Physical Danger
You'll be on your feet a lot, so take care of those tootsies. Make sure you practice proper lifting posture, too, because it's easy to throw your back out when lifting or moving a heavy patient. You also may come into contact with chemicals or malevolent power tools while creating assistive aids for your patients. (And yes, we meant to say malevolent. That power drill looks hungry.)
As for dangers from other people, some patients may become violent, due to brain injuries or other issues. Additionally, you may be exposed to bacteria or communicable diseases through your work with patients. Just be aware that it is difficult to practice occupational therapy while wearing full HAZMAT gear.