Malfunctioning fireworks accidentally detonated in the opening minutes of a Fourth of July display, exploding into the crowd of onlookers and leaving at least 28 injured. The display was called off immediately, and a triage area was set up to handle the casualties at the Simi Valley city run Fireworks Extravaganza, northwest of Los Angeles. The Simi Valley Police Department and 25 units of the Ventura County Fire Department were among the emergency personnel who arrived at the scene. Tim Clunen was watching the fireworks with his family. About 30 seconds into the show we saw that fireworks that were supposed to be shooting up high exploded on the ground, he said.