At least nine senators were among 200 people herded into a Capitol parking garage Wednesday night after a security sensor indicated the presence of a nerve agent in their office building. Later tests proved negative.
"Test results have been cleared and all test results are negative, so that's very good news," said Capitol Police Sgt. Kimberly Schneider.
The all-clear came three hours after an air-monitoring sensor indicated a suspicious substance in the attic of the Russell Senate Office Building. It initially tested positive as a nerve agent.
Lawmakers, aides and other personnel were evacuated to the West Legislative Garage shortly after 6:45 p.m. EST as police conducted several other tests before concluding that it was a false alarm.
"We had this warning system work," said Sen. Jeff Sessions, R-Ala., one of those in the garage. "People in the building followed the directions promptly. There was no panic, no running, no upset or anything like that."
Police said none of the people who were evacuated to the garage showed any signs, such as a runny nose, of exposure to a nerve agent. Schneider did not immediately know what triggered the alarm but said it could have been something as innocuous as a cleaning substance.
"One of the alarm systems that tests air quality went off with a positive reading, and then it went off again with a positive reading, so I guess they thought it was serious enough that they had to take very aggressive action," Sen. Judd Gregg, R-N.H., another of the senators evacuated from the building, said while speaking on a cell phone from the garage.
Gregg said everyone was eager to go home but understood the need for the delay.
"I started out flying in Air Force One and ended up in the garage with 200 of my closest friends," he said. Earlier in the day, Gregg accompanied President Bush on a brief visit to New Hampshire.
A spokesman for Sen. John Thune, R-S.D., said people tried to leave the area but police directed them into the underground parking garage across the street. There, police distributed water and gave regular updates.
"Everybody was in a fine mood, everybody was calm," said the spokesman, Kyle Downey. "Everybody's been up here for a few years now. What does panic get you anyway?"
In addition to Sessions, Gregg and Thune, other senators known to have been in the garage were Mike Enzi, R-Wyo., Gordon Smith, R-Ore., Richard Burr, R-N.C., Larry Craig, R-Idaho, Chuck Hagel, R-Neb., and Christopher Dodd, D-Conn.
Senate Majority Leader Bill Frist said that the alert was prompted by a single sensor and that no suspicious chemicals were found.
"Everybody is safe. This was a false alarm," Frist, a surgeon, said shortly after the all-clear. "I'm sure tomorrow there will be a lot of questions about whether we had to be quarantined, and the answer to that is yes."
In February 2004, the deadly poison ricin was found in Frist's office, and while dozens of Capitol employees were quarantined briefly and decontaminated, none of them got sick.
In October 2001, a month after the terrorist attacks, an anthrax-laced letter shut down Congress briefly and closed the Hart Senate Office Building for months of cleaning. Five people were killed and 17 sickened nationwide after coming into contact with letters containing anthrax.
Associated Press writers Laurie Kellman and Juan-Carlos Rodriguez contributed to this report.