(a) Any person may petition the Associate Administrator for an extension of time to submit comments in response to a notice of proposed rulemaking. The petition shall be submitted in duplicate not less than three days before expiration of the time stated in the notice. The filing of the petition does not automatically extend the time for petitioner's comments.

(b) The Associate Administrator grants the petition only if the petitioner shows a substantive interest in the proposed rule and good cause for the extension, and if the extension is in the public interest. If an extension is granted, it is granted as to all persons and is published in the Federal Register.