Facebook evacuated four buildings as officials determined what caused its Silicon Valley mail facility to test positive for the nerve agent sarin.
No injuries have been reported at the site so far, with officials confirming that two people are being evaluated.
Authorities said the evacuation was ordered after a package tested positive during a standard check at the facebook facility. "Now we’re just waiting to verify whether that’s true or not," an official confirmed.
A Facebook spokesman said they were cooperating with police in the investigation, adding that "authorities have not yet identified the substance found".

Trump says Iran really wants to make a deal with the US
Kuwaiti forces deal with missile, drone attacks on Monday
US says it struck Iranian drone command sites at weekend
US proposes new plan to ease Israel-Lebanon tensions amid fighting
