; (B) flight from prosecution; (C) destruction of or tampering with evidence; (D) intimidation of potential witnesses; or (E) otherwise seriously jeopardizing an investigation or unduly delaying a trial. (3) Standard A district court of the United States shall issue a nondisclosure order or extension thereof under this subsection if the court determines that there is reason to believe that disclosure of the information subject to the nondisclosure requirement during the applicable time period may result in— (A) endangering the life or physical safety of an individual; (B) flight from prosecution; (C) destruction of or tampering with evidence; (D) intimidation of potential witnesses; or (E) otherwise seriously jeopardizing an investigation or unduly delaying a trial. (4) Extension Upon a showing that the circumstances described in subparagraphs (A) through (E) of paragraph (3) continue to exist, a district court of the United States may issue an ex parte order extending a nondisclosure order imposed under this subsection or under section 3486(a)(6)(A) for additional periods of 180 days, or, if the court determines that the circumstances necessitate a longer period of nondisclosure, for additional periods which are longer than 180 days. (b) Closed hearings In all proceedings under this section, subject to any right to an open hearing in a contempt proceeding, the court must close any hearing to the extent necessary to prevent an unauthorized disclosure of a request for records, a report, or other information made to any person or entity under section 3486. Petitions, filings, records, orders, certifications, and subpoenas must also be kept under seal to the extent and as long as necessary to prevent the unauthorized disclosure of a subpoena under section 3486. . (b) Clerical amendment The table of sections at the beginning of chapter 223 of title 18, United States Code, is amended by inserting after the item relating to section 3486 the following: 3486A. Judicial review of nondisclosure requirements. .