49 CFR 511.39: Orders requiring witnesses to testify or provide other information and granting immunity.

(a) A party who desires the issuance of an order requiring a witness to testify or provide other information upon being granted immunity from prosecution under title 18, U.S.C., section 6002, may make a motion to that effect. The motion shall be made and ruled on in accordance with § 511.22, and shall include a showing:

(1) That the testimony or other information sought from a witness or prospective witness may be necessary to the public interest; and

(2) That such individual has refused or is likely to refuse to testify or provide such information on the basis of that individual's privilege against self-incrimination.

(b) If the Presiding Officer determines that the witness' testimony appears necessary and that the privilege against self-incrimination may be invoked, he or she may certify to the Administrator a request that he or she obtain the approval of the Attorney General of the United States for the issuance of an order granting immunity.

(c) Upon application to and approval of the Attorney General of the United States, and after the witness has invoked the privilege against self-incrimination, the Presiding Officer shall issue the order granting immunity unless he or she determines that the privilege was improperly invoked.

(d) Failure of a witness to testify after a grant of immunity or after a denial of the issuance of an order granting immunity shall result in the imposition of appropriate sanctions as provided in § 511.37.