Join War on the Rocks and gain access to content trusted by policymakers, military leaders, and strategic thinkers worldwide.
Editor’s note: This is the fifth article in a limited series celebrating American defense technologies born from wartime and their effects on broader national security, politics, and society. This series will run for several weeks to commemorate America’s 250th anniversary, and winners will be selected by a reader vote undertaken through our newsletter later this summer. Prior installments can be found at the Arsenal of Innovation page.
Have you ever wondered how the United States transitioned from only having local fresh produce to an abundance of perishable goods available year-round across the country, even during the off-season? Today, almost $3 trillion (roughly 2.7 billion pounds) of products, including food, medication, and hazardous chemicals, are transported in temperature-controlled vehicles in the United States per year, thanks to Frederick McKinley Jones’ 1938 invention of the mobile refrigeration system.
Born in response to a commercial problem, then scaled and hardened out of a need to supply troops on the front lines of World War II, Jones’ invention affected what was possible in terms of combat, logistics, and strategy in America’s second great war. Since then, the civilian commercial market has continued to use his invention, which has touched almost every facet of American life as we know it. Mobile refrigeration units are a clear example of a dual-use innovation whose proliferation was made possible initially by our military and whose invention reflects the diverse backgrounds of American inventors.
By the time the Model C was introduced, the civilian cooling industry had come a long way from its humble beginnings. In 1806, Frederic Tudor, the “Ice King,” started the American ice industry, relying on natural ice that was cut from frozen lakes in northern states, such as Minnesota. Extensive trade routes shipped this natural ice to southern states and internationally as the industry stoked demand for cold treats, like ice cream, and preserved foods. The 1834 invention of mechanical ice massively disrupted the industry, as ice no longer needed to be harvested and shipped. Communities could save a fortune by creating and distributing ice locally. However, natural or mechanical, ice still melts in the heat.
The beginning of the 20th century introduced consumer cars, then trucks, to the American market. Prior to Jones’ invention, goods transportation either occurred without any temperature regulation, where temperatures soared, or required ice to cool the vehicle’s interior. Ice, however, is expensive, heavy, and melts.
Thus, during engagements abroad, the United States military relied on finding perishable food and supplies as they travelled or contending with the logistics to build food production centers, such as field bakeries, to feed troops on the front lines. Often, this strategy required troops themselves to carry their allotted daily rations in case they were not able to access supply lines.
During each of the major U.S. wars, food sourcing was of particular concern because lack of food can directly lead to sub-optimal fighting and low troop morale — it’s often quipped that an army marches on its stomach. In World War I, U.S. troops fought overseas, and trench warfare exacerbated the problem as food was easily contaminated with dirt, gas from enemy attacks, and vermin, or arrived infrequently as supply lines were intercepted. One solution to this problem was to ship canned food, but even this often required cooking to be made edible.
The international nature of fighting in World War II demanded a replacement for the inconsistent salt-and-ice-cooled transportation vehicles that required significant manual labor. This was a prime opportunity for Frederick McKinley Jones’ third iteration of his refrigeration unit, the Thermo King Model C, to revolutionize international shipping of perishable goods in 1942.
Frederick McKinley Jones, the “King of Cool,” was a brilliant engineer and inventor who was awarded 61 patents across his lifetime for inventions from portable X-ray machines and engines to sound equipment. He eventually became the first African American to be awarded the prestigious National Medal of Technology posthumously in 1991.
Jones was born in Cincinnati, Ohio, in 1893. He was sent to live at St. Ann Catholic Church in Covington, Kentucky at nine years old when his mother passed away. At the church, he was responsible for cooking, so he became acquainted with the intricacies of food management from a young age. He found solace working at an auto garage when he was 11 years old, where he was able to develop his mechanical skills. These skills turned into a passion, and he began working as a full mechanic by age 14, then extended his skill set to include repairing steamships and other machinery.
Jones’ skills were a hot commodity during his service as a World War I Army mechanic, which saw him promoted from his all-black military unit, the U.S. Army’s 809th Pioneer Infantry (stationed in France), to become an electrician and instructor for other soldiers. After his promotion, Jones used his engineering skills to maintain communication systems, fix military vehicles, and gain proficiency in electrical engineering.
After retiring as a sergeant, Jones moved to Hallock, Minnesota, and, after a few years, created a shock-resistant unit with a compressor that could cool a trailer to transport food without it spoiling. He was responding to a request from a local resident to find a solution for his produce arriving in inedible condition after overland transport. The key was to use a gas engine with the self-starting motor he had invented earlier and custom mounts to stabilize the unit. Working with his business partner Joseph Numero, Jones created the Model A and Model B Thermo King cooling units for refrigerated shipping. These inventions attracted the attention of the U.S. military in 1941, who asked them to invent the more efficient and self-contained Model C cooling unit. This new and improved process allowed the military to provide refrigerated units for trucks to transport food to soldiers starting in 1942.
