It's not often that the head of a mining company sees jail time over safety violations.

Former Massey Energy Company CEO Don Blankenship's one-year sentence for violating mine safety standards, which was handed down Wednesday, is wholly unprecedented -- but it's yet another punch in the gut for a labor force whose safety has, historically, been an afterthought for executives and federal regulatory authorities alike.

For more than a century, the United States has crept forward -- slowly -- in its regulation of the mining industry. In 1916, the first federal child labor law made it more difficult for mines to operate with children under the age of 16. (Previously, children as young as 8 were forced to work.) It wasn't until 1941 that federal inspectors were able to enter and inspect mines for safety, and another few decades of disasters led to the Coal Act of 1969, which required annual inspections for all operations.

Despite that legislation and other safety regulations, companies can often deal with a disaster by simply adding a line to their budget. A 2014 investigation by NPR and Mine Safety and Health News found that thousands of companies with poor federal safety grades failed to pay their fines -- sometimes for up to 10 years -- and continued to operate even after a deadly incident and while owing up to millions of dollars to the government.