures. These include measures to reduce cross contamination such
as using vacuuming instead of pressurized air to dislodge dust, controlling air flow
throughout sorting facilities to isolate potential exposure areas, and adding filters to
air handling systems. The USPS is studying the feasibility of including biological
weapon detectors during the sorting process. Additionally, the USPS is making
gloves, masks, and educational materials available to all postal workers.
More controversial and potentially more costly are plans to sterilize the mail.
Currently, all mail destined for federal offices in the Washington DC metropolitan area
is shipped to sterilizing facilities for irradiation treatment before delivery. The USPS
is studying whether this solution can be scaled up to sterilize all mail from anonymous
senders. To implement irradiation procedures nationwide could cost between three
and five billion dollars with up to another billion dollars each year in operating costs.
This procedure may damage the contents of some mail.
Recent reports of skin rashes, headaches, breathing problems, vomiting and
bleeding by people who handle irradiated mail have raised concerns about the safety
of this treatment. The USPS is working with Congress and federal agencies to find
out if the irradiated mail is causing these problems. Clearly this issue will need to be
resolved before irradiating a larger portion of the mail.
Policymakers will need to balance concerns for safety, cost, and practicality
while to deciding how to alter the practices of the USPS. This report will be updated
as events warrant.

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Contents
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Interest and Role of Congress . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Initial Response . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Long Term Response . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Efficacy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Cost . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Level of Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Postal Worker Safety . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Potential Solutions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Procedural Changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Sterilization Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Useful Links . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
List of Tables
Table 1. Select Projected FY2002 Costs for Bioterrorist Threat Reduction
and Security . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

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The U.S. Postal Service Response to the
Threat of Bioterrorism Through the Mail
Introduction
The use of the U.S. Postal Service (USPS) to deliver agents of bioterror has
caused twenty-two confirmed cases of anthrax including five deaths as well massive
disruptions to Congress and the USPS.1 The contamination caused by processing and
opening of the letters shuttered the Hart Senate Office Building for more than three
months and indefinitely closed mail processing centers in the District of Columbia,
New Jersey and Maryland.
These attacks have radically changed the way the nation views mail delivery and
mail safety. Both the public and private sectors are evaluating a variety of methods
to reduce the risk of similar future attacks. These potential solutions include changing
mail handling procedures, changing the USPS anonymous mailing policy, installing
bio/chem agent detectors and sterilizing the mail.
For the USPS these decisions are complicated by its serious financial difficulties.2
The USPS predicts that it will spend approximately $60 million dollars to provide
medical treatment to affected workers and to test and clean up facilities. Additionally,
the USPS projects costs of $1.2 billion in FY2002 for measures to protect postal
workers and to begin evaluating systems to protect mail recipients. In the face of
these increased costs, the USPS predicts the decrease in mail volume caused by the
attacks will cost $2 billion dollars in lost revenues this fiscal year. USPS feels that
its survival depends on being able to ensure the health of postal workers and to
restore the faith of the American people in the safety of the mail.
Interest and Role of Congress
The efforts of the USPS to respond to the threat of bioterrorism has been the
subject of hearings before the Senate Treasury and General Government
Appropriations Subcommittee, Senate Committee on Governmental Affairs and the
House Committee on Government Reform. At the request of Committee on
1Centers for Disease Control and Prevention. Morbidity and Mortality Weekly Report.
Update: Investigation of Bioterrorism-Related Anthrax --- Connecticut, 2001. December 7,
2001. Vol 48. No. 48. p. 1077.
[http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5048a1.htm].
2 For a thorough review of the USPS financial situation, see CRS Report RL31069 Postal
Service Financial Problems and Stakeholder Proposals, by Nye Stevens.
[http://www.congress.gov/erp/rl/pdf/RL31069.pdf].

