No sarin found in package sent to Facebook that prompted evacuations, FBI says

Facebook buildings that had been evacuated Monday when a toxic chemical was detected in a package at the company’s mail-processing facility in Menlo Park, Calif., reopened Tuesday after further testing revealed no threat, according to the company.

The package was delivered about 11 a.m. Monday to one of Facebook’s mailrooms. Screening equipment in the mailroom indicated the presence of the chemical sarin — a potentially lethal nerve agent — inside the package, prompting officials to evacuate four buildings and call authorities.

Sarin is a human-made, odorless, colorless chemical that has been used in warfare. Exposure can cause convulsions, paralysis and respiratory failure leading to death, according to the Centers for Disease Control and Prevention.

Fire officials and the FBI were called in to investigate. Follow-up testing showed no dangerous chemicals in the package.

The FBI said in a statement Tuesday that law-enforcement labs “thoroughly tested the items in question and determined them to be nonhazardous.”

“Authorities have confirmed test results were negative for any potentially dangerous substance and the buildings have been cleared for repopulation,” Facebook director of corporate media relations Anthony Harrison said.

Harrison added that the company’s “rigorous security and safety procedures worked as intended to limit exposure” and keep employees safe.

hannah.fry@latimes.com

Twitter: @Hannahnfry