Safety Knights

According to the FLSA (federal), there's no restrictions as long as you get paid accordingly and you're at least 16 years old, but always check your state requirements in case they are more stringent than the FLSA.

Heck, during major disasters (responding to hurricanes, train derailment involving hazmat, etc.), it wasn't uncommon for us to work 120-hour weeks (or more) at the fire department.

Don't know that this is really the answer that you are looking for, but we do not allow our service Team to work double time under almost any circumstances. If a job is going to take that much longer, they are going to go back a second trip. There is a point where enough is enough. It's time to pack it up, regroup, and try again tomorrow.

Again I am not sure of your exact question. My undergrad degree is actually in Personnel Adm, what we Baby Boomers and before knew as Human Resources. At the time I was an undergrad OSHA itself was only itself 2-6 years old! Yeah I am old enough to be most of your Dad's, some of you could easily call me Grandpa! As a manufacturing supervisor, most of that in the auto industry , for about 30% of my entire career I sure spent a lot of time working OT! In those days I sure worked more Saturdays then I had off, and worked many a Sunday. Plus I worked many hours covering the other shifts filling in for illness and vacation. In may auto foundry days 70 hour weeks were common! Although not required my company paid overtime to supervisors actually supervising employees. So I was paid 1.5 for all hours over 40, and Saturdays. Sundays we got X2 pay, and on Holidays we got X2 pay plus our Holiday Pay making it X3.
At the time as an undergrad I hated taking and entire class in the Federal FLSA (Fair Labor Standards Act) but as it turned out it had been one of the most useful courses I ever took! There is nothing in OSHA about OT that i know of. The only thing the FLSA says all hours WORKED over 40 for "non-exempt" workers must be paid at time and one half! Now the class talked about what a "non-exempt" employees is, and what an "exempt" employee is. ("Exempt" means exempt from OT pay requirements)! Basically management is "Exempt" and "Non-Exempt" is a typical Hourly worker!
There are state laws to that depend on the state! Some states require OT after 8 hours worked in any one 24-hour period. I know of no upper restriction anywhere!