A DIAGRAM FOR A RED-LETTER DAY 



about Epidemiology & the department

Epidemiology academic information

Epidemiology faculty

Epidemilogy resources

sites of interest to Epidemiology professionals



Last Updated

15 Nov 2002

Source: Washington Post, March 26, 2002

A Diagram for a Red-Letter Day

Brentwood Facility's Size Inspires a Grand Strategy to Oust Anthrax

By Steve Twomey, Washington Post Staff Writer

Each day, a team seemingly clothed for a spacewalk waddles through an improvised air lock of tunnels and curtains. Inside, the quarantined Brentwood mail center is now cleaner than the day it was born. The visitors clean it still more, sample conditions and tackle other tasks, then retreat, leaving the anthrax spores alone again in a cavernous structure where 2,000 people once toiled.

No matter how much cleaning is done by hand, there are still spores, although no one knows how many. Tests find that they alight sometimes on the processing machines, which have moved no mail since Oct. 21. But usually the spores float, invisibly, beneath sodium-vapor ceiling lights that burn constantly to help the hazmat teams.

Brentwood's heating system is dormant, yet the temperature is a steady 80 degrees because of the lights, and because every loading-dock door (100 or so), every skylight (235, give or take), every place where a utility conduit enters or a vent opens, has been taped or blocked or covered. That keeps the spores from infecting the world beyond. That traps them for their coming demise.

Which, if all goes well, is not far off.

U.S. Postal Service officials today will outline how they intend to return Brentwood to service as Washington's mail hub in what experts believe will be the most ambitious reclamation of a biohazardous building in the country's history.

That decontamination is necessitated by two terrorist letters that passed through the facility in October, bound for Capitol Hill. Those letters, and others up and down the East Coast, killed five people, sickened 13 others, forced the Postal Service to begin irradiating mail destined for federal offices in Washington, and led to the evacuation and cleanup of numerous postal facilities and government offices, including the Hart Senate Office Building.

It is the successful cleansing of Hart that is the blueprint for the resurrection of Brentwood, which, along with the decontamination of a Trenton mail facility, will cost $35 million, postal officials said. But less than 100,000 cubic feet of Hart had to be sealed to fumigate it with the agent believed to be most effective, chlorine dioxide gas. Brentwood, a low-slung brick edifice in Northeast Washington, has 17.5 million cubic feet.

In a delicate feat likely to begin soon, contractors will attempt to fill those cubic feet with chlorine dioxide and keep the gas at a specific concentration and a precise level of humidity for 12 hours, without leaks. If they succeed -- and more than one attempt is probable -- the yellow-green gas will curl into every nook, envelop every machine, penetrate the outer shells of spores and kill them more efficiently than human cleaning could.

Only when some 3,000 test strips are analyzed and no spores are detected will Brentwood's workers return from temporary posts in the city and suburbs. Only then will 4 million pieces of mail resume moving through the building each day without fear that spores will infect workers, the mail or anyone who receives it.

"If there's any message I want to give you, it is that we're going to make sure we get it right, so that there is an effective treatment and [Brentwood] is effectively decontaminated," said Thomas G. Day, the Postal Service's vice president for engineering. "We are absolutely committed to getting this done, but we need to get it done right."

The plan, described in interviews before a media briefing this afternoon and in advance of a community meeting near Brentwood tomorrow, poses almost no risk of fire or explosion because the concentration of chlorine dioxide will be kept far below volatile levels, postal officials said.

But District health officials, who said they could stop the project if they deemed it too risky, described it as still "embryonic" and said some details must be resolved, including how to ensure that chlorine dioxide gas does not leak from a building with so many openings. Experts said that any leaks would quickly dissipate, and that anyone exposed might experience burning eyes and a runny nose at the worst.

Theodore J. Gordon, the District's deputy director for public health assurance, said yesterday that "we are nowhere near" ordering a pre-fumigation evacuation of commercial and residential areas that fringe Brentwood, which lies just off Brentwood Road, near the headquarters of Black Entertainment Television to the east and Metro's Rhode Island Avenue station to the west.

