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Trenton Metro Area Local

American Postal Workers Union



Trenton Processing and Distribution Center


Thursday, April 10, 2003


Following are responses to frequently asked questions regarding the upcoming decontamination of the USPS Trenton Processing & Distribution Center (P&DC):

Community Health & Safety

Will the gas used in the fumigation pose any danger to people living or working near the building?

We do no expect the fumigation to endanger anyone who lives or works in the area surrounding the building for four reasons:

First, the gas that will be used, chlorine dioxide (CIO2), is not flammable or explosive in the concentrations that will be used at the facility.  The gas was delivered to the site in the form of five separate chemicals, and will be mixed on site as needed.

Second, chlorine dioxide is a known chemical that has been safely and widely used for more than 70 years to disinfect much of the nation's food and water.  More than 900 water treatment facilities around the world use the chemical every day.

Third, over the past months, contractors have carefully sealed every crack in the building, or any other possible escape route for the gas, to ensure that during fumigation, the gas stays where it's needed - inside the building.

Fourth, several systems will be in place to monitor the air in the area surrounding the building, to immediately alert contractors if the gas begins to escape the building through a small leak somewhere.  In the unlikely event that were to happen, the emitters pumping gas into the building would be immediately shut down, and fumigation would stop until the problem is resolved.

Will road closures or evacuation of nearby homes and businesses be necessary in the vicinity of the building while the fumigation is taking place?

Evacuation was not needed during the decontamination of the Washington facility or the Hart Senate Office Building, thus we don't anticipate the need to evacuate during this fumigation, wither.  In the unlikely event of an emergency, however, we are working with local emergency management officials, who will have established emergency response plans, in the unlikely chance they become necessary.

Is there any danger of the gas used in the fumigation exploding or otherwise harming anyone in nearby homes or businesses?

The use of chlorine dioxide at the P&DC poses much less of a public risk to the neighboring area than a railroad tanker filled with the gas would pose to the surrounding area if it derailed.  The risk posed by the gas diminishes quickly outside the immediate perimeter of the building because it loses effectiveness once it is exposed to sunlight.

What type of air monitoring will take place to make sure that a gas leak doesn't endanger the neighboring area?

Just as we are testing the air inside the facilities for the concentration level of chlorine dioxide, we also will be monitoring the air outside the building at selected points.

The analytical methods being used are so sensitive that they can detect very small amounts of chlorine dioxide.  A weather station will be erected and will be connected to a computer for constant updates on wind direction, temperature and barometric pressure.  This will allow sampling personnel to know where a potential leak may disperse and determine areas for continuous monitoring.

What will happen to the gas or byproducts from the fumigation, once it's complete?

After the decontamination, the gas will be neutralized and removed.  At that point, the only byproducts will be harmless substances we are all familiar with - water, saltwater and oxygen.

This wastewater will be carefully sealed in tanks and disposed of in accordance with federal standards and regulations set by the EPA.

Just in case the gas escapes, what does chlorine dioxide smell like?

The gas smells similar to the chlorine used to disinfect swimming pools.  This slight odor may be noticeable to anyone in the vicinity of the building during the actual fumigation.  This smell is no cause for alarm.

How and when is each of the chemicals that will be used in the fumigation being transported into the Trenton area?

Chemicals will be brought to the facility in tanker trucks prior to their use, and the CIO2 will be mixed on site.  We are working closely with emergency management officials to define the travel route, and they will determine the appropriate security measures along the route.

Are these chemicals explosive or flammable, and do they pose any risk to area motorists?

No.  All five chemicals will be delivered to the facility and the CIO2 mixed on site.  We are working closely with emergency management officials to define the travel route, and they will determine the appropriate security measures along the route.

How will I be notified if there is a leak of chlorine dioxide?

In the very unlikely event of a leak, trained teams from the New Jersey and Hamilton Township Offices of Emergency Management will immediately notify any businesses or residents that might be affected.

