Anthrax has hit an offsite White House mail facility and caused the death of two Washington, D.C., postal workers, authorities announced Tuesday.

"We're making sure the West Wing and the White House is safe," President George W. Bush said in a press conference.

White House spokesman Ari Fleischer told reporters that anthrax had been found Tuesday at a mail-screening facility for the White House on a military installation. That facility was closed for testing and decontamination. All environmental tests at the White House itself have come back negative, he said.

"I don't have anthrax," Bush responded when a reporter asked if he had been tested for the potentially fatal bacterium. 

That was perhaps the only reassuring news in the growing anthrax scare, which Tuesday claimed more victims. Officials said that a New Jersey mail handler and at least two more postal workers were infected with the more-dangerous, inhalation form of the disease.

Two more people affiliated with the central Brentwood mail facility that serves Washington were being treated for inhalation anthrax, though test results confirming the diagnosis were not complete, said Donna Bigler, spokeswoman for Montgomery County, Md., where the two patients were hospitalized.

One of them, a 35-year-old man, works at Brentwood. The second, a 41-year-old woman, is a postal union official and was in the facility regularly, Bigler said.

In addition, local health officials said two other cases showed symptoms of inhalation anthrax.

"We need to treat and to treat quickly," Dr. Ivan Walks, the senior health official in the District of Columbia, said.

He said anthrax spores have been found inside the Brentwood facility and that officials have begun testing to see if anthrax has spread to local post offices. Antibiotics were being dispensed to postal workers across the city.

The Secret Service noted that mail handled at the offsite White House screening facility is processed through the Brentwood facility.

Personnel at the White House facility will also get testing treatment for potential infections, Health and Human Services Secretary Tommy Thompson said.

"We're going to be in there quickly and will be issuing the necessary antibiotics to the people who need it," he said. 

White House spokesman Ari Fleischer defended federal health authorities who initially opted not to test the Brentwood facility after learning it had handled an anthrax-tainted letter sent to Senate Majority Leader Tom Daschle.

"The president believes the cause of death was not the treatment made by the federal government or the local officials, or anyone else, but the cause of death was the attack made on our nation by people mailing anthrax," he said.

Dr. Jeffrey Koplan, director of the Centers for Disease Control and Prevention, said the CDC never suspected that anthrax could leak out of a sealed letter.

"We had had no cases of inhalation anthrax in a mail-sorting facility," he said. "There was no reason to think this was a possibility."

At the same time, Thompson said that if additional tainted letters are found, officials would move more aggressively to test and treat any workers at postal facilities that handled them.

The developments unfolded as Attorney General John Ashcroft said investigators "are not able to rule out an association with the terrorist acts of September 11, but neither are we able to draw a conclusive link at this time."

Congress returned to work for the first time since an anthrax scare spread across Capitol Hill last week. House and Senate office buildings remained closed for additional environmental testing, and two sources, speaking on condition of anonymity, said authorities may decide to burn piles of mail for fear they could never check them adequately for anthrax.

While several of those cases have connections to the news media, including ABC, CBS, NBC and the New York Post, tthe front lines of the anthrax attacks seem to have shifted to America's blue-uniformed postal force.

So far, three people overall are known to have died from inhalation anthrax -- two postal workers in the Washington area and one man in Florida. Three others -- all postal workers -- are hospitalized and believed to be sick with inhalation anthrax, though their diagnoses are not confirmed. In addition, six people have contracted skin anthrax, a highly treatable form of the disease.

In Washington, more than 2,000 workers at Brentwood, where anthrax has been found in 14 spots, will need a full 60-day course of antibiotics. Another 2,000 at auxiliary offices were beginning to take the drugs while their work sites are tested and officials determine if they need a full course.

Walks added that officials were watching another 12 cases but they are of "very low suspicion" for anthrax. That's on top of four who have more suspicious symptoms.

In New Jersey, Health Commissioner George DiFerdinando said a mail handler in his state was believed to have contracted inhalational anthrax and was hospitalized in serious but stable condition. The woman works at a facility that processed at least three anthrax-tainted letters mailed to Washington and New York.

The FBI confirmed it is investigating whether other anthrax letters were processed through the Brentwood facility in Washington. The only known tainted letter was delivered to Daschle's office. Investigators have been unable to explain the presence of anthrax on a mail handling machine that serves the House.

The central facility handles mail not only for congressional offices, but for the entire District of Columbia. It was declared a crime scene Tuesday.

"It's a crime scene because someone has been murdered," said Deborah Willhite, a top Postal Service executive.

Postal workers from as far away as Baltimore lined up outside a district hospital for testing and a supply of antibiotics. Many are angry about the delay in treatment.

"We have not been treated right," said Veola Jackson, a spokesman for the postal workers' union at the Brentwood facility. "I think this could have been avoided when they first saw that first piece of mail on the Hill."

Several days elapsed between the discovery on Monday of anthrax-tainted mail in Daschle's office and initial testing at the Brentwood facility. Officials explained their decision by saying that initial testing was negative at one of the postal facilities that the letter had passed through after leaving Brentwood.

Speaking at the White House, House Democratic Leader Dick Gephardt expressed frustration with a recent statement by Tom Ridge, director of Homeland Security, who said the anthrax had not been "weaponized."

"The words are not particularly helpful," said Gephardt, D-Mo. "Obviously this stuff gets in the air and stays in the air. ... You can call it anything you want to call it. This is not safe stuff."

Gephardt added, "This is weapons-grade material."

Officials identified the two men who died of inhalational anthrax as Joseph P. Curseen, 47, and Thomas L. Morris Jr., 55.