S:\wp11\PERMITS\Issued.c\C30992.ISS.wpd PERMIT #C30992.000

(4/12/10) OWENS CORNING - ELOY 1 OWENS CORNING INSULATING SYSTEMS, LLC - ELOY

1. Introduction ........................................................................ 4 2. Listing of (Currently Federally Enforceable) Applicable Requirements ........................ 4

3. Material Permit Conditions ........................................................... 5 4. Authority to Construct ............................................................... 5 A. Primary Process Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 B. Emission Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 C. Monitoring Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

5. Emission Limitations and Controls ..................................................... 6 A. Applicable Limitations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 B. Allowable Emissions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 C. Fiberglass Insulation Plant - Particulate Emission limitations . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 1. Particulate Emission Limitations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 a. Fuel Burning Equipment ......................................... 6 b. Mass Emission Equation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 2. NSPS Requirements .................................................... 7 a. Emission Limitation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 b. Control Requirement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 i. Scrubber Operation ....................................... 7 ii. Objective Scrubber Flow and Pressure Drop Operating Standard . . . 7 3. Minor Source Status - Particulate Matter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 a. Emission Cap . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 b. Product Throughput Limitations .................................... 8 c. Emission Rate Limitations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 d. Monitoring Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 e. Emission Control Requirements - Process Controls . . . . . . . . . . . . . . . . . . . . . 8 i. Binder Formulation - PM 10 Precursors . . . . . . . . . . . . . . . . . . . . . . . . 8 ii. Expansion of Allowable Binder Formulations - PM 10 Precursors . . . . 9 iii. Maximum LOI .......................................... 9 iv. Batching and Furnace Baghouse Filters. ....................... 9 v. Sand Silo Vent Baghouse Filters . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 vi. Cooling Section and Hammermill Filter . . . . . . . . . . . . . . . . . . . . . . 10 vii. Urea Tank Vent Baghouse . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 4. Particulate Emissions - Opacity Limits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 a. SIP Limitation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 b. Locally Enforceable Limitation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 5. Particulate Emissions - Control of Fugitive Dust . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 6. Particulate Matter Reasonable Precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 D. HAP Emissions - Emission Cap - Minor Source Status . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 1. Emission Cap . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 2. Expansion of Allowable HAP Consumables - Change in Resin . . . . . . . . . . . . . . . . . . 11 E. Fuel Use Limitations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 F. General Maintenance Obligation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 6. Compliance Demonstration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 A. Regular Emissions Monitoring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12S:\wp11\PERMITS\Issued.c\C30992.ISS.wpd PERMIT #C30992.000

(4/12/10) OWENS CORNING - ELOY 2 1. Particulate matter monitoring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 a. Glass Pull Rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 b. Binder Solids Use Rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 2. Particulate matter - Instrumental emissions monitoring . . . . . . . . . . . . . . . . . . . . . . . . 14 3. Non-instrumental emissions monitoring - CO and oxides of nitrogen . . . . . . . . . . . . . 14 4. Non-instrumental Emissions Monitoring - VOCs and HAPs . . . . . . . . . . . . . . . . . . . . 14 B. Recordkeeping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 C. Compliance Reporting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 D. Annual Regular Compliance/Compliance Progress Certification . . . . . . . . . . . . . . . . . . . . . . . . 15 E. Testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 1. NSPS Performance Test - Particulate Matter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 a. Test Requirement and Testing Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 b. Performance Test Schedule . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 i. Initial Performance Tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 ii. Recurring Testing Cycle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 c. Test Report . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 2. PM 10Synthetic Minor Performance Testing - Emission Rate Verification . . . . . . . . . . 16 a. Testing Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 i. Emission points for testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 ii. Test Protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 iii. Operating Rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 iv. Feedstock Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 b. Performance Test Schedule . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 i. Initial Performance Tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 ii. Recurring Testing Cycle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 c. Test Report . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 3. PM 10Synthetic Minor Performance Testing - PM 10 - Curing Oven/Cooling Segment Capture Efficiency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 4. Performance Testing - Hazardous Air Pollutants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 a. Testing Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 i. Test Species . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 ii. Emission points for testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 iii. Operating Rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 iv. LOI Correction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 b. Performance Test Schedule . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 c. Test Protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 d. Test Report . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 5. Opacity Testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 6. Performance Test Mechanics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 7. Performance Test Reports . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 F. Ambient Impact Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 7. Other Reporting Obligations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 A. Deviations from Permit Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 B. Annual emissions inventory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 C. Reconstruction Reporting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 8. Fee Payment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

9. General Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 A. Term . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21S:\wp11\PERMITS\Issued.c\C30992.ISS.wpd PERMIT #C30992.000

(4/12/10) OWENS CORNING - ELOY 3 B. Basic Obligation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 C. Duty to Supplement Application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 D. Right to Enter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 E. Transfer of Ownership . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 F. Posting of Permit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 G. Permit Revocation for Cause . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 H. Certification of Truth, Accuracy, and Completeness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 I. Permit Expiration and Renewal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 J. Severability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 K. Permit Shield . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 L. Permit Revisions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 M. Permit Re-opening . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 N. Record Retention . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 O. Scope of License Conferred . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 P. Excess Emission Reports; Emergency Provision . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 10. Facility Specific Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 A. Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 B. Insignificant Activities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 C. Emission Inventory Table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26S:\wp11\PERMITS\Issued.c\C30992.ISS.wpd PERMIT #C30992.000

