Decontamination of Hart Senate Building enters third day

WASHINGTON -- Poisonous gas was pumped for a third day into the Hart Senate Office Building to kill trace amounts of anthrax spores in the heating and ventilation system.

"Everything is just moving along, and it's simply a matter of doing engineering and mechanical things to keep it working right," Environmental Protection Agency spokeswoman Jennifer Browne said .

Technicians under the direction of the EPA on Friday began pumping chlorine dioxide gas into the heating and ventilation system of the southeast quadrant of the building, an area that tested positive for anthrax spores after an earlier fumigation effort.

Browne said the gassing had been extended beyond one day as a precautionary measure. Another chemical, sodium bisulfite, will be used to break down the gas. Throughout the process, a specially equipped EPA bus monitors the air outside to guard against any dangerous releases.

The building has been closed since Oct. 17, two days after an aide to Senate Majority Leader Tom Daschle opened an anthrax-tainted letter.