A letter mailed to the New York Post has tested positive for anthrax and is similar to anthrax-laced letters sent to NBC news anchor Tom Brokaw and Senate Majority Leader Tom Daschle, police said late yesterday.

The letter addressed to "Editor" was postmarked Sept. 18 - as was a contaminated letter sent to Brokaw - and bore a Trenton, N.J., postmark like the letters to Brokaw and Daschle. The letter to Daschle was postmarked Oct. 9.

The handwriting on the Post letter is similar to that found on the two other letters, according to statement released by New York police and the FBI.

Police found the unopened envelope late Friday night during an investigation launched after a Post employee tested positive for the bacteria. The letter, which contained a small amount of a powdery substance, has been sent to Maryland for testing.

Meanwhile, anthrax was found in the mailroom of a House office building yesterday, while a man who works at a Washington post office that processes letters bound for Congress was hospitalized with a possible anthrax infection.

Investigators who began testing House and Senate offices earlier this week after an anthrax-laced letter arrived at Daschle's office in the Hart Senate building found anthrax on a mail-bundling machine at the Gerald R. Ford House Annex, Capitol police said yesterday.

The annex handles mail for the Longworth House Office Building, where more than 100 lawmakers have their offices. The annex also houses the Congressional Budget Office and a child care center, but no anthrax was found outside the mailroom.

The unidentified postal employee worked at Washington's central post office, which had handled the Daschle letter. Mail headed for lawmakers' offices passes through the post office on Brentwood Avenue in Northeast Washington before being routed to either the House or Senate.

Washington Health Commissioner Ivan Walks declined to identify the man, but said his symptoms were "suspicious" and that he was being tested for anthrax while under treatment at Fairfax Hospital.

Officials said it was too early to draw any links between the sick postal worker, the anthrax finding at the Ford building and the letter that arrived at Daschle's office. Twenty-eight people who worked in or near the office tested positive for anthrax exposure and were placed on antibiotics.

The developments, however, raised the possibility that a second letter contaminated with anthrax was sent to Congress - this one passing through the Ford Annex before making its way to a House office. Officials, however, said one letter could have contaminated others while passing through mail-handling equipment.

Dr. John Eisold, a physician for the Capitol, said employees in the Ford mailroom will be tested and treated if necessary.

Eight people in the United States are known to have contracted the disease, including a man in Florida who died. The others are on antibiotics and are expected to recover.

The discovery of anthrax in the Ford building seemed to validate the decision by Speaker J. Dennis Hastert, an Illinois Republican, to adjourn the House on Wednesday and order its office buildings cleared. The Senate - its members saying they didn't want to send signals of panic - remained in session until Thursday afternoon, though its offices were closed.

Rep. Peter T. King, a New York Republican, told CNN yesterday that the Senate's action was "pompous, posturing windbagging."

House and Senate office buildings were closed Wednesday to allow for environmental testing. Work was to continue through the weekend, but it was unclear yesterday whether the houses would go back into session Tuesday as planned.

In Trenton, FBI agents and other investigators interviewed residents and swabbed mailboxes for clues to the source of anthrax-laden letters sent Brokaw and Daschle.

Residents in Ewing Township were shown photos of the letters and asked whether they recognized the handwriting, whether they had noticed anything suspicious lately, seen any cars with out-of-state licenses or knew any chemists living among them.

Some were asked whether they routinely left outgoing mail in their personal mailboxes for their letter carriers to pick up or typically dropped it in a public box.

"It stops you in your tracks," said Charlotte Kaplan-Piepszak, 48, who pointed to a double-bagged bundle of mail that she picked up at the post office last week but will keep on her back porch until she is sure its safe. "When the planes hit the World Trade Center in New York, New York being 70 miles away, that's close. This is in our own back yard."

Investigators swarmed over the neighborhood after skin anthrax was diagnosed in a mail carrier, a prompt, friendly, pony-tailed woman residents knew as "Terry." Agents hope to trace the sources of two contaminated letters she may have handled, sent to Brokaw and Daschle. They have seized several mailboxes in the past few days.

On Friday, officials said a second New Jersey postal worker has developed skin anthrax - a 35-year-old postal worker from Levittown, Pa., who worked at the regional distribution facility in nearbyHamilton Township, N.J. He was in stable condition yesterday and was responding well to antibiotic treatment, a hospital spokeswoman said. Test results were pending on a third postal worker, a maintenance employee who worked on mail-sorting machines at the Hamilton facility.

Employees at the West Trenton post office in Ewing Township and at a regional processing center in Hamilton Township, 20 miles away, began a seven-day regimen of antibiotics yesterday as recommended by the state health department.

Yesterday, President Bush said there remained no evidence that the anthrax letters were linked to the Sept. 11 terrorist attacks on the World Trade Center and Pentagon. But he vowed to fight whoever is behind them.