(This is not legal advice and is for informational purposes only.)
Effective July 7, 2020, the City of Toronto Bylaw (Bill 511) has made masks mandatory in indoor spaces until at least September 30, 2020. Most employers and private businesses must now require that all employees (as well as visitors to the premises) wear masks or other face coverings within the workplace in effort to combat the transmission of COVID-19. Signs are to be posted indicating that masks are mandatory. Toronto-based employers should review and update their COVID-19 safety protocols accordingly.
There are some limited exemptions for employees and members of the public: for example, for individuals with an underlying medical condition that inhibits their ability to wear a mask or face covering, those who are unable to place or remove a mask or face covering without assistance, those who are reasonably accommodated by not wearing a mask or face covering in accordance with the Ontario Human Rights Code, and employees and agents of the person responsible for the establishment within an area designated for them and not for public access, or within or behind a physical barrier. This last exemption does suggest that employees of the establishment (or those authorized as their agents) would not have to wear masks if they are in an area to which the public has no access, an area designated just for them, or if they are behind a physical barrier such as plexiglass.
Notably, other than asking the person to leave pursuant to the Trespass to Property Act or calling the police if a business owner or employee felt their safety was in jeopardy, the bylaw appears to provide businesses with limited enforcement options if an individual refuses to wear a mask. Businesses also cannot ask for proof of exemption from wearing a mask.
This particular bylaw is also only for the City of Toronto. However, as there is no mandatory order in place (as of right now) for the entire province of Ontario, other municipalities have already enacted (Mississauga, Simcoe-Muskoka, Kingston, Ottawa among others) or as of the date of this posting, are discussing enacting similar mandatory mask bylaws which are various stages of the implementation process (Brampton, Caledon, York Region, and Durham Region among others).
Full language of the bylaw is found at: https://www.toronto.ca/legdocs/bills/2020/bill0511.pdf