Trace amounts of anthrax have been found on four pieces of mail-sorting equipment at a postal distribution center in Wallingford, the U.S. Postal Service and health officials said Sunday.

The 300,000 square-foot Southern Connecticut Processing & Distribution Center sorts and processes about 3 million pieces of mail every day headed for zip codes in Middlesex, New London and New Haven counties — including the town of Oxford, where 94-year-old Ottilie Lundgren lived. Lundgren died of anthrax on Nov. 21.

The testing was conducted Nov. 28, and involved the use of a special vacuum that has a filter designed to trap minute particles, said Mike Groutt, a Centers for Disease Control and Prevention spokesman. It was the fourth time the center had been tested since October, but the first time using the vacuum, Groutt said.

The trace amounts most likely were left on the machines when an anthrax-tainted letter destined for an address in Seymour, a few miles from Lundgren’s home, passed through the plant on Oct. 11, said Jon Steele, vice president of the Postal Service’s Northeast Area Operations.

On Friday, officials announced the discovery of that letter, which contained a single spore of anthrax. So far, investigators have not found any link between Lundgren and the letter.

“This round of testing was very much more intensive and was focused on that mail trail — the trail that mail going to Oxford or Seymour would have taken going through the facility,” Groutt said.

Following the discovery of the Seymour letter, Connecticut Gov. John Rowland suggested Lundgren’s mail might have been cross-contaminated by tainted letters sent to Sens. Tom Daschle and Patrick Leahy.

Those letters were postmarked at a facility near Trenton, N.J., on Oct. 9. Rowland said the Connecticut letter moved through a sorting machine within seconds of one of the Washington letters. It then was sent through Wallingford.

“This [latest] finding is not a complete surprise,” said Steele. “The public should not be panicked by trace elements occurring nearly 60 days ago.”

The sorting machines will be decontaminated, a process that could take several days, Steele said. The center will remain open for business, he said.

The facility was tested on four separate occasions and a combined total of 389 samples were taken, he said. Five samples in the latest round of testing revealed the anthrax, he said.

“This is a very small about of anthrax,” said Dr. Joxel Garcia, the state’s commissioner of public health. “The people of Connecticut should not be concerned about opening their mail.”

Meanwhile, health officials from New York were in Hartford Sunday to compare notes about the anthrax deaths of Lundgren and Kathy Nguyen, a 61-year-old Bronx woman.

Nguyen died on Oct. 31, becoming New York’s first case of inhalation anthrax. Like Lundgren, she was older, lived alone and spent a lot of time by herself.

Investigators have so far been unable to determine conclusively how either woman contracted the disease.

–Associated Press