(a) Within 20 days of the date that the request for certification was received, the Administrator shall provide public notice of the request for certification. Following such public notice, the Administrator shall provide an opportunity for public comment.

(b) If the Administrator determines that a public hearing on a request for certification is appropriate, the Administrator shall schedule such hearing at an appropriate time and place and, to the extent practicable, give all interested and potentially affected parties the opportunity to present evidence or testimony in person or by other means.