20 C.F.R. § 702.216
Failure to give timely notice to the employer's designated official shall not bar any claim for compensation if: (a) The employer, carrier, or designated official had actual knowledge of the injury or death; or (b) the district director or ALJ determines the employer or carrier has not been prejudiced: or (c) the district director excuses failure to file notice. For purposes of this subsection, actual knowledge shall be deemed to exist if the employee's immediate supervisor was aware of the injury and/or in the case of a hearing loss, where the employer has furnished to the employee an audiogram and report which indicates a loss of hearing. Failure to give notice shall be excused by the district director if: a) Notice, while not given to the designated official, was given to an official of the employer or carrier, and no prejudice resulted; or b) for some other satisfactory reason, notice could not be given. Failure to properly designate and post the individual so designated shall be considered a satisfactory reason. In any event, such defense to a claim must be raised by the employer/carrier at the first hearing on the claim.
20 C.F.R. §702.216