Why Early Refrigerators Were So Deadly

Long before they sat in corners of kitchens, refrigerators were iceboxes, simply insulated cabinets with a large block of ice inside that would absorb heat as it melted. They kept food cooler than the air around them. Incredibly, this process required no compressor, refrigerant, or other mechanical equipment. Supplying these iceboxes led to a massive industry. Ice had to be cut from frozen lakes and ponds during winter, then stored in insulated icehouses, and finally delivered to houses when summer came. Mechanical refrigerators had to contend with a trusted system, but there was one clear gap: a melting block of ice wasn’t likely to poison anyone in their sleep.

For generations, scientists experimented with ways to create cooling. In the 18th century, a Scottish physician and chemist named William Cullen showed how evaporation under reduced pressure could generate cooling. He didn’t show off a kitchen fridge to his eager customers, but his discovery was a helpful tip for future inventors.

Jacob Perkins received a patent in 1834 for a crude version of the modern vapor compression refrigeration system. The idea was simple enough: A refrigerant would circulate around a closed loop, absorbing heat when it vaporizes and dissipating the heat when it condenses, with the help of a compressor to maintain the flow. The system proved so effective that modified versions of this basic design remain at the heart of refrigeration today!

Before home fridges were ubiquitous, mechanical refrigeration was popular among industries. Breweries required constant temperatures, meat packers required preservation for their products, and dairies, warehouses, food processing plants, and ice plants all found refrigeration useful. Refrigeration also revolutionized transportation because the transport of perishables would keep them fresh longer, thus allowing meat, dairy, and fruits and vegetables to be transported farther without spoiling, which changed the food system.

The first electrical household refrigerators started to show up in the 1910s and 1920s, but they certainly weren’t commonplace at first. They cost money. Not everyone had access to electricity. Many people already owned an icebox and were satisfied with it, so purchasing a mechanical refrigerator meant taking the leap as an early adopter of the latest technology for your home. But even more, they were arriving while manufacturers were still grappling with some key decisions, such as what poisonous chemical would be moving around inside the refrigeration device in your kitchen. Suffice it to say, that technology wasn’t quite there yet.

There’s a fluid in every mechanical refrigerator, a refrigerant that absorbs and releases heat as it cycles through the cooling system. Early refrigeration engineers didn’t have an ideal choice among these fluids. There were substances such as ammonia, sulfur dioxide, methyl chloride, and methyl formate, all of which worked great for refrigeration but were also toxic, flammable, corrosive, or irritating, often all in the same substance. They were supposed to stay enclosed within the system. Trouble started when they didn’t.

Ammonia absorbed heat efficiently and still is used in large scale industrial refrigeration today. Concentrated ammonia gas, however, is also hazardous, irritating the eyes and lungs, and potentially seriously injuring those exposed at higher concentrations. In a closed space, a large ammonia leak could escalate to a medical crisis almost instantaneously. Engineers simply needed to ensure that the ammonia remained contained.

Then there’s sulfur dioxide. Another refrigerant, sulfur dioxide can also cause eye and respiratory tract irritation, and in high enough doses, can be toxic. Fortunately for us, sulfur dioxide smelled pretty bad. I’d prefer to not have to smell it, but at least it could act as a warning signal.

Methyl chloride was also used in some home refrigerators of the 1920s. The gas was poisonous, however, and could form flammable mixtures with air in some cases. Unlike sulfur dioxide, it did not give off a strong odor, so it could be hazardous without warning.

Could a refrigerator kill you? Yes, in the 1920s, it could. There are accounts of people injured or even killed by a refrigerator’s leaking refrigerant. If a seal was broken, a pipe was damaged, a valve defective, or any other flaw, gas could leak from the appliance. If enough leaked out and filled the small space of a house, the occupants might fall sick. Sometimes they died.

Another challenge with early mechanical refrigerators was that a cooling system had to be completely sealed. There were moving parts in a compressor. Shafts passed through housings. Valves opened and closed. Pipes linked different sections of the system. Every connection offered another potential place for the refrigerant to leak. Engineers found ways to improve seals, and eventually most compressors were hermetically sealed, meaning the motor and the compressor were enclosed in a welded container. Fewer external moving parts meant fewer chances for refrigerants to leak.

