MENLO PARK, Calif. (AP) — The FBI says a package that initially tested positive for sarin at a mail facility near Facebook's headquarters in California did not contain any dangerous substance.

The FBI says in a statement Tuesday the agency and its law enforcement partners "thoroughly tested the items in question and determined them to be non-hazardous."

Authorities put the site under quarantine Monday. Four buildings were evacuated. The suspicious package was delivered around 11 a.m. to one of the company's mail rooms.

Workers who handled the package did not report any ill effects.

There were no reports of injuries, Menlo Park Fire Marshal Jon Johnston said. Incoming mail undergoing routine processing by machine tested positive for sarin, he said.