An envelope filled with white powder was delivered to a San Francisco police station Saturday morning, as well as at the Oakland Police Department Friday evening, San Francisco and Oakland police said.
The two departments join four other Bay Area police departments that received a mysterious substance Friday.
Around 11 a.m. this morning personnel at the Northern Station, located at 1125 Fillmore St. in San Francisco, received an envelope with a white powdery substance, San Francisco police said.
San Francisco fire personnel responded and determined the material was not hazardous.
No one was injured, police said.
Friday evening, after 5 p.m., an unknown powdery substance was delivered to the Oakland Police Department, Oakland police said.
The Oakland Fire Department removed the substance from the building and determined it was not harmful, police said.
Police said evacuations were not necessary, and no one was harmed in the incident.
Hayward, Berkeley, San Leandro and Union City police departments also received deliveries of a mysterious substance throughout the day Friday.
Test results have deemed the substance mailed to those respective agencies was not hazardous, according to Alameda County fire officials.