Nestled close to Kadena’s flight line sits a small, unassuming off-white building with nondescript lettering on the side. Without it, operations at the largest air base in the Pacific would screech to a halt.
The 18th Logistics Readiness Squadron’s cryogenics production facility is the only one in the entire Air Force and produces and supplies the oxygen and nitrogen that keeps every U.S. military aircraft on Okinawa in the sky.
It also supplies lifesaving oxygen to U.S. Naval Hospital Okinawa and locally, when the only civilian provider on the island goes down.
“We are a vital link to Kadena’s success,” said Senior Airman Michael Hall, 26, from Valdosta, Ga. He is one of nine airmen — clad in white utility uniforms, gloves, rubber aprons and plastic face shields — in the Air Force capable of running Kadena’s cryogenics plant by himself.
“People don’t really realize what goes on behind the scenes. We always see the aircraft; we always see the planes flying, but you don’t think, ‘OK if they go to a certain altitude, they can’t breathe.’ We’re a critical link in any mission scenario when it comes to generating any kind of sorties out of Kadena.”
Every Air Force base in the world has a cryogenics storage facility supplying cryogenic products to keep its aircraft airborne. However, only one Air Force facility makes its own, and it is at Kadena.
The airmen in Kadena’s cryogenics lab produce mostly liquid oxygen, which is converted to breathable oxygen for pilots, said cryogenic production operator Senior Airman Christopher Tallan. The product is in high demand, with 35 flight groups at Kadena alone.
Liquid oxygen is also used at the naval hospital for breathable oxygen and in anesthesia.
Liquid nitrogen is not in such high demand, but that too is produced at the facility, Tallan said. It is used in aircraft fire-suppression modules and to fill aircraft tires. Gaseous nitrogen is less volatile than atmospheric air.
It is also used to burn off warts at the naval hospital or at the island’s other military health clinics.
The liquid forms of oxygen and nitrogen are denser than the gaseous forms. Liquid oxygen, for example, generates more breathable air than can be stored as a gas.
“One gallon of liquid oxygen is several hundred cubic feet of breathable air,” Tallan said.
If purchased from an off-base provider, liquid oxygen usually costs about $6 per gallon, Tallan said. By making their own, the airmen at Kadena save the Air Force and the U.S. taxpayers around $4 per gallon.
‘Has to be ready’
Kadena’s plant usually runs for a week straight, 24 hours a day, about every three weeks, filling its depleted stocks before going dormant again, Tallan said. They can produce approximately 50 gallons of product per hour or as much as 1,000 gallons in a day.
The plant was not running Oct. 24; however, the airmen received an order to fill six, 50-gallon liquid oxygen carts, out of its stocks for air operations. The “lox carts” look like a cross between a wheelbarrow and a trailer.
These calls can come at any time, day or night.
Tallan and Senior Airman Jarvis Harper donned their protective gear and exited the building, working alongside their four 6,000-gallon tanks, two for liquid oxygen and two for liquid nitrogen.
Before they filled the order, they collected a sample of the liquid oxygen to check it for any impurities. The air filled with smoky vapor as the minus-300 degree liquid reacted with the sticky, tropical Okinawan air.
The airmen connected a hose to the massive liquid oxygen tank through a centralized docking station. The line immediately turned frosty. One by one they connected the hose to the lox carts and turned the nozzle; the rush of liquid oxygen could be heard splashing against the inside of each tank.
“You’re responsible for the maintenance on the tanks; you’re responsible for making sure the product is good; it has to have a certain purity,” Tallan said. “At the drop of a hat, your shop has to be ready to fill a lox cart. Any hour of the day, Christmas, holidays, weekends, 1 a.m. in the morning.”
Carts are dropped off to be filled and picked up by the air units that need them, Tallan said. Numerous F-15s can be filled off a single lox cart.
There are five basic steps Kadena’s cryogenics producers go through to create their product. The airmen enter their plant, which is a twisted mass of electrical boxes, pipes and containment vessels. A computer turns on the systems.
The first step sees a compressor take in atmospheric air, which rests at 15 pounds per square inch, and compresses “a lot” of it into a really small space, Tallan said. The compressed air heats up to slightly less than 120 degrees Fahrenheit.
