In my 11 years at my transportation job, I've known a number of folks that have either had massive strokes, heart attacks, or have been injured to the point of permanent disability. The latter is what I worry about the most. Repetitive injury is a phrase that can't possibly exist to our "safety" management, though I also know a similar number of people that have been put on light duty, temporary disability, or even extensive surgeries related to doing the same thing day in and day out.
All that doesn't even begin to touch upon the various drug and alcohol abuse that is prevalent in my particular line of work, between hourly and management alike. These are possibly relevant to the aforementioned strokes or heart attacks.
Layoffs are rare for those I directly work with, the insurance is incredible, it's a lot of exercise, and pay is not an issue with enough seniority, so I think it boils down to poor management and demand for more production with fewer people in order to increase profits and appease shareholders. Hard work is rewarded with even more work.
But as keifermiller said, employer negligence is definitely an issue. There are plenty of ways I can be easily hurt to the point of permanent disability or even death, and they can certainly be mitigated, but that would hurt production and therefore profit.