Amended 05-18-10

CC Air Quality Regulations

25-i

SECTION 25: AFFIRMATIVE DEFENSE FOR EXCESS EMISSIONS DUE TO 

MALFUNCTIONS, STARTUP, AND SHUTDOWN

25.1 Applicability ..................................................................................................... 1

25.2 Affirmative Defense for Malfunctions............................................................... 1

25.3 Affirmative Defense for Startup and Shutdown ............................................... 2

25.4 Affirmative Defense for Malfunctions During Scheduled Maintenance............ 3

25.5 Demonstration of Reasonable and Practicable Measures .............................. 3

25.6 Reporting of Excess Emissions....................................................................... 3
Amended 05-18-10

CC Air Quality Regulations

25-1

25.1 Applicability

25.1.1 Section 25 establishes affirmative defenses for certain emissions in excess 

of an emission standard or limitation and applies to all emission standards 

or limitations except for the following standards or limitations:

(a) Promulgated pursuant to Sections 111 or 112 of the Act;

(b) Promulgated pursuant to Titles IV or VI of the Act;

(c) Contained in any Prevention of Significant Deterioration Authority to 

Construct Permit or Nonattainment Area New Source Review (NSR) 

Authority to Construct Permit issued directly by EPA; or 

(d) Included in an Authority to Construct Permit in order to satisfy the 

requirements of Section 12.2.10.

25.2 Affirmative Defense for Malfunctions

25.2.1 Emissions in excess of an applicable emission limitation due to a 

malfunction shall constitute a violation. The owner or operator of a source 

with emissions in excess of an applicable emission limitation due to 

malfunction has an affirmative defense to a civil or administrative 

enforcement proceeding based on that violation, other than a judicial action 

seeking injunctive relief, if the owner or operator of the source has complied 

with the reporting requirements of Section 25.6 and has demonstrated all of 

the following:

(a) The excess emissions resulted from a sudden and unavoidable 

breakdown of process equipment or air pollution control equipment 

beyond the reasonable control of the operator;

(b) The air pollution control equipment, process equipment, or processes 

were at all times maintained and operated in a manner consistent 

with good practice for minimizing emissions;

(c) If repairs were required, the repairs were made in an expeditious 

fashion when the applicable emission limitations were being 

exceeded. Off-shift labor and overtime were utilized where 

practicable to ensure that the repairs were made as expeditiously as 

possible. If off-shift labor and overtime were not utilized, the owner or 

operator satisfactorily demonstrated that the measures were 

impracticable;

(d) The amount and duration of the excess emissions (including any 

bypass operation) were minimized to the maximum extent practicable 

during periods of such emissions;
Amended 05-18-10

CC Air Quality Regulations

25-2

(e) All reasonable steps were taken to minimize the impact of the excess 

emissions on ambient air quality;

(f) The excess emissions were not part of a recurring pattern indicative 

of inadequate design, operation, or maintenance;

(g) During the period of excess emissions there were no exceedances of 

the relevant ambient air quality standards established in Section 11 

that could be attributed to the emitting source;

(h) The excess emissions did not stem from any activity or event that 

could have been foreseen and avoided, or planned, and could not 

have been avoided by better operations and maintenance practices;

(i) All emissions monitoring systems were kept in operation if at all 

practicable; and

(j) The owner or operator’s actions in response to the excess emissions 

were documented by contemporaneous records.

25.3 Affirmative Defense for Startup and Shutdown

25.3.1 Except as provided in Section 25.3.2, and unless otherwise provided for in 

the applicable requirement, emissions in excess of an applicable emission 

limitation due to startup and shutdown shall constitute a violation. The 

owner or operator of a source with emissions in excess of an applicable 

emission limitation due to startup and shutdown has an affirmative defense 

to a civil or administrative enforcement proceeding based on that violation, 

other than a judicial action seeking injunctive relief, if the owner or operator 

of the source has complied with the reporting requirements of Section 25.6 

and has demonstrated all of the following:

(a) The excess emissions could not have been prevented through 

careful and prudent planning and design;

