In our modern society, we seldom deem books as perilous articles. However, specific books encompass elements so perilous that they necessitate examination before placement in public libraries, bookstores, or private residences.
The Poisonous Book Project, a collaborative endeavor between Winterthur Museum, Garden & Library and the University of Delaware, is dedicated to documenting such books. Their focus lies not on the content inscribed on the pages but on the physical constituents of the books themselves – particularly, the hues of the covers.
The project recently influenced the removal of two books from the French national library due to suspicions arising from their vibrant green cloth covers, hinting at possible arsenic content.
This concern traces back to historical bookbinding practices. During the 19th century, as books underwent mass production, bookbinders shifted from employing expensive leather covers to more economical cloth alternatives. To attract readers, these cloth covers were often dyed in striking, eye-catching colors.
One prevalent pigment was Scheele’s green, named after Carl Wilhelm Scheele, a German-Swedish chemist who discovered in 1775 that a vivid green pigment could be derived from copper and arsenic. This dye was not only inexpensive to produce but also exhibited greater vibrancy than the copper carbonate greens used for over a century.
Scheele green eventually fell out of favor due to its propensity to fade to black upon reacting with sulphur-based pollutants emitted from coal. However, new dyes based on Scheele’s discovery, such as emerald and Paris green, proved more enduring and were swiftly adopted for use in various items, including book covers, clothing, candles, and wallpaper.
Nevertheless, these pigments posed a significant drawback: they degraded easily, releasing toxic and carcinogenic arsenic. Frequent reports of green candles poisoning children at Christmas gatherings, factory workers painting ornaments experiencing convulsions and vomiting green fluids, and warnings of poisonous ball gowns raised serious safety concerns regarding these green dyes.
This issue became so notorious that in 1862, the satirical magazine Punch published a cartoon titled “The Arsenic Waltz,” depicting skeletons dancing – a grim commentary on the lethal fashion trend.
The deleterious effects of these pigments have even been implicated in Napoleon’s death from stomach cancer. Napoleon harbored a particular fondness for the new green hues, to the extent that he ordered his dwelling on St Helena, where he was exiled, to be painted in his favorite color.
The notion that the arsenic in the walls contributed to his demise is supported by the elevated levels of arsenic detected in samples of his hair. Despite the clear association between the green pigments and health issues, toxic wallpapers continued to be produced until the late 19th century.
However, green is not the sole color of concern. Red also warrants attention. The brilliant red pigment vermilion, derived from the mineral cinnabar or mercury sulfide, was a popular red paint source dating back millennia. There is even evidence suggesting that Neolithic artists suffered from mercury poisoning. Vermilion red sometimes appears in the marbled patterns inside book covers.
Yellow has also captured the attention of the Poisonous Book Project. In this instance, the culprit is lead chromate. The vivid yellow of lead chromate was favored by painters, including Vincent van Gogh, who extensively used it in his renowned series of paintings, Sunflowers. For Victorian-era bookbinders, lead chromate enabled the creation of a spectrum of colors, from greens (achieved by mixing chrome yellow with Prussian blue) to yellows, oranges, and browns.
Both lead and chromium are toxic. Nonetheless, yellow books pose less concern than green and red ones. Lead chromate is relatively insoluble, making absorption difficult. In fact, it remains a widely used pigment.
So, what should one do upon encountering a 19th-century green cloth book? Initially, there’s no need for undue alarm. You’d likely need to consume the entire book before experiencing severe arsenic poisoning. Nevertheless, casual exposure to copper acetoarsenite, the compound in the green pigment, can irritate the eyes, nose, and throat.
It poses more concern for individuals who regularly handle such books, where frequent contact could lead to more severe symptoms. Hence, anyone suspecting they might handle a Victorian-era book with an emerald green binding is advised to wear gloves and refrain from touching their face. Subsequently, all surfaces should be cleaned.
To aid in the identification of these potentially hazardous books, the Poisonous Book Project has integrated crowd-sourced data into their research. They now distribute bookmarks featuring safety warnings and showcasing various shades of emerald green to facilitate identification. Consequently, they have identified over 238 arsenic editions worldwide.
Mark Lorch, Professor of Science Communication and Chemistry, University of Hull