The air then moves into a chiller unit, which keeps the air compressed but cools it to about 40 degrees Fahrenheit, Tallan said. This is far below room temperature but not quite freezing. It then rests at about 55 pounds per square inch.
Then the product moves to drier beds, which are filled with “molecular sieves,” Tallan said. This allows smaller molecules through but not larger ones. More water and carbon dioxide are pulled out of the product.
“It’s essentially just another really big filter,” Tallan said.
The product, which has now been drained over and over for impurities and sits at about 40-50 degrees Fahrenheit, then moves to a giant column — called the “cold box” — that stretches from floor to ceiling, Tallan said. The product builds up in the column and is spread out. As it expands, the temperature drops.
Forty degrees Fahrenheit and 55 pounds per square inch becomes minus-321 degrees Fahrenheit and one pound per square inch.
“Spreading out a gas makes it colder and compressing it makes it hotter,” Tallan said. “It’s pretty neat.”
The liquid is then pumped outside to the 6,000-gallon tanks. Kadena’s plant usually keeps about 9,000 gallons each of liquid oxygen and liquid nitrogen on hand at any given time.
“We have to do hourly checks to make sure nothing is malfunctioning,” Tallan said in an Air Force statement in August. “We’re responsible for knowing what’s supposed to be going on. With such a big plant and so many pipes, we have to make sure that nothing is in a pipe that shouldn’t be in it, and make sure things are at the right temperature in the pipes they’re supposed to be in.”
‘Spontaneous combustion’
Tallan, a 20-year-old from Chico, Calif., spent over a year pumping and distributing fuel on Okinawa before he was moved to cryogenics.
The cryogenics laboratory seeks out and takes the best and brightest from the fuels career field, he said.
“When you show up to cryogenics from a different section, especially at Kadena, you’re kind of thrust into the situation. You have to learn a massive amount of information about something [that’s] never really been talked about at all in your career field,” Tallan said. “It’s an absolute juggernaut.”
The job has the potential to be incredibly dangerous, Tallan and the other airmen at Kadena said.
Both products can burn skin. Liquid nitrogen can incapacitate someone if it’s not handled in a well-ventilated area.
“It’s fatal,” Tallan said. “The big hazard with nitrogen is asphyxiation and the big hazard with liquid oxygen is spontaneous combustion.”
Liquid oxygen is prone to combust if it comes in contact with a hydrocarbon, which could be anything from fuel to rust, certain plastics or even fingerprints on a tool.
Every month the airmen are forced to go over their tools with a blacklight, searching for the smallest hint of a hydrocarbon, Tallan said. Maintenance on a line that contained liquid oxygen is performed with a separate tool kit that is kept locked up.
“If a drop of fuel were to touch our product, there’d be a massive explosion,” Tallan said. “You have to be pretty thoughtful around this stuff.”
Despite the dangers, the airmen assigned to Kadena’s cryogenics facility say they wouldn’t change a thing.
“It is massively rewarding,” Tallan said. “Every ambulance needs oxygen on it and we provide that to them.”
He said it was rewarding to know that if Okinawa’s sole off-base production facility were to shut down, which has happened before, the island would not be “stranded” without the life-saving liquid oxygen.
Hall said that he and his fellow cryogenics airmen take a lot of pride in their work, because while they might not be well-known, they know how integral they are to operations.
“This is the only plant in the Air Force,” he said. “It’s a pretty big deal. I love this job.”
There is another use for the liquid nitrogen employed by Kadena’s cryogenics lab each year, and it makes the airmen smile each time it’s mentioned. They make ice cream for Department of Defense Education Activity schoolchildren during STEM presentations.
“I think it’s the best ice cream I’ve ever had,” Tallan said. “It’s insanely good.”
The mixture is one part milk, one part half-and-half, a small amount of sugar and some fruit, like cut-up strawberries, and liquid nitrogen, which is poured on top while the mixture is being stirred. The transformation is instant.
“The kids get a kick out of it,” Tallan said. “That’s the scope of our mission, everything from saving lives to making ice cream.”
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