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Government Reform Chairman Dan Burton and Ranking Member Henry Waxman,
the National Academy of Sciences and the General Accounting Office have convened
meetings between USPS officials and outside experts to discuss appropriate
technology and methodological changes to limit the threat of future attacks.
Postmaster General John Potter has stated that he views the plans to reduce the
threat of terrorism through the mail as an integral part of homeland defense and thus
plans to request Congress to appropriate billions of dollars.3 In addition to the $175
million it received from the White House Emergency Response Fund, the USPS
estimated that it would need an additional approximately $1.1 billion in FY2002 to
respond effectively to the bioterror threat and to replace or repair facilities damaged
in the September 11, 2001 terrorist attacks. The 2002 Department of Defense
Appropriations Act (PL 107-117) appropriated $500 million to the USPS for these
expenses. Because of ongoing concerns over plans to screen and sanitize mail, the
Conferees required the USPS to submit an emergency preparedness plan to the
Committees on Appropriations, the House Committee on Government Reform and
the Senate Committee on Governmental Affairs before the money for these activities
will be disbursed.
...As part of its emergency preparedness plan, the conferees expect the
Postal Service to include an assessment of threats to the health and safety
of employees and customers of the Postal Service and the integrity of the
mail; testing and evaluating the options for detecting and/or addressing
those threats, including both technology-based and process-based options;
a comparison of the costs and benefits of options under consideration; an
evaluation of the strengths and weaknesses of the technologies under
consideration for mail sanitization, including an analysis of risks to human
health and safety and to mail products associated with each of those
technologies; and a timetable for implementing the options selected….4
In addition to these questions posed to the USPS, policymakers may want to ask
themselves other questions to define the role the USPS should play. Clearly the
USPS must protect postal workers, but should the USPS also guarantee the safety of
mail recipients? Is that possible? If it is possible, how much are ratepayers or
taxpayers willing to pay? Does safe mean safe from all potential biological attacks or
only anthrax? What about chemical agents? What kind of reductions in USPS service
are acceptable to ensure safety? Will changes to level of service add to the precarious
financial position of the USPS? What portion of the costs should Congress
appropriate and how much of the costs should rate payers bear?
3 Testimony of Postmaster John Potter before the Senate Treasury and General Government
Appropriations Subcommittee November 8, 2001.
4U.S. Congress. House. Making appropriations for the Department of Defense for the fiscal
year ending September 30, 2002 and for other purposes. 107th Congress, 1st session. H. Rept.
107-350. Washington, U.S. Govt. Print Off. 2001. p. 452.

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Initial Response
Previous terrorist attacks via the mail, such as those of the Unabomber, generally
targeted the recipient of the mail. However, because anthrax spores are smaller than
the natural pores in envelopes, the spores can leak out during mail sorting, putting
postal workers at risk. Additionally, spores can be transferred to other envelopes (a
phenomenon called cross contamination), which puts at risk anyone whose mail was
processed at the same facility as the anthrax tainted envelopes. Before these attacks,
these risks were generally considered negligible by experts in biological warfare and
the Centers for Disease Control and Prevention (CDC) because it was thought that
the few spores could be transferred this way would not be sufficient to cause disease.
Because this assumption proved wrong, the initial response of the USPS has focused
on ways to protect postal workers from exposure and how to protect a subset of high
risk addressees.
Shortly after the discovery of the contaminated letters, both mail processing
facilities which handled the letters were closed indefinitely. The approximately 8,500
postal workers deemed at even remote risk for exposure to anthrax were offered a
sixty day course of prophylactic antibiotics.5 Following the initial 60-day course of
antibiotics the CDC has recommended an additional 60-day course. The CDC also
has made the controversial anthrax vaccine available for the workers.
The delay between the discovery of the tainted letters, facility closures and
antibiotic treatments elicited comment both from postal worker unions and Congress.6
The USPS attributed the difference between the immediate closing and testing of
workers in the Hart Senate Office Building and the delay before postal facilities and
workers were tested to a reliance on the evolving recommendations of the CDC.
After these attacks, the USPS examined its practices and found some changes
could be made to reduce the risk to both postal workers and mail recipients. One of
the most obvious changes concerned dust abatement procedures. Processing mail
generates an enormous amount of dust. Compressed air had been the method of
choice to clean the processing machines. The USPS recognized that this practice
would widely distribute fine anthrax particles throughout the processing facility. It
is switching to vacuum systems both to clean the sorting machines and to replace the
general maintenance practice of broom sweeping. Similarly, following the suggestion
by the CDC, the USPS will be installing high efficiency particulate air (HEPA) filters
in all of their heating, ventilation and air conditioning (HVAC) systems to minimize
the spread of bioterror agents. The USPS has also provided antimicrobial wipes,
protective gloves and masks, and their related educational materials to ensure proper
use to all postal workers. Table 1 details the FY2002 projected costs associated with
the changes discussed in this section.
5 Centers for Disease Control and Prevention. Morbidity and Mortality Weekly Report.
Vol.50 No. 47, November 30, 2001, p. 1052.
6 Washington Post. U.S. Officials Defend D.C. Response. October 24, 2001. p. A16.

