Now, 28 years later, Conger and more than a dozen other survivors are reliving the event, literally. They've been working as extras in a movie about it being filmed partly at Whitesides Elementary in Layton. In many cases, they've also invited their children to participate, some of whom are now the same age as they were in 1986.
Why would they want to re-enact that terrible day?
Because to many of the survivors it wasn't a tragedy; it was a miracle.
"It's been a pretty surreal and extraordinary experience to relive this again," Conger said. "It's really caught me off guard a few times and choked me up, but it's been something I'll never forget. It's made me remember again how blessed we were."
The film will focus on the miraculous nature of the day, including the prayers and faith it inspired, said co-producer, Ron Tanner. Tanner is producing the movie with filmmaker T.C. Christensen, who has become known for making LDS films. But Tanner said they hope this movie won't be labeled that way. In fact, the film won't even mention The Church of Jesus Christ of Latter-day Saints, he said, though many of the students were Mormons in real life.
"We think this could have happened anywhere, and we don't want people outside the church to feel this is exclusive to us," Tanner said.
"There is a lot of bad that happens in the world, and a lot of people get hurt, but sometimes good things happen and there are people who are saved, and I think when that happens we have to tell these stories so people have hope," he said.
It's an especially important message now, the survivors feel, amid seemingly weekly reports of school violence across the country.
"Every time one of these kinds of things happens, all of us survivors, our hearts break," said Kamron Wixom, who was in sixth-grade when Cokeville's former marshal, David Young and his wife, Doris Young held him and his classmates hostage.
When the bomb went off, Wixom was blown out the door and ran. He doesn't remember the sound of the bomb detonating, but he does recall seeing a strange, hazy light in the room shortly before the blast. He didn't know what to make of it at the time, but other survivors have since reported seeing angels, and he wonders now if that's what it was.
Wixom, now 40 and living in Saratoga Springs, also remembers praying. Despite the terror that filed the room, the prayers made him feel "like everything was going to be fine."
Joshua Wiscombe, now 34 and living in Layton, also remembers a feeling of peace coming over him right before the bomb exploded.
Wiscombe was only a kindergartner at the time, but he still recalls the blast and the fear that followed.
"I just remember that loud, loud sound going off and then it was pitch black," Wiscombe said. "The last thing I remember seeing was fire at my feet, and I remember thinking, 'I'll never see my mom again.' "