Clarification of 29 CFR 1910.104.

OSHA interpretation letter responding to a request to clarify 29 CFR 1910.104(b)(3)(iii) and (iv), stating that (iii) applies to above-ground outdoor bulk oxygen storage and (iv) to systems in fire-resistive buildings at least 10 feet from adjacent wall openings, with spacing of at least 1 foot.