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Prior to the discovery of the tainted mail, no procedure was in place to sterilize
potentially harmful biological agents in the mail. As an interim measure the USPS has
decided to sanitize mail destined for all federal government offices in the Washington
D.C. metropolitan area (zip codes 20200-20599). Initially this consists of sealing the
mail into secure containers and shipping it to subcontractors in Lima, Ohio and
Bridgeport, New Jersey to be sterilized by irradiation. The USPS claims to have
sterilized and delivered nearly all of the mail that had been held undelivered since
October. This sterilization procedure adds approximately five days to delivery times.
The USPS forecasts that this procedure will be in place for only six months while a
permanent solution is implemented which could reduce the delay to two days.
The USPS has purchased eight sterilization machines from the Titan Corporation
for a total of $40 million. These will be used as part of an interim solution to sterilize
the mail of what is considered high probability targets. These targets were determined
by the USPS in cooperation with the Department of Justice. For national security
reasons, the USPS will not disclose the exact make up of this list. However, they
have publicly stated that some of these initial eight machines will be used to sterilize
the mail destined for government offices in Washington D.C. If the decision to
sterilize all mail is made, it may take several years before all of the required equipment
can be installed. In this case, the target list will be used to prioritize which facilities
to upgrade first.

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Table 1. Select Projected FY2002 Costs for Bioterrorist Threat
Reduction and Security
($ in millions)
Equipment and Building Cleaning Modifications – vacuums for
67.0
machine maintenance and floor washing
Major Equipment Vacuum Modification – changes to processing
145.1
machines to include vacuums to reduce risk of aerosolizing particles
Heating, Ventilation and Air Conditioning System Modification –
97.9
HEPA filters for all processing plants and delivery units
Protective Equipment – masks, gloves and wipes
33.2
Communications and Education – including nationwide mailing to
45.0
customers, employee training and education on threats and use of
protective equipment
Off-Site Radiation Services – an interim solution to sterilize
9.5
government agency mail while final plans are determined
Threat Detection Equipment – to detect the presence of potential
306.5
biological weapon during the sorting process. This figure also include
the installation of protective bags in the collection boxes.
Technology Deployment Costs – costs associated with testing and
53.0
postal worker training for new equipment
Acquisition and Installation of Sterilization Equipment – Although
245.0
the method to sterilize all mail has not yet been determined, this amount
includes testing costs required for evaluating competing technologies
and initial equipment purchases. Final costs could be in excess of $4
billion.
Source: USPS, November 2001
Long Term Response
The future viability of the USPS may depend on its long term response to this
new challenge. The USPS is leaning towards a multilayered response that includes
changes to mail handling and sorting procedures, threat detection and some level of
mail sanitization.
Considerations
Efficacy. Obviously the most important aspect of any proposed solution is
effectiveness; i.e. does the solution solve the problem? In this case, the simplest
analysis of effectiveness is a measure of how well a proposed solution decreases the
probability of a successful terrorist attack through the USPS. This raises further
questions such as: Can we expect the solution to reduce the probability of a successful

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attack to zero; i.e. how safe is safe? How does the proposal address biological,
chemical and conventional attacks? How will the proposal restore the public’s faith
in the safety of the mail?
The USPS is working with the Office of Science and Technology Policy, the
CDC, the National Research Council, the U.S. Army Medical Research Institute of
Infectious Diseases at Fort Detrick, and other experts in the Department of Defense
to determine which technologies are most promising. The USPS will then test these
technologies for adaptability to real world mail sorting conditions.
Cost. Another important feature of any proposal is its cost. Because of the
enormous scale of USPS operations, even many seemingly simple changes are likely
to incur huge costs. For example, one proposal would place sterilizing equipment in
each of the approximately three hundred distribution centers. This remedy has been
estimated to require between three and five billion dollars in capital costs plus perhaps
another one billion dollars annually in operating costs.
Cost will be evaluated with respect to who will pay. Postmaster General John
Potter has testified before Congress that he believes that defending the mail is a
function of homeland security and thus taxpayers rather than rate payers should bear
the costs associated with implementation costs.7 This funding plan has met with some
skepticism in Congress. Given the precarious state of the USPS’s financial situation,
some Members have suggested that giving the USPS another five billion dollars may
not be a judicious use of taxpayers money.8
Level of Service. A few aspects of the USPS’s service are considered so
important that it considers any changes to these policies to be extremely detrimental
either its core mission or to its ability to continue operations. The USPS is reluctant
to implement proposed anti-terrorist measures which significantly decrease the level
of these services.
One relevant aspect of the mail system is anonymous mailings. Currently, two-
thirds of the 680 million pieces of mail the USPS collects each day are from known
commercial mailers. This includes mail such as utility bills, catalogues and other bulk
mail from pre-identified mailing houses. This leaves more than 250 million pieces to
be collected daily from anonymous sources including 300,000 blue collection boxes,
mail slots in the 38,000 post offices, as well as more than 100 million addresses the
USPS serves. It may be that to maintain the ubiquitous nature of mail pickup sites,
some level of sender anonymity must be accepted.
The USPS also contends it is extremely important to not significantly add to
delivery time. The USPS depends on the postage generated through bill payments.
These revenues are already coming under pressure through the increasing volume of
7 Testimony of Postmaster John Potter before the Senate Treasury and General Government
Appropriations Subcommittee November 8, 2001.
8For a summary of the financial problems facing the USPS see CRS Report RL31069 Postal
Service Financial Problems and Stakeholder Proposal by Nye Stevens.
[http://www.congress.gov/erp/rl/pdf/RL31069.pdf]

