Anthrax spores have been found for a second time at a postal sorting center that serves a large portion of Connecticut, including the town where a 94-year-old woman died of inhalation anthrax in November, officials said Thursday night.

Three of 103 samples taken at 71 locations inside the Southern Connecticut Processing & Distribution Center tested positive for anthrax, state Department of Health spokesman William Gerrish said.

"What we feel is that these probably represent residual spores from contamination occurring last October," Gerrish said. "These largely undisturbed spores don't pose an immediate threat to the health and safety of the employees or the public."

Gerrish called the positive results "not totally surprising," saying the testing methods were extremely sensitive.

The 350,000-square-foot complex had been tested six previous times in November and December following the Nov. 21 death of Ottilie Lundgren. The Wallingford center is the largest postal facility in the state and handles nearly all of the state's incoming mail.

About 3 million spores were found late last year during an investigation into Lundgren's death.

The facility was tested again on Sunday and the positive samples were found in the ceiling above three of the four sorting machines that were contaminated last fall.

The Postal Service said in a news release that the samples were taken prior to a routine cleaning of the ceiling. Postal union members and federal safety regulators monitored the testing; union officials had criticized the decision not to close the center during the testing, which the union said could stir up spores.

The postal service said Thursday the center will remain open, with the locations of the positive samples isolated for decontamination. Work will be transferred to other locations in Connecticut and the Northeast during decontamination.

Gerrish said the state's system of monitoring for possible anthrax cases has shown no signs of possible infection. He could not immediately say whether employees at the Wallingford facility would be advised to take antibiotics or other precautions.

Lisa Swinarski, a spokeswoman for the federal Centers for Disease Control and Prevention, said her agency had not been asked for help.

"The Health Department told us about the results, but that's all we know," she said. "The CDC only gets involved when the public health department invites us to. They have complete capability to do the kind of sampling and analysis necessary up there."

The exact route of Lundgren's infection has not been determined, but authorities believe cross-contamination of her mail is the most likely explanation.

Nationwide, more than 20 people became ill and five died following the mailing of anthrax-tainted letters from New Jersey. No arrests have been made despite a $2.5 million reward offered by the Postal Service and FBI.