Poison on the Walls: The Deadly Craze for Arsenic Green

In the spring of 2024, Bielefeld University in Germany did something no library likes to do. It pulled roughly 60,000 books off its shelves at once. Every volume printed between 1800 and 1900 was blocked from lending, whatever color it happened to be, while health and safety staff worked out whether any of them were poisonous.

The worry was a single color: a bright, cheerful, slightly yellowish green. In the 19th century that green was often made with copper and arsenic, and bookbinders loved it. So did wallpaper printers, dressmakers, toymakers, confectioners and the women who made artificial flowers for hats. For a few decades, one of the most fashionable colors in Europe and America was also one of the most toxic things in an ordinary home.

Bielefeld’s story ended quietly. Inspectors went through more than 10,000 of the blocked books looking for colored page edges and old colored cloth bindings, and picked out about 100. They tested the 40 most suspicious. Some did contain arsenic compounds, but in such small amounts that the library ruled out any health risk from normal use; the levels were below the limits set for food. The books went back into circulation.

The green itself has a much darker story. It begins with a brilliant, unlucky Swedish chemist, runs through ballrooms, sweet shops and nurseries, and ends, oddly, in potato fields and malaria swamps.

Hard-luck Scheele

Carl Wilhelm Scheele was born in 1742 in Stralsund, then a Swedish town on the Baltic coast, and trained as an apothecary. He never held a university post. He worked in pharmacies, ended up running one in the small town of Köping, and did his chemistry in the back. From there he identified a remarkable list of substances, including chlorine, several organic acids and, most famously, oxygen.

He had the bad luck to discover oxygen before Joseph Priestley but to publish after him, so the credit went elsewhere. Isaac Asimov later called him “hard-luck Scheele” because so many of his discoveries were first credited to someone else. He died in 1786, aged just 43. Scheele had a habit of smelling and tasting the chemicals he made, and some historians suspect years of exposure to toxic compounds, arsenic among them, contributed to his death.

In 1775 he mixed a solution of sodium carbonate and white arsenic (arsenic trioxide) with copper sulfate and got a vivid green precipitate: copper arsenite. He published the recipe in 1778 in the journal of the Royal Swedish Academy of Sciences. It came to be called Scheele’s green.

Scheele knew what was in it. The art writer Victoria Finlay, as quoted by the Paris Review, says that a year before the color went into production he wrote to a friend that users might want to know it was poisonous. That warning did not travel well. The new pigment was cheap to make, and it was a better green than anything painters had had before. The old copper greens were dull or faded, and mixed greens made from blue and yellow could drift. Scheele’s green looked like new leaves.

By 1814 an improved version was on the market. Copper acetoarsenite, made with vinegar’s acetic acid in the mix, was brighter and more durable still. It went by a confusing pile of names, depending on who sold it and where: Schweinfurt green, Paris green, emerald green, Mitis green. Chemically they are cousins, and in the story of the 19th-century home they behave the same way.

A green for everything

The new greens spread through industry at astonishing speed. According to the U.S. National Library of Medicine, England alone produced 700 tons of the pigment in 1860. It went into toys, candy wrappers, food coloring, artificial flowers, textiles, window blinds, lampshades, the cloth covers of books, and above all wallpaper.

The Michigan chemist Robert C. Kedzie, who spent years campaigning against it, admitted the appeal. “There is not in commerce a green paint so beautiful and unfading as the aceto-arsenite of copper,” he wrote. “When mixed with other colors in toning it still gives a clear and fresh color. The temptation for the paper printer to use it is very strong.”

Printers did not reserve it for green leaves. Arsenic greens were also used to tone the background color of papers, so even a wallpaper that did not look green at all might be coated with it. The NLM puts the average at about 30 grains, roughly 2 grams, of arsenic per square foot of wallpaper. A papered room could hold a startling amount. One English papermaker in the 1860s said his shop went through two tons of arsenic a week.

The color also suited the moment. The industrial cities of Victorian Britain were dark, sooty places (London’s sewage problem was bad enough to produce the Great Stink of 1858), and a fresh green room, a green silk dress or a wreath of green leaves in the hair brought a little countryside indoors. Gaslight made many dyes look muddy at night. Emerald green kept its glow.

The women who made the leaves

The people who paid first were the ones who handled the powder. Artificial flowers and leaves were a big fashion business in Paris and London. Young women sat in crowded rooms shaping and coloring fabric leaves, and to make them look lifelike they dusted them with loose green pigment. The dust settled on their hands, faces and hair, and they breathed it in all day.

In 1859 the French physician Maxime Vernois toured Paris workshops that used arsenic greens and examined the workers’ hands. Under and around their nails he found raw, damaged skin, and injuries of this kind, sores and ulcers on the hands and face, were drawn in color for French medical publications that same year.

