(a) Agricultural operations, including but not limited to:

(A) Growing or harvesting crops;

(B) Raising fowl or animals;

(C) Clearing or grading agricultural land;

(D) Propagating and raising nursery stock;

(E) Propane flaming of mint stubble; and

(F) Stack or pile burning of residue from Christmas trees, as defined in ORS 571.505, during the period beginning October 1 and ending May 31 of the following year.

(b) Equipment used in agricultural operations, except boilers used in connection with propagating and raising nursery stock.

(c) Barbecue equipment used in connection with any residence.

(d) Heating equipment in or used in connection with residences used exclusively as dwellings for not more than four families, except solid fuel burning devices, as defined in ORS 468A.485, that are subject to regulation under this section and ORS 468A.140 and 468A.460 to 468A.515.

(e) Fires set or permitted by any public agency when such fire is set or permitted in the performance of its official duty for the purpose of weed abatement, prevention or elimination of a fire hazard, or instruction of employees in the methods of fire fighting, which in the opinion of the agency is necessary.

(f) Fires set pursuant to permit for the purpose of instruction of employees of private industrial concerns in methods of fire fighting, or for civil defense instruction.

(2) Subsection (1) of this section does not apply to the extent:

(a) Otherwise provided in ORS 468A.555 to 468A.620, 468A.790, 468A.992, 476.380 and 478.960;

(b) Necessary to implement the federal Clean Air Act (P.L. 88-206 as amended) under ORS 468A.025, 468A.030, 468A.035, 468A.040, 468A.045 and 468A.300 to 468A.330; or

(c) Necessary for the Environmental Quality Commission, in the commission’s discretion, to implement a recommendation of the Task Force on Dairy Air Quality created under section 3, chapter 799, Oregon Laws 2007, for the regulation of dairy air contaminant emissions.

(3)(a) Except to the extent necessary to implement the federal Clean Air Act (P.L. 88-206 as amended), the air pollution laws contained in ORS 468A.025, 468A.030, 468A.035, 468A.040, 468A.045 and 468A.300 to 468A.330 do not apply to carbon dioxide emissions from the combustion or decomposition of biomass.

(b) As used in this subsection, "biomass" means:

(A) Nonfossilized and biodegradable organic materials that originate from plants, animals and microorganisms and that are products, byproducts, residues or wastes from agriculture, forestry and related industries;

(B) Nonfossilized and biodegradable organic fractions of industrial and municipal wastes; and

(C) Gases and liquids recovered from the decomposition of nonfossilized and biodegradable organic matter. [Formerly 468.290; 1997 c.473 §2; 1999 c.439 §1; 2007 c.799 §4; 2009 c.387 §14; 2015 c.500 §1]