At two in the morning on July 9, 1937, a heavily fortified concrete and brick film vault in the quiet residential neighborhood of Little Ferry, New Jersey, erupted in horizontal sheets of flame a hundred feet long. This episode reconstructs the Fox vault fire, an event that killed a 13-year-old boy, set five homes ablaze, and incinerated more than 75 percent of 20th Century Fox's feature films made before 1930.

The conversation explains the chemistry of nitrate film, from hydrolysis and nitrogen oxide off-gassing to spontaneous combustion at temperatures around 100 degrees Fahrenheit, and the long trail of earlier disasters including the 1897 Paris bazaar fire and the loss of Thomas Edison's laboratory. It examines contractor William Fehrs' 48-compartment fortress built without ventilation, sprinklers, or a night guard, the July heat wave t ...