I have been told all sorts of stories about selenium toner and, to hear some people tell it, the stuff is like weapons grade plutonium.
Yes, I agree! Selenium is toxic but it is not nuclear waste! If you handle it carefully as you would any other chemical, you will be just fine.
Wear gloves. Wear goggles. Wear an apron. Make sure you have adequate ventilation. Use all the safe practices that, if you are good photographer, you SHOULD already be using.
People use paint thinners and chemicals in their houses every day without a second thought. You sit in your car, sometimes, just two feet away from a tank full of flammable gasoline. Nobody worries about stuff like this in the least but I actually had one guy tell me that a "friend of a friend" got cancer from selenium toner because a few drops of it spilled on the floor. This guy truly believed that!
If you spill some toner, mop it up with plenty of detergent and water then put the dirty mops and utensils in a plastic bag, tie it up well and put it in the trash. If you spill more than a little bit of it, you would be wise to take the soiled materials to your local Haz-Mat Amnesty site.
For cryin' out loud! People shouldn't make this a huge issue.
You just have, there's plenty of equally toxic chemistry used in the dark room.