In the first few days after BP's Deepwater Horizon wellhead exploded, spewing crude oil into the Gulf of Mexico, cleanup workers could be seen on Louisiana beaches wearing scarlet pants and white t-shirts with the words "Inmate Labor" printed in large red block letters. Coastal residents, many of whom had just seen their livelihoods disappear, expressed outrage at community meetings; why should BP be using cheap or free prison labor when so many people were desperate for work? The outfits disappeared overnight.

Work crews in Grand Isle, Louisiana, still stand out. In a region where nine out of ten residents are white, the cleanup workers are almost exclusively African-American men. The racialized nature of the cleanup is so conspicuous that Ben Jealous, the president of the NAACP, sent a public letter to BP CEO Tony Hayward on July 9, demanding to know why black people were over-represented in "the most physically difficult, lowest paying jobs, with the most significant exposure to toxins."

Hiring prison labor is more than a way for BP to save money while cleaning up the biggest oil spill in history. By tapping into the inmate workforce, the company and its subcontractors get workers who are not only cheap but easily silenced—and they get lucrative tax write-offs in the process.

Known to some as "the inmate state," Louisiana has the highest rate of incarceration of any other state in the country. Seventy percent of its 39,000 inmates are African-American men. The Louisiana Department of Corrections (DOC) only has beds for half that many prisoners, so 20,000 inmates live in parish jails, privately run contract facilities and for-profit work release centers. Prisons and parish jails provide free daily labor to the state and private companies like BP, while also operating their own factories and farms, where inmates earn between zero and forty cents an hour. Obedient inmates, or "trustees," become eligible for work release in the last three years of their sentences. This means they can be a part of a market-rate, daily labor force that works for private companies outside the prison gates. The advantage for trustees is that they get to keep a portion of their earnings, redeemable upon release. The advantage for private companies is that trustees are covered under Work Opportunity Tax Credit, a holdover from Bush's Welfare to Work legislation that rewards private-sector employers for hiring risky "target groups." Businesses earn a tax credit of $2,400 for every work release inmate they hire. On top of that, they can earn back up to 40 percent of the wages they pay annually to "target group workers."

If BP's use of prison labor remains an open secret on the Gulf Coast, no one in an official capacity is saying so. At the Grand Isle base camp in early June, I called BP's Public Information line, and visited representatives for the Coast Guard Public Relations team, the Department of Homeland Security, and the Louisiana Fisheries and Wildlife Department. They were all stumped. Were inmates doing shore protection or oil cleanup work? They had no idea. In fact, they said, they'd like to know—would I call them if I found out?

I got an answer one evening earlier this month, when I drove up the gravel driveway of the Lafourche Parish Work Release Center jail, just off Highway 90, halfway between New Orleans and Houma. Men were returning from a long day of shoveling oil-soaked sand into black trash bags in the sweltering heat. Wearing BP shirts, jeans and rubber boots (nothing identifying them as inmates), they arrived back at the jail in unmarked white vans, looking dog tired.

Beach cleanup is a Sisyphean task. Shorelines cleaned during the day become newly soaked with oil and dispersant overnight, so crews shovel up the same beaches again and again. Workers wear protective chin-to-boot coveralls (made out of high-density polyethylene and manufactured by Dupont), taped to steel-toed boots covered in yellow plastic. They work twenty minutes on, forty minutes off, as per Occupational Safety and Health Administration safety rules. The limited physical schedule allows workers to recover from the blazing sun and the oppressive heat that builds up inside their impermeable suits.

During their breaks, workers unzip the coveralls for ventilation, drink ice water from gallon thermoses and sit under white fabric tents. They start at 6 AM, take a half-hour lunch and end the day at 6PM, adding up three to four hours of hard physical labor in twenty-minute increments. They are forbidden to speak to the public or the media by BP's now-notorious gag rule. At the end of the day, coveralls are stripped off and thrown in dumpsters, alongside oil-soaked booms and trash bags full of contaminated sand. The dumpsters are emptied into local HazMat landfills, free employees go home and the inmates are returned to work release centers.

Work release inmates are required to work for up to twelve hours a day, six days a week, sometimes averaging seventy-two hours per week. These are long hours for performing what may arguably be the most toxic job in America. Although the dangers of mixed oil and dispersant exposure are largely unknown, the chemicals in crude oil can damage every system in the body, as well as cell structures and DNA.

Inmates can't pick and choose their work assignments and they face considerable repercussions for rejecting any job, including loss of earned "good time." The warden of the Terrebonne Parish Work Release Center in Houma explains: "If they say no to a job, they get that time that was taken off their sentence put right back on, and get sent right back to the lockup they came out of." This means that work release inmates who would rather protect their health than participate in the non-stop toxic cleanup run the risk of staying in prison longer.

Prisoners are already subject to well-documented health care deprivations while incarcerated, and are unlikely to have health insurance after release. Work release positions are covered by Worker's Compensation insurance, but pursuing claims long after exposure could be a Kafkaesque task. Besides, there is currently no system for tracking the medical impact of oil and dispersant exposure in cleanup workers or affected communities