It's 40hrs per week.
However it's how you get those 40hrs that sucks.
As a new hire, expect no weekends off for at least 5-6years if you're lucky.
Expect split shifts. 4 hours on, 4off, 4on again. But only get paid for 8hrs.
Expect to work all hours of the day and night.
They are only obligated to give you 8hours off. So you may get a shift that ends at midnight but they expect you to be driving again at 8am. It's only 8 hours off work, they don't care about your commute, taking a shower, eating etc. As long as you have 8 hours off the job you can go back again.
On a average day one could work 8 to 12 hours in one day depending on what your job is.