May 4, 1988. Just before noon, the Pacific Engineering and Production Company of Nevada - better known as PEPCON - exploded.
Alta Hinkle was at home with her grandson when more than 9 million pounds of ammonium perchlorate blew up, sending shockwaves through the desert. Ammonium perchlorate is used for rocket fuel.
"I was sitting right here in my living room and all of a sudden I heard a big boom," said Alta. "All of the windows in the back of my house were blown out."
While emergency crews raced to evacuate workers at the plant, teacher Lynnette Bushman watched in horror.
"My principal came in, and she saw me and said, 'You are white as a sheet! What's going on with you?' I said, "I think my dad's dead. He works over there,'" Lynnette recalled.
Lynnette's dad, Dr. Raymond Rhees, was the Vice President of Research at the plant. He escaped alive. Two of his coworkers did not.
"[One worker] was in a wheelchair. And when they finally got in there, the only thing they found was his glasses. He was just gone," said Lynnett.
The explosions were blamed on a welder's torch that ignited the rocket fuel material. They ruptured a natural gas line, which burned for hours.
It caused more than $155 million in today's currency in property damage to schools, homes, and businesses within a 10-mile radius. 300 people were also hurt.
At the time, it was the worst non-nuclear disaster in American history.The aftermath looked like an alien landscape. And it grabbed the attention of the nation and President Ronald Reagan.
The EPA and OSHA investigators went through the wreckage, and almost immediately the finger-pointing began.
"OSHA inspectors concluded that this plant was among the most unsafe he's ever seen and that it was a wonder that it had not blown up already," said one unnamed official.
Reports from inspectors blamed many factors including poor housekeeping of the explosive material and no fire suppression system.
The PEPCON plant was renamed after the disaster and relocated to Iron County, Utah, where it still operates today.