WASHINGTON (AP) _ A renewed attempt to kill lingering spores of anthrax in the Hart Senate Office Building got underway Friday, with a poisonous gas being pumped into the building's heating and ventilation system.
Capitol Police Lt. Dan Nichols announced that deadly gas chlorine dioxide gas would be concentrated in the ventilation system of the southeast quadrant of the building, an area that tested positive for anthrax spores after an earlier fumigation effort.
The building has been closed since Oct. 17, two days after an anthrax contaminated letter was opened in the offices of Sen. Thomas Daschle, D-S.D.
In a first clean up attempt, technicians, under the direction of the Environmental Protection Agency, pumped chlorine dioxide gas into Daschle's office early in December. Liquid and foam decontaminants were used in 11 other senator's offices.
Later tests showed that some anthrax spores lingered. Daschle said that senators and their staff members would not return to the building ``until it's been certified as absolutely safe.''
A second attempt last week failed when equipment problems kept the gas fumigant from reaching a saturation point experts believe is necessary to kill the anthrax spores. EPA officials said Friday that the goal was to reach a concentration of 750 parts per million.
The new fumigation effort is expected to take up to 24 hours, said EPA spokesperson Jennifer Browne. Afterward, technicians will conduct tests to see if any dangerous anthrax spores remain.
The anthrax-by-mail bioterrorism attack was directed at media offices in New York and Florida, and at senators in Washington. It left a trail of buildings contaminated with anthrax. There was widespread contamination in a number of postal facilities where the letters were processed, along with mail-handling sites in other buildings.
The Centers for Disease Control and Prevention in Atlanta has confirmed 18 cases of anthrax infection nationwide _ 11 cases of inhalation anthrax and seven through the skin _ since the anthrax-by-mail attacks began in October. Five people have died, all from inhaled anthrax.