Anthrax colonies found in N.Y. mail facility

NEW YORK (CNN) -- Bacteria colonies found on four sorting machines in Manhattan's largest mail distribution center were anthrax, the U.S. Postal Service confirmed late Thursday.

Peter Nash, head of postal inspection in New York, said the machines at the Morgan processing and distribution facility were shut down. The facility itself remains open.

"Initially bacteria cultures were found, and later that turned out to be anthrax," he said.

Nash said further tests were ongoing to determine how much anthrax was present on the machines. When testing is complete, he said, the machines will be cleaned, sterilized and retested before they are put back into service.

The postal inspection spokesman had no information about employees who worked near the machines, but said officials were "handing out Cipro all day yesterday."

Nash said samples were taken from the building at Ninth Avenue and W. 30th Street Sunday. Tainted letters sent to the New York Post and NBC News anchor Tom Brokaw likely traveled through the Morgan facility. More than 5,000 workers are employed at the center.