Decontamination Contracts

Who has been hired to do the decontamination?

Shaw Environmental & Infrastructure, Inc. (E&I) of Baton Rouge, LA has been onsite at the Trenton facility since it's closure and is under contract with the Postal Service to provide various decontamination services, such as surface decontamination and preparatory work.  The Postal Service also awarded contracts to Ashland Inc. of Covington, KY and Sabre Oxidation Technologies Inc. of Odessa, TX for additional decontamination activities.

All three contractors were active in the decontamination of the Curseen- Morris P&DC in Washington, DC, which has been completed, the building is expected to reopen this summer.

Why did the USPS decide on these companies, and how experienced are they in biohazard cleanup?

The U.S. Environmental Protection Agency (EPA) evaluated cleanup technologies based on current environmental science.  These companies are experienced suppliers with the capability to provide the necessary services, equipment and chemicals required for this cleanup.  These are the same three companies that handled the successful cleanup of the only other large facilities in our nation's history to undergo decontamination from anthrax - the Hart Senate Office Building in Washington, DC in December 2001 and January 2002, and the Curseen-Morris P&DC on Brentwood Road in Washington, DC, in December 2002.

When did the contractors begin work at the Trenton P&DC, and how long will it take?

Immediately after the contracts were signed, the contractors began reviewing site plans and evaluating which equipment from the Washington fumigation will be needed for the Trenton project.  Once they determine the equipment needed, it will be transported to Trenton and installed soon after its arrival.  In order to begin the actual fumigation, we were required to respond to all the established requirements under FIFRA (the Federal Insecticide Fungicide Rodenticide Act).  After we have met those requirements, the EPA will issue a FIFRA Crisis Exemption to the Postal Service authorizing us to use chlorine dioxide to fumigate the facility.  The Crisis Exemption stipulates that we begin the fumigation process within 15 days from its receipt.  The process will continue until we achieve the necessary results - "no growth" of anthrax spores on all environmental samples taken in the facility.

Shaw Environmental & Infrastructure, Inc.  (E&I) of Baton Rouge, LA, one of three contractors the Postal Service has hired to conduct the decontamination, has been on-site at the Trenton facility since its closure conducting various decontamination activities such as surface decontamination and preparatory work.

Decontamination Process

Who is coordinating this decontamination, what other government agencies were involved in the planning, and will they have any role during the actual decontamination process?

The USPS as the lead agency set up and Incident Command Structure (ICS) to safely and effectively manage the large complicated anthrax decontamination effort.

In addition to the EPA, many other federal and local agencies have served in overall advisory roles to the USPS over the past several months.  These include:  The New Jersey Department of Environmental Protection, the New Jersey Department of Health, the New Jersey Office of Emergency Management, the National Institute for Occupational Safety and Health, the Occupational Safety and Health Administration (OSHA), the Armed Forces Radiobiology Research Institute, the U.S. Army Center for Health Promotion and Preventative Medicine and the Centers for Disease Control and Prevention (CDC).  They will continue to help support the USPS until the cleanup is complete.

Why has it taken so long to decontaminate this facility?

Logistically speaking, this effort requires complex planning, coordination and execution.  A team of professional engineers and scientists began planning fumigation of both the Trenton and Washington facilities in November 2001.  This team includes civil, mechanical and chemical engineers, chemists, building and environmental scientists, and specialty technicians.  All key team members are experienced in environmental response and cleanup.  After spending thousands of work hours learning, in detail, about the facilities - both inside and outside - the team prepared detailed engineering drawings and used scientific models to simulate actual air currents in the buildings.

In order to protect employee health, we felt it was important to properly look into every possible issue that could surface during the cleanup.  This has helped us to fully understand what we were faced with before moving ahead.  This included making sure we hadn't overlooked any corner or any crevice, as well as, determining that we hired the right people to perform the fumigation.

