This really is a big problem. Having worked on exploration wells in Indonesia and checked recently with colleagues, steel pipes “casing” which line wells, also surface pipes, are nothing more than mild steel. Frack fluids, gas and oil content are corrosive. So contamination is inevitable after very few years. Unfortunately, even when surface is sealed off, seepage into acquires can cause trouble for decades and more. Too big a risk to make a few people rich, while everybody else can suffer forever.