A simple solution (Score 5, Interesting)

People have been drilling wells in CA for over 100 years, and most of those that did so are dead, and most of the companies that did so are long gone. Collecting from them is impossible and trying to get them to remediate the damage is impossible. The solution is simple. Everyone seeking to drill a new well in CA must plug 10 old wells, and CA should tell them which 10 to plug. The state should make a list ordered by the worst offender, and force them to be plugged from the worst on down. On top of that, anyone wishing to drill a new well in CA must leave in escrow with the state funds that guarantee the well they are drilling will be properly plugged at the end of its life. If they are forced to leave 10 times the cost of plugging the well with the state, then at the ends of its productive live they will surely plug it (or someone else will) to recover those funds. It is all about using incentives to "encourage" the right behavior. Almost no one does the right thing by choice, and it doesn't matter whether they are Republicans or Democrats. Everyone is greedy.