Approximately 0.0013% and 0%, respectively. I'm not sure what you're getting at. My point is that we already deal with many substances that are toxic forever.

Approximately 0.0013% and 0%, respectively. I'm not sure what you're getting at. My point is that we already deal with many substances that are toxic forever. Something about the danger reducing over the course of thousands of years seems to make people more concerned about the future than when the danger is permanent.