(b) If the excess emissions were the result of a bypass of control 

equipment, the bypass was unavoidable to prevent loss of life, 

personal injury, or severe damage to air pollution control equipment, 

production equipment, or other property;

(c) The source’s air pollution control equipment, process equipment, or 

processes were at all times maintained and operated in a manner 

consistent with good practice for minimizing emissions;

(d) The amount and duration of the excess emissions (including any 

bypass operation) were minimized to the maximum extent practicable 

during periods of such emissions;
Amended 05-18-10

CC Air Quality Regulations

25-3

(e) All reasonable steps were taken to minimize the impact of the excess 

emissions on ambient air quality;

(f) During the period of excess emissions there were no exceedances of 

the relevant ambient air quality standards established in Section 11 

that could be attributed to the emitting source;

(g) All emissions monitoring systems were kept in operation if at all 

practicable; and

(h) The owner or operator’s actions in response to the excess emissions 

were documented by contemporaneous records.

25.3.2 If excess emissions occur due to a malfunction during routine startup and 

shutdown, then those instances shall be treated as other malfunctions 

subject to Section 25.2.

25.4 Affirmative Defense for Malfunctions During Scheduled Maintenance

If excess emissions occur due to a malfunction during scheduled maintenance, 

then those instances will be treated as other malfunctions subject to Section 

25.2.

25.5 Demonstration of Reasonable and Practicable Measures

For an affirmative defense under Section 25, the owner or operator of the source 

shall demonstrate, through submission of the data and information required by 

Section 25.6, that all reasonable and practicable measures within the owner or 

operator’s control were implemented to prevent the occurrence of the excess 

emissions.

25.6 Reporting of Excess Emissions

25.6.1 The owner or operator of any source required to obtain a permit under 

Section 12 shall report to the Control Officer emissions in excess of an 

applicable requirement or the emission limits prescribed by the permit. The 

report shall be in two (2) parts:

(a) Notification by telephone, facsimile or electronic mail within twentyfour (24) hours of the time the owner or operator first learns of the 

excess emissions; 

(b) Written notification by submission of an excess emission report 

containing the information required by Section 25.6.3 within seventytwo (72) hours of the notification required by paragraph (a) above.
Amended 05-18-10

CC Air Quality Regulations

25-4

25.6.2 The owner or operator of any source required to obtain a permit under 

Section 12 shall report to the Control Officer emissions that are in excess of 

an applicable requirement or emission limit that pose a potential imminent 

and substantial danger to public health, safety or the environment as soon 

as possible, but in no case later than twelve (12) hours after the deviation is 

discovered, with a written report submitted within two (2) days of the 

occurrence.

25.6.3 An excess emission report shall contain the following information:

(a) The identity of each stack or other emission point where the excess 

emissions occurred;

(b) The magnitude of the excess emissions expressed in the units of the 

applicable emission limitation and the operating data and calculations 

used in determining the magnitude of the excess emissions;

(c) The time and duration or expected duration of the excess emissions;

(d) The identity of the equipment from which the excess emissions 

emanated;

(e) The nature and cause of the emissions;

(f) The steps taken if the excess emissions were the result of a 

malfunction, to remedy the malfunction and the steps taken or 

planned to prevent the recurrence of the malfunctions;

(g) The steps that were or are being taken to limit the excess emissions; 

and

(h) If the source's permit contains procedures governing source 

operation during periods of startup or malfunction and the excess 

emissions resulted from startup or malfunction, a list of the steps 

taken to comply with the permit procedures.

25.6.4 In the case of continuous or recurring excess emissions, the notification 

requirements of Sections 25.6.1 and 25.6.2 shall be satisfied if the source 

provides the required notification after excess emissions are first detected 

and includes in the notification an estimate of the time the excess emissions 

will continue. Excess emissions occurring after the estimated time period or 

changes in the nature of the emissions as originally reported shall require 

additional notification pursuant to Sections 25.6.1 and 25.6.2.

History: Amended: March 27, 1980; September 3, 1981; April 21, 1983; July 8, 1985; November 18, 1993; December 

19, 1996; April 9, 2001; June 3, 2003; July 1, 2004; May 18, 2010.