Today marks one year since the largest prison labour strike in US history. More than

24,000 prisoners across 29 prisons in 12 states protested against inhumane conditions, timing it around the anniversary of the Attica Prison uprising, a prisoner strike now 46 years old.

That violent uprising originated from prisoners rebelling against overcrowded cells, unsanitary conditions, medical neglect and abuse. From Attica to the strike led by the Incarcerated Workers Organizing Committee last year, these protests draw attention to an ugly truth: Prisoner abuse runs rampant and it has extended into modern-day versions of slavery. Last year's strike organisers described slavery-like conditions in prisons in the nationwide call to action.

Slavery persists by another name today. Young men and women of colour toil away in 21st-century fields, sow in hand. And Corporate America is cracking the whip.

Influenced by enormous corporate lobbying, the United States Congress enacted the Prison Industry Enhancement Certification Program in 1979 which permitted US companies to use prison labour. Coupled with the drastic increase in the prison population during this period, profits for participating companies and revenue for the government and its private contractors soared. The Federal Bureau of Prisons now runs a programme called Federal Prison Industries (UNICOR) that pays inmates under one dollar an hour. The programme generated $500m in sales in 2016 with little of that cash being passed down to prison workers. Stateside, where much of the US addiction to mass incarceration lies, is no different. California's prison labour programme is expected to produce some $232m in sales in 2017.

These exploited labourers are disproportionately African American and Latino - a demographic status quo resulting from the draconian sentencing and other criminal justice policies ransacking minority communities across the United States. African Americans are incarcerated at a rate five times higher than that of whites. In states like Virginia and Oklahoma, one in every 14 or 15 African American men are put in prison.

We lock people of colour up at alarming rates. We put them to work. Corporations gain. This story is an age-old American tradition. Throughout history, our nation has successfully pulled back corporate greed, but private corporations have always found new ways to reap enormous wealth from cheap labour.

The historical circumstances following the abolition of slavery provide the necessary context to understand how corporations function in a de facto replacement for slavery. Although the US Constitution's Thirteenth Amendment prohibited slavery and involuntary servitude, it made an exception - a loophole for "punishment for crime whereof the party shall have been duly convicted", which made prison labour possible.

Workers flipping burgers and frying french fries for minimum wage at McDonald's wear uniforms that were manufactured by prison labourers.

Following the Civil War, the Southern economy was in shambles and the slaves were emancipated. A cheap labour source was needed, and the convict lease system was invented. States leased out their convicts to industrialists and planters to work in locations such as railroads, coal mines and plantations, and entrepreneurs bought and sold these leases.

With little capital investment required and no need to care for the health of the prisoners, the system of economic exploitation became highly profitable for businesses and states and even cheaper than slavery. For example, in 1883 convict leasing provided Alabama with 10 percent of its revenue, 73 percent in 1898. Leased convicts were treated abysmally, with death rates 10 times higher than prisoners in states that did not employ leased convict labour. Secret graveyards contained the bodies of prisoners who had been tortured and beaten to death.

The viability of the convict lease system required that black people be returned to their former status as a source of labour. Hence, the Black Codes were enacted to suppress the rights of the recently emancipated African Americans, and criminalise them for minor offences such as vagrancy. Under the vagrancy laws, any black person under the protection of a white person could be swept up by the system for simply loitering, as black people were rounded up in this manner to provide a source of nearly free labour.

Today, prison labour is a billion-dollar industry, and the corporate beneficiaries of this new slavery include some of the largest corporations and most widely known brands. For example, Walmart has purchased produce from farms, where women prisoners face bad working conditions, inadequate medical care and very low pay.

Workers flipping burgers and frying french fries for minimum wage at McDonald's wear uniforms that were manufactured by prison labourers.

Further, UNICOR manages 83 factories and more than 12,000 prison labourers who earn as little as 23 cents an hour working at call centres, manufacturing items such as military body armour, and in past years, defective combat helmets. In 2013, federal inmates made $100m worth of military uniforms.

UNICOR has also provided prison labour in the past to produce Patriot missile parts for defence contractors Raytheon and Lockheed Martin, and parts for others such as Boeing and General Dynamics.

Corporations such as Starbucks, AT&T, Target, and Nordstrom have also profited from prison labour at some point in the past as well.

Some critics oppose the characterisation of the US prison system as a slave labour camp. For example, James Kilgore argues that prison labour is infrequently used, and identifying multinational corporations that profit from it loses sight of the key issues behind mass incarceration.

Kilgore is correct in his analysis that a lack of economic opportunity coupled with draconian laws results in a perverse private incentive to drive up mass incarceration. We should enhance employment options for former inmates to reduce recidivism and integrate returning citizens back into society. However, this does not mean that corporations do not profit from prisons and prison labour today and it is obscene that this still happens.

The Trump administration reversing the Obama-era order to phase out private prisons and enacting new law-and-order policies to increase arrests and fill these prisons will only increase opportunities for profit for Trump's corporate donors and their many investments in mass incarceration. Exploiting prison labour is consistent with this troubling trend.

Over a century and a half since the abolition of slavery, the dreaded institution still lives on in another, dressed up form. Taking advantage of a constitutional loophole, corporate profiteers continue the modern-day version of the convict lease system. In the land of the free, the dollar still takes precedence over human rights, and that which can be monetised and exploited for profit will be, regardless of ethical or moral considerations.

Once again, race, criminal justice and capitalism have joined forces to deprive captive black and brown bodies of their human rights. In the age of President Donald Trump and hardliner Attorney General Jeff Sessions, the return to "law and order" and a war on drugs signals a reversal of progress the US was making untethering itself from the expansive grip of a carceral state.

The anniversary of last year's prison strike is a chilling reminder that one need not point to authoritarian regimes in distant countries to find examples of blatant labour rights violations. If you want to find slavery in the US, look no further than its penitentiaries, jails and detention centres where the consequences of being locked-up extend much farther than doing time.

Vijay Das is a Washington-based essayist and policy advocate who writes on social, economic and criminal justice issues.

David A Love is a Philadelphia-based freelance journalist and commentator, and adjunct instructor at the Rutgers University School of Communication and Information.

The views expressed in this article are the authors' own and do not necessarily reflect Al Jazeera's editorial policy.