Significant work has been going on inside these facilities for months to prepare them for final decontamination:

Rolling stock, mail bins and trays have been removed from the building and decontaminated.

Mail processing equipment has been cleaned and wiped down with approved cleaning solution

Items that have been identified as trash have been decontaminated and removed for disposal.

Cafeteria and vending areas have been wiped down with a solution of chlorine bleach.

Exactly what has been done to seal the building, to prevent the gas from escaping?

The entire building has gone through an extensive sealing process to prevent the escape of chlorine dioxide into the atmosphere, and is sealed from both the interior and exterior.

Inside:  Visible cracks in the floors, walls, and ceilings have been sealed with expanding foam sealant or silicone caulking; all floor drains have been sealed; and windows on outside walls have been covered with foil-backed foam insulation.  Seals have been checked throughout the process on a weekly basis and on a more frequent basis in case they have been affected by inclement weather.

Outside:  All visible cracks in the walls have been sealed with foam sealant or caulking; all skylights and any other openings in the roof have been covered, sealed, and insulated with poly-sheeting and foil tape; the truck dock areas have been framed and covered with poly-sheeting; and roof leaks have been sealed.

Why isn't the latest method being used to decontaminate the Trenton P&DC. instead of chlorine dioxide gas?

Chlorine dioxide gas is the only proven technology available for eliminating anthrax from a large building such as the Trenton P&DC.  Although other methods may also one day prove to be just as effective, this is not the case today.  Chlorine dioxide has been safely used for more than 70 years and was successfully used in December 2001 and January 2002 to eliminate anthrax from the contaminated areas in the Hart Senate Office Building in Washington, as well as the Postal Service's P&DC in Washington in December 2002.  We're using it because it works.

Exactly what are the various steps that will be used to decontaminate the building?

Clean all surfaces and equipment with approved cleaning solution;

Seal all openings in building with thermal foam, including all cracks, vents, truck bays and skylights;

Adjust and maintain environment at 75 degrees F and 75% relative humidity for best results;

Use existing HVAC system and delivery system to pump in chlorine dioxide gas;Maintain 750 parts-per-million concentration of the chlorine dioxide gas for 12 hours;

Conduct extensive environmental sampling to ensure safety;

Ventilate completely before re-opening.

Different sanitization methods have been used inside the facility in preparing for fumigation, these include:

Bleach disinfectant

Dust removal

Equipment removal

Heating and air conditioning filters removal

Debris removal

Gas fumigation

HEPA filtration

What are the exact chemicals that will be used to mix chlorine dioxide?

Sodium Chlorine

Sodium Hypochlorite

Hydrochlorite Acid

Sodium Hydroxide

Sodium Bisulfite

Exactly how will the fumigation be performed?

Based on tests conducted in October and November 2001 by the EPA, as well as the decontamination conducted at the Hart Senate Office Building, chlorine dioxide gas was selected and recommended as the best treatment approach and best available technology for the contaminated facilities, because it is proven  to kill the anthrax-causing bacteria.

In preparation for the fumigation, the interior environment of the building will be brought to a temperature of 75 degrees F and a 75 percent relative humidity.  For the gas to be as effective as possible, it will be generated just prior to the time of use.  The chlorine dioxide gas will be mixed in specially constructed tanks once fumigation is about to begin.  Water and liquid chlorine dioxide will be pumped into the building through a specially designed system of 25,000 feet of piping and the gas stripped and then dispersed through the HVAC system and 17 emitters.  During the fumigation process, 50 monitors inside the building will constantly monitor chlorine dioxide levels, temperature and humidity so that numerous systems can control the environment throughout the entire operation:

Temperature System - Maintains a 75 degree F minimum temperature.

Humidification System - Maintains relative humidity of 75 percent.

Chemical Plant and Gas Emission System - Stores and delivers the liquid chemicals that create the fumigating gas.

