That's difficult, because there are fewer resources and less anonymity. The employee is going to feel much more exposed. They're probably going to feel much more intimidated coming forward.
In my experience, the size of the organization shouldn't matter in their obligations in the workplace. However, perhaps some of the plants.... In Ontario, if there are six or more employees, every obligation applies. Under five employees, you don't have to post everything and you don't have to do some of the other things that are required as a bare minimum, because you're so small.
I think the general obligations as a duty of an employer to ensure the health and safety of their workplace should apply no matter the size of the organization. The difficulty is going to be having another person they can report to, but it doesn't necessarily have to be someone internal to the organization. In Ontario, you are allowed to have someone outside the organization as that safety valve, and that could be considered by the small workplaces.