How did Atlantic slavery stimulate British industry? This article answers that question through a study of five firms that supplied gunpowder to the slave trade. It first demonstrates that the Atlantic slavery trade certainly expanded Britain's explosives industry during the eighteenth century. British merchant capitalists established five plants in the proximity of Bristol and Liverpool to meet African demand, provincializing the gunpowder industry for the first time. The slave trade also inflated the gunpowder industry's volume, with twelve percent of all powder going to Africa before abolition. This article next reveals that supplying the slave trade was likely a lucrative pursuit for British manufacturers, with investors in the five mills earning profits that exceeded those of slaving. The boost given to the explosives industry faded considerably as abolition neared, however, and so this article concludes that Atlantic slavery's stimulus was likely of limited importance for driving the later Industrial Revolution.