(2) For purposes of this section:

(a) "Bypass" means the temporary discharge of waste or an air contaminant in violation of ORS chapter 465, 466, 468, 468A or 468B or any rule adopted or order or permit issued thereunder, under circumstances in which the defendant reasonably believed that the discharge was necessary to prevent loss of life, personal injury or severe property damage, or to minimize environmental harm.

(b) "Upset" includes an exceptional and unexpected occurrence in which there is unintentional and temporary violation of the requirements of ORS 824.050 to 824.110 or ORS chapter 465, 466, 468, 468A, 468B or 825 or of any rule adopted or permit or order issued under ORS 824.050 to 824.110 or ORS chapter 465, 466, 468, 468A, 468B, or 825 because of factors beyond the reasonable control of the regulated person or entity. "Upset" does not include a violation caused by:

(A) Operational error;

(B) Improperly designed facilities;

(C) Lack of preventive maintenance; or

(D) Careless or improper operation.

(3) To establish the affirmative defense of upset or bypass, the defendant must prove the occurrence of an upset or bypass and that the defendant:

(a) Reported the upset or bypass to the Department of Environmental Quality or other appropriate agency within 24 hours or as required by statute, rule, permit or order, whichever is sooner, and, if the original notice was oral, delivered written notice to the Department of Environmental Quality or other agency with regulatory jurisdiction within four calendar days;

(b) Submitted complete documentation of the upset or bypass to the Department of Environmental Quality or other agency with regulatory jurisdiction as required by statute, rule, order or permit; and

(c) Took appropriate corrective action, including action to minimize damage, as soon as reasonably possible.

(4) It is an affirmative defense to an offense under ORS 468.922 to 468.946 that the defendant:

(a) Did not cause or create the condition or occurrence that constitutes the offense;

(b) Reported the condition or occurrence to the Department of Environmental Quality or other agency with regulatory jurisdiction as soon as practicable after the defendant discovered it; and

(c) Took reasonable steps to correct the violation. [1993 c.422 §17]