What I find interesting on reading a thread like this is it seems to become a competition. OP asks if it's legal to work 12 hours without a break. Many of us have, and try to one up on how many shifts in a row we've had to work without a break. I wonder why we all try to justify why working 12 hours non stop is perfectly fine. Yes, it's legal, yes many of us have done it, but honestly - I think it's wrong. If a person is working 12 hours straight, I think they should be entitled to 30 minutes to grab something to eat, to take a walk, to meditate, or whatever it is that helps a person regain energy and balance in their life.
As far as labor laws go, it varries state by state and looks to get worse for the worker bee (trying to get rid of overtime and minimum wage), I think now, more than ever we need to start looking at the big picture on quality of life. Can a person work 12 hours a day, without breaks, 6 days a week??? Absolutely. But is that the kind of existence we, as a society should be striving for?