40 CFR 78.11 - Intervenors.
(a) Within 30 days (or other shorter, reasonable period established by the Administrator when giving notice) after notice is given under § 78.9 of this part that the petition for administrative review has been filed, any person listed in § 78.3(a) of this part may file a motion for leave to intervene in the proceeding. A motion for leave to intervene under this section shall set forth the grounds for the proposed intervention and may respond to the petition for administrative review. Late motions to intervene may be granted only for good cause shown.
(b) The Environmental Appeals Board of Presiding Officer will grant a motion to intervene only upon an express finding that:
(1) The motion to intervene raises matters relevant to the factual or legal issues to be reviewed;
(2) The intervenor consented to be bound by all stipulations previously entered into by the existing parties, and all orders previously issued, in the proceeding; and
(3) The intervention will promote the interests of justice and will not cause undue delay or prejudice to the rights of the existing parties.