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electronic bill paying.9 Billions of dollars in bill payments and remittances flow
through the USPS each year. The amount of interest that could be accruing on the
money while it is in transit (known as the “float”) is enormous. Increasing delivery
time will increase the float and therefore decrease the profits of billing companies.
This could cause the billing companies to increase pressure on consumers to use
electronic bill payment options, greatly decreasing postal revenue.
Postal Worker Safety. Any changes to mail handling and sorting procedures
designed to reduce the threat of terrorism should not increase risk to postal workers.
For example, some of the sanitizing proposals could decrease workplace safety by
requiring storage of radioactive material or very toxic gases. These risks might be
manageable but the costs associated with ensuring workplace safety must be included
in the proposal.
Potential Solutions
The procedures discussed below are not mutually exclusive. The USPS foresees
a multifaceted response consisting of layers of semi-redundant procedures to at least
ensure postal worker safety and reduce the risk of cross contamination.10
Procedural Changes. Some of the procedural changes discussed above will
undoubtably play a part in the USPS long term solution and other changes are under
consideration. Procedural changes are potentially attractive because they could be
less expensive than plans to sterilize all mail. However because of the sprawling size
of the USPS operations, even seemingly inexpensive, easy changes to procedures can
quickly become expensive when multiplied by the more than 35,000 USPS facilities.
Changes in anonymity policy. Some have noted that USPS competitors
(such as Federal Express and United Parcel Service) that have more stringent sender
identification procedures have not been used to deliver biological weapons. There
have been suggestions that decreasing the anonymity of senders through the use of
“smart stamps” and/or better tracking methods such as sender identifying bar codes,
could significantly decrease the probability of another attack.11 The USPS maintains
that sender anonymity is a very important aspect of its service. However, the USPS
has also changed this policy in the past due to previous threats. In response to
vulnerabilities highlighted by the Unabomber, the USPS began requiring packages
weighing more than one pound enter the postal system via postal clerk; i.e. someone
who wanted to mail such a package needed to go in person to a post office and hand
it to a postal worker.
9U.S. Federal Reserve System. Retail Payments Research Project: A Snapshot of the U.S.
Payment Landscape. January, 2002.
[http://www.frbservices.org/Key-Initiatives/CheckElecPayResearch.cfm]
10 Testimony of Postmaster John Potter before the Senate Treasury and General Government
Appropriations Subcommittee November 8, 2001.
11House Committee on Government Reform Chairman Dan Burton and Ranking Member
Henry Waxman, Letter to General Accounting Office Comptroller General David Walker.
November 20, 2001.