(4/12/10) OWENS CORNING - ELOY 4 1. Introduction This permit renewal pertains to an existing fibe rglass insulation manufacturing facility, operated by Owens Corning Insulating Systems, LLC. The SIC Code is 3296. The facility is located at 1825 W. Battaglia Road, Eloy, Arizona, upon a parcel also identified by Pinal County Assessor's Parcel # 408-01-003-8. The source is situated in an area classified as "attainment" for all pollutants. The emissions sources include electric glass melting furnaces, a fiberizing/forming section, and a curing oven, as more fully described in the E ngineering Review/Technical Support Document. During the review for this renewal, Owens Corning in formed PCAQCD of their intent to make a conversion to a starch based binder. In order to begin the trans ition period to this conversion, and still be able to use the current binder, this permit includes the new bi nder as an alternative operating scenario (AOS#1). Preliminary stack testing indicates that the use of th e starch based binder would signify a reduction in PM10 and PM2.5 emissions in the Forming, Curing and Coo ling sections of this facility. Also, total HAPs, formaldehyde and methanol emissions would be re duced by approximately 92%. CO and NOx emissions are not expected to change. Owens Corning informed PCAQCD during the renewal pro cess that while historically, melting of cullet had been minimal, as part a new Sustainability Policy, cullet now makes up approximately 85% of the feedstock. Therefore, the permit has been revised to require maximum cullet feed during the performance test in order to determine emission rates during cullet melting. In the absence of the limitations under this revision, the source would potentially constitute a "major emitting source" as defined in CAA §302(j), CAA §112, and §169(1). To avoid the additional regulatory burdens associated with such a classification, at the source operator's request, this permit includes proposed "federally enforceable provision(s)" ("FEP" ), designated pursuant to Code §3-1-084. A complete list of equipment from which emissions are allowed by this permit is given in Section 10 of this permit. This facility is subject to a fiberglass manufacturi ng new source performance standard ("fiberglass NSPS", "Subpart PPP"), promulgated under §111 of the Clean Air Act ("CAA"). This NSPS regulates particulate matter, as defined in 40 CFR 51.100(oo). The af orementioned "synthetic minor" limits also serve to impose strict particulate matter (PM10 and smaller) emissions limits. For additional information, see the Technical Support Document " (TSD) for this permit C30992.000, which outlines the facility configuration, operation, emissions, permitting history and other information. 2. Listing of (Currently Federally Enforceable) Applicable Requirements A. Those specific provisions of the Pinal-Gila C ounties Air Quality Control District ("PGAQCD") Regulations, as adopted by the Pinal County Board of Supervisors on March 31, 1975, and approved by the Administrator as elements of the Arizona State Implementation Plan ("SIP") at 43 FR 50531, 50532 (11/15/78), and specifically the following rules:

7-3-1.1 Visible Emissions - General 7-3-1.2 Particulate Emissions - Fugitive Dust 7-3-1.7.A Particulate Emissions - Fuel Burning Equipment 7-3-1.7.C Particulate Emissions - Fuel Burning Equipment 7-3-1.7.D Particulate Emissions - Fuel Burning EquipmentS:\wp11\PERMITS\Issued.c\C30992.ISS.wpd PERMIT #C30992.000

(4/12/10) OWENS CORNING - ELOY 5 7-3-1.7.E Particulate Emissions - Fuel Burning Equipment 7-3-1.8 Particulate Emissions - Process Industries 7-3-4.1 CO Emissions - Industrial B. Those specific provisions of the Pinal-Gila Coun ties Air Quality Control District Regulations, as last amended by the Pinal County Board of S upervisors on June 16, 1980, and approved by the Administrator as elements of the Arizona SIP at 47 FR 15579 (4/12/82), specifically, the following rules: 7-3-1.1 Visible Emissions; General 7-3-1.7.F Fuel Burning Equipment C. Those specific provisions of the Pinal County Ai r Quality Control District Regulations, as last amended by the Pinal County Board of Superv isors on October 27, 2004, and approved by the Administrator as elements of the Arizona SIP at 75 FR 17307 (4/6/2010), specifically, the following rules: 4-2-040 (Reasonable Precautions) Standards D. The New Source Performance Standard ("NSPS") for wool fiberglass insulation manufacturing plants, 40 CFR Part 60, Subpart PPP [ 40 CFR §§60.1 - 60.18, 60.680 - 60.685 (1993)].

3. Material Permit Conditions (Code §3-1-109) "Material permit conditions," as defined in Code §3- 1-109, are identified throughout the body of this permit by a designation of " MPC " in the heading of the section or subsection. 4. Authority to Construct [Federally enforceable - Code §§3- 1-010, 3-1-030, 3-1-040 (as amended 10/12/95) approved as a SIP Element at 61 FR 15717 (4/9/96)] This section is included to clearly define those lim its and requirements imposed as minor or major "new source review" requirements under PCAQCD's EPA-approved new source review program. A. Primary Process Equipment 1. Legacy Facility This document assumes, without affirmation, that process equipment, other than that enumerated below under a specific revision, is either "grandfathered" relative to minor new source review requirements, or alternatively has been properly installed pursuant to a competent minor new source review; the assumption of this subparagraph does not in any way excuse any prior or current violation, nor does it in any way shield the Permittee from a possible enforcement action. 2. Revision C30680.R01 expressly ratifies authority to install a third fiberizer, which may be operated without operational limitation.

B. Emission Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . MPC 1. Legacy FacilityS:\wp11\PERMITS\Issued.c\C30992.ISS.wpd PERMIT #C30992.000

(4/12/10) OWENS CORNING - ELOY 6 This document assumes, without affirmation, that control equipment, other than that enumerated below, is either "grandfathe red" relative to minor new source review requirements, or alternatively has been properly installed pursuant to a competent minor new source review; the assumption of this subparagraph does not in any way excuse any prior or current violation, nor does it in any way shield the Permittee from a possible enforcement action. 2. Revision C30608.R01 expressly requires that emissions from the third fiberizer be controlled by the existing scrubber. C. Monitoring Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . MPC 1. Legacy Facility Not applicable. 2. Revision C30680.R01 expressly requires: a. Installation and operation of a real-time monitoring and data management system, configured to continuously monito r, and subsequently aggregate, glass pull rates for each of the melting furnaces;

5. Emission Limitations and Controls A. Applicable Limitations (Code §3-1-082) Where different standards or limitations apply under this permit, the most stringent combination shall prevail and be enforceable. B. Allowable Emissions (Code § 3-1-081.A.2.) The owner/operator ("Permittee") is authorized to discharge or cause to discharge into the atmosphere those emissions of air contaminants as set forth in this permit. Unless exempted under Code §3-2-180, Permittee shall not use any material , process, or equipment not identified in this permit which will cause emissions of any regulated air pollutant in excess of the 5.5 pound-per-day de minimis amount, unless authorized by a permit revision as allowed under this permit, or by a separate permit issued by the District or other competent authority. C. Fiberglass Insulation Plant - Particulate Emission limitations

1. Particulate Emission Limitations a. Fuel Burning Equipment [Currently federally enforceable pursuant to PGAQCD Reg. 7-3-1.7 (3/31/75) approved as a SIP element at 43 FR 50531 (11/15/78)] For any individual piece of fuel burning equipment with a total heat input ("Q") defined in millions-of-BTU-per-hour, Permittee shall not allow emissions ("E") to exceed: E = 1.02Q 0.769 pounds-per-hour.S:\wp11\PERMITS\Issued.c\C30992.ISS.wpd PERMIT #C30992.000

