Spectators watch the beginning of the fireworks show July 4 in Simi Valley.… (Corey Allen / For The Times )
The explosion felt like a sonic boom.
Danny Morales, 42, heard it crack through his ears and then he felt a sharp blow to his face. A piece of fireworks had hurtled through a crowd of Fourth of July revelers in Simi Valley and hit him between the eyes.
Blood poured down Morales' face. He looked for his family and friends. Like everyone else, they were sprinting for cover, desperate to get away from the staging area where fireworks were exploding into the crowd instead of into the sky.
The Morales family had staked out front-row seats for the fireworks show two days earlier. On Thursday night, their great views turned into a liability. Morales' sister-in-law saw a fireball flying straight toward her. The flames singed her hair. Several of Morales' cousins suffered minor burns. His brother, Victor Morales, 40, thought he was fine until he got home and noticed a welt on his side where debris had hit him.
In all, more than three dozen people were treated for injuries suffered at the fireworks show. They included a toddler and a 71-year-old.
Authorities on Friday were trying to determine what caused the accident. The chaos was captured in numerous cellphone videos. "Run, run, run, run!" a man can be heard yelling on one of them as explosions filled Rancho Santa Susana Community Park.
Simi Valley Police Cmdr. Blair Summey said that the incident began when at least one explosive detonated early inside its canister. That explosion caused a chain reaction that tipped over other canisters, firing them toward the crowd.
Summey said the fireworks exploded about five minutes into what was supposed to be a 25-minute show.
"These things were coming through low," Summey said. "They were skipping along the ground. Some of these projectiles, they were exploding as they were coming out of the canisters."
Authorities said that there were no indications of foul play and that officials have not opened a criminal investigation. The Simi Valley bomb squad deemed the area safe and workers from the pyrotechnic company — New York-based Bay Fireworks — were scheduled to remove the remaining explosives.
An estimated 10,000 people were watching the event, some heeding appeals from firefighters to attend professional pyrotechnic displays rather than light fireworks of their own.
Not far from the Morales' party of about 30, another onlooker, 16-year-old Josh Antonucci, was in a large group of spectators about 500 feet from the fireworks stand, close enough to see part of the staging area tip over and see fireworks begin shooting into the crowd.
Antonucci turned to run and a projectile struck him in the back. "It felt like a punch," he said. "I knew I just had to get away."
Antonucci became part of the crowd running to the park's edges and away from trouble. Dustin Fields, 22, who was recovering from a recent knee surgery, was trampled because he couldn't move quickly enough. Paramedics took him to a hospital, where he remained Friday morning, his father said.
On Friday, with the park still littered by barbecues, folding chairs and other personal items abandoned by fleeing revelers, authorities held a news conference to discuss the incident.
The Simi Valley Police Department, state fire marshal and Ventura County Fire Department are all investigating.
One major issue is whether spectators were a safe enough distance from the fireworks.
State regulations establish minimum standards for fireworks displays, but county authorities can impose additional conditions. The regulation states that the crowd must be 70 feet away for every one inch of a mortar shell's diameter. The largest mortar shells in Simi Valley were five inches, making the safe distance 350 feet, according to Mike LaPlant, deputy chief of the Ventura County Fire Department.
Authorities estimated that the closest spectators were 800 feet from the fireworks but stressed that they were still investigating. LaPlant said that buffer "saved many more injuries."
Bay Fireworks did not respond to additional requests for comment but issued a written apology. It said it was cooperating with investigators and would conduct its own "thorough and complete" investigation into the incident.
"Public safety has always been a major priority of Bay Fireworks," the statement said.
In 2008, during a show run by Bay Fireworks in New York, three spectators and two fireworks technicians sustained minor injuries when a chain-reaction blast knocked down a launch tube that discharged into the crowd, according to news reports at the time.
The same summer, a box of fireworks shells fell off a barge being used as a staging area for a Bay Fireworks show, causing the evacuation of a popular Long Island beach when dozens of the shells washed ashore. In another incident, three technicians had to be rescued from a Bay Fireworks barge that turned into a floating bonfire after flames ignited a rack of fireworks.
The Morales family was trying regroup Friday. Some were released from the hospital, others returned to the park to pick up belongings.
Coming to the fireworks show has been an annual tradition for 10 years.
Asked whether he planned to come back to the celebration next year, Danny Morales paused.
"Next year? I don't know," he said. Right now, "I don't even want to flick on a lighter."
Times staff writer Kate Mather contributed to this report.