45 C.F.R. § 1174.9 – Answer to a complaint.

(a) A defendant may file an answer with the reviewing official within thirty days of service of the complaint. An answer will be considered a request for an oral hearing.
(b) In the answer, the defendant—
1. (1) Must admit or deny each allegation of liability contained in the complaint (a failure to deny an allegation is considered an admission);
2. (2) Must state any defense on which the defendant intends to rely;
3. (3) May state any reasons why the penalties, assessments, or both should be less than the statutory maximum; and
4. (4) Must state the name, address, and telephone number of the person the defendant authorized to act as the defendant's representative, if any.
(c) If the defendant is unable to file a timely answer which meets the requirements set forth in paragraph (b) of this section, the defendant may file with the reviewing official a general answer denying liability, requesting a hearing, and requesting an extension of time in which to file a complete answer. The defendant must file a general answer within thirty days of service of the complaint.
(d) If the defendant initially files a general answer requesting an extension of time, the reviewing official must promptly file with the ALJ the complaint, the general answer, and the request for an extension of time.
(e) For good cause shown, the ALJ may grant the defendant up to thirty additional days within which to file an answer that meets the requirements of paragraph (b) of this section. The defendant must file such an answer with the ALJ and must serve a copy on the reviewing official.