In London, the death of one flower maker became a public scandal. Matilda Scheurer was 19 when she died in November 1861. The historian Alison Matthews David, quoted in the Paris Review, describes her final illness: “She vomited green waters; the whites of her eyes had turned green, and she told her doctor that ‘everything she looked at was green.'” An autopsy found arsenic in her stomach, liver and lungs. Her job had been dusting artificial leaves with green powder.

The case was widely reported, and some accounts were more lurid than others. Still, it helped turn a quiet occupational hazard into a talking point. In 1862, Punch published “The Arsenic Waltz,” the cartoon at the top of this page, under the subtitle “The new Dance of Death.” It shows a skeleton gentleman bowing to a skeleton lady in a vast crinoline with a wreath of flowers on her skull. The joke was aimed at the ballroom as much as the workshop. Arsenic greens also colored dresses, waistcoats and the artificial leaves in fashionable headdresses, so the dancers could be wearing the poison themselves.

It is hard not to think of a later group of young women in a later industry: the radium watch painters of the 1910s and 1920s, who were also told their work was safe and also paid for an attractive glow with their bodies.

Sweets, cakes and a fatal mistake

Arsenic was not only in the green. In the mid-19th century white arsenic was cheap, sold over the counter as rat poison, and easy to mistake for flour or sugar. Some sweet makers used green pigments to color their products, and bakers sometimes did the same to cakes and decorations.

The worst food disaster of the era did not involve green at all. In Bradford, in northern England, in 1858, a sweet maker was supposed to bulk out peppermint lozenges with a cheap filler known as “daft,” usually powdered gypsum, to save on expensive sugar. A mistake at the druggist’s meant he was given arsenic trioxide instead. About five pounds of the sweets were sold at a market stall. Around 20 people died and more than 200 were poisoned.

Punch responded with John Leech’s cartoon “The Great Lozenge-Maker,” a skeleton grinding sweets beside barrels marked Arsenic and Plaster of Paris. Britain had already passed the Arsenic Act of 1851, which required sellers to keep a register of buyers and to color arsenic sold in small amounts so it could not be confused with food. Bradford pushed Parliament further. The Adulteration of Food or Drink Act followed in 1860, and the deaths were a factor in the Pharmacy Act of 1868. Neither law did much about green wallpaper.

Death in the wallpaper

Wallpaper was where most middle-class families met arsenic every day, and it was the hardest danger to pin down. Doctors began reporting cases in the 1850s. A Birmingham physician, William Hinds, described abdominal cramps and light-headedness that he blamed on the green paper in his own study in 1857. Two of his patients reported sore throats, weakness and inflamed eyes that cleared up when they left home for a seaside holiday.

In 1862 the deaths of four children in a house in Limehouse, in London’s East End, caused a public outcry. The children had shared a room decorated with Scheele’s green wallpaper. Even royalty was not immune: Buckingham Palace is said to have had its arsenical papers removed in 1879.

How exactly the paper hurt people was argued over for decades. One theory was that flakes and dust came off the walls, especially when papers were rubbed, brushed or peeled, and were inhaled or swallowed, something that would have been easy in a child’s room. Another held that the paper gave off a poisonous gas. Visitors to damp green rooms sometimes noticed a garlic smell, a sign of volatile arsenic compounds. In 1893 the Italian physician Bartolomeo Gosio showed that molds growing on arsenical materials could produce a garlicky gas, which was later identified as trimethylarsine and came to be known as Gosio gas.

For much of the 20th century, Gosio gas was the standard explanation for wallpaper poisoning. Modern toxicologists are more skeptical. In a 2005 paper titled “The toxicity of trimethylarsine: an urban myth,” the Canadian chemist William Cullen argued that the gas is far less toxic than once assumed and probably could not have been produced in dangerous amounts. Dust is now seen as the likelier route. Either way, the arsenic was real, and people living for years in green rooms were exposed to it.

In the United States, Kedzie went further than anyone in making the danger visible. In 1874 he published Shadows from the Walls of Death, a book that was mostly wallpaper. It held 86 real samples of arsenical papers collected in Michigan, bound in heavy volumes, with a short warning introduction. One hundred copies went out to libraries. Because the books were themselves poisonous, nearly all were later destroyed, and only a handful survive. The National Library of Medicine has digitized its copy, so you can leaf through the deadly samples online without touching them.

The designer and the mine

No figure sums up the contradictions of the arsenic green better than William Morris, the designer, poet and socialist who did more than anyone to shape Victorian taste in wallpaper. His first paper, Trellis, designed in 1862 and produced from 1864, is a charming tangle of roses, birds and wooden lattice. Some of its early printings contained arsenical green.

Morris was also tied to the source. His family’s wealth came largely from shares in Devon Great Consols, a copper mine in the west of England that turned into one of the largest arsenic producers in the world. Morris himself was a major shareholder, and dividends from the mine helped underwrite his firm in its early years.

