ROUGH CUT (NO REPORTER NARRATION).
Amateur video shows fireworks from an Independence Day celebration in Simi Valley, California accidentally flying into a crowd of thousands of onlookers.
Authorities say 28 people were injured in the accident, which took place shortly after a Simi Valley Rotary Club fireworks show began late Thursday.
The fireworks landed in a crowd of 8,000 to 10,000 onlookers gathered in a park, the Simi Valley Police Department said on its Facebook page.
"Although the investigation is ongoing, it is believed that at least one of the firework launching stations fell over after the fireworks were ignited, resulting in ignited fireworks going into the waiting crowd," the statement said. It was not clear at what point the fireworks ignited.
Twenty-eight people ranging in age from 8 to 78 suffered injuries consistent with shrapnel and projectile wounds. Police said 20 people were taken to hospitals, with four seriously injured.