Thanks for asking. Apart from federal government departments some businesses such as banks, telecommunications, rail, air and trucking that crosses provincial or federal borders are regulated by the Federal Government’s labour program at ESDC (formerly known as Labour Canada). Those that are not are regulated by provincial regulations. The federal labour program determines if a business is federally or provincially regulated. If federal the fall under the Canada Labour Code vs the provincial acts.
Although labour laws and health and safety regulations are similar they are not always the same.
I hope this helps. I am a retired Occupational Health and Safety Officer from ESDC’s Labour Program.