Lead may sit in modern bodies at levels up to a hundred times higher than in pre industrial people, and Beethoven’s suffering is linked in this episode to cheap wine laced with it. The episode explains how the metal works as a systemic toxin: acute doses bring colic, shock, and burst red blood cells, while chronic exposure stiffens and scars blood vessels and kidneys, causes the blue Burton line on the gums, and brings saturnine gout. Because lead mimics calcium and iron, the body stores it in bone, and pregnancy can release it into the blood and across the placenta. Children absorb four to five times more than adults, and lead strips myelin in the developing brain.

Humans began using lead in Anatolia around 6500 BC, and Romans lined aqueducts with it and boiled grape juice in lead pots to make sweet sapa. A January 2025 study of Greenland ice cores tied Pax Romana lead pollution to measurable cognitive decline. In the 1920s Thomas Midgley Jr. and General Motors chose patentable tetraethyl lead over ethanol to stop engine knock. Today the burden falls hardest on the Global South, with a 2019 cost estimated at $6.0 trillion.

• An estimated 5.5 million cardiovascular deaths worldwide in 2019 were attributed to lead
• The CDC reference level for children is 3.5 micrograms per deciliter, and the episode stresses there is no known safe level
• Devonshire colic traced by Sir George Baker to lead in cider presses
• Midgley poured tetraethyl lead on his hands at a press conference while himself suffering from lead poisoning
• Lead chromate coating turmeric in Bangladesh and backyard battery recycling, among exposures for an estimated 800 million children