1. Various postal employees waiting for anthrax testing in auditorium of DC General Hospital

2. Exterior Brentwood Post Office

3. Postal employee looking at anthrax fact sheet

4. Close shot of anthrax fact sheet

5. Various postal workers waiting inside hospital for anthrax testing

6. Exterior shot of DC General Hospital

7. SOUNDBITE (English) Dr. Ivan Walks, Washington, DC Chief Health Officer

"What's going on today here at DC General, we are testing from 9am to 10pm, but we'll stay open as we did last night until every employee who worked in the back of the Brentwood mail station and every employee at the Maryland air handling station comes in. We will contact them through the postal service and if they haven't gotten here, we're gonna find them and make sure they get the care they need."

8. Various tourists outside the empty US Capitol complex

9. Various area set up on Capitol Hill for emergency rescue and investigators

10. Emergency rescue truck

11. Shots of crews working outside a big white tent

12. Wide shot of orange cones and other security measures outside US Capitol building

Health officials in Washington DC are waiting for test results from five patients who have symptoms consistent with anthrax, after a local postal worker was diagnosed with a rare and dangerous form of the disease.

More than 2200 postal workers in the Washington area are being tested for exposure to the disease, and the Postal Service has closed two facilities where the sick man worked.

The man, identified as Leroy Richmond, is in serious but stable condition at a suburban Virginia hospital near his home.

The Postmaster General, John Potter, said the U-S Postal Service was increasing security at its facilities and introducing technology to sanitise mail.

Potter said postal workers were not being ordered to wear gloves and face masks.

Washington's chief health officer said the authorities were watching five other postal workers who have flu-like symptoms that might indicate inhalation anthrax.

The five are receiving treatment in hospital.

Over the last two and a half weeks three men have been diagnosed with inhalation anthrax, a disease not seen in the United States since 1978.

A Florida man died from the disease.

Six others, including two postal workers in New Jersey, have been infected with a treatable form of anthrax that is contracted through the skin.

Health and postal officials said they do not know how the Washington postal worker came into contact with enough anthrax to allow the bacteria to travel into his respiratory system and lodge deep in his lungs.

Meantime, congressional leaders reopened the Capitol building on Monday, although House and Senate office buildings remained closed until results from environmental testing are complete.

Officials said one building - the Longworth House office building - was receiving particularly close scrutiny.

A mail-sorting machine in a nearby House annex building found to be contaminated over the weekend handles mail for the Longworth building, so investigators want to learn if tainted mail ended up in Longworth.

The buildings were closed after an anthrax-tainted letter arrived a week ago at the office of the Senate Majority Leader,Tom Daschle.