40. The board may, on its own initiative or on the application of any interested person filed within 30 days after the person was notified of the decision, review or revoke any of its decisions(1) when a new fact is discovered which, if it had been known in due time, might have justified a different decision;
(2) where the applicant, who is a party to the issue, was, for reasons considered sufficient, prevented from being heard;
(3) where a substantive or procedural defect is likely to invalidate the decision.