(4/12/10) OWENS CORNING - ELOY 7 b. Mass Emission Equation [Currently federally enforceable pursuant to PGCAQCD Reg. 7-3-1.8 (3/31/75) approved as a SIP element at 43 FR 50531 (11/15/78)] (Code §5-24-1032) Permittee shall not cause or permit the emission of particulate matter into the atmosphere in any one hour from any process source, in total quantities in excess of the amount calculated by one of the following equations: For process sources having a process weight rate (“P”) of 60,000 pounds per hour (30 tons per hour) or less, the maximum allowable emissions (“E”) shall not exceed:

E = 4.10 P 0.67 pounds-per-hour 2. NSPS Requirements [Currently federally enforceable pursuant to 40 CFR §60.680 et seq., Code §6-1-030.11 and a delegation from the EPA Administrator dated 2/24/93].

........................................................................................ MPC

a. Emission Limitation Permittee shall not allow particulate matter (PM) from the affected facility to exceed 11 pounds per ton of glass pulled. PM means any airborne finely divided solid or liquid material with an aerodynamic diameter smaller than 100 micrometers (PM100 or less). For purpos es of this limitation, the affected facility includes the equipment comprising the forming section, where molten glass is fiberized and a fiberglass mat is formed; the curing section, where the binder resin in the mat is thermally "set" and the cooling section, where the mat is cooled. b. Control Requirement i. Scrubber Operation A cyclonic scrubber shall be operated by the Permittee to control particulate matter emissions from the fiberizing and forming section. The scrubber shall be equipped with monitoring devices that measures the gas pressure drop across the scrubber and the water flow rate to the scrubber. The pressure drop monitor is to be certified by its manufacturer to be accurate within ±0.1 inch water gauge over its operating range and the flow rate monitor is to be certified by its manufacturer to be accurate within ±5 percent over its operating range. The monitoring devices shall be recalibrated quarterly. ii. Objective Scrubber Flow and Pressure Drop Operating Standard Permittee shall maintain pressure drop across the scrubber within 2.31" w.c and 4.68" wc and the scrubber flow within 101.734 gallons per minute and 206.938 gallons per minute. These ranges represent 70 percent of the lowest and 130 percent of the highest respective flow and pressure drop values obtained during the most recent performance test.

3. Minor Source Status - Particulate Matter [Federally enforceable provision, pursuant toS:\wp11\PERMITS\Issued.c\C30992.ISS.wpd PERMIT #C30992.000

(4/12/10) OWENS CORNING - ELOY 8 Code §3-1-084 (8/11/94)] (Code §3-1-081.A)

............................. MPC a. Emission Cap Permittee shall limit emissions, in any consecutive twelve-month period, such that emissions of particulate matter, measured as PM 10 , do not exceed 95 tons. b. Product Throughput Limitations i. Permittee shall limit the glass pull rate to a maximum of 3,278 #/hr., based on a 12-month rolling average of calendar month-averages of hourly glass-pull rates. ii. Permittee shall limit binder solids use to 164 pounds/ton-of-glass , based on a 12-month rolling average of calendar month-averages of resin use and glass-pull rates.

c. Emission Rate Limitations The following limitations define approximately 91.5% of allowable facility-wide PM 10emissions. i. Permittee shall limit aggregate filterable and condensible PM 10 emissions from the line’s fiber/pack forming section, curing oven and cooling section to a maximum of 9.9 #/ton-of-glass pulled. For purposes of this limitation, the affected facility includes the equipment comprising the forming section, where molten glass is fiberized and a fiberglass mat is formed; the curing section, where the binder resin in the mat is thermally "set" and the cooling section, where the mat is cooled. ii. Permittee shall limit aggregate filterable and condensible PM 10emissions from the melting furnaces to a maximum of 1.16 #/ton-ofglass pulled. iii. Permittee shall limit aggregate filterable and condensible PM 10 emissions from the melting molten glass delivery system to a maximum of 1.72 #/ton-of-glass pulled. For purposes of this limitation, the affected facility includes the molten glass risers, gas-heated channels, and forehearths. d. Monitoring Requirements i. Permittee shall install and operate a real-time monitoring and data management system, configured to continuously monitor, and subsequently aggregate, glass pull rates from each fiberizer. e. Emission Control Requirements - Process Controls

i. Binder Formulation - PM 10 Precursors To conform to the emission projections upon which this permit isS:\wp11\PERMITS\Issued.c\C30992.ISS.wpd PERMIT #C30992.000

(4/12/10) OWENS CORNING - ELOY 9 based, Permittee shall use a specific binder formulation constituents, namely: - Owens Corning RE176 resin; - ammonium sulfate; - urea; - emulsified oil; - silane; - dye; - fresh and/or reclaimed water; - lignosulfonates; - urea formaldehyde resins; - silicone oils; - Starch Resin; - Citric Acid; - Sodium Hypophosphite. ii. Expansion of Allowable Binder Formulations - PM 10 Precursors Permittee may change the specification of the binder formulation, by: - Making a written determination for any added PM 10 precursor product that the continuous use of the new product at the maximum possible use rate will still not cause the Permittee to produce PM 10 emissions that exceed 95% of the PM 10 cap imposed under this permit; - Following the change-notice procedures set forth in Code §3- 2-180, and including within the notice to the District a copy of the written determination described in the preceding paragraph; and - unless a convincing showing that the PM 10 PTE will not increase is submitted, within 30 days of a change in binder formulation, Permittee shall conduct a performance test to verify that the change in PM 10 emissions from the emissions points identified in §5.C.2.a. will not result in PM 10emissions that exceed 95% of the PM 10 cap imposed under this permit. A convincing showing may consist of performance tests from other facilities, showing no impact on particulate emissions as a result of the same change in binder formulation.

iii. Maximum LOI LOI of the finished product, exclusive of any backing, shall not exceed 6.25% by weight for the phenol-formaldehyde formulation and 7% for the Starch formulation. Compliance shall be based on a 12-month rolling average of monthly LOI values, as determined below. iv. Batching and Furnace Baghouse Filters. Permittee shall operate two (2) MikroPul Pulse Jet filters, configured to limit emissions to no more than 0.05 grain/dscf, to control particulateS:\wp11\PERMITS\Issued.c\C30992.ISS.wpd PERMIT #C30992.000