Gas Transfer and Mixing Systems - Allows the gas to be generated and emitted in the building, keeping it at the necessary level of 750 parts-per-million for at least 12 hours.

Process Control System - Allows the engineers to control all aspects of the equipment and operations.

Negative Air Pressure System - Helps keep chlorine dioxide gas contained in the building.

Ambient Air Monitoring - Provides detailed information regarding the concentrations of chemicals and contaminants both inside and outside of the building.

Support System - Includes all of the personnel necessary to run all systems properly and safely.

In addition to the new emitters that have been constructed for the decontamination, the buildings' existing heating ventilation and air conditioning (HVAC) system will be used.  Fans have also been installed to help spread the gas throughout the building.

All processing equipment in the building will be turned on remotely while the gas is inside, to be sure that all parts of the machines are exposed to the gas.  This will also help create more airflow.  The contract calls for the fumigation process to be repeated up to five times necessary, until no spore growth is achieved through environmental sampling.

Is chlorine dioxide dangerous?

Chlorine dioxide is a known chemical that has been safely used for more than 70 years, including regular use at more than 900 water treatment facilities around the nation.  The science behind this gas is well documented, and it is the only proven technology available for killing anthrax spores in a large building such as the Trenton P&DC.

In solid state, it can be a very volatile agent at high temperatures; however, it will never be in this state at Trenton.  It will be delivered in the form of five separate chemicals that will be mixed on-site before use.  After the decontamination, the gas will be neutralized and removed.  At that point, the only byproducts will be harmless substances we are all familiar with - water, salt water and oxygen.

The gas is not flammable and it is not explosive in the concentrations that will be used at the Trenton facility.

What does chlorine dioxide smell like, and what type of warning signs or symptoms should I be on the lookout for, in case I'm exposed to the gas?

The gas smells like the chlorine used in swimming pools, but this will not be an issue.  The chlorine dioxide gas will be completely removed from the building before employees or the public is allowed inside the building, so no one will experience any symptoms resulting from the fumigation process.  We will allow plenty of time to air out the building before it reopens.

What if this strain of anthrax is resistant to the chlorine dioxide gas?

Remember, the source of the anthrax at both the Hart Senate Office Building and the Washington postal facility was a letter that passed through the Trenton P&DC.  So we know the strain of anthrax was the same in all three places.  And we know that chlorine dioxide was successful in killing the anthrax at both the Hart building and the Washington postal facility.  Multiple tests conducted at both buildings following decontamination revealed no live anthrax spores whatsoever.  In addition, every expert we have consulted assures us that the gas works.  Studies by the United States military also have proven its effectiveness.

What is chlorine dioxide gas commonly used for?

Chlorine dioxide is a yellow-green gas with an odor similar to the chlorine used in swimming pools.  It has been recognized as a disinfectant since the early 1900s and is approved for many uses by the Environmental Protection Agency.

Every day in the United States, 4 to 5 million pounds of chlorine dioxide are used safely for a variety of purposes, including:

Treating and disinfecting drinking water.

Bleaching wood pulp used in papermaking.

Disinfecting food products such as flour, spices, shrimp, fruits and vegetables.

Sanitizing food-processing equipment.

Eliminating odors in industrial scrubbers and fish plants.

Sterilizing medical equipment and for other biomedical and pharmaceutical uses.

Should people living in the neighborhood be concerned about any risk of the gas - or even anthrax particles - escaping into the surrounding community during the cleanup process?

The entire building has gone through an extensive sealing process to prevent the escape of chlorine dioxide or anthrax spores into the atmosphere.  It is sealed from both the inside and the outside.

We also will be monitoring the air outside the buildings at various strategically selected points.  A weather station will be erected on the premises and will be connected to a computer for constant updates on wind direction, temperature and barometric pressure.  This will allow sampling personnel to know where the gas would disperse from a potential leak, helping to identify areas for special monitoring.  In the highly unlikely event that a leak is detected, we will immediately shut down the delivery systems for the gas.


