Affirmative Defenses

(1) It shall be an affirmative defense to any enforcement action that the noncompliance was caused by an Upset as defined in 360 CMR 10.004: General Requirements. In such action, the Person seeking to establish the occurrence of an Upset shall have the burden of proof, which will be met if the Person: (a) Has reported the following information to the Authority within 24 hours of becoming aware of the Upset (if the information is provided orally, a written submission must be provided within five days): 1. A description of the discharge and cause of noncompliance; 2. The period of noncompliance, including exact dates and times or, if not corrected, the anticipated time the noncompliance is expected to continue; and 3. Steps being taken and/or planned to reduce, eliminate, and prevent recurrence of the noncompliance; and (b) Demonstrates through properly signed contemporaneous operating logs or other relevant evidence that: 1. An Upset occurred and that the Person can identify the cause(s) of the Upset; and 2. The facility was at the time being operated in a prudent and skillful manner and in compliance with applicable operation and maintenance procedures and with the requirements of 360 CMR 10.013(5)(a). 9/6/19 360 CMR - 33 2.23: continued (2) It shall be an affirmative defense to any enforcement action brought for noncompliance with 360 CMR 10.021: General Prohibitions that: (a) the Person did not know or have reason to know that its discharge, alone or in conjunction with a discharge or discharges from other sources, would violate 360 CMR 10.021: General Prohibitions; and (b) the Person's discharge complied with 360 CMR 10.023: Specific Prohibitions and 360 CMR 10.024: Specific Discharge Limitations/Local Limits, the specific discharge limitations and prohibitions in any permit issued to it by the Authority, and any applicable National Categorical Pretreatment Standard.