HEALTH

Tests by EPA and CDC Find Anthrax Spores Don't Stay Put

By CHAD TERHUNE, Staff Reporter of THE WALL STREET JOURNAL

Contrary to the widely held scientific belief that anthrax spores settle and stay put, limiting the spread of the deadly disease, an experiment by federal officials inside Sen. Tom Daschle's office found that a significant number of anthrax spores re-entered the air when officials mimicked regular office activities.

And a test in recent weeks on a sorting machine at the Brentwood mail processing facility in Washington, D.C., also found "reaerosolization" of anthrax spores. These findings could point to increased risk of inhalation anthrax and could complicate cleanup efforts of contaminated equipment and offices.

The findings by the Environmental Protection Agency, which conducted the Daschle test, and the Centers for Disease Control and Prevention were discussed at the opening day of a CDC anthrax conference in Atlanta, attended by more than 100 government scientists and officials.

CDC and EPA officials cautioned that the results are preliminary and that the health implications remain unclear. Based on experiments conducted by the military, officials have thought that anthrax spores under five microns behave much like a gas when released and then clear the area in a few hours. Larger spores, 15 microns or more, have tended to "settle out and anchor themselves to surfaces," said D.A. Henderson, head of the Office of Public Health Preparedness at the Department of Health and Human Services, in an interview. Once the spores settled, it was very difficult to relaunch them into the air.

That is one reason health officials have been skeptical about blaming cross-contaminated mail for the inhalation anthrax deaths of a Connecticut woman and a New York woman. Once anthrax spores anchor to a piece of mail, they wouldn't be expected to fly into the air and infect someone's lungs. "We have not felt this was going to be a lingering problem... provided you clean up the immediate area of the release," Dr. Henderson said.

In testing Sen. Daschle's office, investigators last month acted out regular office activities, including changing fax-machine paper, shuffling paperwork and opening letters. This "active" test produced positive anthrax culture on 16 of 17 sample plates and higher spore counts inside the air-sampling machines.

"The spores did go into the air in concentrations significantly higher during active office work," said Chris Weis, a Denver-based regional toxicologist for the EPA, who led the experiment. "We saw a maximum increase of 100-fold in airborne spores." Some health officials at the CDC meeting suggested the anthrax spores might have remained suspended in the air, since the ventilation system was shut off shortly after the Daschle letter was opened.

Meanwhile, further testing of mail at the Federal Reserve has so far failed to yield a letter that might have contaminated a mail bin with anthrax, spokeswoman Michelle Smith said. Federal Bureau of Investigation officials said they believed the contamination, which prompted the Fed to cancel a meeting Friday, was the result of cross-contamination. About 600 letters are being tested individually for signs of anthrax -- hand-addressed letters first. Tests of the Fed building found no sign of anthrax, and operations Monday returned to normal.

The Postal Service also announced that 50 postal inspectors will monitor letters and packages bound for the 2002 Olympic games in Salt Lake City. Mail headed to the media center, the athletes' village and elsewhere will be checked by X-ray for bombs, officials said, and irradiation gear that sanitizes the mail could be used as well.

Officials also said Monday that irradiating mail isn't turning out to be a panacea for dealing with the anthrax threat. The process has proved "slow, expensive and having lots of adverse effects" on the affected mail, said Bernie Ungar, director of physical infrastructure issues for the General Accounting Office, speaking at a conference on how to improve mail safety. The Postal Service has been sending some mail to private contractors for irradiation and plans to install its own irradiation equipment in some facilities. Postal officials said they have no plans to stop irradiating mail. But the conference explored other options, including requiring identification of stamp buyers; setting up a system to identify "anonymous" mail -- mail dropped off in mail-collection boxes, in contrast to bulk mail requiring senders to have permits -- and putting windows in envelopes. The Postal Service plans to submit by the end of March a plan to transform its structure, including how to enhance mail security.

-- Sarah Lueck and Kathy Chen contributed to this article.