How will you know that the equipment used for the decontamination is working properly?

The very same systems and equipment that will be used in Trenton were successfully used in Washington, so we know that they work.  The Postal Service conducted a series of tests of these systems before beginning the fumigation, and these same tests will be repeated here in Trenton after the systems are installed to ensure they are again working properly.

How will you know if the treatment is successful?

We will meet all measures established by regulators and health officials.  The standard we will achieve is "no growth" of anthrax bacterial from the extensive environmental sampling that will be done throughout the facility following fumigation.  This will establish that all spores have been neutralized or killed.

How will you know all the anthrax has been killed following fumigation and that the Trenton P&DC will truly be safe again?

Thousands of environmental test samples have been taken in the facility since it closed - including wipe, swab, HEPA and air -sample spore strips.

After the fumigation and before the facility reopens, we will conduct extensive sampling.  Spore strip tests will be taken throughout the facility, with a biased toward areas where contamination was identified.  Samples will be taken to approved labs for culture testing.  Only when all environmental samples come back with "no growth" will the facility be considered safe to reopen.  The building will open only after deemed safe by the appropriate regulatory authorities.

Experts will determine when the facility is safe for occupation again - only when we can assure our employees, our customers and the American public that they have nothing to fear at the facility will it reopen.

What is test results after fumigation continue to show contamination?

Depending on what sampling data indicates, we'll determine whether additional surface cleaning should be applied to specific areas or further fumigation will be necessary.

Wouldn't it be more cost-effective and safer if the USPS just tore down or abandoned this facility?

That may sound like an easy solution, but it's not.  The Postal Service is a responsible corporate citizen and good neighbor in the communities that host our facilities.  Even if we were to abandon a contaminated facility, we still would be responsible for decontaminating it using the same process.  Abandoned buildings don't stay abandoned.  Eventually someone will need to use the facility.  So we cannot leave it contaminated and allow it to become a public health hazard.  The same is true for demolishing the building without first decontaminating it, which would expose the surrounding community to anthrax.

And, if abandoned or demolished, we would still have to construct a new replacement facility at greater additional cost, assuming a suitable site could be found.

We have no choice but to clean this facility.  We know from the experience at both the Hart Senate Office Building and the Washington postal facility that Trenton can be successfully cleaned using the decontamination process we have selected.  This will make it safe for occupancy again.  We are not in any hurry to do this; we will take our time to make sure the decontamination is done correctly and thoroughly.

Public Health

Is there any health risk associated with long-term exposure to any residue of agents used in the decontamination?

There is no demonstrated long-term risk whatsoever associated with the procedures planned for these decontamination operations.

Following fumigation, cleanup and painting, we will be continually monitoring the building's air quality, to ensure that no residue from the decontamination process is left behind.  We will reopen only after tests show the air to be fully safe for everyone.

How can you guarantee that all the gas has been removed before the facility reopens?

On completion of the chlorine dioxide fumigation, the following final clean-up activities will be performed before personnel will be allowed to return to work.  These additional steps are being taken to further safeguard employees as well as the community.

Prior to final cleaning of the interior, the building will be cleared of all residual chlorine dioxide gas using a chemical scrubber to neutralize any remaining gas.  In addition, large-volume exhaust fans, air filters and sensor equipment will be used.  Once the interior has been cleared of the gas, secondary cleaning will begin.  Areas suspected to be contaminated prior to fumigation, as well as all walls, ceilings, joists and carpeting, will be vacuumed using High Efficiency Particulate Air (HEPA) vacuums to remove any dust or residue left over from the fumigation process.  The dust collected will be sealed in containers and disposed of.  Special attention will be given to cleaning the sorting machines and the areas where contaminated letters were processed.

