The anthrax situation in New York City was ratcheted up yet another notch when a non-postal worker struggling for her life tested positive for the deadliest form of anthrax.

The 61-year-old hospital worker's case is the first inhaled infection of a New Yorker in what appears to be a coordinated attack on U.S. government offices and media conglomerates.

The woman, a stockroom employee of the Manhattan Eye, Ear and Throat Hospital, was on a respirator and "struggling for her survival," health officials said Tuesday.

The source of the infection is not known. Environmental samples from the hospital tested negative, and no one else is showing signs of the disease, Mayor Rudolph Giuliani said.

Officials in New Jersey also disclosed another new case of inhalation anthrax. They said the victim, a female postal worker whose name was not announced, was released from the hospital last week and is recovering at home.

Meanwhile, more postal facilities are being closed after testing positive for anthrax.

Postmaster General John Potter told a Senate hearing that two facilities in Washington, D.C., have been shut down after traces of anthrax were found. He also said trace amounts were found in a plant in West Palm Beach, Fla.

The hospital employee's diagnosis brings the number of confirmed anthrax cases nationwide to 17. That includes 10 cases of the inhalation form of the disease, three deaths among them — and an additional seven people with the less severe skin form of the illness.

The woman did not handle mail.

But Dr. Jeffrey Koplan, head of the Centers for Disease Control and Prevention, suggested a possible link. He said the mailroom and the stockroom were combined until a remodeling was undertaken over the past two weeks.

The woman started showing possible symptoms of anthrax on Thursday, Giuliani said. By Sunday she was in severe respiratory distress and went to the emergency room of Lenox Hill Hospital.

"There was a rapid progression from Saturday to Sunday," Health Commissioner Neal Cohen said.

Other hospitals in the city have been alerted "to take precautions ... and share their findings with us," Cohen said.

After the initial tests returned positive showing the woman had contracted inhalation anthrax, a hazardous materials unit was dispatched to the woman's workplace for environmental samples. Nasal swabs were taken from 25 workers and those tested were given antibiotics. About 300 full-time employees work at the hospital, which does not admit patients overnight.

Repeated phone calls to the hospital went unanswered, but employees entering the hospital Tuesday morning said the facility was closed.

Giuliani said that as employees came to work, they would be taken to a separate area and interviewed as part of the investigation.

Authorities late Monday were tracing mail routes that lead to the hospital, and city health officials are also contacting patients who visited the hospital over the past two weeks, the incubation period for anthrax.

New York City has been a focus of the anthrax investigation since an assistant to NBC anchorman Tom Brokaw was infected earlier this month. The city has had five confirmed skin anthrax cases — all at media outlets — but none of the more-serious inhaled form.

In Florida, New Jersey and Washington, D.C., three people have died from inhaled anthrax, three others have confirmed cases, and one has survived.

Earlier Monday, a postal union filed a lawsuit against the U.S. Postal Service to force the closing of New York's biggest mail-sorting center for testing.

"We're simply asking the post office to close the building and make sure it's safe," William Smith, the union president said of the 2-million-square-foot Morgan Processing and Distribution Center. "Test everybody and tell us they haven't been exposed. If that's not done, we shouldn't be in that building."

The Postal Service also announced that absenteeism there had climbed to nearly 30 percent since traces of anthrax were found on sorting machines.

But despite the anthrax difficulties, there have been only "minor, minor disruptions" of mail delivery, a Postal Service executive said.

No postal employees in New York have come down with anthrax.

Potter defended the postal service's handling of the situation, saying officials were first led to believe that anthrax couldn't escape out of letters that were taped around the edges.

He said several billion dollars will be needed to safeguard the nation's mail system.

The Associated Press contributed to this report.