The factories around the Warrens employ a lot of unskilled labor (F-series ESP exams). Rather than investing in expensive hardware and robotic technology that costs more in the long-term due to upgrades and breakage, the companies have decided to "invest" in man-power.
One of the factory jobs that are commonly available to F-4 or F-5 involves the lubing of the various mechanical parts in the factory. Using a cobalt blue substance similar to axel grease, the employee must wait by the part until it's 90 second maintenance cycle (ever hour or so) and then slop the grease into various parts, by hand, and pull their fingers from the machine before it reactivates.
Officially there is a siren and a light that flashes at the 10 second warning but they're not always accurate. Those who work in this "profession" will commonly have their hands turn blue from the cobalt grease. Another side-effect is that the substance will cause callous growth on the hands so much so that they're almost stiff as leather and almost numb to minor damage.
Those who do this kind of work will commonly hide their hands in public for fear that they'll be spotted by others - a sign that they couldn't get any other job than "Factory Fodder".