(a) Whenever a person refuses, on the basis of a privilege against self-incrimination, to testify or provide other information during the course of any investigation conducted under this subpart, the presiding officer may, with the approval of the United States Attorney General, or the delegate of the Attorney General, issue an order requiring the person to give testimony or provide other information. However, no testimony or other information so compelled (or any information directly or indirectly derived from such testimony or other information) may be used against the person in any criminal case, except in a prosecution for perjury, giving a false statement, or otherwise failing to comply with the order.
(b) The presiding officer may issue an order under this section if -
(1) The testimony or other information from the witness may be necessary to the public interest; and
(2) The witness has refused or is likely to refuse to testify or provide other information on the basis of a privilege against self-incrimination.
(c) Immunity provided by this section will not become effective until the person has refused to testify or provide other information on the basis of a privilege against self-incrimination, and an order under this section has been issued. An order, however, may be issued prospectively to become effective in the event of a claim of the privilege.