In the 1993 trade center bombing, an armored Secret Service limousine was parked about 100 feet from a truck bomb. Although the bomb crashed through five stories of concrete and the concussion destroyed cars all over that floor, the Secret Service limousine ''did not even have a broken windshield,'' according to a government official on the scene that day. The condition of the limousine after September's attack was not known yesterday. ''We haven't gotten anything back yet,'' Mr. Ball said.

Asked about reports that his agency also kept what looked like ordinary taxis and telephone company trucks in the basement, Mr. Ball laughed. ''What I would say is that it is not unusual for law enforcement agencies to have these kinds of things,'' he said.

Besides the Secret Service, the building named for the United States Customs Service also housed an office of the C.I.A.

That building is now partly collapsed, with a rubble pit 30 feet deep. Somewhere in there are drugs, weapons and contraband seized by the Customs Service at the region's airports. The Bureau of Alcohol, Tobacco and Firearms also lost two evidence vaults, according to a spokesman for that agency, Joseph Green. They have not yet been recovered.

''There could be several hundred weapons -- somewhere between 200 and 400, ranging from small-caliber semiautomatic pistols to assault rifles,'' Mr. Green said, adding that a few of the guns had been found. Agents plan to be on the scene when the remains of the building are demolished sometime in the next two weeks, he said.

''After that, we'll be working at the landfill to search for any important items that are still missing.''

For people who have seen the surface destruction, either in pictures or in person, it may be hard to imagine that anything is intact below ground. But engineers and recovery officials say that large parts of the underground perimeter are undamaged, even though the buildings above them are partly collapsed.