When, by reason of emergency conditions, the Chairman is not available and capable of acting, his functions are delegated to the Commissioner available and capable of acting and who is designated by the President. Until such time as the President designates, or if no such Commissioner is designated, such functions are delegated to the Commissioner designated by the Chairman as Acting Chairman, but if such Acting Chairman is not available and capable of acting such functions are delegated to the Commissioner who is available and capable of acting and who has the longest tenure as a member of the Commission. If there is no Commissioner available and capable of acting, such functions are delegated to the person on the Commission staff who is available and capable of acting and who is highest on the list set forth in § 376.204(b)(2).