Only you would know.....most sources sale diluted only. The pure stuff is fairly rare. Allot pf people pass their oregano off as "PURE", but also diluted down with 11 parts olive oil, so public misuse won't harm them selves.
I believe I am the only person to use pure oregano for most any situation and have learned more about using it for hot tub use than anyone on earth...but just guessing.