On the Fourth of July weekend of 1957, Darrell Robertson was on a train from Fort Lewis, Wash., to southern Nevada. He was one of hundreds of young men with orders in hand to take part in a training exercise that they were told was crucial to the fight against communism.

The native of Lamar was headed deep into the burnt landscape of the Mojave Desert, to a place called Camp Desert Rock. There, between 1945 and 1958, the U.S. military conducted 106 atmospheric nuclear tests.

At the time, Robertson said, military brass believed a nuclear confrontation with the Soviets was likely. They were intent on developing a group of troops hardened by repeated exposure to radiation. They thought exposure to radiation was like sunning on the beach: First you burn, then you tan.

“Today, you think, ‘How would you ever harden troops to that?’ ” Robertson said in an interview this week at the Tribune. “It’s not something that you can become accustomed to or environmentally be exposed to and continue to go on. That’s just not a fact. But see, they didn’t know that then.”

On one of his first days in the tent city, Robertson was roused at 4 a.m. — the time of least wind and highest humidity in the desert — and driven to a lookout spot known as Newsman’s Knob to observe his first-ever “shot.”

Putting on a heavy jacket, helmet, goggles and leather gloves, Robertson and more than 100 others were instructed to crouch, cover their eyes and turn away from the cloud. What followed was a relatively minor detonation — only a few kilotons — but many of the newbies in his group weren’t prepared for the “blowback” that came moments later. They “just rolled around on the ground like footballs,” he said.

It was an awesome force. A nuclear bomb thrusts so much air away from its center that it creates a vacuum moments later that sucks wind back in until it can achieve normal air pressure. The rushing blowback can hit onlookers like a wooden bat to the stomach.

And when the blast went off, Robertson saw something that has been emblazoned forever in his memory. He says he could see through his gloves and flesh all the way to his bones. He can’t explain this brief X-ray vision, but the image shook him so deeply that he didn’t talk about it until decades later, when he heard other atomic veterans of that era report similar phenomena they attribute to radiation exposure.

In the coming weeks, Robertson and his men from the First Battle Group, 12th Infantry observed 12 to 15 nuclear blasts. Typically they waited two to four hours after the shot before they went to ground zero for maneuvers. Each man was given a tiny “film badge” to record the level of radiation he encountered.

Scientists also maintained on-site labs where animals from pigs to rats were exposed to the toxic dust that lingered in the air for hours, depending on the wind.

Destruction at these sites was total: Robertson saw a 100-foot steel tower incinerated in an instant. The largest blast he observed, code named “Smoky,” was a magnitude of 44 kilotons — about three times the force of the bomb dropped on Hiroshima. It was enough to turn sand into glass several feet deep.

“Were we guinea pigs? Yes, very much so. If that’s the vernacular you want to use,” he said. He and others just trusted their government. “You know you’re in harm’s way, but you assume that they’re not putting you out there to absolutely crucify you.”

Robertson completed the work and eventually moved back home, where he and his wife, Barbara, operated a dairy farm and raised two children. Darrell even was a member of the National Guard for 35 years after leaving active duty.

But the legacy of his time in Nevada has stayed with him. Robertson only has two-thirds of a kidney and one-third of his pancreas; the rest was lost to cancer. He also has had traces of cancer show up in his liver and prostate and has spots on his lungs.

Yet somehow it took him three years of compiling evidence for the Army to acknowledge a service connection between his radiation exposure and his cancer. In 2002 he held the first Missouri meeting for atomic veterans in Joplin. He expected a few local vets to attend, but dozens showed up from nine different states, including Alaska. Many told heart-wrenching stories about their medical problems.

“If you sat there and listened to their stories, you’d almost go out crying,” Barbara Robertson said.

Since the 1950s, thousands of residents of towns downwind from the blast sites have developed cancers. In 1956, the John Wayne film “The Conqueror” was filmed in St. George, Utah, downwind of the test site. Many in that production eventually died of cancer, including Wayne himself.

It’s enough to make a person bitter about his government, but somehow Robertson isn’t. Today, as he and his wife commute regularly back and forth from Lamar to Truman Memorial Veterans’ Hospital and Ellis Fischel Cancer Center in Columbia for his treatments, he sometimes daydreams about seeing just one more blast. Only this time he’d like to bring along world leaders such as Barack Obama, Vladimir Putin, Angela Merkel and others.

That’s because, he said, if they ever saw a nuclear bomb detonate with their own eyes, they’d never, ever want to dream of ordering one dropped in combat.

“I do believe it would change their minds,” he said.

Tribune reporter T.J. Greaney’s column runs on Thursdays. Reach him at (573) 815-1719 or tjgreaney@columbiatribune.com.