It seems strange to me that the framing of this is all about child labor laws--no one should have died working at any of these jobs, regardless of age--and OSHA is investigating all three incidents
And when they DO actually try to enforce, there's generally pressure from the top to "go light" and give the company a chance to amend their procedure (at least until after the next inspection) rather than charging them with manslaughter or whatever.
The number of minors employed in violation of child labor laws has increased by 37% within the last year, according to a March report by the left-leaning Economic Policy Institute in Washington. The report identified 10 states that have introduced or passed bills within the last two years that would weaken child labor standards.
Adults tend to be less reckless around dangerous equipment, yet companies are increasingly breaking the law hiring underage workers leading to these types of accidents. The article highlights the trend of these inexperienced teenagers being hired to work jobs that have danger closer than they expect, loosening child labour laws a factor among that.