Prior to the Industrial Revolution, most production took place on a very small scale. One household might grow their own food, grow fibers for cloth, weave their own cloth, and even make their own furniture. The invention of a number of industrial machines both cut down on production times and made it possible for one person to produce far more than they could ever consume. In the pre-industrial setting of household production, a person could exercise almost total control over their own labor. Of course, they had to work in accordance with the seasons and their needs, but they held far more autonomy than was later seen in a factory setting.
The transition of labor to factory settings removed people from their household unit of production and, in exchange for a wage, engaged them in highly repetitive tasks on a line of production. On a household basis, a person might be involved from start to finish in producing goods. In the factory, that same person would be doing one part of production over and over all day. Such repetitive tasks often resulted in bodily pains or illness from long periods of sitting or standing, hand-sewing, or exposure to dangerous materials.
In addition to these work-related illnesses, there was an added risk of injury in the factory setting. Early on, many people were injured while using or trying to repair machines. Children were often employed in factories because they were small enough to fit inside of delicate machinery and could be paid a lesser wage than an adult.
With so many people working in one tight, and usually poorly ventilated space, illness was a major problem in working conditions. The Industrial Revolution brought people to the city seeking work, but housing and accommodations couldn't always keep up. Many working class people lived in tiny apartments shared with other families, and during the day they would go to work in an equally crowded factory. If just one person brought an illness like the flu, cholera, or tuberculosis to work from their apartment, it could take out the entire workforce and their families.
The period immediately following the Industrial Revolution saw terrible depreciation of working conditions as spaces became more cramped, dirty, and inhospitable to human health. Over time, workers began fighting back against such poor treatment and developed labor unions. These unions fought for things like fair pay, limits on working hours, clean working conditions, safer machinery, and child labor laws. Today, most people working in an industrial setting experience a higher amount of risk than someone who has an office job, but it is leagues better than compared to the conditions during and immediately after the Revolution.