Section 4.406 - Intervention; amicus curiae(a) A person who wishes to intervene in an appeal must file a motion to intervene within 30 days after the person knew or should have known that the decision had been appealed to the Board.(b) A motion to intervene must set forth the basis for the proposed intervention, including: (1) Whether the person had a right to appeal the decision under § 4.410 or would be adversely affected if the Board reversed, vacated, set aside, or modified the decision; and(2) How and when the person learned of the appeal.(c) The Board may: (1) Grant the motion to intervene;(2) Deny the motion to intervene for good cause, e.g., where granting it would disadvantage the rights of the existing parties or unduly delay adjudication of the appeal; or(3) Grant the motion to intervene but limit the person's participation in the appeal.(d) A person may file a motion at any time to file a brief as an amicus curiae. (1) The motion must state the person's interest in the appeal and how its brief will be relevant to the issues involved.(2) The Board may grant or deny the motion in its discretion. The Board may also allow a person to file a brief as amicus curiae if it denies the person's motion to intervene.(e) A person granted full or limited intervenor status is a party to the appeal, while an amicus curiae is not. A person granted amicus curiae status must serve its brief on the parties to the appeal. 75 FR 64665 , Oct. 20, 2010