At least 28 people were hurt when an Independence Day fireworks display in California collapsed, sending pyrotechnics into the crowd.
The BBC reports spectators fled as explosions shot along the ground after a wooden platform holding the display gave way. The closest were sitting 900ft from the fireworks as they exploded.
About 10,000 people were in attendance at the 4 July celebration in Simi Valley on Thursday evening.
Four people are in hospital with serious injuries, including a police officer. The BBC reports many others were treated for their injuries at a triage area set up in the park.
Officials said there is no indication of foul play.
Simi Valley, the home of the Ronald Reagan Presidential Library, has held an Independence Day fireworks display for 43 years.
"There was a big boom. Everybody started running down the street. People were screaming," Justice Allen told the Los Angeles Times.
"Everybody was just terrified. People hid in bushes."