Introduction
Paris green was a popular green pigment and pesticide used in the 19th and early 20th centuries. However, it was eventually banned due to its high toxicity to humans and the environment. Paris green contains arsenic and was used both as a pesticide to kill rats and insects, as well as a pigment for paintings, fabrics, wallpaper, and even children’s toys. While effective, Paris green was extremely poisonous and led to many cases of accidental and intentional poisoning. This ultimately led to its ban for most uses by the early 20th century.
What is Paris Green?
Paris green is an inorganic compound known by the chemical formula Cu(C2H3O2)2·3Cu(AsO2)2. It is a highly toxic emerald green pigment containing arsenic. Paris green’s vivid color and insecticidal properties made it a popular pigment and pesticide in the 18th and 19th centuries. It was commonly used in paints, fabrics, wallpapers, and other materials across Europe and North America.
Paris green pigment was created by combining copper(II) acetate and arsenic trioxide. The pigment gets its color from the copper, while the arsenic provides insecticidal properties. First developed in the 1810s, Paris green offered a durable, inexpensive green pigment at a time when vivid green dyes were hard to produce. It became widely used during the Victorian era and remained popular into the early 1900s.
In addition to being used as a pigment, Paris green was utilized as an agricultural insecticide to protect crops against pests. When insects consumed foliage or fruits treated with Paris green, the arsenic would eliminate the pests. Farmers found it to be an effective means of protecting important cash crops like cotton, fruit, rice, and more. The arsenic in Paris green disrupts cellular metabolism, leading to the death of the insects.
Early Uses of Paris Green
Paris green first came into use in 1814, when it was synthesized by a French chemist. It offered a bright, affordable green pigment during a time when vivid green dyes were scarce. By the 1820s, Paris green became widely produced and used across Europe and North America.
As a pigment, Paris green was commonly applied in oil paints, watercolors, fabrics, leather goods, wallpapers, and other decorative materials. Its vivid emerald green color and low cost made it an ideal choice for manufacturers of textiles, leather, wallpaper, toys, and more. Many of these items were exported globally, spreading the use of Paris green pigments around the world.
By the 1850s, Paris green also became a popular pesticide, especially in agriculture. Farmers would coat seeds or spray plant leaves with Paris green to eliminate insects eating their crops. It was inexpensive and thought to be safe and effective. Paris green protected important food crops like fruits, vegetables, cotton, tobacco, rice and more.
The pesticide application created a new global demand for Paris green. It was used to protect agriculture not just in Western countries, but throughout European colonies in Asia, Africa, and Latin America.
Toxicity of Paris Green
Although Paris green was abundant, its arsenic content made it highly toxic and dangerous. The first documented case of Paris green poisoning was in 1851. As its usage as a pesticide spread in agriculture, accidental and intentional poisonings became more common.
When ingested in significant quantities, Paris green causes vomiting, abdominal pain, diarrhea, and a burning sensation in the mouth and throat. Arsenic disrupts cellular metabolism, leading to cell death and organ failure at high doses. Lethal oral doses of Paris green can lead to death in 10-30 hours. Long-term low level exposure can also lead to nervous system damage, skin lesions, and cancer.
In addition to direct ingestion, Paris green is also toxic through absorption and inhalation. It easily rubs off of textiles, wallpapers, and other household items, exposing people through touch. The arsenic content also makes fumes from Paris green pigments and pesticides hazardous to breathe.
By the late 19th century, many thousands of accidental poisonings were attributed to Paris green in wallpapers, clothing, toys, and food contaminated with the pesticide. Intentional poisonings using Paris green also occurred, since it was easy to acquire in many common household products.
Paris Green Banned as a Pigment
In the 1890s, doctors began raising concerns about the health hazards of Paris green pigments and dyes in common household products. Wallpapers and textiles colored with Paris green were found to rub off on people’s hands and poison those who handled them. In 1893, the German government studied the toxic risks of Paris green and banned its use as a pigment. Other European nations followed suit shortly after.
France banned the use of Paris green in paints and lacquers in 1909. Britain banned Paris green in all wallpapers and fabrics in 1964. Most Western countries had prohibited virtually all decorative uses of Paris green pigments by the 1920s and 30s. However, some limited textile dyeing uses continued until the 1960s.
Alternatives like chrome green, malachite green, and verdigris were adopted to replace Paris green in paints, fabrics, and other materials. These pigments provided a similar vibrant green color without the same level of toxicity hazards.
Paris Green Banned as a Pesticide
While Paris green was banned for decorative uses early on, it continued to be used as an agricultural pesticide into the 20th century. Farmers depended on Paris green to control pests and protect important crops. Alternatives like DDT were not available until after World War 2. Despite the known hazards of Paris green, its effectiveness as a pesticide made governments reluctant to restrict its use.
However, concerns over food safety and occupational hazards eventually led to bans on using Paris green in agriculture. Denmark, Sweden, and France prohibited Paris green’s pesticide use between 1905-1919. The United States did not act until 1968, when Paris green was federally banned as a pesticide. Most other Western countries phased out all agricultural applications by the 1970s and 80s.
Bans often came in response to new safer pesticide alternatives, rising chemical environmentalism, and growing awareness of the long-term toxicity of arsenic. While incredibly effective in the short term, Paris green left dangerous arsenic residue on crops and soil, increasingly seen as unacceptable.
Legacy of Paris Green
While Paris green has been banned for over 50 years now, its legacy remains complex. It offered a cheap, vivid green pigment that democratized access to colorful dyes and paints. It enabled farmers to protect valuable crops from agricultural pests. However, these applications came at a terrible cost to human and environmental health.
Widespread use of Paris green over decades led to many thousands of deaths and illnesses. Those most affected were often vulnerable textile workers, agricultural laborers, and children in households decorated with Paris green wallpapers and fabrics. Its liberal use as a pesticide also left arsenic contamination in agricultural lands that still persists today.
Paris green exemplifies the double-edged nature of many pesticides and pigments historically used before their long-term toxicity was understood. The arsenic content that made Paris green effective also led to immense health costs that took decades to curtail through bans and restrictions. While Paris green is now obsolete, its history provides an important lesson on the need to balance chemical effectiveness with human and environmental safety.
Conclusion
Paris green was a highly toxic pigment and pesticide that was eventually banned worldwide by the 1960s-1970s. Its effectiveness came from arsenic trioxide, which gave it a vivid green color and made it poisonous to insects. Paris green was widely used in paints, fabrics, wallpapers and as an agricultural pesticide in the 19th and early 20th centuries.
However, thousands of accidental and intentional poisonings led to growing awareness of the severe toxicity of Paris green to humans through ingestion, absorption and inhalation. Its arsenic content could cause organ failure and death at high doses. Concerns over food safety and occupational exposure led France, Germany, and other countries to prohibit its use as a pigment in the late 1800s. Agricultural applications continued until safer pesticide alternatives appeared mid-century.
While important historically, Paris green caused many deaths and illnesses before its toxicity was recognized. Its history provides an important lesson on ensuring chemicals used in consumer and agricultural products balance effectiveness with long-term safety.
