Rule 711  Evidence.

          A.   Oral evidence shall be taken only on oath or

          B.   Each party shall have these rights:

               1.   To call and examine witnesses;

               2.   To introduce exhibits;

               3.   To cross-examine opposing witnesses on any
                    matter relevant to the issues, even though
                    that matter was not covered in the direct

               4.   To impeach any witness regardless of which
                    party first called him to testify;

               5.   To rebut the evidence against him.

          C.   If a respondent does not testify in his own
               behalf, he may be called and examined as if under

          D.   The hearing need not be conducted according to
               technical rules relating to evidence and
               witnesses.  Any relevant evidence shall be
               admitted if it is the sort of evidence on which
               responsible persons are accustomed to rely in the
               conduct of serious affairs, regardless of the
               existence of any common law or statutory rule
               which might make improper the admission of such
               evidence over objection in civil actions.  Hearsay
               evidence may be used for the purpose of
               supplementing or explaining any direct evidence
               but shall not be sufficient in itself to support a
               finding unless it would be admissible over
               objection in civil actions.  The rules of
               privilege shall be effective to the same that they
               are now or hereafter may be recognized in civil
               actions, and irrelevant and unduly repetitious
               evidence shall be excluded.

          E.   All evidence, oral or written, and all exhibits,
               shall be  recorded at the time of the hearing and
               all records shall be maintained for a period of
               time as specified by law or as determined by the
               Air Pollution Control Board.