Legislative requirements would be laws that have been enacted in your location that would place requirements on your facility. Obviously, each country/territory/state/government unit would have their own legislative requirements, which would be found in that region's government resources. That term could also cover regulations that government agencies may promulgate.
You should also know the laws and regulations in countries where your product would be sold.
You are from Canada, so you would look at the resource that pertains to your facility's location for the legislative requirements that are imposed on you.
In many countries, these are on websites, but they would also be published in some kind of book form and maintained in the government's law library.
The BRC standards can't tell you where to look, because everyone would have a different place, but I'm sure that the agency that inspects you could direct you to the proper location.
Many governments publish proposed agency regulations before they are imposed, so knowing where they are published and following that is a good way to stay ahead of changes that will impact your business. It's good to have someone who knows about how these laws and regulations work to keep track of this, as well as proposed changes in countries where you will be sending/selling your products.
"...everything can be taken from a man but one thing: the last of the human freedoms--to choose one's attitude in any given set of circumstances, to choose one's own way." Viktor E. Frankl
"Life's like a movie, write your own ending." The Muppets