(A) Particulate matter (PM) emission limit of fifteen-thousandths (0.015) pound per million Btu (lbs/MMBtu).

(B) A baghouse shall be operated all times the unit is combusting coal.

(C) The PM emission rate shall be determined using reference methods specified in 40 CFR 60, Appendix A, Method 5*, using stack tests, or alternative methods that are requested by SIGECO and approved by the department and U.S. EPA. SIGECO shall calculate the PM emission rate from biennial stack tests in accordance with 40 CFR 60.8(f)*. The results of each PM stack test shall be submitted to U.S. EPA within forty-five (45) days of completion of each test.

(B) As an alternative to the emission limitations specified in clause (A), beginning August 1, 1991, sulfur dioxide emissions from Culley Units 1 and 2 shall be limited in pounds per million Btu as follows:

	Facility Description	Emission Limitations
	Unit 1	0.0006
	Unit 2	4.40

(C) SIGECO shall notify the department and the U.S. EPA via certified mail at least fourteen (14) days prior to its intention to rely on the set of limits in clause (B) or to switch between sets of limits listed in clauses (A) through and (B).

(D) For the purposes of 326 IAC 7-2-1(c)(1), 326 IAC 7-2-1(e)(1), during thirty (30) day periods in which SIGECO relies on more than one (1) set of limits contained in clauses (A) through and (B), a separate thirty (30) day rolling weighted average for each set of limits shall be determined. Each thirty (30) day rolling weighted average shall be based on data from the previous thirty (30) operational days within the last ninety (90) days for that set of limits. If SIGECO does not operate thirty (30) days under any one (1) set of limits within the last ninety (90) days, the rolling weighted average shall be based on all operational days within the last ninety (90) days for that set of limits.

(E) Units 2 and 3 shall maintain a thirty (30) day rolling average sulfur dioxide (SO₂) removal efficiency of at least ninety-five percent (95%) using continuous emissions monitoring system (CEMS) data from both the inlet and outlet of the control device determined in accordance with 40 CFR 75*. A thirty (30) day rolling average sulfur dioxide (SO₂) removal efficiency means the percent reduction in the mass of a pollutant achieved by a unit's pollution control device over a thirty (30) day period using the thirty (30) day rolling average emission rate. A thirty (30) day rolling average emission rate shall be determined by calculating an arithmetic average of all hourly emission rates in lb/MMBtu for the current day and the previous twenty-nine (29) operating days. A new thirty (30) day rolling average emission rate shall be calculated for each new operating day. Each thirty (30) day rolling average emission rate shall include all startup, shutdown, and malfunction periods within an operating day.

(F) SIGECO shall continuously operate the flue gas desulfurization system (FGD) serving Units 2 and 3 at all times the units are in operation. Following startup of the units, SIGECO need not operate the FGD until either unit is fired with any coal. In the event of a planned FGD outage, SIGECO may continue to operate Unit 2, but shall burn down the coal existing in the Unit 2 bunker to the extent practicable, and, prior to shutting down the FGD, load compliance coal into the bunker for use until such time as the FGD resumes operation. In the event of an unplanned FGD outage, SIGECO shall feed compliance coal to the Unit 2 bunker until such time as the FGD resumes operation. Compliance coal is defined as two (2.0) lb/MMBtu SO₂, as demonstrated by a four (4) hour composite sample of the feed stock.

(A) As an alternative to the emission limitations specified in subdivisions (1) through (2) and upon fulfilling the requirements of clause (B), sulfur dioxide emissions from the Warrick and Culley Plants shall be limited to one (1) of the sets of limitations in pounds per million Btu specified as follows:

	Source	Facility Description	Emission Limitations
	(i) Warrick Plant SIGECO Culley	Units 1–4	5.4 per stack
		Unit 1	2.0
		Unit 2	2.0
		Unit 3	5.4
	(ii) Warrick Plant SIGECO Culley	Units 1–4	5.4 per stack
		Unit 1	0.0006
		Unit 2	3.2
		Unit 3	5.4
	(iii) Warrick Plant SIGECO Culley	Units 1–4	5.4 per stack
		Unit 1	5.4
		Unit 2	0.0006
		Unit 3	5.4

(B) SIGECO and ALCOA shall jointly provide notification via certified mail to the department and to the U.S. EPA prior to December 1, 1989, of their intention to begin permanent reliance on one (1) of the sets of limitations specified in clause (A). The written notification shall contain written evidence of a notarized agreement between SIGECO and ALCOA concerning the applicable set of limitations. Beginning December 31, 1989, sulfur dioxide emissions from each unit shall be limited to five and four-tenths (5.4) pounds per million Btu. Beginning August 1, 1991, SIGECO shall achieve compliance with the applicable emission limitation for each unit with a final emission limitation of three and two-tenths (3.2) pounds per million Btu or less.