Editing a text

I got a question regarding my homework. The task is to find the mistakes in a given text but the last sentence confuses me so much that I lost the overview. I'll copy the sentence below and hope that someone can help me.

"But to protect against children from labor abuse, U.S. law sets the minimum age for employment at 14 years of any age for most non-agricultural work and limits to 18 hours the number of hours that minors under the age of 16 may work for during a school week."

I think that it's "But to protect children from..." and "may work during..." but the rest is as I said pretty confusing.

Thanks a lot!