The following commentary comes from an independent investor or market observer as part of TheStreet's guest contributor program, which is separate from the company's news coverage.NEW YORK ( TheStreet) -- Is fracking environmentally safe? That's a key question surrounding the fast-growing method of gas and oil extraction -- and one that's triggered debate since the process became more economically viable. It isn't hard to see where the concerns come from: The fracking process involves injection of fluids -- mostly sandy water, but some chemicals as well -- to bore holes in rock, releasing trapped gas and oil. The fluids are then pumped out of the well, treated and disposed (or possibly, reused). Few take issue with the injected water and sand. But the chemicals have long been a source of contentious debate.