I was once asked by a student whether I knew of any paper that demonstrated that fracking was safe.
Of course, no such paper exists, nor can it exist in theory. How might one demonstrate that there is a complete absence of risk of doing anything?
Or to put the question quite another way, and I wished I were clever enough to ask it initially, “Do you know of any paper that demonstrated that water is safe?” What about ____? I suspect that the answer would have been, “well, water is different.” It’s not.