if there are any rulings from 1917-1919, i don't know how useful they are today.
generally speaking, if you're a worker that feels unsafe then you should call your union rep and if you don't have a union rep then you should call the ministry. in the end, if you decide to push the issue, then it's going to be up to a judge, and that judge is probably going to be making a novel ruling that is subject to challenge at a higher court.
my substantive legal/scientific opinion is that because risks associated with contracting the disease are so low for people of working age, almost all arguments around workplace safety are going to be reducible to hypochondria. but, if you get a certain type of judge, they might be subject to the hypochondria and panic, themselves - and the issue might need to go through a few levels of the system before a correct outcome is come to.
i know that this contradicts a lot of what the government has been saying. i mean, they shut the society down, right? this must be dangerous! no - we overreacted in a ridiculous way, and much of what we did didn't make any sense.
so, you shouldn't base your judicial expectations on what the government did, because much of what the government did would have probably been overturned by review, if it was available or reasonable or timely.
the facts suggest that it's really just the flu, if you're working age. it really is.