Determination of exempt noise emission sources; rules. (1) In addition to the powers of the Environmental Quality Commission described in ORS 467.060, the commission by rule may exempt a class of activity within a category of noise emission sources from the application of a rule establishing maximum permissible levels of noise emission for that category of noise emission sources

(2) In determining whether to grant an exemption pursuant to subsection (1) of this section, the commission shall consider:

(a) Protection of the health, safety and welfare of the citizens of this state;

(b) Feasibility and cost of noise abatement; and

(c) Past, present and projected patterns of land use and such state and local laws and regulations as are applicable thereto. [1977 c.511 §3]