The history of refrigeration before Freon is full of leaks, explosions, and near-misses that most people today have never heard of — and it opens, oddly enough, with Albert Einstein reading his morning paper in 1926. A family in Berlin had died in their sleep after a seal failed on their refrigerator, filling the apartment overnight with toxic gas. Einstein, twenty years past his theory of special relativity by then, decided this was a problem worth his attention. He teamed up with his former student Leo Szilard, and together they designed a refrigerator with no moving parts at all — an electromagnetic pump with nothing to wear down, nothing to leak. It never went into mass production. But the fact that one of the most famous scientists alive felt compelled to drop everything and fix a kitchen appliance tells you something about how dangerous refrigerators actually were.
The Appliance Everyone Quietly Feared
Before the 1930s, keeping food cold at home meant using one of three refrigerant gases: ammonia, sulfur dioxide, or methyl chloride. All three worked well at cooling food. All three were also toxic, and two of them were flammable. If a seal cracked, a pipe corroded, or a compressor failed — and mechanical failures were common in these early systems — the gas didn’t just stop cooling your food. It filled your kitchen.
Newspaper archives from cities like Cincinnati read like a slow-motion disaster report. A university club had to be evacuated after an ammonia leak. A baking company suffered a massive ammonia spill in 1924. Firefighters needed gas masks to enter a packing plant in 1928 after ammonia seeped from its refrigeration system. None of these made national news individually — leaks like this were common enough to barely register as unusual.
Not every close call made it into a newspaper archive. Historians estimate that hundreds of smaller leaks went unreported each year throughout the 1920s, treated as routine maintenance issues rather than safety hazards — the kind of near-misses that only become visible in hindsight, once someone finally adds up the pattern. It’s the same reason a single dramatic outage gets a postmortem while a hundred smaller, quietly-patched incidents never do.
The History of Refrigeration Before Freon Turns Genuinely Deadly
The history of refrigeration before Freon includes at least one incident that did make headlines nationwide. In 1929, a leak connected to a methyl chloride refrigeration system was linked to an explosion that killed more than 100 people. Whatever the exact chain of events, the disaster became a turning point in the public conversation — consumers, understandably, started to prefer their old-fashioned iceboxes over these new “convenience” appliances that occasionally killed people.
I think about this every time I read a bug report from a customer who says our software crashed and they just switched back to the old spreadsheet they were using before. Adoption doesn’t happen because a new tool is theoretically better. It happens once people stop being afraid of it.
Servel, Sulfur Dioxide, and a 22-Death Recall That Took 57 Years
The danger didn’t disappear the moment the industry noticed it. Servel gas refrigerators, manufactured between 1933 and 1957, carried a serious risk of carbon monoxide leakage from their cooling systems. At least 22 people died from these units over the following decades before the model was finally recalled — in 1990, more than three decades after production had already stopped. General Electric’s 1927 Monitor Top, often credited as the first genuinely affordable home refrigerator, used sulfur dioxide or methyl formate, both toxic, both theoretically contained safely within a sealed system that occasionally wasn’t sealed at all.
There’s a pattern here that feels uncomfortably familiar from a software career: a known defect, a workaround that mostly holds, and a company that ships the next version anyway because the alternative is admitting the whole architecture needs to change.
Thomas Midgley and the Miracle Compound
By the late 1920s, three companies — General Motors, DuPont, and Frigidaire (which GM had purchased after World War I) — pooled their research into finding a refrigerant that wouldn’t kill anyone. The task fell to a chemical engineer named Thomas Midgley Jr., working alongside colleagues Albert Henne and Robert McNary. Midgley noticed that the refrigerants already in common use clustered around a specific intersection of the periodic table, near the element fluorine. Fluorine itself was toxic. But compounds built around it, Midgley theorized, might not be.
He was right. In 1928, Midgley and his team synthesized dichlorodifluoromethane — a chlorofluorocarbon that would become known by its trade name, Freon. It was stable, nonflammable, and nontoxic to breathe. According to the U.S. Environmental Protection Agency’s history of refrigerant safety, Freon effectively eliminated the immediate physical dangers that had plagued home refrigeration for three decades. Sales of mechanical refrigerators took off. The icebox, and the iceman who delivered blocks of ice door to door, quietly disappeared from American life within a generation.
The Same Man, Two Catastrophes
Here’s the part of this story I keep turning over. Thomas Midgley Jr. wasn’t only responsible for Freon. A few years earlier, working for the same company, he had also developed tetraethyl lead — the additive that made “leaded gasoline” possible, and that spent the next 5 decades poisoning the bloodstreams of children living near highways before it was finally banned. Midgley solved two genuinely urgent industrial problems in his career, and both of his solutions turned out to be slow-motion catastrophes that nobody could see coming from inside the timeline they were living in.
Freon’s hidden cost didn’t surface until 1974, three decades after Midgley’s death in 1944, when chemists Mario Molina and F. Sherwood Rowland published research showing that CFCs drift into the upper atmosphere and break down the ozone layer that shields the planet from ultraviolet radiation. The compound that had made kitchens safe was slowly punching a hole in something much larger.
I don’t bring this up to villainize Midgley. I bring it up because I recognize the shape of the mistake. As a developer, I’ve shipped fixes that solved the ticket in front of me and introduced a dependency nobody thought to question for years. Midgley’s fixes just operated on a planetary timescale instead of a sprint cycle, and the blast radius was correspondingly larger. Solving the problem you can see is not the same thing as solving the problem.
What Happened to Freon After That
Once the ozone research became impossible to ignore, the world moved with unusual speed for an environmental issue: the 1987 Montreal Protocol phased out CFC production globally, and manufacturers shifted to hydrofluorocarbons and other alternatives that don’t carry the same ozone-depleting risk. The ozone layer, measured by satellite since the 1980s, has been slowly recovering ever since — one of the few times humanity identified a self-inflicted planetary wound and actually closed it.
Modern refrigerators, running on chemicals most of us have never heard of and will never need to think about, owe their safety to a century-long relay race: Einstein’s failed side project, Midgley’s flawed miracle compound, and a generation of scientists who caught the mistake before it became permanent.
More Stories Like This
Refrigeration’s dangerous early decades sit right alongside another kitchen appliance with a rocky origin story: Josephine Cochrane’s invention of the dishwasher, built not to save labor but because she was tired of her servants chipping her good china. More kitchen-invention stories like this one are coming soon.