(4/12/10) OWENS CORNING - ELOY 10 emissions from the batching bin and furnaces. v. Sand Silo Vent Baghouse Filters (Code 3-1-081.) Permittee shall operate eight (8) micro pulse bin vent filters, configured to limit emissions to no more than 0.02 grain/dscf, to control particulate matter emissions from the batch ingredient and mixed batch storage silos. vi. Cooling Section and Hammermill Filter Permittee shall direct exhaust from the cooling section and the product recovery hammermill to a filter box, configured to limit emissions to no more than 0.01 grain/dscf, to control particulate matter emissions from the cooling section and hammermill. vii. Urea Tank Vent Baghouse (Code 3-1-081.) Permittee shall operate a baghouse, configured to limit emissions to no more than 0.02 grain/dscf, to control particulate matter emissions from the urea storage tank. 4. Particulate Emissions - Opacity Limits

a. SIP Limitation - [Federally enforceable pursuant to PGAQCD Reg. 7-3-1.1 (6/16/80) approved as a SIP Element at 47 FR 15579 (4/12/82)] The opacity of any plume or effluent shall not be greater than 40 percent as determined by reference method 9 in the Arizona Testing Manual. b. Locally Enforceable Limitation (Code §2-8-300) The opacity of any plume or effluent from any point source not subject to a New Source Performance Standard adopted under Chapter 6 of the Code, and not subject to an opacity standard in Chapter 5 of the Code, shall not be greater than 20% as determined in Method 9 in 40 CFR 60, Appendix A. Affected facilities are those not subject to the NSPS including, but not limited to: raw material handling, glass melting, and product finishing. 5. Particulate Emissions - Control of Fugitive Dust [Currently federally enforceable pursuant to PGAQCD Reg. 7-3-1.2 (3/31/ 75) approved as a SIP element at 43 FR 50531 (11/15/78)] Permittee shall not cause, suffer, allow or pe rmit a building or its appurtenances or open area to be used, constructed, repaired, altered or demolished without taking reasonable precautions to prevent particulate matter fro m becoming airborne. Particulate emissions shall be kept to a minimum by such measures as wetting down, covering, landscaping, paving, treating or by other reasonable means.

6. Particulate Matter Reasonable Precautions [Currently federally enforceable pursuant to PCAQCD Reg. 4-2-040 (10/27/04) approved as a SIP element at 75 FR 17307]S:\wp11\PERMITS\Issued.c\C30992.ISS.wpd PERMIT #C30992.000

(4/12/10) OWENS CORNING - ELOY 11 a. Permittee shall not cause, suffer, allow, or permit a building or its appurtenances, subdivision site, driveway, parking area, v acant lot or sales lot, or an urban or suburban open area to be constructed, used, altered, repaired, demolished, cleared, or leveled, or the earth to bemoved or excavated, or fill dirt to be deposited, without taking reasonable precautions to effectively prevent fugitive dust from becoming airborne. b. Permittee shall not cause, suffer, allow, or permit a vacant lot, or an urban or suburban open area, to be driven over or used by motor vehicles, such as but not limited to all-terrain vehicles, trucks, cars, cycles, bikes, or buggies, without taking reasonable precautions to effectively prevent fugitive dust from becoming airborne. c. Permittee shall not disturb or remove soil or natural cover from any area without taking reasonable precautions to effectively prevent fugitive dust from becoming airborne. d. Permittee shall not crush, screen, handle or convey materials or cause, suffer, allow or permit material to be stacked, piled or otherwise stored without taking reasonable precautions to effectively prevent fugitive dust from becoming airborne. e. Stacking and reclaiming machinery utilizedat storage piles shall be operated at all times with a minimum fall of material and in such a manner, or with the use of spray bars and wetting agents, as to prevent excessive amounts of particulate matter from becoming airborne. Other reasonable precautions shall be taken, as necessary, to effectively prevent fugitive dust from becoming airborne. f. Permittee shall not cause, suffer, allow or permit transportation of materials likely to give rise to fugitive dust without taking reasonable precautions to prevent fugitive dust from becoming airborne. Earth and other material that is tracked out or transported by trucking and earth moving equipment on paved streets shall be removed by the party or person responsible for such deposits. D. HAP Emissions - Emission Cap - Minor Source Status [Federally enforceable provision, pursuant to Code §3-1-084 (8/11/94)] (Code §3-1-081.A)

.......................... MPC 1. Emission Cap Permittee shall limit emissions, in any consecutive twelve-month period, such that: a. Emissions of any single HAP, specifically methanol, formaldehyde, and phenol, are less than 8 tons; and

b. Emissions of all HAPs combined are less than 20 tons. 2. Expansion of Allowable HAP Consumables - Change in Resin Permittee may change the resin by: a. Making a written determination for change in resin that the use of a new resin or binder ingredient at the maximum possible use rate will still not cause theS:\wp11\PERMITS\Issued.c\C30992.ISS.wpd PERMIT #C30992.000

(4/12/10) OWENS CORNING - ELOY 12 Permittee to produce HAP or VOC emissi ons that exceed 80% of the relevant "major source" threshold; and b. Following the change-notice procedures set forth in Code §3-2-180, and including within the notice to the District a copy of the written determination described in the preceding paragraph.; and c. unless a convincing showing that the formaldehyde and methanol PTEs will not increase is submitted, within 30 days of a change in resin, Permittee shall conduct a performance test to verify that the change in formaldehyde and methanol emissions, in accordance with the requirement of §6.E.4., and verify that continued use of the new resin will not result in violation of the HAP limitations under this permit. A convincing showing may consist of performance tests from other facilities showing that emissions of VOC and HAP will not exceed 80% of the relevant “major source” threshold as a result of the same change in resin or binder ingredient. E. Fuel Use Limitations [Code §§3-1-081.] 1. Primary Fuel The Permittee is allowed to burn only natural gas. 2. Other Fuels (Code §§3-1-081.G, 5-23-1010.F) The Permittee shall not use used oil, used oil fuel, hazardous waste, and hazardous waste fuel (as defined in federal, state, or c ounty codes and rules) without first obtaining a separate permit or an appropriate permit revision. F. General Maintenance Obligation (Code §§3-1-081.E., 8-1-030.A.3) At all times, including periods of start-up, shutdow n, and malfunction, owners and operators shall, to the extent practicable, maintain and operatethe permitted facility including associated air pollution control equipment in a manner consistent with good air pollution control practice for minimizing emissions. 6. Compliance Demonstration A. Regular Emissions Monitoring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . MPC 1. Particulate matter monitoring [Federally enforceable provision, pursuant to Code §3-1- 084 (8/11/94)]

a. Glass Pull Rate Within ten days of the end of every calendar month, Permittee shall log the aggregate monthly glass pull rate from all furnaces; Permittee shall further calculate a 12-month rolling average of monthly average glass pull rates, and shall note whether that calculated aver age conforms to the glass-pull-ratelimitation defined above; and

b. Binder Solids Use RateS:\wp11\PERMITS\Issued.c\C30992.ISS.wpd PERMIT #C30992.000

