(a)  In any action maintained under § 10-20-3, where the subject of the action is conduct governed by an environmental quality standard promulgated or issued by an environmental control agency, whenever the plaintiff shall have made a prima facie showing that the conduct of the defendant violates or is likely to violate the environmental quality standard, the defendant may rebut the prima facie showing by the submission of evidence to the contrary.

(b)  In any other action maintained under § 10-20-3, whenever the plaintiff shall have made a prima facie showing that the conduct of the defendant has, or is likely to cause the pollution, impairment or destruction of the air, water, land, or other natural resources located within the state, the defendant may rebut the prima facie showing by the submission of evidence to the contrary. The defendant may also show, by way of an affirmative defense, that there is no feasible, prudent, and economically viable alternative and the conduct at issue is consistent with the reasonable requirements of the public health, safety, and welfare.