At any time after the institution of a proceeding and before it has been submitted to the Secretary for final consideration, the Secretary or the examiner as defined in § 47.2(i)(1) may, upon petition in writing and for good cause show, permit any person to intervene therein. The petition shall state with preciseness and particularity:

(a) The petitioner's relationship to the matters involved in the proceeding; (b) the nature of the material the petitioner intends to present in evidence; (c) the nature of the argument the petitioner intends to make; and (d) any other reason that the petitioner should be allowed to intervene.