In September, after months of organizing via smuggled cellphones and outside go-betweens, prisoners across the country launched a nationwide strike to demand better working conditions at the numerous facilities that employ inmate labor for little or no pay.

The strike, which spread to dozens of institutions in 22 states, briefly called attention to a fact about prison labor that is well-understood in America’s penal institutions but scarcely known to the general public: Inmates in America’s state prisons — who make everything from license plates to college diploma covers — are not only excluded from the U.S. Constitution’s prohibition on slave labor, but also exist largely outside the reach of federal safety regulations meant to ensure that Americans are not injured or killed on the job. Excluded from the U.S. Occupational Safety and Health Administration’s mandate of protecting American workers, these inmates lack some of the most basic labor protections other workers take for granted.

This vacuum of oversight causes the labor performed behind prison walls to be doubly invisible because it excludes inmates from federal record-keeping rules requiring non-prison employers to report serious job-site injuries to the federal government.

Yet injury logs generated by the California Prison Industry Authority (CALPIA) — the agency in charge of overseeing the prison work programs in the country’s second largest prison system — provide a rare window into the varied dangers that face inmate laborers. Since 2012, inmates in California have reported more than 600 injuries while working for as little as a 35 cents an hour, according to the documents obtained by The Intercept. The logs contain a wide range of job-site harms, from fingers being smashed in steel molds or sucked under sewing machine needles to less serious maladies like carpel tunnel syndrome and other common overuse conditions.

In some severe cases, inmates’ appendages were amputated after being crushed or severed in machinery. “[The inmate’s] sleeve became caught in gear and pulled hand into assembly,” one log reads, “resulting in amputation of r. hand.”

California generally pays its some 7,000 inmate workers between 35 and 95 cents an hour for their labor, and it is unclear whether any of the inmates listed as having lost appendages while working in California prisons have yet received any compensation for the amputations. A CALPIA spokesperson told The Intercept that the state had provided each of the inmate amputees with workers’ compensation forms, but the injured prisoners could take no action to pursue their claims until released from prison. California state law prohibits inmates from receiving workers’ compensation while still incarcerated, meaning that inmates serving life without parole sentences would never be entitled to a penny of compensation even for losing limbs on the job.

A common theme running among throughout the logs is the potential for many of the injuries to have been averted. “I did not really see anything in here that wouldn’t have been preventable,” said Linda Delp, the director of University of California Los Angeles’s Labor Occupational Safety and Health program, who reviewed the injury logs. Delp said that entries in the CALPIA logs conform to patterns she has seen on non-prison worksites where there is too little training of workers or where the employees are impelled to cut corners because management is requiring too much work to be done in too little time — or both.

A variety of recurring and preventable injury-types caught Delp’s attention. For instance, repeated entries describe objects becoming lodged in inmates’ eyes while they use industrial grinders. A possible solution, according to Delp, would be to ensure that inmate workers wear appropriate safety goggles or visors and have adequate training. Many other logs involve workers losing control of unwieldy objects, which then fall on workers, causing injuries in which body parts are strained, crushed, or lacerated. A solution to this, said Delp, would be to make sure inmates have enough help lifting and maneuvering heavy objects. There are also recurring cases where workers’ fingers become stitched through under sewing machine needles, or have their hands pulled into moving parts on sanders or other machinery — all of which could be prevented by proper machine guarding mechanisms and training, Delp said.

“In looking at these,” Delp said, “there’s something going on in terms of not providing the training and equipment that they need.”

Michele Kane, a CALPIA spokesperson told The Intercept that the office reports all inmate injuries to the state’s department of labor. “They implement and enforce safety regulations over all employers in California,” Kane said, “including state agencies such as CALPIA.”  In response to questions from The Intercept regarding the potential preventability of injuries, a CALPIA spokesperson assigned workers responsibility for their injuries. “In spite of training and proper safety equipment provided by CALPIA,” Kane said in a statement, “there are times when inmates violate training protocols.”

While Delp cannot say anything for certain about CALPIA management practices by reviewing the logs alone, she took notice of the agency’s tendency to blame workers for their injuries.

“I always look for how these things are described and whether individual workers are blamed for what happened,” Delp said. “What’s fairly common across different types of jobs is for management to look the other way when people are breaking the safety rules because they want them to work faster, until someone gets hurt. And then that person is blamed for not following the safety rules.”

A typical example of CALPIA’s allocation of blame appears in one of the several logs that describe an incident resulting in an inmate suffering an amputation, in this case, a finger in garment machinery at the California Men’s Colony prison in San Luis Obispo County in April 2014. “While inmate was cutting fabric, inmate removed his glove to adjust machine, and failed to put his glove back prior to operating the machine,” the log reads, adding no additional information other aside from its result: amputation of “Finger(s)/Thumb(s).”

Top photo: James Dickert, age 68, sews socks together in a prison factory at California Men’s Colony prison on December 19, 2013 in San Luis Obispo, California.