The Orange County Sheriff's Department bomb squad found a suspicious substance in an envelope that was delivered to the Huntington Beach Fire Department on the fifth floor of City Hall, according to city Fire Capt. Bob Culhane.
He said the Huntington Beach hazardous materials team will take a sample for testing.
Huntington Beach police and fire departments evacuated the City Hall building at 2000 Main St. after a worker found the envelope about 8:30 a.m., Culhane said.
Culhane said earlier theat the envelope looked like it could have an explosive inside. He said officials placed the envelope in a stairwell after it was discovered, and the building was evacuated. There were about 300 workers in the building.
Police have all entrances and exits to the parking lots of City Hall closed off, the Huntington Beach Independent reported.
Huntington Beach High School, which is across the street, was on a precautionary lockdown but was cleared by the Police Department to resume normal activity, Culhane said.