The introduction of this “cold chain” or cold line transportation meant that supplies stayed cold from sourcing to ocean transport to the front lines. This innovation coincided with the U.S. government’s first food rationing mandate for the civilian population, along with restrictions on other commodities like gasoline, oil, shoes, and metal products. Civilians were also encouraged to plant Victory Gardens to grow additional food for the civilian supply, which allowed farmers to send more food to the military via refrigerated transportation.
Food was not the only supply that benefited from refrigerated transportation. Medical supplies, such as blood plasma and the antibiotic penicillin, were also rationed for civilians. They were able to reach field hospitals in functional condition to treat blood loss and bacterial infections thanks to the “Penguin Fleet.” Refrigerated cars enabled work on blood transfusions, leading to the establishment of an American blood bank for British soldiers, where American volunteers could donate blood to be shipped in refrigerated cars overseas. One project led by Charles Drew collected over 14,500 blood donations and 5,000 liters of plasma to be sent to the war front. In 1944, the U.S. government shipped 200 million units of penicillin to the Air Force, 330 million units to the Navy, and 1.5 billion units to the Army, which is estimated to have saved millions of lives.
World War II is largely considered a war of attrition, where the side that outlasted the other in terms of supplies, troop health, morale, and economic stability would earn a decisive victory. The Allies had a significant advantage over the Axis Powers in terms of force employment, resources, and troop health due to robust civilian economies and labor supplies in the United States. The Axis Powers could not match this advantage in many respects, including refrigerated shipping.
Innovation in logistics heavily influenced policy and frontline defensive capacity, enabling policymakers to dream bigger in strategy and operations. This allowed the Allies to move their forces from fixed and vulnerable bases to mobile, decentralized operations; a phenomenon relied upon heavily in warfare since the 1940s, especially in the Global War on Terror.
The Thermo King Model C refrigeration unit was a major technological accomplishment that had far-reaching policy and financial implications.
First, using cooled transportation introduced a need for more technical positions in the military to install and repair systems critical for resupply and logistics. Working on cooling, like maintaining tanks and planes, became a transferable skill once the war ended.
After World War II, Thermo King and the U.S. government allowed the civilian market to use Model C refrigeration units for commercial shipping in trucks, boats, and planes. Facing the same challenges of using salt-and-ice shipping, the agriculture and medical markets were eager to use Jones’ invention to distribute goods. In 1949, Jones improved on his invention, creating a roof-mounted refrigeration system for long haul trucks and railroad cars, which made use of the country’s growing rail and freight lines. This expanded the cold chain shipping market to transport arctic animals, art, flowers, and other perishable goods. The Federal-Aid Highway Act of 1956 saw a sprawl of over 40,000 miles of highways built across the United States over the next few decades. Instead of primarily relying on cooled rail cars to ship produce and medical supplies, suburban development prompted reefer trucks to transport goods from rail depots to towns designed to only be reached by car, thus increasing demand for refrigeration units. Urban expansion, paired with cold chain shipping innovation, allowed civilian markets to facilitate medical advances and the creation of the modern supermarket.
Jones’ story exemplifies how critical military innovations developed by those from non-traditional backgrounds can be for the military itself and how those benefits can translate to civilian industry. Emerging technologies need not only be measured by how much of an increase to lethality they provide or in terms of exquisite capability — improving troop morale and easing logistical burdens can significantly improve military readiness when it matters. And as shown in Ukraine today, having a population that is ready and willing to fight can see enormous success even with limited cost-intensive technological resources.
Evolving past its wartime use, mechanical refrigerated shipping affects nearly every industry in the US. In fact, even 65 years after Jones’ death, the Thermo King brand is still one of many refrigerated shipping companies that runs the North American multi-trillion-dollar reefer shipping industry. So, the next time you pass (or get stuck behind) a refrigerated shipping truck on the highway, think of the man who made it all possible, the King of Cool and wartime inventor, Frederick McKinley Jones.
Caitlan Fealing is a Ph.D. candidate in the Carnegie Mellon Institute for Strategy and Technology, pursuing a degree in International Relations, Security, and Technology. She has completed the Institute for Defense Analyses Data Science Fellowship and has an interdisciplinary background with a bachelor’s degree from Williams College, where she majored in Economics, Mathematics, and Psychology. Her current academic research investigates how civilians posting witnessed accounts of conflict events on social media (“civilian witnessing”) affects public opinion and foreign policy attitudes, with a specific focus on the Gaza War, the Russia-Ukraine War, the Sudanese Civil War, and the Nagorno-Karabakh Conflict.
Image: U.S. National Archives. Digitized by Signal Corps Archive via Flickr.
