After slavery ended, Southern states arrested Black people under Black Codes and vagrancy laws for offenses like loitering or changing employers. States then leased those people to plantations, coal mines, railroads, brickyards and turpentine camps. Companies paid the state, and the state collected the money. The companies had little reason to keep workers alive, and death rates were high.
The journalist Douglas Blackmon documented the system in Slavery by Another Name, which won the 2009 Pulitzer Prize. In 2018, construction workers in Sugar Land, Texas, found the remains of 95 people believed to be leased convicts who died between 1878 and 1911.
Convict leasing was replaced by state chain gangs and prison farms, some of which were built on former plantations. The same punishment exception still allows incarcerated people to be required to work for little or no pay, which is why prison labor remains a civil rights issue.