First of all, I'd like to thank everyone whose provided answers, as I have viewed some of the topics and most of my questions were answered without having to ask.
Onto my question:
I work in a(n) 'nursing home', and as a manager, we are required to fill in the next position if there is a call-off. This is no where in my job description, nor in any of my companies policies. Every Saturday and Sunday, I work 16 hours straight. Now if there is a call off for the midnight shift (I work from 7am - 11pm) I never oblige to stay, due to the fact that someone mentioned we are not allowed to work more than 16 hours without 8 hours off. I've also never seen this anywhere in the companies policies.
I'm not sure if there are laws pertaining to work in nursing homes or not.
Thanks for your help.