(4/12/10) OWENS CORNING - ELOY 13 i. Within ten days of the end of every calendar month, Permittee shall log the aggregate monthly binder solid use rate and verify whether that average use rate conforms to the permit requirement defined above; ii. Permittee shall further calculate the monthly average relationship of binder solid use versus glass-pull-rate, expressed as gallons-resin/tonof-glass, and from that value shall calculate a 12-month rolling average of monthly average binder solid use rates, and shall note whether that calculated average conforms to the resin-use limit defined above.

c. Finished Product Production Rate Since the emissions authorized under this permit constitute a direct function of the material throughput at the source, the Permittee shall maintain records, updated at least monthly, of the weight of material shipped from the plant.

d. Uncured Batt Moisture Content For purposes of establishing a relati onship between emissions and moisture content of the glass fiber insulation, Permittee shall keep records of the measurements of ramp moisture content of the glass fiber insulation entering the curing oven in accordance with current practices. Within 10 days following the close of every calendar month, permittee shall calculate the monthly average moisture content for the preceding month based on an average of those values, and based on that new monthly value, shall calculate a new 12-month rolling average of moisture content values.

e. Maximum LOI On an hourly basis, permittee shall determine and record the LOI of finished product. Within 10 days following the close of every calendar month, permittee shall calculate the average monthly LOI for the preceding month based on an average of those hourly values, and based on that new monthly value, shall calculate a new 12-month rolling average of LOI values, and shall note whether the calculated value conforms to the LOI limit established above. f. Baghouses and Filter Box Inspections To verify effective control of the baghouses, micro pulse bin vent filters and cooling segment filter box, their exhausts shall be checked for visible emissions with the following frequency at least: i. Raw material bin baghouses: at the time of product delivery.

ii. Furnace exhaust and furnace hall batch bin dust collectors: at least once daily. iii. All other baghouses and filter boxes: on a quarterly basis. If visible emissions are observed during any of the checks, the baghouse or filter box shall be inspected and cleaned or re paired as necessary. Permittee shall maintain records of these inspections, th e cause for the visible emissions and theS:\wp11\PERMITS\Issued.c\C30992.ISS.wpd PERMIT #C30992.000

(4/12/10) OWENS CORNING - ELOY 14 corrective measures taken. 2. Particulate matter - Instrumental emissions monitoring [Currently federally enforceable pursuant to 40 CFR §60.684(a), Code §6-1- 030.11 and a delegation from the EPA Administrator dated 2/24/93]. Permittee shall measure and record the gas pressure drop across the scrubber and the scrubber water flow at least once each four hours the plant is in operation, and note whether those values comply with the permit limitations above. 3. Non-instrumental emissions monitoring - CO and oxides of nitrogen As a surrogate means to monitor emissions of CO and oxides of nitrogen, Permittee shall maintain monthly records of fuel used. 4. Non-instrumental Emissions Monitoring - VOCs and HAPs As a surrogate means to monitor emissions of VOCs and HAPs, Permittee shall maintain monthly records of the use of any VOC-Cont aining Materials. For purposes of this section, VOC-Containing materials shall mean those materials that contain VOCs as defined in Pinal County Code §1-3-140.147 except for materials with anticipated use of less than 2,000 tons per year and with a VOC concentration less than 1% by weight. B. Recordkeeping [Federally enforceable provision, pursuant to Code §3-1-084 (8/11/94)] (Code §3-1-083)

Permittee shall maintain records of: 1. All information required pursuant to any federally enforceable provision of this permit, recorded in a permanent form suitable for inspection. 2. Permittee shall maintain records of the weight of product produced and the amount of resin purchased for inclusion into the semi-annual report. 3. The occurrence and duration of any start-up, shutdown or malfunction in the operation of the permitted facility or any air pollution control equipment. For purposes of this provision, a "shut-down" means a cessation of operations at the entire facility for more than seven days, and a "start-up" constitutes the reactivation of the facility after a "shutdown." C. Compliance Reporting [Federally enforceable provision, pursuant to Code §3-1-084 (8/11/94)] (Code §3-1-083.A) In order to demonstrate compliance with the provisions of this permit, the Permittee shall submit a semi-annual report containing a summary of the information required to be recorded pursuant to this permit, which summary shall clearly show that Permittee has complied with the operational and emissions limitations under this permit. All instances of deviations from permit requirements shall be clearly identified in such reports. For brevity, such deviation reports may incorporate by reference any written supplemental upset reports filed by Permittee during the reporting period. The report shall be submitted to the District within 30 days after the end of each calendar half. Appendix A of this permit is a form which may be used for the report.S:\wp11\PERMITS\Issued.c\C30992.ISS.wpd PERMIT #C30992.000

(4/12/10) OWENS CORNING - ELOY 15 D. Annual Regular Compliance/Compliance Progr ess Certification (Code §3-1-083.A.4.) Permittee shall annually submit a certification of compliance with the provisions of this permit. The certification shall: 1. Be signed by a responsible official, namely the proprietor, a general partner, the president, secretary, treasurer or vice-president of the corpor ation, or such other person as may be approved by the Control Officer as an administrative amendment to this permit; 2. Identify each term or condition of the perm it that is the basis of the certification; 3. Verify the compliance status with respect to each such term or condition; 4. Verify whether compliance with respect to each such term or condition has been continuous or intermittent; 5. Identify the permit provision, or other, compliance mechanism upon which the certification is based; and 6. Be postmarked within thirty (30) days of each anniversary date of the issuance of the permit. E. Testing (Code §3-1-170.)

