the article said pollution was reduced by over eighty percent. if that meant eighty percent less death and disease, wouldn't that be worth it? what's the dollar value of death and disease? i can see your point in the abstract, but if you look at the specific numbers, it doesn't look like we should be letting mercury go unchecked.
This is where the statistical analysis is misleading. When you look at levels of heavy metal and heath effects..it is rarely an exact 1 to 1 ratio throughout all intervals.
As you reduce the levels of heavy metals, the benefits to health translate to more and more insignificant benefits, as it is very hard to tell the health differences between small concentrations, say 1 part per million and 2 parts per million mercury. Because these are relatively very small amounts of mercury we are looking at, 2 parts per million may be 100% more than 1 part per million but it does not necessarily mean we will get 100% more cases of illnesses, as you need to cross some biological thresholds before the body becomes compromised.
Again, Trump is not saying the states cannot impose stricter standards if they feel that power plants are killing off their voters. There is a very real issue of a voter outrage calculus where if you raise to price of energy too much, the voters begin to shift priority over the outrage of deaths due to mercury poisoning. In the end, politicians have to decide policy by appeasing the most prominent outrage. If they fail to do this, then you have situations like California where people leave the state because the politicians did not do a proper outrage analysis.
If you have a way to convince voters that expensive energy is not something for voters to be outraged over, I am sure the local politicians would be all ears. After all, the raison d'etre for politicians is to pander to outrage.