29 CFR § 103.20 - Election procedures and blocking charges.
(a) Whenever any party to a representation proceeding files an unfair labor practice charge together with a request that the charge block the election process, or whenever any party to a representation proceeding requests that its previously filed unfair labor practice charge block the election process, the party shall simultaneously file, but not serve on any other party, a written offer of proof in support of the charge. The offer of proof shall provide the names of the witnesses who will testify in support of the charge and a summary of each witness's anticipated testimony. The party seeking to block the election process shall also promptly make available to the regional director the witnesses identified in its offer of proof.
(b) If charges are filed alleging violations other than those described in paragraph (c) of this section, the ballots will be promptly opened and counted at the conclusion of the election.
(c) If charges are filed that allege violations of section 8(a)(1) and 8(a)(2) or section 8(b)(1)(A) of the Act and that challenge the circumstances surrounding the petition or the showing of interest submitted in support of the petition, or a charge is filed that alleges an employer has dominated a union in violation of section 8(a)(2) and seeks to disestablish a bargaining relationship, the regional director shall impound the ballots for up to 60 days from the conclusion of the election if the charge has not been withdrawn or dismissed prior to the conclusion of the election. If a complaint issues with respect to the charge at any point prior to expiration of that 60-day post-election period, then the ballots shall continue to be impounded until there is a final determination regarding the charge and its effect, if any, on the election petition. If the charge is withdrawn or dismissed at any time during that 60-day period, or if the 60-day period ends without a complaint issuing, then the ballots shall be promptly opened and counted. The 60-day period will not be extended, even if more than one unfair labor practice charge is filed serially.
(d) For all charges described in paragraphs (b) or (c) of this section, the certification of results (including, where appropriate, a certification of representative) shall not issue until there is a final disposition of the charge and a determination of its effect, if any, on the election petition.