29 CFR 2700.68: Substitution of the ALJ.

(a) Generally. Should an ALJ become unavailable to the Commission, the proceedings assigned to that ALJ shall be reassigned to a substitute ALJ.

(b) Substitution following a hearing. The substitute ALJ may render a decision based upon the existing record, provided the parties are notified of the ALJ's intent and they are given an opportunity to object. An objection to the ALJ rendering a decision based upon the existing record shall be filed within 10 days following receipt of the ALJ's notice, or the objection shall be deemed to be waived. An objection shall be founded upon a showing of a need for the resolution of conflicting material testimony requiring credibility determinations. Upon good cause shown the ALJ may order a further hearing on the merits, which shall be limited, so far as practicable, to the testimony in dispute.