In any industry that involves exposure to blood borne pathogens such as Hepatitis B or HIV the importance of educating your employees is not only important for the safety of your employees but also required by law. Symptoms can sometimes take years to show themselves so reporting as soon as an incident happens is of the upmost importance.
Simple mistakes like cross contaminating dirty linens, not sanitizing your tools after job completion, compressing a trash bag containing needles, or not wearing proper protection such as gloves and eye wear can put an employee in a life threatening situation. Simple contact with employees nose, eyes, mouth or breaks in skin will expose them to these diseases and all incidents should be treated as if they were exposed to contamination.
As an employer it is imperative that you have a exposure plan on hand at all times, you provide each employee with this plan, you keep a kit on hand for protection, and you provide your employee with proper vaccinations if they request it.
More info on bloodborne pathogens here.