Thousands of prisoners around the country are launching a 19-day strike on Tuesday to protest ultra-low pay, forced labor, and otherwise poor conditions in prisons across the U.S.

The strike, which was organized by a group of incarcerated prisoner rights advocates, is planned to conclude on the 47th anniversary of the 1971 Attica prison riot in upstate New York that ended with the deaths of 29 inmates and 10 hostages. Inmates plan to refuse to work, and a smaller number plan to go on hunger strikes and conduct sit-ins. Organizers expect prisoners in at least 17 states will participate, according to Vox.

The prisoner rights advocates speaking out against what they see as exploitative labor practices have gained attention in recent weeks as thousands of California inmates were sent off to fight what has become the largest wildfire in the state’s history for just $1 an hour. These firefighters, who volunteered for a vocational training program offered by the California Department of Corrections and Rehabilitation, are often disqualified from the work after release because a required credential is denied to anyone with a criminal record.

Hundreds of thousands of prisoners are also employed in jobs outside and inside the prisons, most commonly doing work to maintain the prisons. According to the Prison Policy Initiative, the average prison worker makes around 85 cents an hour. In 2017, inmates in Alabama, Arkansas, Florida, Georgia, and Texas were not paid for most of their work. Proponents of these low-paying jobs have argued that inmates benefit from the work experience and that prisons, which are already often cash-strapped, cannot afford to pay more; opponents have argued that prisoners do need real wages to be able to buy basic necessities other than food in the prisons.

The 13th Amendment of the U.S. Constitution bans slavery and involuntary servitude, except “as punishment for crime whereof the party shall have been duly convicted.” This explicit reference to forced labor for prisoners in an amendment banning slavery has led advocates to feel justified in arguing much of the billion-dollar prison industry is reliant on slave labor. The strike is calling for a public boycott of companies, such as Victoria’s Secret, Starbucks, Microsoft, and JC Penney, that have benefited from prison labor

On top of their labor complaints, prisoners are also protesting what they describe as poor prison conditions, often arising from overcrowding and underfunding. Earlier this year, a prison riot in South Carolina that caused seven inmate deaths sparked protests by those who partially blamed understaffing for the violence.

The group organizing the protests has released a set of 10 demands, including improvements to prison conditions, an end to unpaid or underpaid labor, and an increase in rehabilitation programs. “Fundamentally, it’s a human rights issue,” the group said in a statement. “Every day prisoners are harmed due to conditions of confinement. For some of us it’s as if we are already dead. So what do we have to lose?”