The material that once burned for ancient Greek lanterns and saved millions from fires is now killing more people than the attacks themselves. That's the unsettling story at the heart of Derek Muller's investigation into asbestos — a mineral we never fully stopped using.
The Inextinguishable Rock
The Greeks called it inextinguishable. Around 2,000 years ago, they found something poking out of the ground that looked like cotton but refused to burn. It was actually rock — a naturally occurring mineral made of silicon and oxygen atoms forming incredibly stable structures. The ancient Greeks called this asbestos, meaning "inextinguishable." They used it to line their lanterns so fires could burn for a whole year without going out.
The atomic structure is deceptively simple: silica tetrahedrons that link together in chains and sheets. These formations create tiny scroll-like tubes that don't break down under heat. The material stays stable up to around 600 degrees Celsius. When twisted, the fibers don't break — it's literally a rock you can weave.
How It Saved Millions
By the 1800s, cities were packing together. In America alone, between 1790 and 1870, the number of people living in urban areas jumped from one in twenty to one in four. Buildings were made of wood, and people cooked with open flames, lit gas lamps, and candles. One accident could torch an entire neighborhood.
New York City learned this in December 1835, when three separate fires erupted within just two days. A bystander described the aftermath as "an ocean of fire with roaring, rolling, burning waves." By the end, a third of a mile of Manhattan was engulfed, destroying nearly 700 buildings at a cost equivalent to over $730 million today. Similar catastrophes struck Chicago, London, Hamburg, and Tokyo.
Twenty-three years after New York's great fires, a 21-year-old named Henry Ward John set out to break that chain reaction by making roofs fireproof. He discovered that the short asbestos fibers — the scraps normally swept aside — were exactly what he needed. Fireproof, tough, and cheap.
In 1868, Johns patented his invention. By 1927, his company was generating $45 million in annual sales — over $800 million in today's money. People wove asbestos into theater curtains, insulation blankets for steam engines, and fireproof clothing. The most important use came around the late 1800s: roofing materials.
Across America, consumption grew from around 20,400 tons in 1900 to a peak of 803,000 tons in 1973. Pretty much every building in the U.S. — public or private, commercial or residential — used some form of this material. During that same period, fire-related deaths dropped by around 80%.
But asbestos didn't just protect against flames.
The Hidden Cost
In the early 1900s, a young woman named Nelly Kershaw worked in a factory spinning asbestos fibers into threads. Every day, she breathed in the dust that those machines threw into the air. By her early thirties, she was so sick she could barely breathe.
When she asked the factory for help, they refused — helping workers would set a dangerous precedent. Nelly died shortly after at age 33.
Her case caught the attention of pathologist Dr. William Cook. When he opened up her chest, her lungs were gray and scarred, almost blue-black like a huge internal bruise. When his scalpel passed through them, it rasped like scraping against sandpaper. The tissue was full of mineral grit.
Her lungs were gray and scarred, almost blue-black like they had a huge internal bruise. It was like scraping against sandpaper.
In 1924, Dr. Cook published the first medical description of this condition — asbestososis. When these fibers lodge into the lungs, the body treats them like invaders. Specialized cells called macrophages move in to engulf and digest bacteria, dust, or debris. But asbestos fibers are too long and stiff to swallow — it's kind of like trying to eat a toothpick sideways.
The macrophages keep trying and failing, releasing inflammatory chemicals that damage surrounding lung tissue. When doctors examined hundreds of workers, they found more than 25% already showed signs of lung disease. For workers with over 20 years of exposure, that number was closer to 80%.
By the mid-20th century, asbestos was everywhere: inside brake pads, toasters, ironating boards, hair dryers, surgical dressings and blankets. Brewers filtered beer through it. One brand of toothpaste even used it for extra polish. The fake snow in department store windows — and in movies like The Wizard of Oz — all contained asbestos.
A Bigger Problem Than Thought
But here's what's unsettling: today, this same material has been detected in places most people would never expect. In popular off-roading spots. In makeup. Even in kids' toys — Mickey Mouse crayons. It's been found in the dust around schools and homes.
The particles from the World Trade Center collapse were pulverized to microscopic size and released into the air. They remained airborne for days, and thousands of people unknowingly breathed them in. The particles buried themselves deep within people's lungs, wreaking havoc and causing all sorts of diseases.
By 2035, nearly 2.8 million people might die because of this material. Some countries are still importing hundreds of thousands of tons each year.
Critics might note that the health impacts vary significantly depending on exposure levels and fiber type. Not all asbestos varieties carry equal risk, and some formulations have been used safely in certain applications for decades. The complexity of dose-response relationships means any simple generalization about danger is scientifically incomplete.