Facebook Mail Site Evacuated After Sarin Scare, No Dangerous Substance Found

Sean Gallup/Getty Images

Authorities put the site under quarantine as they conducted testing, but "test results were negative for any potentially dangerous substance."

A Facebook mail facility near company headquarters in the San Francisco Bay area was evacuated Monday after a routine check found mail possibly containing the nerve agent sarin. But the company later said no traces of sarin were found.

Authorities put the site under quarantine as they conducted additional testing. Four buildings were evacuated, with three later cleared for people to come back in, Facebook spokesman Anthony Harrison said in a statement. The suspicious package was delivered around 11 a.m. to one of the company's mail rooms, he said.

"Authorities have not yet identified the substance found," Harrison initially said on Monday. In a Tuesday update, he said: "Authorities have confirmed test results were negative for any potentially dangerous substance, and the buildings have been cleared for repopulation. Our rigorous security and safety procedures worked as intended to limit exposure and keep our people safe."

There were no reports of injuries, Menlo Park Fire Marshal Jon Johnston said. Incoming mail undergoing routine processing by machine tested positive for sarin, but it could have been a false positive, he had said on Monday.n."

The FBI was assisting in the investigation, as is common in incidents such as this one.

The federal Centers for Disease Control and Prevention says sarin is a chemical warfare agent that is a clear, colorless, odorless and tasteless liquid. It can evaporate into the environment, prompting symptoms within seconds.

A drop of sarin on skin can cause sweating and muscle twitching, and exposure to large doses can result in paralysis and respiratory failure leading to death.

The CDC says people who are mildly exposed usually recover completely.

July 2, 5 a.m. PT Updated with tests finding no dangerous substance.