FOX-WASHINGTON — The Postal Service closed its government mail facility Thursday night while authorities ran tests to determine whether anthrax was detected at the Navy site that handles mail for federal agencies. Postal Service spokesman Azeezaly Jaffer said the V Street mail facility was closed as a precaution.

Equipment that routinely monitors the air at the Naval Automated Processing Facility (search), also located in the District of Columbia, indicated Wednesday the presence of “small amounts of biological pathogens, possibly anthrax,” said Rachael Sunbarger, a Homeland Security spokeswoman.

That facility receives mail from V Street.

After the initial field test, eight air samples were sent to Fort Detrick, Md., for testing, according to Lt. Cmdr. Edward Zeigler, spokesman for the Naval District of Washington. One sample tested positive for anthrax and seven tested negative, he said.

As a result, more testing was being done, he said.

A Navy spokesman at the Pentagon, Cmdr. Conrad Chun, said the Fort Detrick test showed a spore count of 138.

A contractor, Shaw Inc., participated in the testing.

There were no illnesses reported, Sunbarger said.

Few people work at the automated naval facility. Chun said the workers wear protective clothing and that an air monitor worked as designed. Mail is screened there before going to a mail-handling facility nearby, he said. The facility also handles mail distributed to Navy personnel throughout the Washington area.

Chun said the matter is being further investigated by the FBI, the Naval Criminal Investigative Service, postal inspectors and others.

All mail destined for Congress and federal agencies is irradiated before being delivered to the postal facilities.