1. NSPS Performance Test - Particulate Matter [Currently federally enforceable pursuant to 40 CFR §§60.685 & 60.684(a), Code §6-1-030.11 and a delegation from the EPA Administrator dated 2/24/93]. (Code §§3-1-160 & 3-1-170) a. Test Requirement and Testing Conditions Performance stack testing for particulate matte r, using standard EPA test methods 5, 5E and/or 5/202 combined (40 CFR Part 60, Appendix A.), shall be conducted on the fiber/pack forming section stack (scrubber), both curing oven exhaust stacks, and the cooling section vent. Three tests of at least 2 hours duration with a sample volume of 2.55 dscm shall be run on each tested stack. These tests shall be performed at the maximum practical production rate while the product with the highest LOI expected to be produced is being manufactured. At 30-minute intervals during each test run, the gas pressure drop across the scrubber and the water flow rate to the scrubber shall be measured and recorded. The test plan protocolfor the tests, required below, shall indicate which test method will be used and include provision for verifying that the pressure pickup locations correctly reflect gas flow changes.

b. Performance Test Schedule

i. Initial Performance Tests The first of these tests shall be conducted within the later of 180 days from the issuance of this permit revision or (1) one year from the previous performance test for particulate matter. ii. Recurring Testing CycleS:\wp11\PERMITS\Issued.c\C30992.ISS.wpd PERMIT #C30992.000

(4/12/10) OWENS CORNING - ELOY 16 Testing shall be performed every 5 years, no later than the anniversary date of the initial performance test. c. Test Report The test report shall: i. Quantify the PM 10 emission rate, expressed in terms of pounds of PM 10/ton of glass pulled ii. Define the scrubber operating parame ters, namely the range of pressure drops across the scrubber and the range of volumetric flows of water through the scrubber. Upon submittal of the corresponding test report, those test-revised parameters shall constitute de facto revisions to this permit, and in accord with §5.C.2. b.ii, Permittee shall operate the scrubber within the newly derived parameters.

2. PM 10Synthetic Minor Performance Testing - Emission Rate Verification . . . . . . . . MPC a. Testing Conditions i. Emission points for testing This testing requirement applies to PM 10 emissions, both filterable and condensible, from: - the melting furnaces - the molten glass delivery system that buffers and delivers molten glass to the fiberizers, including the channel and forehearth; - the fiber and pack forming system (scrubber); - the pack curing system; and - the pack cooling system.

ii. Test Protocol Permittee shall develop and execute a test protocol that will define what test methods will be used, how the test will quantify capture efficiency at the affected emission points, and how the test will quantify the mass of emissions, expressed as # PM 10/ton of glass pulled. The protocol shall also include a summary of the various materials formed over the past year and the percent of time during which those materials were produced that would have a higher potential PM10 emissions. If the test is performed while producing a material that does not have the highest potential PM10 emissions, a retest may be required if the test results do not demonstrate a sufficient margin to assure compliance during all operating scenarios. iii. Operating Rate Tests shall be run at a maximum operating capacity, at a minimum of at least 95% of the nominal 3,278 #/hr. glass pull rate.S:\wp11\PERMITS\Issued.c\C30992.ISS.wpd PERMIT #C30992.000

(4/12/10) OWENS CORNING - ELOY 17 iv. Feedstock Materials The furnace and glass delivery systems shall be tested while charging feedstock that utilizes the maximum amount of cullet.

b. Performance Test Schedule

i. Initial Performance Tests Initial performance tests shall be conducted within the latter of 180 days from the issuance of this permit revision, or one (1) year from the previous performance test. ii. Recurring Testing Cycle Testing shall be performed every 5 years, no later than the anniversary date of the initial performance test. Additionally, a performance test shall be conducted within 60 days if the glass pull rate increases by 5% or more (as averaged over any daily period) from the test glass pull rate established during any performance test within the last 5 years conducted. The performance test shall be performed within 5 percent above or below the glass pull rate that triggered this re-testing requirement. c. Test Report The test report shall identify the test-derived pound-per-ton emission rates for the melting furnaces and the molten glass delivery system, and shall state whether those observed emission rates conform to the corresponding limitations imposed above under this permit. The te st report shall further recalculate the facility-wide annual PM 10 emission potential, based on the test-derived shortterm PM 10 emission rates, adjusted upward to reflect an allowable 6.25% LOIphenol formaldehyde formulation and 7.0% LOI Starch formulation, and a glasspull-rate corresponding to continuous operation at the allowable average glasspull-rate defined under this permit. The test report shall include average LOI and batt moisture content observed during the test. The test report shall also include opacity observations of the sc rubber exhaust, curing segment exhaust and cooling segment exhaust, all of which shall reflect opacity during the corresponding PM 10 stack test.

3. PM 10Synthetic Minor Performance Testing - PM 10 - Curing Oven/Cooling Segment Capture Efficiency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . MPC To verify that all emissions from the curing oven and cooling segment are in fact being accounted for in assessing compliance with the emission caps under this permit, permittee shall either: a. Conduct a performance test to define the inlet velocities at regulated openings in the curing oven and cooling segment.; or b. During the testing required by other s ubsections, conduct visual confirmations that the tell-tale indicators on the inlet and outlet from the curing oven/coolingS:\wp11\PERMITS\Issued.c\C30992.ISS.wpd PERMIT #C30992.000

(4/12/10) OWENS CORNING - ELOY 18 segment each show a net inward velocity, and log those observations. 4. Performance Testing - Hazardous Air Pollutants [Federally enforceable provision, pursuant to Code §3-1-084 (8/11/94)]

................................... MPC A performance stack testing for formaldehyde, phenol, and methanol shall be conducted, using EPA test methods 316 and 308 for formaldehyde and methanol respectively, and BAAQMD Method ST-16 for phenol, on the scrubber stack, the curing oven exhaust stacks, and the cooling segment stack within five (5) years from the date of the previous performance test for these pollutants. Three tests shall be run on each stack emitting gases from the plant, specifically, the scrubber stack and the exhausts from the curing oven and the cooling segment. These tests shall be performed at the maximum practical fiberglass production rate, and under substantia lly identical operating conditions. A test plan protocol for each test shall be submitted to the District at least sixty (60) days, or such other period as may be approved in writing by the Control Officer, before the testing; the protocol shall call for the test process to conclude in a report, defining the mass of formaldehyde emissions expressed as a function of the volumetric quantity ( i.e. gallons) of resin used or the relationship with binder solids used per ton of glass. a. Testing Conditions i. Test Species The tests shall quantify emissions of methanol, formaldehyde and phenol. ii. Emission points for testing This testing requirement applies to the scrubber stack, the curing oven stacks, and the cooling segment stack. iii. Operating Rate Tests shall be run at a maximum operating capacity, at a minimum of at least 95% of the nominal 3,278 #/hr. glass pull rate.

