Pursuant to § 4-212(b) of Model State Administrative Procedure Act (1981) all testimony of parties and witnesses must be made under oath or affirmation.  In Heard v. Foxshire Assocs., LLC, 145 Md. App. 695 (Md. Ct. Spec. App. 2002), the court held that  even when testimony is being by an attorney, that attorney must be under oath, and cannot provide statements or narrative as an advocate, rather than as a sworn witness.  It is essential that evidence given before an adjudicatory body be under oath, whether from an attorney or lay person, a lay witness or an expert witness.

If an agency fails to comply with the procedural requirements like administering oaths and affirmation, the agency action can be reversed by a trial court and a remand for a rehearing.  However, the failure of an agency to administer an oath or affirmation to a witness is waived, if the party does not raise the claim that oath or affirmation was omitted or defective, at the time of trial.  5 U.S.C.S. § 556(c)(1) provides that the officer proceeding at the hearing “may” administer oaths and affirmations.  The Federal Administrative Procedure Act does not require that testimony received be sworn under oath.[i]  Therefore, cautioning by an administrative law judge to all witnesses that giving false statements results in statutory penalties is sufficient to notify witnesses of the gravity of the hearings and the need for complete truth.  

[i] Leitman v. McAusland, 934 F.2d 46 (4th Cir. Va. 1991)