Fourth Of July Accident: Simi Valley Fireworks Show 2013 Results In 28 Injuries [VIDEOS]

What was meant to be a patriotic celebration ended in tragedy Thursday after a Fourth of July fireworks show explosion left 28 out of 10,000 audience members at a Simi Valley, Calif., injured.

The explosion, which occurred seconds following the start of the show, is being deemed an "industrial-type accident," according to local officials, NBC News reports. Despite claims that the incident was not intentional, eye witnesses said they believe the fireworks were aimed directly toward viewers.

"They were actually aiming at us," viewer James Wilhite said. "That one row -- all of the fireworks went off." Other witnesses said they saw the structure supporting the explosives tilt, causing the fireworks to aim horizontally, directly in line with the audience. "At this point, there are absolutely no indications of foul play," Simi Valley Police Commander Stephanie Shannon said.

One YouTube clip from the show gone wrong shows fireworks resulting in screams from spectators followed by large groups of people running from the show. “It was just a loud explosion,” viewer Michelle Rodriguez told NBC. “We felt the heat pull back toward us.”

Ventura County Fire Department Captain Mike Lindberry said, out of the 28 injured, four were immediately transported after suffering from moderate to severe injuries. Twenty others were transported to local hospitals to treat minor cuts. All injuries were reportedly shrapnel-related.

The case is currently under investigation. Officials said they're unsure how the structure fell prior to the performance. The company hired to put on the performance, Bay Fireworks, said they're also conducting a separate investigation following the incident.