(1) The degree of emission limitation required of any source or stack for control of any air pollutant regulated under the Clean Air Act of Montana may not be affected by so much of any source's stack height that exceeds good engineering practice or by any other dispersion technique, except as provided in ARM 17.8.403.

(2) Before a new or revised state implementation plan emission limitation that is based on good engineering practice stack height that exceeds the height allowed by ARM 17.8.401(2)(b)(i) or (ii) is submitted to the Environmental Protection Agency, the department must provide notice and opportunity for public hearing of the availability of any demonstration study as provided by ARM 17.8.401(2)(c). Such notice and public hearing will be conducted in accordance with the Montana Administrative Procedure Act.

(3) This rule does not require a source owner or operator to restrict, in any manner, the actual stack height of any source.