(a) The Administrator may, upon notice and opportunity for a public hearing, exempt the owner or operator of a source if he finds with respect to a particular instance of noncompliance, that such noncompliance was de minimis in nature and duration, and was caused solely by a sudden and unavoidable breakdown of process or pollution control equipment.

(b) A petition for an exemption on the ground that the violation was de minimis and was caused by a sudden and unavoidable breakdown of process or pollution control equipment may only raise issues related to entitlement to an exemption and shall contain or be accompanied by supporting documentation. Issues relating to entitlement to an exemption that are not raised in the petition shall be deemed waived. In making such finding the Administrator shall consider whether:

(1) The violation was de minimis in nature and duration within the meaning of § 66.32;

(2) The air pollution control equipment, process equipment, or processes, including appropriate back-up systems, were designed, and have been maintained and operated in a manner consistent with good practice for minimizing emissions;

(3) Repair of the malfunctioning equipment was undertaken and carried out in an expeditious fashion as soon as the owner or operator knew or should have known that the malfunction existed or that applicable emission limitations were being violated or were likely to be violated;

(4) All practicable steps were taken to minimize the impact of the excess emissions (including any bypass) on ambient air quality;

(5) The excess emissions were not part of a pattern indicative of inadequate design, operation, or maintenance;

(6) Off-shift and overtime labor were utilized where necessary to ensure that repairs were made as expeditiously as possible or that emissions were minimized to the maximum extent possible; and

(7) The level of economic savings, if any, accruing to the source owner or operator was de minimis.

(c) Any activity that could have been foreseen, avoided or planned for, or any breakdown that could have been avoided by the exercise of reasonable diligence shall not constitute grounds for an exemption under this section. Such activities include, but are not limited to, sudden breakdowns avoidable by better maintenance procedures, phasing in and out of process equipment and routine maintenance.

(d) A hearing on any petition for an exemption based upon the unavoidable breakdown of pollution control equipment shall be informal. The hearing shall be scheduled upon notice to the public. Reasonable opportunity to testify and for submission of questions by the public to the petitioner shall be afforded. The decision of the hearing officer will be made in writing within a reasonable period of time after the close of the hearing.