In 1885, brushing aside the growing alarm about arsenical papers, he wrote that the doctors had been “bitten by witch fever,” a phrase the historian Lucinda Hawksley later took for the title of her book on the subject. His reasoning was simple: nobody in his own house had fallen ill. Many people with green walls never did. But the evidence of harm was already strong, and his firm did move to arsenic-free colors. Accounts differ on exactly when, with dates from the 1870s to around 1880 given by different sources.

What about Napoleon?

The most famous suspected victim of a green room is Napoleon Bonaparte, who died in exile on St Helena in 1821 at Longwood House, a damp, mold-prone building in a windswept part of the island. Analyses of his hair in the 20th century found high levels of arsenic, and some writers argued he had been deliberately poisoned.

Then a surviving fragment of wallpaper said to come from Longwood was analyzed, with results published in Nature in 1982. Its green pattern contained arsenic. The X-ray analysis suggested there was enough to be capable of causing illness, but probably not death. In damp conditions, molds acting on the paper might have added to the exposure.

A 2008 study by Italian researchers complicated the story further. They measured arsenic in hair samples taken from Napoleon as a boy in Corsica, during his exile on Elba, on the day he died and the day after, and in samples from his son and his first wife, Joséphine. All of them had high levels, and Napoleon’s did not change much over his lifetime. The average in his hair was about 10 parts per million, and all the 200-year-old samples were roughly 100 times higher than modern averages. People of that era, the authors suggested, simply lived with far more arsenic in their environment. The official cause of Napoleon’s death, stomach cancer, still stands as the most widely accepted explanation.

How the fashion faded

Britain never passed a law banning arsenic in wallpaper. What ended the craze was a mix of publicity, medical pressure and the market. Some manufacturers saw the opportunity early. William Woollams and Co. stopped making arsenical wallpapers as early as 1859 and kept advertising the fact for decades, with ads like the one above promising papers “guaranteed free from arsenic.”

Fashion was shifting too. By the 1880s the brilliant green had come to look gaudy and slightly sinister, and tastes turned to softer, more muted colors. Safer greens took over: viridian, a stable chromium oxide pigment, and in the 20th century phthalocyanine green. By 1900, a Home Office report could declare British wallpaper “practically” free of arsenic. Cases of wallpaper poisoning, already rare by the 1890s, faded away.

A second life in the fields

The same property that made the pigment dangerous in a bedroom made it valuable on a farm. In the 1860s, the Colorado potato beetle was eating its way east across American potato fields, and farmers found that Paris green killed it. By the 1880s, Paris green had become the first widely used chemical insecticide in the world. It was dusted on orchards and vineyards, and was joined in the 1890s by lead arsenate, another arsenical spray.

It also went to war on malaria. Paris green kills mosquito larvae, and in the first half of the 20th century public health workers spread it on swamps and ponds. The 1943 U.S. Public Health Service poster above, with its complaining wrigglers, comes from the wartime push against malaria in the United States. Arsenical pesticides were gradually replaced by newer chemicals, and in the United States, registrations for Paris green and its relatives were eventually cancelled.

Not all of that arsenic went away. Old orchards, cattle dips and spray sites still carry it in the soil, and many of the problems with arsenic today come from nature rather than paint. The World Health Organization estimates that at least 140 million people in at least 70 countries drink water containing arsenic above its guideline of 10 micrograms per liter, mostly from natural deposits in groundwater. Chronic exposure is linked to skin lesions, cancers and heart disease. Like the hidden hazards in common household chemicals, it is a reminder that what is in our homes and taps is not always what it seems.

The poison book on your shelf

Which brings us back to the libraries. In early 2019, analysis of 19th-century cloth bindings at the Winterthur Library in Delaware turned up bookcloth colored with emerald green, and the Poison Book Project was born. Using X-ray fluorescence and Raman spectroscopy, the team and its partners have since tested many more 19th-century books. In their early survey, 39 green cloth bindings tested positive for arsenic. Most were British or American bindings from the 1840s to the 1860s, the height of the emerald green fashion.

The pigment on bookcloth turned out to be very friable, meaning it rubs off easily, and the project found measurable amounts of arsenic transferred by handling. It now maintains a public list of known emerald green books and recommends sensible precautions: store suspect books in sealed bags, handle them with nitrile gloves, keep them away from food and children, and wash your hands afterward. The color is distinctive. If you own a Victorian book with a bright, slightly yellow green cloth cover, it is worth a closer look.

That is roughly what Bielefeld concluded too. The risk from an old green book is real but small, and it is managed with gloves and common sense rather than panic. The deeper lesson is about how easily a society can fall in love with something dangerous when it is cheap, beautiful and everywhere. In the 1860s the most fashionable green in the world lived on walls, in sweets and in ballrooms. It took decades of dead children, sick workers and stubborn chemists before people looked at that lovely color and saw what was in it.

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