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These suggestions may require a shift in the general philosophy of the USPS.
For example requiring the use of “smart stamps” encoded to identify the sender, may
greatly decrease the wide availability of stamps. Instead of buying postage at a
vending machine, or grocery checkout lane, a person might be required to go to a
post office where their identity could be verified. Alternatively, some vending
machines could be altered to accept credit cards which obviously could be linked to
an individual sender. However this could also make it harder for people without
credit cards to purchase stamps. These suggestions appear to be less expensive than
comprehensive sterilization procedures, but they might not be. Even if smart stamps
could be manufactured nearly as cheaply as paper stamps, the increase in work force
for identity verification could prove cost prohibitive. These suggestions also raise
questions of equal access to service such as: Do you need to have a permanent
address to purchase stamps? Do you need a government issued identity card?
There are two likely assumptions needed for a change in the anonymity policy
to decrease the threat of bioterrorism through the mail. The first assumption is that
such a system could not be easily subverted by a terrorist, through an assumed identity
while purchasing postage or even by the theft of already purchased stamps. The other
assumption is that a terrorist would be dissuaded by the chance of being identified.
In the September 11, 2001 attacks, terrorists were willing to die to accomplish their
goals. Such individuals are unlikely to be dissuaded by the possibility of identification.
The lag between the act of dropping off the tainted letter and the detection of the
attack could give the determined terrorist ample opportunity for escape, even if
positively identified. However policymakers may feel that these proposed solutions
could reduce the number of likely terrorists and decrease the chances of a successful
attack to an acceptable level of risk.
Changes in Mail Handling. The USPS contends that the mail carriers who
collect the mail from the more than 300,000 blue mail drop boxes may be particularly
vulnerable to exposure to envelopes leaking a biological weapon such as Bacillus
anthracis spores. In addition to providing gloves and masks to these workers, the
USPS plans to modify the boxes slightly. Currently, when mail is dropped through the
opening it falls into a plastic mail tray that sits in the bottom of the box. The USPS
is designing a bag system that catches the mail in an attempt to ensure that the postal
carrier will not be exposed to leaking envelopes.
In mail sorting facilities, the USPS is no longer using pressurized air to remove
dust from machines and is changing to vacuuming for all of its maintenance and
general janitorial cleaning. The air handling processes are also being changed to
minimize the risk of a tainted envelope contaminating the facility. This may include
the use of negative pressure zones and the use of HEPA filters.

Detection. The same properties of the agents that made the recent attack so
damaging may make it possible for the USPS to screen some or all of the mail for
known bioterror weapons. During the initial phase of sorting, the mail is grabbed and
propelled by pinch belts. The USPS found that much of the cross contamination is
because these belts forcefully squeeze the air out of the envelopes, which in the case
of the tainted envelopes produced a puff of spores. By enclosing this area, it may be
possible to analyze the puff for the presence of dangerous materials as each piece of
mail passes.

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If it is possible to detect a tainted piece of mail within seconds of passing
through the pinch belts, this could be used to trigger an immediate shut down of the
sorting line. The mail could be quarantined and the workers would know to take the
appropriate precautionary measures. This would greatly reduce the risk to postal
workers, the chance for cross contamination of the mail and the risk of tainted mail
being delivered.
According to a recent National Research Council report, the technology required
for this type of detection has generally been plagued by false positives.12 However the
USPS is testing systems that may have much lower rates of false positives because of
the specific design requirements of this application.13 Based on the unique
spectrographic signatures of agents, in theory, this method could be used to detect a
wide range of threats. However questions remain about how well and how many
types of threat these detectors could detect in practice.
Sterilization Methods. The USPS appears to be leaning towards including
systematic sanitization of at least some of the mail stream as part of its comprehensive
long term response. Because this part of the plan will probably be the most expensive
component and since Congress will be asked to appropriate the necessary money, it
is likely that policymakers will carefully scrutinize this decision.
Opponents of sterilization can argue that it may provide a false sense of security.
While sterilization will reduce the risk of an attack using Bacillus anthracis or other
bacteria, it will probably not reduce the risk of attack by other agents such as
biotoxins (e.g. aflatoxin, botulinum toxin and ricin) or nerve agents. However
policymakers may decide that these agents are less likely to be used in future attacks
and the benefits of reducing the risk of only some biological weapons is worth the
cost.
If policymakers decide that the USPS should sanitize the mail, the appropriate
method of sterilization will need to be decided. The USPS is working with the White
House Office of Science and Technology Policy (OSTP), National Academy of
Sciences, and experts from the Department of Defense to evaluate sterilization
technologies. This is a complicated question since nothing on this scale has been
previously attempted and each method has its strengths and weaknesses. If
policymakers decide that the costs of systematic sterilization (both financial and in
terms of damage to the mail) outweigh the benefits, the USPS evaluations of these
methods may prove useful to individual companies which may chose to adopt them
on a small scale for their incoming mail.
The USPS is obligated to ensure the safety of postal workers. Sanitizing the
mail as it enters the mail sorting stream should reduce the risk to many postal
12National Research Council. Chemical and Biological Terrorism: Research and
Development to Improve Civilian Medical Response. National Academy Press. Washington
D.C. 1999. pp.78-95.
13USPS Vice President of Engineering Tom Day. Update on technology issues related to
safeguarding the mail. Briefing for congressional staff. November 27, 2001.

