Section 57.304 - Bypass, excess emissions and malfunctions(a)Definition of excess emissions. For the purposes of this subpart, any emissions greater than those permitted by the NSO provisions established under § 57.302 (performance level of interim constant controls) or § 57.303 (plantwide emission limitation) of this subpart shall constitute excess emissions. Emission of any gas stream identified under § 57.301 (a), (b), (c), (d) or (e) of this subpart that is not treated by a sulfur dioxide constant control system shall also constitute an excess emission under this subpart.(b)The excess emission report. Each NSO shall require the smelter to report all excess emissions to the issuing agency, as provided in § 57.305(b) . The report shall include the following: (1) Identity of the stack or other emission points where the excess emissions occurred;(2) Magnitude of the excess emissions expressed in the units of each applicable emission limitation, as well as the operating data, documents, and calculations used in determining the magnitude of the excess emissions;(3) Time and duration of the excess emissions;(4) Identity of the equipment causing the excess emissions;(5) Nature and cause of such excess emissions;(6) Steps taken to limit the excess emissions, and when those steps were commenced;(7) If the excess emissions were the result of a malfunction, the steps taken to remedy the malfunction and to prevent the recurrence of such malfunction; and(8) At the smelter owner's election, the demonstration specified in paragraph (c) of this section.(c)Malfunction demonstration. Except as provided in § 57.302(e)(2) or in paragraph (d) or (e) of this section, any excess emission shall be a violation of the NSO unless the owner demonstrates in the excess emissions report required under paragraph (b) of this section that the excess emission resulted from a malfunction (or an unavoidable start up and shut down resulting from a malfunction) and that:(1) The air pollution control systems, process equipment, or processes were at all times maintained and operated, to the maximum extent practicable, in a manner consistent with good practice for minimizing emissions;(2) Repairs were made as expeditiously as practicable, including the use of off-shift labor and overtime;(3) The amount and duration of the excess emissions were minimized to the maximum extent practicable during periods of such emissions; and(4) The excess emissions were not part of a recurring pattern indicative of serious deficiencies in, or inadequate operation, design, or maintenance of, the process or control equipment.(d)Scheduled maintenance exception. Excess emissions occurring during scheduled maintenance shall not constitute violations of the NSO to the extent that: (1) The expected additional annual sulfur dioxide removal by any control system (including associated process changes) for which construction had not commenced (as defined in 40 CFR 60.2 (g) and (i) ) as of August 7, 1977 and which the smelter owner agrees to install and operate under subpart F, would have offset such excess emissions if the system had been in operation throughout the year in which the maintenance was performed;(2) The system is installed and operated as provided in the NSO provisions established under subpart F; and(3) The system performs at substantially the expected efficiency and reliability subsequent to its initial break-in period.(e) An NSO may provide that excess emissions which occur during acid plant start-up as the result of the cooling of acid plant catalyst due to the unavailability of process gas to an acid plant during a prolonged SCS curtailment or scheduled maintenance are not excess emissions. If the NSO does so provide, it shall also require the use of techniques or practices designed to minimize these excess emissions, such as the sealing of the acid plant during prolonged curtailments, the use of auxiliary heat or SO2 injected during the curtailment, or the preheating of the acid plant before start-up of the process equipment it serves.(f) Requirements for a smelter with constant controls that applies for a waiver. (1) If a smelter that has some interim constant controls applies for a waiver in accordance with subpart H, the following requirements shall apply pending action on the waiver application and following final action granting or approving a waiver: (i) The NSO shall require the smelter to implement maintenance and operation measures designed to reduce to the maximum extent feasible the potential for bypass of existing interim constant controls.(ii) Upon application for a waiver under subpart H, the smelter shall submit to the issuing agency for its approval and to EPA proposed maintenance and operation measures for compliance with the requirements of paragraph (i).(iii) The remainder of this subpart shall apply except that:(A) The emission limitations required under this subpart shall be based only on existing constant control equipment as upgraded through the improved maintenance and operation required by this paragraph, and(B) bypass of existing controls shall not constitute excess emissions, provided the maintenance and operation requirements and emission limitations prescribed by the NSO are satisfied.(2) After any denial of a waiver by the issuing Agency, or any disapproval by EPA of a waiver granted by the issuing agency, the NSO shall be amended consistent with the requirements of this subpart and § 57.702 .