Cumulative trauma injuries may take months or even years to develop; other slaughterhouse injuries can happen in an instant. Lives are forever changed by a simple error, a wrong move, a faulty machine. Raul Lopez worked as a carpenter in Mexico, making tables, chairs, and headboards, before coming to the United States in 1995 to do construction work in Santa Fe, New Mexico. He was 20 years old at the time, and after laying concrete foundations for two years, he moved to Greeley and got a job at the Monfort Beef plant, where the pay was higher. He trimmed hides after they came up from the kill floor, cutting off the legs and heads, lifting them up with mechanical assistance, and placing the hides on a hook. It was one of the most difficult jobs in the plant. Each hide weighed about 180 pounds, and he lifted more than 300 of them every hour. He was good at his job and became a "floater," used by his supervisor to fill in for absent workers. Lopez's hands and shoulders were sore at the end of the day, but for two years and two months he suffered no injuries.

At about seven in the morning on November 22, 1999, Lopez was substituting for an absent worker, standing on a four-foot-high platform, pulling hides from a tank of water that was washing blood and dirt off them. The hides were suspended on hooks from a moving chain. The room was cold and foggy, and it was difficult to see clearly. There were problems somewhere up ahead on the line, but the chain kept moving, and Lopez felt pressure to keep up. One of his steel-mesh gloves suddenly got snagged in the chain, and it dragged him down the line toward bloody, filthy water that was three feet deep. Lopez grabbed the chain with his free hand and screamed for help. Someone ran to another room and took an extraordinary step: He shut down the line. The arm caught in the chain, Lopez's left one, was partially crushed. He lost more than three pints of blood and almost bled to death. He was rushed to a hospital in Denver, endured the first of many operations, and survived. Five months later, Lopez was still in enormous pain and heavily medicated. Nevertheless, he says, a company doctor ordered him back to work. His previous supervisor no longer worked at the plant. Lopez was told that the man had simply walked off the job and quit one day, feeling upset about the accident.

I recently visited Lopez on a lovely spring afternoon. His modest apartment is just a quarter mile down the road from the slaughterhouse. The living room is meticulously neat and clean, filled with children's toys and a large glass display case of Native American curios. Lopez now works in the nurse's office at the plant, handling files. Every day he sees how injured workers are treated-given some Tylenol and then sent back to the line-and worries that ConAgra is now planning to get rid of him. His left arm hangs shriveled and lifeless in a sling. It is a deadweight that causes severe pain in his neck and back. Lopez wants the company to pay for an experimental operation that might restore some movement to the arm. The alternative could be amputation. ConAgra will say only that it is weighing the various medical options. Lopez is 26 years old and believes his arm will work again. "Every night, I pray for this operation," he says, maintaining a polite and dignified facade. A number of times during our conversation, he suddenly gets up and leaves the room. His wife, Silvia, stays behind, sitting across from me on the couch, holding their one-year-old son in her arms. Their three-year-old daughter happily wanders in and out to the porch. Every time the front door swings open for her, a light breeze from the north brings the smell of death into the room.

"The Chain Never Stops" is available here at MotherJones.com