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workers. However, workers and work sites will still be at some risk. For instance,
workers who handle mail before sterilization and even workers who work in areas
where mail is handled before sterilization will still be at risk of exposure. Some
policymakers may feel that workers would be better protected by an aggressive
detection regime that could identify an exposure as one happens.
However the question remains whether it is the responsibility of the USPS to
ensure the safety of mail recipients. In past the USPS has taken steps to reduce the
risk of mail recipients but has refrained from ensuring their safety. For example, to
reduce the risk of explosives being sent through the mail, the USPS altered its
anonymous mailer policy as discussed above. This did not ensure the safety of mail
recipients, it moderately increased the difficulty of mailing a letter bomb. If the USPS
concludes that it is imperative to reduce the risk to mail recipients, then some sort of
sanitization may be the most effective method. If Congress does not reach the same
conclusion and does not appropriate funds for large scale sanitization, the USPS may
be forced to re-evaluate its decision in the light of how much of the costs it feels it can
pass on to the ratepayers while remaining in business.
On the other hand, policymakers may also conclude that the USPS is uniquely
situated to serve as a centralized point for mail sterilization. This analysis grows from
the assumption that if the USPS does not ensure the safety of the mail, then many
companies will invest in expensive mail handling and sterilization equipment to reduce
their vulnerability to massive financial losses that could be triggered by a bioterror
attack through their incoming mail. It is possible that if enough businesses would
otherwise resort to sanitizing their own mail, the economic savings by having the
USPS sterilize all the mail could justify the expense of its implementation. This leaves
open the question of who should bear the costs of the USPS sterilizing the mail. It
can be argued that if the USPS sterilizes all the mail then companies would not have
the costs associated with implementing their own procedures, so they should support
a postage rate increase. On the other hand, it can be argued that in spite of support
for higher rates, any postage increase will increase pressure to shift to electronic
communications, which may irrevocably damage the USPS.
Irradiation. This controversial term describes the use of subatomic particles
such as electrons and photons (electromagnetic radiation) as in ultraviolet light, X-
Rays and gamma rays. However because there is a strong negative image associated
with the term “irradiation,” some companies, especially those treating food, prefer
terms such as “cold pasteurization.” All of these methods work on the same principle,
high energy particles bombard the organism causing disruptions in its genetic material,
either killing it or destroying its ability to propagate.
The Food and Drug Administration (FDA) and the U.S. Department of
Agriculture (USDA) have approved these forms of radiation to control or eliminate
insects, Trichinella spiralis (the cause of trichinosis), Salmonella, and other food-
borne pathogens.14 For treating food for general consumption, the FDA and USDA
14 21 CFR179.26. For a thorough review of the use of irradiation to treat food see
GAO/RCED-00-217, Food Irradiation: Available Research Indicates that Benefits Outweigh
(continued...)

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limit radiation dose to less than 30 kiloGrays (kGy), although an exception exists for
U.S. astronaut food which receives more than 40 kGy. The World Health
Organization recommends at least a 40 kGy dose to kill anthrax spores.15 The USPS
would probably plan to use more than 60 kGy to ensure a large margin of safety.16
Gamma Rays. Gamma rays are a form of electromagnetic radiation just like
visible and ultraviolet light. Gamma rays, generated by the radioactive isotopes
cobalt-60 or cesium-137, are currently used to treat food and some medical devices.
Because gamma rays can penetrate through several feet, they could be used to
sterilize large palettes of mail. However this benefit is outweighed by several other
considerations such as relatively long processing times (probably several hours to
achieve effective dose) and the large amount of shielding required to ensure worker
safety. In addition, the USPS is wary of distributing to their processing facilities
radioactive material that may act as a target for future terrorist attacks.
Electron Beam. An electron beam, also known as e-beam, is essentially a very
powerful verison of the electron gun found in the cathode ray tubes of televisions and
computer monitors. E-beams are currently used to sterilize many medical supplies,
including baby bottle nipples and bandages. The eight machines and two sterilization
facilities that were described above as part of the initial response of the USPS rely on
e-beam technology.
E-beams have relatively shallow penetration through mail, greatly limiting the
amount of mail that can be treated simultaneously and their ability to sterilize
packages more than a few inches deep. However, the focused radiation of the e-beam
means that a single letter could be sterilized in fractions of a second. The USPS
contends that e-beam machines could be positioned early in the mail sorting process;
just as the mail enters the sorting stream. The USPS also maintains that by placing
one or two e-beam machines in each of its processing facilities, it could maintain
current average delivery times. However this could boost the cost of system-wide
implementation to three to four billion dollars. Another drawback of this approach
is the limited production capacity of the e-beam manufacturers is likely to require at
least two to three years to make the required number of machines.17
E-beam machines have the advantage over gamma rays in that they can be
produced without radioactive isotopes. E-beams are generated by electricity and
when the machine is switched off they do not produce radiation. They also require
much less shielding to ensure postal worker safety than if gamma rays were used.
14(...continued)
Risks.
15 World Health Organization. Guidelines for the Surveillance and Control of Anthrax in
Humans and Animals. Geneva, Switzerland.1998. p. 38.
16 USPS Vice President of Engineering Tom Day. Update on technology issues related to
safeguarding the mail. Briefing for congressional staff. November 27, 2001.
17Postmaster General Potter. Testimony before the Senate Treasury and General Government
Appropriations Subcommittee. Nov. 8, 2001.