After areas are completely vacuumed, they will be wiped thoroughly with a wet bleach solution to further ensure decontamination.  This includes all floors and hard surface areas throughout the facility.  Environmental samples will be taken throughout the building to ensure that the decontamination was successful before employees can enter.  Once the building is deemed successfully decontaminated and fully safe, decontamination crews will join Building Engineering and Maintenance staff in preparing the postal equipment with this decontamination effort.

Investigation/Future Risk

What procedures are you putting into place to ensure the safety of the mail from known mailers?

The Postal Service has been working with the mailing industry to develop an "identified mailer" program, which will benefit both the Postal Service and the mailing industry in two ways.  First, it allows us to track mail back to the sender.  Second, we capitalize on customer relationships to bypass the sanitization stream, avoiding damaging or delaying the mail.  The identified-mailer initiative serves as a deterrent to acts of bio-terrorism and allows the Postal Service to trace mail back to its point of origin.

This identified mailer program is still under review by the Mail Security Task Force.  If the program is approved, the Postal Service will work with the mailing industry to disseminate information about this program.

Once this cleanup removes the existing anthrax in the facilities, what ongoing precautions are being taken to help guard against any future threats?  Will we have to go through the same ordeal next time?

As identified in the Emergency Preparedness Plan presented to Congress in March 2002, the Postal Service has identified and is currently pilot testing a new biohazard detection system.  This system, if effective, will allow the Postal Service a quick response once biohazards are detected in the mail stream and reduce the risk of cross-contamination in the network.

We have been documenting the process, procedures and lessons learned since day one of this emergency last fall.  We are ensuring that we have adequate Statements of Work, sources and contacts at the EPA and other agencies that can provide assistance in biohazard situations.  We are also working with our four national environmental suppliers to ensure they are ready to help us meet any future needs.

In addition, we are improving processing equipment for collection mail by providing for continuous dust vacuuming and air filtration at all mail processing and distribution centers.  This provides a continuous flow of air across the mail, away from operators, through the equipment and into filtration units, where the air undergoes two stages of filtration, the final stage using HEPA filters.  This equipment is now being tested and will be installed within two months of the time appropriated funds are available and a contract is awarded.

Will security be increased at the Trenton Processing and Distribution Center once it reopens?

All of our Processing and Distribution Centers nationwide already have strong security measures, such as requiring a photo ID for entry and postal police controlling access to the buildings.  We will continue to vigilantly enforce security precautions at all facilities, including the Trenton Processing and Distribution Center.  In addition, new detection equipment capable of identifying anthrax is now being tested for possible nationwide deployment.

What other plans are in place for helping protect employees at the Trenton P&DC as well as all other postal facilities around the country from any future biohazard?

While no system is 100 percent safe, prevention and early detection will do much to help guard against any and future biological threats.  Our goal is to install equipment capable of detecting a bio-threat at the point it enters our sorting process, and then immediately seal off any area where a threat is first identified, to minimize the chance for cross contaminating a wider area and ensure that we limit employee exposure.

Mail then identified as contaminated will be treated at one of the irradiation facilities.  Any necessary medical intervention would be immediately provided to employees or anyone else inside the building during the incident.

To help protect against any future threats, we are moving forward on testing a reliable new biohazard detection system to detect anthrax.  This system was custom-built specifically for the Postal Service's needs, after extensive consultation with several private-sector companies, various federal agencies and experts from academic institutions.

To be phased in over the next year and a half, this system will quickly alert us within one hour of any release of anthrax inside a work area - and will be modified in the future to detect additional biological agents.

This system already has been tested over the past year in Baltimore, and will be installed in 14 additional sites in June as part of a pre-production test.  This time frame is necessary to properly test and ensure reliability and manufacturing of the devices.  Following the testing period, the Trenton P&DC will be among the first to receive these new devices to protect against bio-threats.

This system is part of more than $2 billion the Postal Service is spending on decontamination, irradiation, protection and other strategies to reduce health risks to our employees and customers.

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