A U.S. Senate office building was evacuated late Wednesday after sensors detected the possible presence in the air of what was initially described as a nerve agent. The building was later reopened after police reported negative test results.
At approximately 6:30 Wednesday evening, an alarm sounded in the Russell Office Building on Capitol Hill.
Police immediately ordered an evacuation of the building.
However, as a precaution about 200 people, including some senators and staff, were confined for a time to a garage area.
A hazardous material response team, its members wearing protective suits, entered and conducted tests.
Although the initial alarm was for a suspicious substance detected in the attic of the building, Capitol Police Chief Terrance Gainer said later tests proved negative.
Kimberly Schneider also spoke for the Capitol Police.
"We have also worked with the Office of the Attending Physician," she said. "No
reported symptoms and if there are any reported symptoms people would be
treated as if they have been exposed to a nerve agent. We don't have
any indication of that at this time. We have very good news all around."
Officer Schneider said an investigation was continuing into what substance might have triggered the initial alarm.
None of the lawmakers or staff prevented from leaving the building exhibited any symptoms of having been exposed to any nerve agent.
However, as an additional precaution they have been told to monitor their health in coming days.
Activity in the nearby U.S. Capitol building, where members of the House of Representatives continued floor speeches, was not disrupted.
Alerts, involving suspicious objects, packages or substances, have become a fact of daily life on Capitol Hill in the more than four years since the September 11, 2001 terrorist attacks.
In the weeks after those attacks, letters containing potentially deadly anthrax bacteria were mailed to two U.S. senators, and major media offices.
Twenty-two people developed anthrax infections, 11 of them suffering from inhalation rather than exposure anthrax, and five persons died.
The crime has never been solved, despite intense government efforts since then.