Sorry, sorry... that was sarcasm. It was mostly slavery of orphans, guised as trade-skills. As well as the cancers, they also had hellish injury/death, because ya know... 7 year olds are climbing chimneys

"Put their feet to the fire"... sometimes kids were too afraid to keep climbing, so they lit a fire under them. Sometimes, they became too grown and got stuck in the chimney, possibly dying. Hellish