But Gordon said the city has raised the possibility of conducting the fumigation in stages, by sectioning off Brentwood's interior to minimize the amount of chlorine dioxide that is made and pumped at any one time. He said, however, that the city had no overall objection to using chlorine dioxide gas, and believed that Brentwood could be contaminated using it, a conviction shared by others outside the Postal Service.

"I think the choice was absolutely the right choice," said Gilbert Gordon, professor of chemistry at Miami University in Ohio, who has assisted the Environmental Protection Agency with anthrax decontamination reports. "I've heard nothing adverse in terms of worries that chlorine dioxide [used] in that way would be misapplied or dangerous."

Commonly used in water treatment systems and pulp-making, it is "a chemical we understand well. We know how to make it. We know how to use it. We know how to destroy it," Gordon said. He would not hesitate to stand in the Brentwood parking lot during the decontamination process, he said.

But Pat Johnson, president of the American Postal Workers Union local that represents most of Brentwood's workers, said her membership would prefer to see the building torn down -- not salvaged -- because "everybody's a little distrustful about going back." Two of their colleagues died of inhalation anthrax and two more became seriously ill, and the entire workforce was urged to take antibiotics to ward off infection.

Johnson said that some members have said that they would not return, no matter how thoroughly the Postal Service cleans, but "a lot of people say things out of haste," and she expected that most workers will return. "When you're told the facility is reopening, what can you do?"

Reopening seemed the best option, postal officials said. Bulldozing the building could fill the air with anthrax spores, and leaving it as a sealed hot spot would not be fair to the neighborhood or the city. Moreover, no one at Hart has become sick with anthrax since it reopened in January, which suggests that the chlorine dioxide method can make a building safe.

As recently as three years ago, such a revival of a site tainted by anthrax spores was not thought possible, said Charles N. Haas, a professor of environmental engineering at Drexel University in Philadelphia, who testified before Congress in November about the anthrax problem. But many assumptions about anthrax have proved wrong since October, including the belief that inhalation anthrax is almost always fatal and that spores could not leak from envelopes.

In tests before the decontamination attempts at Hart, scientists learned that chlorine dioxide gas can kill anthrax spores if injected into a sealed environment that has a humidity of 75 percent and a temperature of 75 degrees. That humidity level softens a spore's outer shell, allowing the gas to penetrate, and that temperature helps the gas interact "with protein and DNA inside the spore to cause killing," Haas said.

Temperature can vary widely without hurting the outcome, but humidity cannot, officials said. It should not go below 70 percent, said Richard Rupert, who was the EPA's coordinator during the Hart cleanup. Right now, humidity inside Brentwood averages 25 percent to 30 percent. It will be raised with humidifiers when the time comes to inject the gas.

Because chlorine dioxide is too unstable to transport as a gas, Gilbert Gordon said, a "precursor" substance will be brought to the Brentwood parking lot, probably in a large tank truck. There, a huge machine will convert that substance to chlorine dioxide gas, which will then enter a three-foot-wide pipe for the short journey through one of Brentwood's outer walls.

Before that pipe enters the building, a secondary pipe will branch upward from it and carry gas to Brentwood's 16 heating and air-conditioning systems on the roof, said Dennis Baca, the Postal Service's manager for environmental management policy. Those systems will blow the gas inside. Meanwhile, the main distribution pipe will carry gas to 14 "emitters" that hazmat teams will place at key locations inside Brentwood.

No one will be inside during decontamination. Engineers will remotely operate Brentwood's ranks of processing machines during the gassing, both to improve circulation and to ensure that every part of every machine is exposed to the gas. Baca said that there was no risk that a spark from the equipment would ignite the gas, and tests have shown that the gas would not harm the machines.

Using monitors inside, engineers will adjust humidity, temperature and gas concentration as needed, and after 12 hours at the right conditions, the chlorine dioxide will be sucked out of the building through scrubbers that will render it harmless. Hazmat teams then will collect strips inside, which will be tested to see if any spores remain.

Baca said the Postal Service has obtained data on spring wind currents in the area from the National Weather Service, so it will know how escaping gas might move. It also will test Brentwood for leaks before filling it with the gas. And during the decontamination itself a special EPA van will cruise the area, trying to detect any trace of chlorine dioxide. The EPA's Rupert said there were no problems with leaks during the Hart cleanup.