Four years and a tonne of pitchblende
Marie and Pierre Curie announced radium in December 1898, having inferred its existence from radioactivity in pitchblende that neither uranium nor thorium could account for.
Inferring it was not the same as having it. Isolating a visible quantity took four more years of processing pitchblende residues in an unheated shed — grinding, dissolving, precipitating, recrystallising, tonnes of ore for fractions of a gram.
They ended with about a decigram of radium chloride, and enough data to fix the atomic weight.
⚠️ Marie Curie received the Nobel Prize in Physics in 1903, shared, and the Nobel Prize in Chemistry in 1911, alone — the first person to win in two sciences. Her notebooks are still radioactive and are kept in lead-lined boxes.
Why the body keeps it
Radium sits below calcium in group 2, forms the same Ra²⁺ ion, and is close enough in size that biological systems do not distinguish them.
The body treats radium as calcium and builds it into bone.
Once there it stays, emitting alpha particles into bone tissue and marrow at point-blank range for the rest of the person’s life. The half-life of 1,600 years means the amount does not meaningfully decrease.
⚠️ This is the single fact that explains everything that follows. Radium is not especially dangerous outside the body — alpha particles cannot penetrate skin. Swallowed, it goes to the one place it can do the most harm and never leaves.
The dial painters
From 1917 the United States Radium Corporation and its competitors hired young women to paint luminous numerals on watch and instrument dials.
The work needed a fine point. The women were taught to shape the brush with their lips between strokes — lip, dip, paint — swallowing a trace of radium each time. Some painted their nails and teeth with it for fun.
From the early 1920s they began to fall ill: anaemia, fractures from small knocks, and necrosis of the jaw so severe that bone could be removed by hand. Dentists were baffled.
⚠️ The companies denied any connection, commissioned studies that found none, and in at least one case attributed the deaths to syphilis — a diagnosis that attacked the women’s reputations as well as their claims.
Five women from US Radium sued in 1927. Grace Fryer, the lead plaintiff, could no longer walk unaided by the time it came to court. The case settled, and others followed.
The result outlived them. It established that an employee could sue an employer for an illness caused by their work, and it fed directly into the industrial safety standards and the eventual regulation of workplace radiation.
Radium as a tonic
At the same time, radium was being sold as medicine.
The reasoning was that radioactivity stimulated the body. Radium water, radium suppositories, radium toothpaste, radium face cream and radium-impregnated underwear were all on sale through the 1920s.
Radithor was radium dissolved in distilled water, sold by the bottle. Eben Byers, a steel industrialist and amateur golf champion, drank several bottles a day for years on his doctor’s advice.
He died in 1932. His jaw had disintegrated, his skull was full of holes, and he weighed under 40 kilograms. The Wall Street Journal headline was “The Radium Water Worked Fine Until His Jaw Came Off.”
⚠️ Byers was wealthy and prominent, and his death did what the dial painters’ deaths had not: it ended the patent medicine trade almost overnight.
What is left
Radium has been displaced from everything it was once used for. Cobalt 60 and caesium 137 took over its role in radiotherapy; tritium and phosphorescent compounds replaced it on dials.
Old radium items still circulate — clock faces, aircraft instruments, compasses. They are not dangerous behind glass but become so if the paint flakes, and several radiological incidents have started with someone finding an old instrument in an attic.
⚠️ One radium isotope has come back. Radium 223 is licensed for prostate cancer that has spread to bone, and it works precisely because of the property that killed the dial painters: it goes to bone, and its alpha particles have a range of a few cells.
The affinity for bone was never the problem. Where the radium ended up, and in whose bones, was.