As a precaution, health officials are distributing antibiotics to 2,100 workers at a mail center in the district and to 150 workers at an express mail center at .
The man, who was not identified, is the ninth person who has contracted anthrax and the third with the inhaled variety, which is fatal about 80 percent of the time. He split his time handling express mail at the Brentwood mail-sorting center in the district and at BWI, where he worked three days a week. Both facilities handle mail addressed to Capitol Hill, where Senate Majority Leader Tom Daschle's office received an anthrax-laced letter last week.
The man was listed in serious but stable condition at a hospital in Fairfax, Va., not far from his home, officials said. He complained of a fever and chest pains in the middle of last week but did not feel sick enough to go to the hospital until Friday.
"The kind of anthrax this person has is a very serious form," said Maryland Health Secretary Dr. Georges Benjamin at a news conference yesterday outside the BWI postal center that investigators are examining.
"So we want to meet with other postal workers at these centers, talk to them to find out if they are sick and start them on antibiotics as a precaution," Benjamin said.
Five other D.C. postal workers have symptoms that are consistent with anthrax, and health officials are awaiting the results of testing to determine if they have the disease, said Jack Pannell, spokesman for the city health department.
At least two of them are in hospitals, Pannell said.
Hundreds of postal workers lined up yesterday for nasal swabs at a district testing center to determine if they inhaled anthrax spores. Those not tested yesterday are to report from 9 a.m. to 10 p.m. today at D.C. General Hospital, 19th Street and Massachusetts Avenue, SE.
Employees are being given a 10-day supply of antibiotics to ward off infection in case they were exposed.
It is not clear how or where the postal worker contracted the disease, officials said.
Investigators are looking into whether the employee handled Daschle's letter or other correspondence laced with anthrax spores. A complicating factor is that Daschle's letter was sent first class and the sick employee normally handled express mail, said Patrick Bernardo, an inspector with the Postal Service.
After express mail arrives on aircraft, the employee and other postal workers at BWI sort it and distribute it to other mail offices, including the Brentwood center, which serves Capitol Hill.
"We are trying to follow the route of the mail as part of our investigation," Bernardo said.
At 1 p.m. yesterday, postal officials evacuated 12 employees from the BWI express mail center, located in a cargo-handling complex on Route 170 near the airport. Movement of mail inside the building has been temporarily halted as investigators try to find traces of anthrax or other evidence, officials said.
The BWI and Brentwood mail centers are being scrutinized for anthrax spores and other clues by Postal Service inspectors, investigators with the Centers for Disease Control and Prevention, and other investigative agencies.
Letters and parcels arriving at the airport are being handled at a temporary center in the same cargo complex. The post office has offered all employees protective gloves and masks and does not expect any disruption of service, said Robert Novak, a postal spokesman.
Maryland Transportation Secretary John D. Porcari said the cargo complex is separate from the part of the airport used by the public so there is little chance that passengers were endangered.
"This is in no way a reflection on the portion of the airport that the public goes through and interacts with. ... BWI continues to be safe and convenient," Porcari said at the news conference.
Postal union representatives said they were upset about their co-worker's illness but were determined to prevent terrorists from shutting down the nation's mail system.
"We live in the greatest country in the world - and if we let these people get into our heads and hearts, they will shatter us. We won't let that happen to us," said Johnny D. Martin Sr., executive vice president of the Baltimore-area American Postal Workers Union Local 181.
Federal officials suspect terrorists might be responsible for sending letters spiked with the deadly bacteria to a tabloid newspaper in Florida, NBC news anchor Tom Brokaw in New York and the New York Post, as well as Daschle's office.
Investigators have been examining mailboxes and questioning people in Trenton, N.J., where some of the tainted letters were mailed. Officials said yesterday that 13 of 23 samples taken from workstations at a regional mail-processing center in a Trenton suburb had tested "presumptive positive" for anthrax.
Of the nine anthrax victims, only Robert Stevens, a photography editor at the Sun supermarket tabloid in Florida, who had inhalation anthrax, has died. A co-worker of Stevens', Ernesto Blanco, also has inhalation anthrax but is taking antibiotics and doing well, his stepdaughter said yesterday.
Six other people, including two postal workers in New Jersey, have been treated for a milder form of the disease that manifests itself as a black rash.
Surgeon General Dr. David Satcher said inhalation anthrax - which is not contagious - has been fatal about 80 percent of the time in the past. But because so few cases have been recorded in the United States, the prognosis for the postal worker might be better than that. "We have different technology today," Satcher said on CNN's Late Edition. "It is not yet hopeless."
Investigators have found traces of anthrax in four federal buildings, and 28 people in Daschle's office tested positive for exposure, though none has been found to have the disease.
Last week, the House shut down, to allow for a sweep for spores.
More than 6,000 workers on Capitol Hill, including postal employees, congressional staffers and maintenance employees, police officers and visitors, have been tested since a letter containing anthrax was discovered a week ago in Daschle's office, officials said.
Members of Congress are wondering where else anthrax might linger. "Now, you got to look at, well, where did that mail go from there?" asked Senate Minority Leader Trent Lott, a Mississippi Republican, on ABC's This Week. "We're dealing with a new situation."
Wire services contributed to this article.