iv. LOI Correction The LOI of the finished insulation material produced during the performance test shall be determined, and observed HAP emission rates shall be proportionally increased in linear fashion to reflect an LOI of 6.25% with phenol formaldehyde formulations and 7% for Starch formulation.

b. Performance Test Schedule Initial performance tests shall be conducted within the latter of 180 days from the issuance of this permit revision, or one (1) year from the previous performance test.

c. Test ProtocolS:\wp11\PERMITS\Issued.c\C30992.ISS.wpd PERMIT #C30992.000

(4/12/10) OWENS CORNING - ELOY 19 The protocol shall also include a summary of the various materials formed over the past year and the percent of time during which those materials were produced that would have a higher potential HAP emissions. If the test is performed while producing a material that does not have the highest potential HAP emissions, a retest may be required if the test results do not demonstrate a sufficient margin to assure compliance during all operating scenarios. d. Test Report The test report shall identify aggregat e HAP, and individual HAP emission rates for each of the tested species for each of the affected emission points, and shall show the LOI correction required above. The test report shall further include average LOI and batt moisture content observed during the test. 5. Opacity Testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . MPC a In addition to the opacity monitoring described in a previous section of this permit, within 6 months of the issuance of this permit, and every 6 months after that, Permittee shall conduct a full Method 9 opacity test performed by a certified opacity observer on the all stacks and emission points during operations, and shall provide a copy of the resulting report to the District. b. Method 9 opacity tests shall consist of at least 1 hour of data, averaged in blocks of consecutive 6-minute periods. The average opacity for each 6-minute period shall be recorded at the end of each period.

6. Performance Test Mechanics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . MPC In all cases, tests shall be run: a. In accord with a District-approved test plan, which shall be submitted at least 30 days (or such other time as the Control Officer may approve in writing) prior to the scheduled test date; b. With appropriate prior written notice to the District, which notice shall be not less than five (5) working days; c. The performance tests shall be run at the maximum practical load possible; d. Using the reference methods and procedures set forth in 40 CFR Part 60, Appendix A; or such other alternative reference methods and procedures as the EPA Administrator may approve in writing, provided copies of any such alternative and Administrator-approval shall be included in the test plan submitted to the District. 7. Performance Test Reports . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . MPC A copy of any test report required shall be submitted to the District for approval within forty-five (45) days after the test. F. Ambient Impact Analysis (Code §3-1-150)S:\wp11\PERMITS\Issued.c\C30992.ISS.wpd PERMIT #C30992.000

(4/12/10) OWENS CORNING - ELOY 20 Within 90 days of the submission of the test reports for the initial round of PM 10 and formaldehyde performance tests required above, Permittee shall u tilize that refined emission data, and submit for PCAQCD approval a protocol for a modeling analysis designed to quantify off-site PM 10 and formaldehyde impacts. The modeling analysis shall be based on emission rates reflecting the testderived short-term emission rates, adjusted upward to reflect an allowable 6.25% LOI phenol formaldehyde formulation and 7% for Starch fo rmulation, and a glass-pull-rate corresponding to the greater of 45 tons-per-day or the highest daily (24-hour) glass pull rate actually observed in the preceding 24 calendar months. That protocol shall address both downwash and non-downwash conditions. Within 90 days of PCAQCD approval of the protocol, Permittee shall submit a report defining the results of that analysis, including a clear definition of anticipated 24-hour ambient PM 10impacts from the facility. 7. Other Reporting Obligations A. Deviations from Permit Require ments (Code §3-1-81.A.5.b.) Permittee shall report any deviation from the requirements of this permit along with the probable cause for such deviation, and any corrective actions or preventative measures taken to the District within ten days of the deviation unless earlier notification is required by the provisions of this permit. B. Annual emissions inventory [Code §3-1-103. (Nov. '93)] Since this source would be subject to an ADEQ permitting requirement, Permittee shall complete and submit to the District an annual emissions inventory, disclosing actual emissions for the preceding calendar year. The submittal shall be made on a form provided by the District. The inventory is due by the latter of March 31, or nine ty (90) days after the form is furnished by the District. C. Reconstruction Reporting [Currently federally enforceable pursuant to 40 CFR Part 60, Subpart A, Code §6-1-030.1 and a delegation from the EPA Administrator dated 2/24/93]. If the Permittee proposes to replace components of the wool fiberglass insulation manufacturing facility, and the fixed capital cost of the new components exceeds 50 percent of the fixed capital cost that would be required to construct a co mparable entirely new facility, the Permittee shall notify the District of the proposed replacements. The notice shall be postmarked 60 days (or as soon as practicable) before construction is comme nced, and must include the information required under 40 CFR §60.15(d) (1993). 8. Fee Payment (Code §3-7-600.) As an essential obligation under this permit, a permit fee shall be assessed by the District and paid by Permittee in accord with the provisions of Code Chapter 3, Article 7, as they may exist at the time the fee is due. The permit fee shall be due annually on or before the anniversary date of the issuance of an individual permit, or formal grant of approval to operate under a general permit, or at such other time as may be designated now or hereafter by rule. The District w ill notify the Permittee of the amount to be due, as well as the specific date on which the fee is due.

