12 hours a day 7 days a week, isn't that illegal to be working that much?
Depends on the trade, company/union, and state.
At my last job I was legally required to be allowed the15th day in a row off, regardless of the day of the week (eg Mon-fri are my normal work week I could take off Monday if I wished for my 15th day). I could also volunteer to work past that and often worked many weeks straight; my longest stint was 3 mo straight with only 2 days off for family occasions, if 12s were available I would have worked them.
Then I have a friend that works at a non union shop that is required the 8th straight day of work off, even if he wanted to work it he couldnt. Strangely he can volunteer for back to back shifts (16s), whereas 14s were my max.