The air in the cotton mills had to be kept hot and humid (65 to 80 degrees) to prevent the thread breaking. The air in the mill was thick with cotton dust which could lead to byssinosis - a lung disease, which could kill, though luckily mainly led to chronic coughing & wheezing & breathing difficulties. Eye inflammation, deafness, tuberculosis, cancer of the mouth where common conditions caused by the work. Cancer of the scrotum (mule-spinners cancer) could also be attributed to the mineral oils used to grease the cotton spinning machines, which would spray out & cover workers clothing at groin height in carcinogenic oil. Children were often employed as they were cheaper, small & considered to have more nimble fingers to replace spindles. Note machines did not stop to replace full spindles & it would have to be done while the machine was still going. Children as young as 7 or 8 would often work doffing (removing spindles) & spinning.
https://regencyredingote.wordpress.com/2013/08/23/the-rise-of-the-paper-hats/