Killing Your Great Great Great Great Great Grandchildren?

Regarding the following story in the Village Voice about Yukka Mountain:

If you don’t want to read the whole story, the upswing is that the proposed Yukka Mountain nuclear waste dump will hold so much nuclear waste that in thousands and thousands and more years, it will be site of death to any happless cultures digging for water, archiological ruins or just trying to plant a potato. How do you warn people and in what language? Assuming you landed on some foreign planet, what universal sign would keep you AWAY from a particular area?

(By the way, aside from the above question, to any of the politically minded readers of this post, please contact your Senator(s) and beg them to vote no on approving this site as a dump!)