Many barons used slave labour for their mines, salvage operations and so forth.
This has created a new breed of slavers in the Deathlands that has not been seen since the sixteen and seventeen hundreds. It was a cheap and effective way to get work done for the Barons, as all they need to do is provide shelter (and usually it's barley adequate), and enough food to survive. Those who die can easily be replaced. Some of the most notorious slavers were the Scalies in New York city who were constantly capturing people to work in their salvage operations, and Major Commissar Zimyanin who used the Gateways to scour the land for new 'recruits' for his Sulphur mine.