A few months later, William L. Stevens was chosen to head Sandia’s new Nuclear Safety Department. Stevens had earned a degree in electrical engineering at Virginia Polytechnic Institute, served as an officer in the Army, and spent a few years in Baton Rouge, Louisiana, working for an oil company. He joined Sandia in 1957, at the age of twenty-eight. Bob Peurifoy had hired him, and the two worked together on the electrical system of the W-49 warhead, the first one to contain a trajectory-sensing switch as a safety device. When Stevens was assigned to lead the new safety department, he wasn’t convinced that nuclear weapon accidents posed a grave threat to the United States. But he’d been closer to a nuclear detonation than most scientific observers — and seen firsthand how unpredictable one could be.
While serving in the Army, Stevens had been trained to assemble the warheads of tactical weapon systems. In May 1953 members of his battalion participated in the test of an atomic cannon. Its shells could travel twenty miles and produce a yield equivalent to that of the bomb that destroyed Hiroshima. For the test in the Nevada desert, all sorts of things were placed near ground zero to study the weapon’s effects: trucks, tanks, railroad cars, aircraft panels, oil drums and cans of gasoline, household goods and materials — denim, flannel, rayon curtains, mops and brooms — a one-story brick structure, steel bridges, buildings that resembled motels, one hundred tall pine trees, field crops, flowers, insects, cages full of rats and mice, fifty-six dogs tethered inside aluminum tubes, forty-two pigs dressed in U.S. Army uniforms whose skin would respond to thermal radiation in a manner similar to that of human skin, and more than three thousand soldiers, including Bill Stevens, who huddled in a trench about three miles from ground zero.
The troops were part of an ongoing study of the psychological effects of nuclear warfare. They’d been ordered to climb out of their trenches and march toward the mushroom cloud after the blast. The Army Field Forces Human Research Unit hoped to discover how well they would follow the order, whether they’d obey it or come unglued at the sight of a large nuclear explosion. The atomic shell would fly directly over the heads of Stevens and the other soldiers. They were told to crouch in their trenches until the weapon detonated, then rise in time to brace against the blast wave and watch the explosion. At eight thirty in the morning, a great fireball lit up the desert, about ninety miles from Las Vegas.
As the troops stood, a powerful shock wave blew past, catching them by surprise. It was a “precursor wave,” a weapon effect that hadn’t been predicted. Highly compressed air had come down from the fireball, hit the ground, and spread outward, traveling faster than the blast wave. When Stevens and his unit climbed from the trenches to march toward ground zero, they were engulfed by a cloud of dirt and dust. Their lead officer couldn’t read the radiation dosage markers and led them closer to ground zero than planned. After returning to their base in Albuquerque, Stevens shook the dirt out of his uniform and saved some of it in a can. Twenty years later, he had the dirt tested at Sandia — and it was still radioactive.
After becoming the head of the nuclear safety department at the lab, Stevens looked through the accident reports kept by the Defense Atomic Support Agency, the Pentagon group that had replaced the Armed Forces Special Weapons Project. The military now used Native American terminology to categorize nuclear weapon accidents. The loss, theft, or seizure of a weapon was an Empty Quiver. Damage to a weapon, without any harm to the public or risk of detonation, was a Bent Spear. And an accident that caused the unauthorized launch or jettison of a weapon, a fire, an explosion, a release of radioactivity, or a full-scale detonation was a Broken Arrow. The official list of nuclear accidents, compiled by the Department of Defense and the AEC, included thirteen Broken Arrows. Bill Stevens read reports that secretly described a much larger number of unusual events with nuclear weapons. And a study of abnormal environments commissioned by Sandia soon found that at least 1,200 nuclear weapons had been involved in “significant” incidents and accidents between 1950 and March 1968.
The armed services had done a poor job of reporting nuclear weapon accidents until 1959—and subsequently reported about 130 a year. Many of the accidents were minor: “During loading of a Mk 25 Mod O WR Warhead onto a 6X6 truck, a handler lost his balance… the unit tipped and fell approximately four feet from the truck to the pavement.” And some were not: “A C-124 Aircraft carrying eight Mk 28 War reserve Warheads and one Mk 49 Y2 Mod 3 War Reserve Warhead was struck by lightning…. Observers noted a large ball of fire pass through the aircraft from nose to tail…. The ball of fire was accompanied by a loud noise.”
