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Study Backs Massive Anthrax Cleanup in D.C.

Finds that minimal office activity could have reactivated spores

TUESDAY, Dec. 10, 2002 (HealthDayNews) -- A new study finds that last year's massive cleanup of the anthrax attack on the Hart Senate Office Building wasn't a case of overkill.

The anthrax spores sent to that building were so fine, the report says, that had the office not been closed and given a thorough scrubbing, even the most minor office activity could have stirred them up and threatened workers anew.

In the fall of 2001, white-suited figures decontaminated the building to clean up the first-ever anthrax attack on the nation's capital. A letter laden with the bacteria was sent in mid-October to Senate Majority Leader Tom Daschle (D-S.D.), whose offices were in the Hart building.

Few people watching the cleanup personnel or hearing that the entire building had been closed down and the ventilation system shut off would have thought there was any overreaction to the threat presented.

But the situation was not one that had ever been encountered before, and scientists were not absolutely sure that the contingency methods employed were the right ones.

When the unthinkable happened, experts had the opportunity to get answers to this and other questions. The report on their work appears in tomorrow's issue of the Journal of the American Medical Association.

"It was important to assess anthrax measurement tools to help guide the cleanup and assure the safety of workers and the public," says Christopher P. Weis, lead author of the study and a toxicologist with the U.S. Environmental Protection Agency's National Enforcement Investigations Center in Denver. "In retrospect, it's probably obvious that that was the right thing to do. But at the time, it wasn't obvious how much overkill or what level of resources needed to be applied."

Before the cleanup commenced, a small team of specialists from four different government agencies collected air samples and surface dust (nasal swabs were done by a different team) in the contaminated office suite under two conditions: when there was minimal movement in the office and, again, while simulating regular office conditions. They then estimated how high the concentrations of anthrax in the air might get under both situations so as to estimate possible exposure and to help protect the health of workers and the public.

In fact, common office activities did cause the anthrax spores to be reaerosolized, or stirred up.

"This is nothing new for the people who are the specialists in this field," says Dr. Tareg Bey, associate clinical professor at the University of California, Irvine Medical Center in Orange, Calif., and one of only about 200 board-certified medical toxicologists in the United States. "All it means is that once you have anthrax contamination, especially with this type of powder, you need to have a very good cleaning effort."

But it does mean that the clean-up effort was guided by sound principles.

"If we didn't go in and do what we did, which is close down the building and send in forensic people to decontaminate, if we had just cleaned up the immediate surface which was exposed, it could migrate down the hall," says Tom Johnson, director of respiratory therapy at Long Island University in Brooklyn. "We did the right thing, and if we didn't send in people with the right respiratory protection, they, too, could have been victims. It's as bad as we thought it was but our reaction was clearly appropriate."

In their natural environment, spores of Bacillus anthracis bacteria tend to cluster together. "This reduces their ability to disperse through the air, causing them to cling to fabrics, carpets, and other charged surfaces," Weis explains.

The anthrax found in the Hart Senate Office Building and elsewhere, on the other hand, was manipulated for maximum effect: The particles are much smaller in size, so they can stay in suspension for a good amount of time, Johnson says. Also, they don't have the electrostatic coating of natural anthrax so they don't clump together. The result is that you have scores of miniscule particles flying around. "It's what we suspected. We're not going to mess around with this stuff," Johnson says.

It also means that what you find in nature is not necessarily what you're going to find in a terror attack. "Our previously held concepts about pathogen behaviors might not hold during terror events, when people are trying to manipulate these agents to behave differently," Weis says. "The anthrax spores had been toyed with. They were manipulated to make them behave in a way that was not the way they would behave in nature."

The building was reopened three months later.

What To Do

For more on anthrax, visit the CDC or the Michigan Department of Community Health.

SOURCES: Christopher P. Weis, Ph.D., toxicologist, U.S. Environmental Protection Agency's National Enforcement Investigations Center, Denver; Tom Johnson, director, respiratory therapy, Long Island University, Brooklyn, N.Y.; Tareg Bey, M.D., associate clinical professor, University of California at Irvine, Orange, Calif.; Dec. 11, 2002, Journal of the American Medical Association
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