Cleanup at the slaughterhouse is as dangerous as it is repulsive, and the immigrants who do the work are under pressure to complete it faster than ever.

No one knew her real name. At work she was Tiffany Sisneros, until her arm got crushed in a conveyor belt. She filed for workers’ comp as Martha Solorzano, born 1966. The doctor who evaluated her wrote down her last name as Torres. We’ll call her Martha, the name her lawyer uses. Like millions of undocumented immigrants, Martha lived in the shadows. She slept by day, worked at night, shifted names as circumstances demanded, and supported her family with scraps that fell her way from the U.S. labor market. 

She worked as a cleaner on the graveyard shift at Tyson Foods Inc.’s cavernous meatpacking plant in Holcomb, Kan. Every day up to 6,000 cows clamber off 18-wheelers lined up at the facility, 200 miles west of Wichita. They’re watered, then ushered into the kill box, knocked unconscious by a bolt gun, hung upside down with their hearts still pounding, and bled to death by a slash to the jugular.

After the heads, hides, and hooves are removed, the carcasses are sawed in half, checked by U.S. Department of Agriculture inspectors, and sent down a network of conveyor belts to be butchered, boxed, and bar-coded by 3,800 workers in two shifts. The journey, from carcass to cargo ramp, takes about 40 minutes.

After 11 p.m. the procession halts, and the sanitation crews move in. The only slaughterhouse job worse than eviscerating animals is cleaning up afterward. The third-shift workers, as the cleaners are often called, wade through blood and grease and chunks of bone and flesh, racing all night to hose down the plant with disinfectants and scalding water. The stench is unbearable. Many workers retch.

It was about 3:30 a.m. on July 7, 2011, when Martha finished cleaning conveyor belt FC-3A on the main factory floor. After powering the machine back on, she realized she had forgotten to wipe down a spot where fat collects under the side rail. Such deposits, if neglected, can shut down a processing line, at considerable cost in lost output, if a USDA inspector discovers it during daily swab tests.