Oxyclean is sodium percarbonate and detergent mixed together, which breaks down into hydrogen peroxide and salt. Neither of which is bad for the enviornment, but if you use a septic system I would not recommend putting large amounts of the stuff down the drain.
Star san on the other hand is acid based and once the PH drops below 3 the solution becomes inert and the residual chemicals can be used by bacteria and yeast as nutrients, so it could actually be considered "good" for the environment. That is if you consider microorganisms the environment.