Interscan in the news > Decontamination plan stirs concerns

Decontamination plan stirs concerns

Some private-sector scientists say using the toxic chlorine dioxide gas to decontaminate the District's central mail processing center on Brentwood Road will be too dangerous.
     "It's highly toxic," said Michael Shaw, the vice president of Los Angeles-based Interscan Corp., which makes tools to monitor toxic gas. "I don't believe anyone has attempted to use chlorine dioxide to fumigate such a large area before."
     The U.S. Postal Service says if the gas successfully killed anthrax spores in the Hart Senate Office Building, where it was used on Sunday, it very soon will be pumped into the Brentwood facility.
     Mr. Shaw said the size of Brentwood — about 200,000 square feet, compared with Senate Majority Leader Tom Daschle's 3,000-square-foot office suite — will make using chlorine dioxide extremely dangerous.
     "You have a massively large facility and you're going to have to deploy this gas in an unknown way," he said. "Unless you're breaking the building up into small quadrants and pumping the gas in that way, this could be potentially very dangerous."
     But Mike Brown, the director of technology at B.J. Unichem Chemical Services in Houston is not as skeptical about chlorine dioxide and believes it may be the only "efficient way to sanitize the building."
     "It's not inherently dangerous because it dissipates quickly," Mr. Brown said. "In terms of gasses used to sanitize, chlorine dioxide is relatively low on the danger scale."
     "In any application of chemicals, you have to weigh the hazards against the benefits," he said. "In this case, I'd rather take my chances with chlorine dioxide than with anthrax."
     Widely used as a bleaching agent in the paper industry, chlorine dioxide is yellowish-green and has a chlorinelike odor. Decontamination specialists say that when it is produced and handled properly, it is an extremely powerful disinfectant.
     The Environmental Protection Agency is still waiting for test results to find out whether the gas worked in Mr. Daschle's suite in the Hart Building, where an anthrax-filled letter was opened on Oct. 14.
     EPA spokesman Dave Bary said test results could be in as early as today.
     A batch of mail being processed at a temporary mail-handling facility set up in a courtyard of the Federal Reserve's headquarters has tested positive for exposure to anthrax, officials said late yesterday.
     Officials said that the positive reading was obtained for a batch of mail containing about 100 to 150 letters and it had not been determined whether any of the letters actually contained anthrax spores or whether some of the mail had been contaminated by other letters.
     Fed spokeswoman Michelle Smith stressed that none of the mail had been inside the Fed's imposing headquarters on Constitution Avenue.
     Federal Reserve Chairman Alan Greenspan and other members of the Fed board were briefed on the development late yesterday. Officials said they a public board meeting that had been scheduled for today had been canceled but otherwise the central bank would be open for business.
     The mail that tested positive for anthrax was being processed by three Fed employees and three contract employees all wearing protective suits and breathing through respirators, Fed officials said.
     Brentwood, which processed the Daschle letter and another anthrax-packed letter to Sen. Patrick J. Leahy, Vermont Democrat, has been sealed off since Oct. 21, when two employees there died of inhalation anthrax. Environmental tests found anthrax spores on at least six mail-sorting machines inside Brentwood, the Postal Service said.
     Kit Bowen, a chemistry professor at Johns Hopkins University in Baltimore, said he doesn't see any reason to be worried about using chlorine dioxide in Brentwood.
     "I don't understand why it would be particularly hazardous," he said. "If you use it in a small building, you can use it in a larger building."
     Mr. Bowen said the thing about chlorine dioxide that concerns him is making sure the toxic gas does not linger "in the walls of a building" weeks or months after the decontamination work is done.
     When the gas was used in the Daschle suite, faint traces escaped outside, but they were well below the 25 parts per billion exposure level acceptable to D.C. health officials, the EPA said.
     The gas was piped into Hart for more than 20 hours, beginning before dawn Saturday after a delay caused by difficulty reaching the high humidity levels needed for the gas to most effectively kill anthrax spores. The gas, which was broken down by sodium bisulfite, was undetectable in the office by Sunday evening.
     Meanwhile, federal law enforcement authorities yesterday said the Leahy and Daschle letters were identical.
     Army scientists at Fort Detrick, Md., opened the Leahy letter Wednesday. Investigators hope evidence from the letter will help track the culprit in the anthrax attacks.
     Opening the letter was delayed more than two weeks while technicians determined the best way to protect evidence retrieved from the letter.
     The FBI said both the Leahy and Daschle letters have the same wording in them, with "09-11-01" written at the top and "Death To America Death To Israel Allah Is Great," written at the bottom.
     Federal law enforcement authorities plan to decontaminate the letter, which was taped around the edges and is believed to be loaded with billions of anthrax spores, before testing it for fingerprints, DNA and fibers.
     The Centers for Disease Control and Prevention yesterday said the risk of getting anthrax from cross-contaminated mail is "very low," but issued guidelines for people worried about the threat.
     Concerned people should keep mail away from their faces, avoid blowing on, sniffing, tearing or shredding mail before throwing it away, and frequently wash their hands, the agency said.

     • This article is based in part on wire service reports.

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