If the Administrator decides that a public hearing under this part is necessary, he issues a notice of public hearing in the Federal Register, to advise interested persons of the time, place, and subject matter of the public hearing and invite their participation. Interested persons may submit their views through oral or written presentation, or both. There is no cross-examination of witnesses. A transcript of the hearing is kept and exhibits may be accepted as part of the transcript. Sections 556 and 557 of title 5, U.S.C., do not apply to hearings held under this part. When appropriate, the Chief Counsel designates a member of his staff to serve as legal officer at the hearing.