50 CFR § 221.42 - When must a party supplement or amend information it has previously provided?
(a) Discovery. A party must promptly supplement or amend any prior response to a discovery request if it learns that the response:
(1) Was incomplete or incorrect when made; or
(2) Though complete and correct when made, is now incomplete or incorrect in any material respect.
(b) Witnesses and exhibits.
(1) Within 10 days after the date set for completion of discovery, each party must file an updated version of the list of witnesses and exhibits required under §§ 221.21(c), 221.22(c), or 221.25(c).
(2) If a party wishes to include any new witness or exhibit on its updated list, it must provide an explanation of why it was not feasible for the party to include the witness or exhibit on its list under §§ 221.21(c), 221.22(c), or 221.25(c).
(c) Failure to disclose.
(1) A party will not be permitted to introduce as evidence at the hearing testimony from a witness or other information that it failed to disclose under §§ 221.21(c), 221.22(c), or 221.25(c), or paragraphs (a) or (b) of this section.
(2) Paragraph (c)(1) of this section does not apply if the failure to disclose was substantially justified or is harmless.
(3) A party may object to the admission of evidence under paragraph (c)(1) of this section before or during the hearing.
(4) The ALJ will consider the following in determining whether to exclude evidence under paragraphs (c)(1) through (3) of this section:
(i) The prejudice to the objecting party;
(ii) The ability of the objecting party to cure any prejudice;
(iii) The extent to which presentation of the evidence would disrupt the orderly and efficient hearing of the case;
(iv) The importance of the evidence; and
(v) The reason for the failure to disclose, including any bad faith or willfulness regarding the failure.