If you are killed or injured on the job then isn't the employer liable? Maybe I'm naive but why is OSHA necessary at that point? Are they not liable enough (is the payout for wrongful death too low)?
With OSHA regulations there is much less wiggle room. "They weren't using trench boxes, as required..." leaves much less room for debate.
Sometimes it takes a powerful organization to get redress from another powerful organization.
Typical tactics involve settling for whatever maximizes the $/hour the lawyer earns (e.g., they might take a low-ball settlement the first week instead of spending months on discovery to get to trial), and having fine print in the contract saying you have to pay for expenses regardless of the case outcome (and then racking up all sorts of expenses on your behalf, and perhaps settling for a value so low your cut doesn't cover the bills).
This is probably part of the reason bigger firms are often more compliant, also that executives are more exposed to personal liability as the number of workers grows, all else equal.
You would get no compensation.