The Monitor Top, an iconic early GE refrigerator that entered production in 1927, got its name because of the bulky cylindrical compressor housed on top of the refrigerator. It brought electric refrigeration a step closer to the average home. Some versions used sulfur dioxide as a refrigerant, a reminder that this was an era when engineers were still balancing effective cooling against less-than-ideal chemical choices. The Monitor Top wasn’t the first refrigerator; it just made the refrigerator a more familiar object.

A gleaming new household gadget that could kill a family was a perfect story for the newspapers, and as people died or were injured from refrigerant leaks, newspapers naturally wrote about the events. What made the contradictions more poignant was that the refrigerator itself was being promoted as an appliance that kept families safe by protecting food from rotting. A breakdown in the machine, however, could make it a source of poison gas. People were listening, and there was even more incentive for engineers to come up with a solution.

Oh, yes. In the 1920s, Einstein teamed up with the Hungarian physicist and inventor Leo Szilard to design refrigerators, after a newspaper report told of a Berlin family killed by fumes from a leaking refrigerator seal. They were keen to create systems that depended less on the types of moving parts and seals that were vulnerable to failure and leaks, and they ended up filing a number of patents for their work.

One technique developed by Einstein and Szilard utilized absorption refrigeration instead of a traditional mechanically driven compressor. In other words, heat and absorption could cycle refrigerants through the system without employing the usual set of moving compressor components. Einstein and Szilard obtained a US patent in 1930 related to their refrigeration work. And their designs took into account safety issues as well; another of their refrigeration technologies had an electromagnetic pump that had no conventional moving mechanical parts at all. Yes, lots of physics for what would ultimately be a machine designed to keep milk from spoiling, but at least they were way ahead of their time!

While that was happening, traditional vapor-compression refrigerators were still improving, hermetic compressors decreased potential leakage points, and production was becoming more consistent. But on another front, chemical scientists were going at the problem in an entirely different way: rather than building an entire refrigerator around the threat posed by toxic refrigerants, they tried to find safer alternatives for the toxic refrigerants themselves. This turned out to be a far greater commercial success.

By the late 1920s, it was pretty clear that refrigerator companies wanted a refrigerant that cooled well, ideally one that didn’t burn, didn’t easily kill people or break the equipment, and was stable enough that it could be run in a continuous loop. In response, researchers at General Motors and Frigidaire started their own systematic search for a chemical with a better mix of these qualities.

With others, like Albert Henne, and as part of a research program tied to General Motors and Frigidaire, chemist Thomas Midgley Jr. synthesized a family of chemical compounds called chlorofluorocarbons, or CFCs. One, dichlorodifluoromethane, also known as CFC-12, R-12, or Freon, is a particularly important refrigerant. In contrast with some of the chemicals refrigerators had used, this one was amazing: It was nonflammable, relatively nontoxic, stable, and a great refrigerant. For engineers, who wanted to stop refrigerators from leaking deadly gases, it seemed too good to be true.

Midgley inhaled a chestful of the new gas during a demonstration and then blew out a candle. The demonstration was meant to show the gas was neither acutely toxic (since he could inhale it) nor flammable (since a candle flame in its presence didn’t ignite).

R-12 went into commercial production around 1931, and CFCs gradually appeared in domestic refrigerators through the 1930s. Along with improved compressor design and production, they solved one of the most troubling problems facing the industry: a leak no longer implied venting dangerously toxic or flammable gas. The result was that refrigerators became much safer and easier to market to everyday consumers. However, many old refrigerators were still operating, companies brought new technology on board at different speeds, and potentially dangerous refrigerants were not immediately banished when the CFCs arrived. Still, the trend was evident: the home refrigerator had become much less threatening.

It’s also quite easy to forget why we needed fridges in the first place (given their lethal beginnings): because of a lack of safe food storage due to spoilage and the proliferation of bacteria. Food like milk and meat can easily become dangerous if it is left out at warm temperatures for too long. Thanks to efficient cooling, the storage of cold food was made much more accessible within households.

One reason CFC refrigerants were attractive was that they were chemically stable. Because they weren’t highly reactive with other substances, they were pretty excellent substances to have circulating through a refrigeration system. Fast forward several decades, and researchers found that the same chemical stability meant that CFC molecules stayed in the atmosphere long enough to drift up to the stratosphere. There, ultraviolet light broke down the molecules and freed chlorine atoms, which can destroy ozone molecules. Since CFC-12 has been linked to ozone layer destruction, it is no longer produced. In its place, manufacturers use less harmful substitutes, such as HFC-134a and R-600a.

This content was created with the help of AI.