(a) Except as hereinafter provided, the department will promulgate no rule, regulation, order or amendment thereof, except in an emergency, without a public hearing upon at least 10 days notice, exclusive of the date of the service.

(b) The public hearing shall be held at such time and place as may be prescribed by the department. The hearing shall be conducted by the director or such of his staff as he shall designate. Testimony shall be under oath. The proceedings of all such hearings shall be recorded by a reporter designated by the department and a transcript of same shall be prepared and filed by such reporter as a part of the department's records. Alternatively, the proceedings may be recorded by tape or other mechanical device with the recording or a written transcript thereof forming the department record.

(c) The notice of hearing, which may be by personal service, newspaper publication or by mail, will specify the purpose, style and number of the proceedings, as well as the time and place of the hearing.

(d) In calling a hearing, the department may act upon its own motion or upon the application of any interested person, with hearings called in the latter instance to be scheduled without undue delay.

(e) The department will make its ruling within 60 days after the conclusion of any hearing.

(f) Except as hereinafter provided, unless there is a significant indication of changed conditions, the department will not hold a hearing on any matter which has already been the subject of a prior hearing.

(g) The department may further enter an emergency order without notice or hearing where it is demonstrated that immediate action is necessary to prevent waste, pollution or to protect correlative rights. No emergency order shall be effective for more than 15 days.