In October 1858, a market seller known as Humbug Billy sold discounted peppermint lozenges in Bradford, England. They had been accidentally made with arsenic instead of the cheap plaster filler called daft. About 20 people died, mostly children, and around 200 more were seriously sickened in one of the most shocking food disasters of the Victorian era.

This episode explains the world of food adulteration that made the tragedy possible, from chalk and plaster in bread to toxic colorants. It follows the chain of mistakes: identical barrels in a pharmacy attic, an untrained assistant, warning signs ignored in the candy kitchen, an initial misdiagnosis as cholera, and a trial that convicted no one.

• Why a price gap between sugar and cheap substitute powders made adulteration standard practice
• How the Arsenic Act of 1851 regulated buyers but not the shopkeepers who sold arsenic
• The warning signs, including odd texture, dark color, and vomiting, that the makers and seller explained away
• How police linked the deaths to the lozenges and warned the city through pubs, town criers, and printed notices
• How the disaster pushed forward the 1860 adulteration act and the Pharmacy Act of 1868