The kind of green light, red light labelling you're talking about with respect to a global harmonized system is more a product warning than a green or red light for the product. We haven't really talked about a “Good Housekeeping seal of approval” label.
I think the move toward a global system of labelling makes a lot of sense. Following Europe's interpretation of GHS, this would make a lot of sense for Canada. Having one label instead of three or four would help matters. You'd have one label saying there was a problem, and then you'd describe it—reproductive toxin, carcinogen, whatever.
As to the other part of your question, I think what you're talking about is synergistic effects. We understand what one chemical or another does, but we don't really understand what they do together. Our understanding of that is very poor. We have some isolated examples, some isolated studies, but part of the problem is that government's not really in the testing business. Since about 1995, we've gotten out of that business, and we rely primarily on industry data on a per chemical basis.