A fire alarm inside the Library of Congress' Rare Book Division was triggered on Monday, according to the Architect of the Capitol.
It was false but that didn't stop police from evacuating the building, blocking First Street S.E. and calling in a hazardous-material truck.
The alarm sounded--but the automatic sprinklers were not triggered--and the books were unharmed, according to Library of Congress spokeswoman Gayle Osterberg.
The malfunctioning alarm is part of a new fire-detection system that the Architect of the Capitol is installing. AOC spokeswoman Eva Malecki said the alarm should not have activated and the agency is investigating why it did.
"We are making adjustments now while [the fire system] is being installed and before the system goes through its final testing to ensure that today's occurrence doesn't happen after the system is fully installed and operational," Malecki said.