The anthrax fright continued to spread yesterday as four new suspected cases surfaced among postal workers in Maryland and New Jersey, and spores were found at two mail-handling facilities in Washington - including one that screens letters addressed to the White House.

All three new cases of suspected anthrax in Maryland involve employees at the capital's main mail-sorting facility in Brentwood. One person was hospitalized yesterday at the Greater Baltimore Medical Center in Towson; the other two were at Holy Cross Hospital in Silver Spring.

Authorities also said another New Jersey postal worker - the third in that state - is suspected of having anthrax.

Despite the discovery of anthrax at the White House mail-sorting center in Anacostia, none has been found at the White House.

"I'm confident when I come to work tomorrow that I'll be safe," President Bush said yesterday.

As Congress resumed business, hundreds of postal workers lined up outside D.C. General Hospital to collect their 10-day supplies of the antibiotic Cipro.

Some were frustrated by the delay in testing and treatment; others seemed fatalistic.

"When it's my time to go, it's my time to go," said mail truck driver Benjamine Stevenson, 53, as he left the hospital with his prescription. "But I sure am going to take all the precautions I can to make sure that time is as far off as possible."

Environmental testing continued at the Brentwood postal facility, where authorities confirmed yesterday finding anthrax spores.

Similar testing had not yet begun at the Express Mail handling facility near Baltimore-Washington International Airport. It remained closed yesterday.

"I guess they're getting held up at Brentwood," said Postal Service spokesman Robert Novak. Once it begins, the environmental testing was expected to last three or four days.

So far, 200 postal workers at the BWI facility have been tested and started on antibiotics, with 20 remaining, Novak said. Test results weren't expected for several days.

The facility was closed Monday after it was learned that Leroy Richmond, 57, a mail handler who worked there and at Brentwood, had contracted inhalation anthrax.

In Washington, federal officials acknowledged that they erred in not moving faster to protect postal workers.

Health and Human Services Secretary Tommy G. Thompson told a congressional hearing that if another anthrax letter emerges, officials would begin testing and treatment not only where the letter is discovered, but at every postal facility it passed through.

"We're going to err on the side of caution in making sure people are protected," Thompson said.

But White House spokesman Ari Fleischer said that the deaths of the two Brentwood workers should not be blamed on federal or local health authorities.

"The cause of death was the attack made on our nation by people mailing anthrax," he said.

Calling the mailing of contaminated letters "terrorist acts," Attorney General John Ashcroft released the texts, two of which had similar language.