Sec 77.  EXCEPTIONS.  The provisions of Section 76 do not apply to:

                A.  Smoke from fires set by or permitted by any public
                    officer if such fire is set or permission given in the
                    performance of the official duty of such officer, and 
                    such fire in the opinion of such officer is necessary:

                    1.  For the purpose of the prevention of a fire
                        hazard which cannot be abated by any other means, or

                    2.  for the instruction of public employees in the
                        methods of fighting fires.

                B.  Smoke from fires set pursuant to permit on property
                    used for industrial purposes for the purpose of 
                    instruction of employees in methods of fighting fire.

                C.  Agricultural operations.

                D.  Orchard or citrus grove heaters which do not produce
                    unconsumed solid carbonaceous matter at a rate in 
                    excess of one (l) gram per minute.

                E.  The use of other equipment in agricultural operations
                    in growing of crops or raising of fowls or animals.

                F.  Smoke from fires set for the disposal of solid waste
                    at dump sites operating under permit from the Air 
                    Resources Board pursuant to Section 39297.4 of the 
                    Health and Safety Code.