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X-rays. Although X-rays are similar to gamma rays in that they are also a form
of electromagnetic radiation, X-rays can be generated using electricity the same way
as e-beams. They penetrate mail better than e-beams but not as well as gamma rays.
However X-ray machines would take longer to treat the mail and use much more
electricity than e-beam machines.
One great advantage of X-rays is that they can be generated by the same machine
as e-beams. Thus a combination of e-beam and X-rays could be used in the same
sorting line, e-beam for the regular mail and X-rays for the packages more than a few
inches deep.
Problems with using irradiation. Perhaps the largest barrier to choosing to
irradiate all mail is the high cost associated with implementation and ongoing
operation. According to the USPS, installing enough machines to ensure the
irradiation of all anonymous mail could cost three to four billion dollars. The
machines could also cost one billion dollars each year to operate and maintain.
Irradiating mail may also cause unwanted changes to items in the mail. Because
nearly anything can be mailed, it is impossible to predict all the changes that the
irradiation process could affect. However some things are known to be adversely
affected by irradiation including:
•
Paper can become discolored, dried, and embrittled. This may damage
important papers and decrease the length of time paper or books can be
archived.
•
Plastics can be made brittle or discolored. It is also possible some plastics
could give off minute quantities of undesirable compounds such as ozone,
nitric oxide, cyanide, and chlorinated organic compounds including PCBs.18
Credit cards can be damaged.
•
Food could have its taste and smell changed.
•
Unexposed film will be exposed.
•
Pharmaceuticals could be weakened unpredictably.
•
Explosives could be triggered.
•
Medical samples could be destroyed. Currently many medical laboratories
send samples to be analyzed through the mail.
•
Some electronic equipment including semiconductors may be damaged.19
•
Contact lenses may be damaged.
•
Seeds would be destroyed.
Some of these issues could be addressed by a combination of solutions. For
example, limiting irradiation to anonymous mailers could reduce problems for
commercial mailings of credit cards and food. The USPS could create a known
mailer program to include small businesses such as physicians who rely on mailing
medical samples to laboratories for analysis. However as it becomes easier to become
18Robert Woods and Alexi Pikaev. Applied Radiation Chemistry: Radiation Processing.
John Wiley & Sons New York, NY, 1994. pp. 126-153.
19 CompactFlash Association. Press release January 7,2002.
[http://www.compactflash.org/pr/020107b.pdf].

