Possible detection of Sarin reported at Facebook facility in Menlo Park, 'no employees exposed,' may be false positive

No employees have been exposed to the substance, officials said.

Multiple San Francisco Bay Area news outlets are reporting that firefighters are on the scene of what is described as a possible exposure to “sarin gas” or another chemically similar nerve agent at a Facebook mailing facility in Menlo Park, California. It may have been a false positive machine detection.

Menlo Park Fire officials say an automated threat-sniffing machine at the Facebook mail facility alerted staff on site that an incoming mail package might contain sarin.

The substance has not been confirmed to be sarin.

No employees show signs of exposure to or poisoning by the substance, the Menlo Park District said.

The specificity of initial reports seems suspect -- it's hard to know what is accurate at this early stage.

Sarin gas is a man-made chemical that attacks the central nervous system.

It is a clear, colorless liquid, and is classified as a nerve agent. Exposure to sarin gas can lead to convulsions, paralysis, and can cause death.

More: 2 employees reportedly exposed to sarin at Menlo Park warehouse owned by Facebook