28 CFR 68.19 - Written interrogatories to parties.
(a) Any party may serve upon any other party written interrogatories to be answered in writing by the party served, or if the party served is a public or private corporation or a partnership or association or governmental agency, by any authorized officer or agent, who shall furnish such information as is available to the party. A copy of the interrogatories shall be served on all parties to the proceeding.
(b) Each interrogatory shall be answered separately and fully in writing under oath or affirmation, unless it is objected to, in which event the reasons of objection shall be stated in lieu of an answer. The answers and objections shall be signed by the person making them. The party upon whom the interrogatories were served shall serve a copy of the answer or objections upon all parties to the proceeding within thirty (30) days after service of the interrogatories, or within such shorter or longer period as the Administrative Law Judge upon motion may allow.
(c) An interrogatory otherwise proper is not necessarily objectionable merely because an answer to the interrogatory involves an opinion or contention that relates to fact or the application of law to fact, but the Administrative Law Judge may upon motion order that such an interrogatory need not be answered until after designated discovery has been completed or until a prehearing conference or other later time.
(d) A person or entity upon whom interrogatories are served may respond by the submission of business records, indicating to which interrogatory the documents respond, if they are sufficient to answer said interrogatories.