Federal overtime pay laws are based on weekly 40 hour weeks. There is no federal restriction on the amount of hours per day. Employers can schedule 4 ten hour days, or 3 twelve hour days, and many operations that run 7 days a week have to do this. California is the only state that has a state overtime pay law that restricts daily shifts to 8 hours per day before overtime pay is required under state law. There are no federally required meal or rest breaks either, only that if an employee needs to use the restroom, and if they take less than so many minutes, like 10 minutes, they won't be docked on their pay, and if they eat their lunch while working, they also can't be docked on their pay. A handful of states have some state laws that require some breaks. Most Americans have always worked under these conditions and tens of millions of Americans still are. Many companies go beyond the requirements of the law and have breaks but they are not required by federal or most state laws to do so.