19 CFR § 210.29 - Interrogatories.
(a) Scope; use at hearing. Any party may serve upon any other party written interrogatories to be answered by the party served. Interrogatories may relate to any matters that can be inquired into under § 210.27(b) or § 210.61, and the answers may be used to the extent permitted by the rules of evidence. Absent stipulation of the parties, any party may serve upon any other party written interrogatories not exceeding 175 in number including all discrete subparts. Related respondents are treated as one entity. The presiding administrative law judge may increase the number of interrogatories on written motion for good cause shown.
(b) Procedure.
(1) Interrogatories may be served upon any party after the date of publication in the Federal Register of the notice of investigation.
(2) Parties answering interrogatories shall repeat the interrogatories being answered immediately preceding the answers. Each interrogatory shall be answered separately and fully in writing under oath, unless it is objected to, in which event the reasons for objection shall be stated in lieu of an answer. The answers are to be signed by the person making them, and the objections are to be signed by the attorney making them. The party upon whom the interrogatories have been served shall serve a copy of the answers and objections, if any, within ten days of service of the interrogatories or within the time specified by the administrative law judge. The party submitting the interrogatories may move for an order under § 210.33(a) with respect to any objection to or other failure to answer an interrogatory.
(3) 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 order that such an interrogatory need not be answered until after designated discovery has been completed or until a prehearing conference or a later time.
(c) Option to produce records. When the answer to an interrogatory may be derived or ascertained from the records of the party upon whom the interrogatory has been served or from an examination, audit, or inspection of such records, or from a compilation, abstract, or summary based thereon, and the burden of deriving or ascertaining the answer is substantially the same for the party serving the interrogatory as for the party served, it is a sufficient answer to such interrogatory to specify the records from which the answer may be derived or ascertained and to afford to the party serving the interrogatory reasonable opportunity to examine, audit, or inspect such records and to make copies, compilations, abstracts, or summaries. The specifications provided shall include sufficient detail to permit the interrogating party to locate and to identify, as readily as can the party served, the documents from which the answer may be ascertained.