Ontario International Airport was evacuated early Wednesday as police and fire personnel swarmed the terminals following reports of a bomb.
At 5:29 a.m., baggage screeners spotted a round object that looked similar to a hand grenade inside a bag going through an X-ray scanner, said Officer Rob Pedregon, a Los Angeles International Airport police spokesman.
Airport police and bomb investigators were called to examine the object and determined it was safe and did not pose a threat, he said.
Alarmed passengers posted videos on Twitter showing a bomb squad officer carrying a box.