Manufacture of pure white lead pigment was developed in the 17th century and is called the "Dutch Process". First the dull blue-gray lead is thinly cast in the shape of large belt buckles. These lead buckles are then exposed to acid in the presence of carbon dioxide. Next, the lead buckles are stacked in ceramic pots that contain acetic acid in diluted form, usually vinegar. The stack room is filled with layers of spent, tanbark filled pots and boards. In 6-14 weeks a chemical reaction is complete. Sometimes the white lead coating the buckles grows so thick it cracks the ceramic pots.
Workers then dumped the ceramic pots onto separating tables, manually scraping and pounding the white lead carbonate from the buckles. Mechanical separators sometimes performed this task. Next, the powder is dried and then stored in wooden casks for shipment. White lead pigment was mixed with a base of linseed oil and turpentine along with other tints to create lead-based paint.
Lead pigments were known to cause serious illness and death in lead industry workers and the public as long as 100 years ago. Lead workers became ill in both the lead manufacturing process and lead paint application and removal. Painter's colic, also known as plumbism, is a toxic condition caused by elevated blood lead levels. Many lead industry workers were routinely sent for lead poisoning treatment within the early months of employment.
The House of Representatives decided in 1910 to conduct a hearing for a bill to keep lead-based paint out of American homes. Representative Marion E. Rhodes testified, "the most eminent scientists and doctors of Great Britain have reached the conclusion that white lead is poison. Small particles that result from chalking, when taken by inhalation into the lungs, are absorbed and become poison to the system." In May of 1910 another bill was introduced in the house which called for federal intervention, regulating the manufacture, sale, and use of paint containing white lead, and included a measure to require all lead-based paints to be "labeled with a skull and crossbones and the words Poison: white lead ."
Edward J. Cornish, the president of the National Lead Company, said in a letter to David Edsall, the dean of Harvard Medical School in 1921, "lead is a poison when it enters the stomach of man--whether it comes directly from the ores and mines and smelting works or from the ordinary forms of carbonate of lead, lead oxides, and sulfate and sulfide of lead."
Lead paint manufacturers admitted the dangerous nature of lead as had the entire international community. The League of Nations held the Third International Labor Conference in Geneva in 1921 where 400 delegates from 40 nations discussed lead trade regulation. The US did not attend that Conference and didn't agree to the resolution to ban lead-based paints from homes. It was not until 1977 that the federal government prohibited the use of lead paint from most residential applications. From 1910 through 1977, over 4,000 tons of lead pigments were used in homes and products throughout the United States.
References:
Cincinnati Children's Hospital Medical Center. "History of Lead Advertising".
Warren, Christian. Business History Review. "Toxic Purity: The progressive era origins of America's lead paint poisoning epidemic". Winter 1999, Vol. 73, Iss. 4.
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