Fifty-three years ago, at a nuclear silo outside Vale, South Dakota, there was an explosion, the force of which blew the cap off a nuclear missile, sending its warhead falling 75 feet down the shaft of the 80-foot silo. What happened next could’ve been disaster, which was averted, but kept in secrecy for decades. Now, thanks to the intrepid work of a local reporter, we’re learning what really happened.

The reporter is Seth Tupper . Tupper FOIA’d records relating to the incident, which previously had only been disclosed in seven sentences in a government report. Tupper also spoke to an airman on the scene.

According to Tupper’s reporting, the trouble started on December 5, 1964 when an airman who had been sent to perform maintenance on the missile removed a fuse with a screwdriver.

From the Rapid City Journal:

According to the Air Force report on the accident, one of the airmen removed a fuse as part of a check on a security alarm control box. The report says the airman was “lacking a fuse puller,” so he used a screwdriver to pry the fuse from its clip.

When the fuse was re-inserted, the report says, it was supposed to click. The sound of a click indicated good contact with the holder. But there was no click, so the airman repeated the procedure. Still not certain he heard a click, he pulled the fuse out a third time and pushed it back into the holder again.

“At 1500 hours MST,” the report says, referencing 3 p.m. Mountain Standard Time, “simultaneously with the making of this contact, a loud explosion occurred in the launch tube.”

[...]

When one of the retrorockets fired inside the missile in the Lima-02 silo, pressure built up in the space where the retrorockets were housed, and the cone of the missile — which was about 5 feet tall, nearly 3 feet in diameter at its base, and about 750 pounds in weight — burst off and fell down in the few feet of space between the missile and the silo wall.

The cone hit the wall of the silo, bounced back toward the missile and grazed it in two spots along the second fuel stage, hit two of the three suspension cables that supported the missile, and finally crashed to the concrete floor of the silo and came to rest on its side. Luckily, the cone did not do enough damage to the missile to cause the missile to explode.

Neither of the airmen immediately knew what had happened. The bureaucratically written accident report says they “expeditiously evacuated” after hearing the explosion, as the silo filled with gray smoke.

What happened next? A salvage operation involving Bob Hicks, now 73-years-old and living in Texas. By the time Hicks got to the scene, he told the Rapid City Journal, there was a lot of guys standing around with no clear idea about what to do.

“As we later joked,” Hicks recalled in his slight Texas drawl, “They were standing around not knowing whether to scratch their watch or wind their butts.”

You can—and should—read the whole story .