Employers of recreational diving instructors and diving guides are not required to comply with the decompression-chamber requirements specified by paragraphs (b)(2) and (c)(3)(iii) of § 1910.423 and paragraph (b)(1) of § 1910.426 when they meet all of the following conditions:
The instructor or guide is engaging solely in recreational diving instruction or dive-guiding operations;
The instructor or guide is using a nitrox breathing-gas mixture consisting of a high percentage of oxygen (more than 22% by volume) mixed with nitrogen;
The instructor or guide is using an open-circuit, semi-closed-circuit, or closed-circuit self-contained underwater breathing apparatus (SCUBA); and
The employer of the instructor or guide is complying with all requirements of Appendix C of this subpart.
The instructor or guide is diving within the no-decompression limits in these operations;