Since they were able to prevent labor unions they could control the wages, making them as close to nothing as possible. .
In addition to the low wages, the lack of true government working place standards made the job's environment atrocious. Since the companies didn't have to meet regulations they could cutback on spending on amenities for employees. Due to this, many workers got physically injured or sick. Consequently, the worker loses his job. But that's not a problem for the packing house, there are hundreds begging to replace him on the front step. Meaning, once the worker is healthy, chances are he had already been replaced. In addition to the loss of a job, he experiences the aftermath of being bed ridden, like weakness and inability. After Jurgis came back from his broken ankle, "He was no longer the finest-looking man in the throng, and the bosses no longer made for him; he was thin and haggard, and his clothes were seedy, and he looked miserable (Sinclaur, 119)." So, he will also be unable to get a different job because he isn't as productive as the person who just immigrated and is at full strength. .
The factories knew that in order to maximum profits they needed to get maximum production out of their workers. That's why they had "pace-makers" to make sure workers followed their lead and are going at a faster than satisfactory pace. Jurgis had to look out for them in risk of losing his job, "You might easily pick out these pace-makers, for they worked under the eye of the bosses, and they worked like men possessed. This was called "speeding up the gang," and if any man could not keep up with the pace, there were hundreds outside begging to try (Sinclair, 56)." The workers were forced to work at a pace that exhausted them. After several years their overworked bodies became vulnerable to physical injury or sickness. The factories had the workers in the palm of their hands.