At least eight senators were among 200 people being held in a Capitol parking garage Wednesday night after a security sensor initially indicated the presence of a nerve agent in their office building. "Tests initially indicated a nerve agent," said Capitol Police Sgt. Kimberly Schneider. "A subsequent test indicated it is not a nerve agent." Schneider said the senators were among 200 people who were asked to remain in the West Legislative Garage. Senate aides inside the garage said they were told they would be held for up to an hour as authorities awaited the results of a third test for more conclusive results. Republican Sen. Chuck Hagel was among the lawmakers inside the garage. He and several of his staff were headed out of the Russell Senate Office Building around 7 p.m. when security closed the doors and told everyone to go to the garage, said his spokesman, Mike Buttry. "We're stuck until they get the results back," Buttry said. Schneider said none of the people gathered in the garage was showing any signs of sickness or other adverse symptoms, such as a runny nose, that might indicate the presence of a nerve agent. She did not know whether sensors positioned in the attic of the Russell building, which picked up the suspicious material, were able to tell whether it was in powder, liquid or gas form. Earlier, police said they had discovered a suspicious powder in the attic. The Homeland Security Department did not have an immediate comment, but a senior counterterror official said it did not immediately appear to be an emergency. Among the other senators in the building according to aides were: Republican Mike Enzi of Wyoming; Republican Gordon Smith of Oregon; Republican Richard Burr of North Carolina, Republican Larry Craig of Idaho; Republican John Thune of South Dakota; Republican Jeff Sessions of Alabama; and Democrat Christopher Dodd of Connecticut.