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part of a known mailer program, it may also become easier for this program to be
subverted by a terrorist.
Other concerns such as the production of ozone and worker safety have been
raised.20 However the USPS considers these risks to be manageable through worker
training and proper safety procedures. As pointed out by the GAO study, the few
workplace injuries associated with these machines occurred because control systems
or safety systems had been bypassed.21
Another concern is that the irradiation procedure may interact with the mail,
creating irritants. There are reports of postal workers complaining of nausea after
opening bags of irradiated mail.22 The USPS attributed this to carbon monoxide being
generated when the plastic wrapping the mail was irradiated and felt that this could
easily be addressed by modifying the procedure slightly.
Perhaps even more alarming are the recent reports that staff from at least six
Senate offices have complained of headaches, nausea, skin irritation and bleeding from
their noses and ears after handling irradiated mail.23 Although it is not clear yet that
the irradiation process has caused these symptoms, there are prior reports of
irradiation causing some materials to become irritating and perhaps allergenic.24 The
consumer advocacy group Public Citizen maintains that irradiating food and perhaps
mail can produce toxic byproducts.25 The USPS currently maintains that irradiated
mail is safe.26 The Senate Sergeant-at-Arms has formed a task force with the USPS,
OSTP, the Office of Personnel Management and the Capitol Hill Police to determine
if there is a link between the irradiated mail and the symptoms of the congressional
20J.A. Savage. An X-rayed X-mas: Should the USPS Irradiate Your Mail? AlterNet Nov. 5,
2001. [http://www.alternet.org/story.html?StoryID=11852].
21 U.S. General Accounting Office. GAO/RCED-00-217, Food Irradiation: Available
Research Indicates that Benefits Outweigh Risks. August 2000. p. 14.
22The Oregonian. Postal Service has Plans to Zap Mail for Anthrax. December 17, 2001.
p. A01.
23Roll Call Daily. Health Scare Over Irradiated Mail Moves to the House. January 28,2002.
[http://www.rollcalldaily.com/rollcalldaily/1_80/news1/456-1.html], Roll Call Daily. Officials
Urge Staffers to Come Forward as Physician Logs 11 Cases of Reactions to Irradiated
Mail. January 29, 2002.
[http://www.rollcalldaily.com/rollcalldaily/1_81/news1/461-1.html].
24U.S. Food and Drug Administration Center for Devices and Radiological Health. Medical
Glove Report. September 1997. [http://www.fda.gov/cdrh/glvpwd.html].
25 Public Citizen. Hidden Harm: How the FDA is Ignoring the Potential Dangers of Unique
Chemicals in Irradiated Food. December 2001. Washington D.C.
[http://www.publiccitizen.org/publications/release.cfm?ID=7113]
Roll Call Daily. Consumer Advocate Questions Safety of Irradiated Mail. January 31, 2002.
[http://www.rollcalldaily.com/rollcalldaily/1_84/news2/484-1.html]
26 Roll Call Daily. Postal Service Says Staffer Ailments Not Linked to Irradiated Mail.
January 30, 2002.
[http://www.rollcalldaily.com/rollcalldaily/1_83/news2/476-1.html]

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staff.27 Clearly this issue will need to be addressed before deciding to begin a larger
scale program of mail irradiation.
Gaseous. Certain gases, including chlorine dioxide, ethylene dioxide and
paraformaldehyde vapor have proven useful for decontaminating buildings and
equipment. Chlorine dioxide may be the most promising of these since it has also
been used extensively to treat drinking water for many years. However, it is not yet
clear if these methods could be adapted for mail sterilization. In practice, the use of
these gases is very complicated as demonstrated with the reoccurring problems in
chlorine dioxide fumigation of the Senate Hart Building. The USPS is currently
testing the efficacy of the most promising of these gases under likely operational
conditions.
It has been suggested gaseous sterilization could be considerable less expensive
than irradiation. This could be true, since this method would not require the purchase
of the expensive irradiation machinery. However, it is not clear how much the postal
sorting facilities would have to be modified to ensure the proper handling of these
extremely toxic and potentially carcinogenic gases. Furthermore, the storage of these
toxic gases on-site could pose a new target for terrorism.
Other methods. Several other methods that are used for sterilizing items in
other circumstances have also been suggested to the USPS as a means of treating the
mail. These include the use of ultraviolet light (UV) or heat. The USPS has generally
found that these methods unsuitable for treating the mail for various reasons. For
example, UV cannot penetrate envelopes. On the other hand, heat might be less
expensive to implement than irradiation, but would likely have higher operating costs,
be much slower and still have problems with causing changes to mailed items.
Conclusions
The series of decisions to be made in the wake of the Bacillus anthracis mailings
will affect nearly everyone in the U.S. and may alter the fate of the USPS. Perhaps
the most important decision to be made is what is an acceptable level of risk? Tightly
wrapped up in this decision is how much are we willing to pay and who should bear
the costs? Policymakers may also chose to carefully scrutinize the methods that the
USPS chooses to implement to ensure that the best and most cost effective plans are
executed.
27Roll Call. Mail Sparks Fears: Irradiated Mail Latest Cause for Concern. January 28,2002
[http://www.rollcall.com/pages/news/00/2002/01/news0128a.html].

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Useful Links
USPS Mail Security Page
[http://www.usps.gov/news/2001/press/serviceupdates.htm]
Centers for Disease Control and Prevention Bioterrorism Page
[http://www.bt.cdc.gov/]
Federal Bureau of Investigation: Anthrax Investigation Page
[http://www.fbi.gov/majcases/anthrax/amerithraxlinks.htm]
GAO Report Benefits and Risks of Food Irradiation (GAO/RCED-00-217)
[http://www.congress.gov/erp/rl/pdf/RL31069.pdf]

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