A machine at a Facebook mailing facility in Menlo Park, California, alerted employees Monday that a package might contain sarin, according to fire officials.
No employees have been exposed to the substance, fire officials said. The Centers for Disease Control and Prevention defines sarin as a “human-made chemical warfare agent classified as a nerve agent.”
Facebook runs all of its mail and packages through a machine that can detect dangerous substances, according to the fire district. The machine notified workers that the package in question might contain sarin. Fire officials initially reported that at least two people may have been possibly exposed.
Four buildings in the area were initially evacuated. Only one building remains evacuated. An investigation into the incident is ongoing.