The missile’s oxidizer, nitrogen tetroxide, was even more hazardous. Under federal law, it was classified as a “Poison A,” the most deadly category of manmade chemicals. In its liquid form, the oxidizer was a translucent, yellowy brown. Although not as flammable as the fuel, it could spontaneously ignite if it touched leather, paper, cloth, or wood. And its boiling point was only 70 degrees Fahrenheit. At temperatures any higher, the liquid oxidizer boiled into a reddish brown vapor that smelled like ammonia. Contact with water turned the vapor into a corrosive acid that could react with the moisture in a person’s eyes or skin and cause severe burns. When inhaled, the oxidizer could destroy tissue in the upper respiratory system and the lungs. The damage might not be felt immediately. Six to twelve hours after being inhaled, the stuff could suddenly cause headaches, dizziness, difficulty breathing, pneumonia, and pulmonary edema leading to death.
Powell and Plumb were missile repairmen. They belonged to Propellant Transfer System (PTS) Team A of the 308th Strategic Missile Wing, whose headquarters was about an hour or so away at Little Rock Air Force Base. They’d been called to the site that day because a warning light had signaled that pressure was low in the stage 2 oxidizer tank. If the pressure fell too low, the oxidizer wouldn’t flow smoothly to the engine. A “low light” could mean a serious problem — a rupture, a leak. But it was far more likely that a slight change in temperature had lowered the pressure inside the tank. Air-conditioning units in the silo were supposed to keep the missile cooled to about 60 degrees. If Powell and Plum didn’t find any leaks, they’d simply unscrew the cap on the oxidizer tank and add more nitrogen gas. The nitrogen maintained a steady pressure on the liquid inside, pushing downward. It was a simple, mundane task, like putting air in your tires before a long drive.
Powell had served on a PTS team for almost three years and knew the hazards of the Titan II. During his first visit to a launch complex, an oxidizer leak created a toxic cloud that shut down operations for three days. He was twenty-one years old, a proud “hillbilly” from rural Kentucky who loved the job and planned to reenlist at the end of the year.
Plumb had been with the 308th for just nine months. He wasn’t qualified to do this sort of missile maintenance or to handle these propellants. Accompanying Powell and watching everything that Powell did was considered Plumb’s “OJT,” his on-the-job training. Plumb was nineteen, raised in suburban Detroit.
Although an oxidizer low light wasn’t unusual, Air Force technical orders required that both men wear Category I protective gear when entering the silo to investigate it. “Going Category I” meant getting into a Rocket Fuel Handler’s Clothing Outfit (RFHCO) — an airtight, liquidproof, vaporproof, fire-resistant combination of gear designed to protect them from the oxidizer and the fuel. The men called it a “ref-co.” A RFHCO looked like a space suit from an early-1960s science fiction movie. It had a white detachable bubble helmet with a voice-actuated radio and a transparent Plexiglas face screen. The suit was off white, with a long zipper extending from the top of the left shoulder, across the torso, to the right knee. You stepped into the RFHCO and wore long johns underneath it. The black vinyl gloves and boots weren’t attached, so the RFHCO had roll-down cuffs at the wrists and the ankles to maintain a tight seal. The suit weighed about twenty-two pounds. The RFHCO backpack weighed an additional thirty-five and carried about an hour’s worth of air. The outfit was heavy and cumbersome. It could be hot, sticky, and uncomfortable, especially when worn outside the air-conditioned silo. But it could also save your life.
The stage 2 oxidizer pressure cap was about two thirds of the way up the missile. In order to reach it, Powell and Plumb had to walk across a retractable steel platform that extended from the silo wall. The tall, hollow cylinder in which the Titan II stood was enclosed by another concrete cylinder with nine interior levels, housing equipment. Level 1 was near the top of the missile; level 9 about twenty feet beneath the missile. The steel work platforms folded down from the walls hydraulically. Each one had a stiff rubber edge to prevent the Titan II from getting scratched, while keeping the gap between the platform and the missile as narrow as possible.