Anthrax found at offsite White House mail facility

"I don't have anthrax," President Bush said Tuesday.

WASHINGTON (CNN) -- President Bush said Tuesday he is "confident when I come to work tomorrow that I'll be safe," despite the detection of anthrax at an offsite mail facility that screens White House mail.

Asked by reporters whether he had been tested for anthrax and whether he was taking antibiotics, Bush said only, "I don't have anthrax."

"Our government is responding very quickly. We're working hard to find out who's doing this and bring them to justice. We're also working to develop measures necessary to protect American citizens and postal workers," he said.

Anthrax was found Tuesday on a device that opens mail at the Anacostia Naval Station in Washington, where mail bound for the White House is screened.

Environmental tests detected no anthrax within the executive mansion itself, said White House press secretary Ari Fleischer.

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Fleischer said security procedures at the White House provide "high confidence that there is not an issue here."

Government sources told CNN that when mail is opened and checked at the Anacostia facility, it is also irradiated to kill germs before going to the White House mailroom, which is near the executive mansion but not in the building.

Employees at the offsite mail facility are being tested for anthrax exposure and are getting nasal swabs, Fleischer said. Antibiotics will be made available to them, he said.

The facility has been closed for further testing and decontamination. Fleischer said all mail at the facility is being checked to try to determine the source of the anthrax.

According to the Secret Service, no one connected with the facility has reported symptoms consistent with anthrax. The workers had previously been provided with "protective equipment," the Secret Service said in a written statement.

Mail destined for the White House has been screened at the offsite facility for "a number of years," according to the Secret Service.

Mail travels there from the U.S. Postal Service's Brentwood sorting station in Washington, the workplace of two postal employees who died from inhalation anthrax and two others who are ill from it.

Because no letter or package with anthrax was discovered among the White House mail, investigative sources told CNN they assume a small amount of anthrax may have gotten on White House mail at the Brentwood facility.

Asked about the positive test at the White House mail facility, Health and Human Services Secretary Tommy Thompson said health officials would perform an "aggressive environmental assessment" and provide antibiotics to anyone believed to have been exposed.

When asked if he would recommend that Bush begin taking Cipro, an antibiotic for anthrax, Thompson said, "If he's been exposed, yes. If not, no."

The test that led to the positive result was part of "enhanced security procedures" implemented in the wake of the September 11 terrorist attacks, Fleischer said.

He said a "regular program" of environmental sampling at the White House has turned up no positive tests for anthrax.

Asked if he believed the al Qaeda terrorist network, suspected in the September 11 attacks, was behind the anthrax threat, Bush said he had no "hard evidence."

But he said anyone who would send anthrax through the mail is a "terrorist," and that "it wouldn't surprise me that they're involved with this.

"It's hard for Americans to imagine how evil the people are who are doing this," Bush said.

-- CNN Senior White House Correspondent John King contributed to this report.