Authorities confirmed test results were negative for dangerous substances after mail discovered in a facility on Facebook’s campus was believed to contain Sarin.
On Monday, around 2 p.m. ET, a piece of mail delivered to a facility in Menlo Park, Calif., was deemed suspicious, said the social networking giant.
During screening, a “potentially dangerous substance” was identified, prompting the evacuation of four nearby buildings.
“Authorities have confirmed test results were negative for any potentially dangerous substance and the buildings have been cleared for repopulation,” said Facebook spokesperson Anthony Harrison in a statement. “Our rigorous security and safety procedures worked as intended to limit exposure and keep our people safe.”
Menlo Park Fire District chief Harold Schapelhouman said a machine Facebook uses to detect dangerous substances in mail warned of the potential for sarin. “The machine thinks it’s Sarin,” said Schapelhouman on Monday. “We don’t know that it’s Sarin.”
According to the Centers for Disease Control and Prevention, sarin is a human-made chemical warfare agent classified as a nerve agent.
Jefferson Graham contributed to this report. Follow Brett Molina on Twitter: @brettmolina23.