28 injured at fireworks show in California at an annual 4th of July fireworks display.

The 28 injured at fireworks show took place in Simi Valley, which is outside Los Angeles. It took place at the Fireworks Extravaganza inside a large community park.

It was an accidental detonation around 9:20 p.m., according to police Cmdr. John Parks that caused 28 injured at fireworks show. A bomb squad was on the scene to put an end to the remaining fireworks that could have caused more injury.

"There was a big boom, everybody started running down the street, people were screaming," Justice Allen, 17, of Simi Valley told the Los Angeles Times. "Everybody was just terrified. People hid in bushes."

Among the 28 injured, 20 had to be taken to a hospital. There were another eight that were treated at the show. It is unknown how many people were in attendance, but this nearly 50-year tradition has thousands in attendance every year.

The video on KCAL-TV showed a pair of firework blasts at or near the ground. It wasn't known how close people were to the blast's origin. Another clip posted on YouTube shot from a distance shows three ground-level bursts. The fireworks continue for almost another minute before stopping, according to the Associated Press.