Oxygen Bleaches
Per say aren't going to cause harm, but OxyClean and other cheap "oxygen bleaches" are anywhere from 25% to 75% sodium carbonate (washing soda), which is a very corrosive substance indeed. IIRC, Oxyclean is either 50% or 75% washing soda, perhaps somewhere in between, but it is not pure sodium percarbonate, or even 80%.
Tip, if one picks up a container of oxygen bleach and it feels very dense, then it is more likely than not heavy on washing soda, just pick up a box of the stuff to compare.
Both sodium perborate and sodium percarbonate work best in alkaline solutions. However to an extent sodium percarbonate can provide on it's own due it being made from washing soda. In any case the pH of wash water is normally quite well taken care of by the washing powder, most of which contain varying amounts of sodium carbonate.
When possible always purchase straight sodium percarbonate or perborate. Ecover makes an oxygen bleach that is pure sodium percarbonate, and one can order either of the above from chemical supply stores in bulk.
L.