9. General Conditions A. Term (Code §3-1-089)S:\wp11\PERMITS\Issued.c\C30992.ISS.wpd PERMIT #C30992.000

(4/12/10) OWENS CORNING - ELOY 21 This permit shall have a term of five (5) years, measured from the date of issuance. B. Basic Obligation (Code §3-1-081.) Permittee shall operate in compliance with all c onditions of this permit, the Pinal County Air Quality Control District ("the District") Code of Regulations ("Code"), and all State and Federal laws, statutes, and codes relating to air quality that apply to these facilities. Any permit noncompliance is grounds for enforcement action; for a permit termination, revocation and reissuance, or revision; or for denial of a permit renewal application and may additionally constitute a violation of the CAA. C. Duty to Supplement Application (Code §§3- 1-050.H., 3-1-081.A.8.e., 3-1-087.A.1.c., 3-1-110.) Even after the issuance of this permit, a Permittee, who as an applicant who failed to include all relevant facts, or who submitted incorrect info rmation in an application, shall, upon becoming aware of such failure or incorrect submittal, promptly submit a supplement to the application, correcting such failure or incorrect submittal. In addition, Permittee shall furnish to the District within thirty days any information that the Control Officer may request in writing to determine whether cause exists for modifying, revoking and reissuing, or terminating this permit or to determine compliance with this permit and/or the Code. D. Right to Enter (Code §§ 3-1-132, 8-1-050) Authorized representatives of the District sh all, upon presentation of proper credentials and a showing that the District representative is equippe d with certain safety equipment, namely a hard hat, be allowed: 1. To enter upon the premises where the source is located or in which any records are required to be kept under the terms and conditions of this permit; 2. To inspect any equipment, operation, or method required in this permit; and 3. To sample emissions from the source. E. Transfer of Ownership This permit may be transferred from one person to another by notifying the District at least 30 days in advance of the transfer. The notice shall contain all the information and items required by Code § 3-1-090. The transfer may take place if not denied by the District within 10 days of the receipt of the transfer notification. F. Posting of Permit (Code §3-1-100) Permittee shall firmly affix the permit, an appr oved facsimile of the permit, or other approved identification bearing the permit number, upon such bu ilding, structure, facility or installation for which the permit was issued. In the event that suchbuilding, structure, facility or installation is so constructed or operated that the permit cannot be so placed, the permit shall be mounted so as to be clearly visible in an accessible place within a reasonable distance of the equipment or maintained readily available at all times on the operating premises. G. Permit Revocation for Cause (Code §3-1-140)S:\wp11\PERMITS\Issued.c\C30992.ISS.wpd PERMIT #C30992.000

(4/12/10) OWENS CORNING - ELOY 22 The Director of the District ("Director") may revoke this permit for cause, which cause shall include occurrence of any of the following: 1. The Director has reasonable cause to believe that the permit was obtained by fraud or material misrepresentation; 2. Permittee failed to disclose a material fact required by the permit application form or a regulation applicable to the permit; 3. The terms and conditions of the permit have been or are being violated. H. Certification of Truth, Accuracy , and Completeness (Code § 3-1-175.) Any application form, report, or compliance certification submitted pursuant to the Code shall contain certification by a responsible official of truth, accuracy, and completeness. This certification and any other certification required under Chapter 3 of the Code shall state that, based on information and belief formed after reasonable inquiry, the statements and information in the document are true, accurate, and complete. I. Permit Expiration and Renewal [40 CFR §§70.5(a)(1)(iii), 70.7(c)] (Code §3-1-050.C) Expiration of this permit will terminate the facility’s right to operate unless either a timely application for renewal has been submitted in accordance with §§3-1-050, 3-1-055, 3-1-060, or a substitute application for a general permit under §3-5-490. For Class I permit renewals, a timely application is one that is submitted at least 6 months, but not greater than 18 months prior to the date of permit expiration. For Class II or Class III permit renewals, a timely application is one that is submitted at least 3 months, but not greater th an 12 months prior to the date of the permit expiration. J. Severability (Code §3-1-081.A.7) The provisions of this permit are severable, and if any provision of this permit is held invalid the remainder of this permit shall not be affected thereby. K. Permit Shield (Code § 3-1-102.) 1. Compliance with the terms of this permit shall be deemed compliance with any applicable requirement identified in this permit. 2. It shall not be a defense for a permittee in an enforcement action that it would have been necessary to halt or reduce the permitted activity in order to maintain compliance with the conditions of this permit. L. Permit Revisions (Code Chapter 3, Article 2) 1. This permit may be revised, reopened, re voked and reissued, or terminated for cause. Other than as expressly provided in Code Chap ter 3, Article 2, the filing of a request by the permittee for a permit revision, revocation and reissuance, or termination, or of a notification of planned changes or anticipated noncompliance does not stay any permit condition. 2. The permittee shall furnish to the Control Officer, within a reasonable time, anyS:\wp11\PERMITS\Issued.c\C30992.ISS.wpd PERMIT #C30992.000

(4/12/10) OWENS CORNING - ELOY 23 information that the Control officer may request in writing to determine whether cause exists for revising, revoking and reissuing, or terminating the permit or to determine compliance with the permit. 3. Permit amendments, permit revisions, and changes made without a permit revision shall conform to the requirements in Article 2, Chapter 3, of the Code. 4. Should this source become subject to a standard promulgated by the Administrator pursuant to CAA §112(d), then Permittee shall, within twelve months of the date on which the standard is promulgated, s ubmit an application for a permit revision demonstrating how the source will comply with the standard. (Code §3-1-050.C.5) 5. Revision to Permit Provisions Designated as Federally Enforceable Pursuant to Code §3- 1-084 [Federally enforceable provision, pursuant to Code §3-1-084 (8/11/94)] As an express condition of preserving the fe deral enforceability of any provision of this permit designated "federally enforceable" pursuant to Code §3-1-084, Permittee shall not make any facility allowed change that would contravene such provision, until thirty (30) days after the Permittee has previously furnished notice of the proposed change to the District and to the Administrator, to thereby allow the Administrator opportunity to comment upon the continued "federal enfor ceability" of the subject provision after the proposed change. M. Permit Re-opening (Code §3-1-087.) If the EPA objects to the "federally enforceable" de signations under this permit, insofar as they are based on Code §3-1-084, then this permit may be subject to a Title V applicability determination after the EPA approves the District's Title V operating permit program. If a Title V permit is required, this permit will need to be re-opened, will be subject to EPA review and public review, and may require additional revision. While the District will notify Permittee if the EPA objects to any of those federally enforceable designati ons under Code §3-1-084, the Permittee bears the responsibility of determining when-and-or-if sucha Title V permit application must be filed. N. Record Retention (Code §3-1-083.A.2.b) Permittee shall retain for a period of five (5 ) years all documents required under this permit, including reports, monitoring data, support information, calibration and maintenance records, and all original recordings or physical records of required continuous monitoring instrumentation. O. Scope of License Conferred (Code §3-1-081.) This permit does not convey any property rights of any sort, or any exclusive privilege. P. Excess Emission Reports; Emergency Provision (Code §3-1-081.E, Code §8-1-030) 1. To the extent Permittee may wish to offer a showing in mitigation of any potential penalty, underlying upset events resulting in excess emissions shall reported as follows: a. The permittee shall report to the Control Officer any emissions in excess of the limits established by this permit. Such report shall be in two parts: I. Notifications by telephone or facsimile within 24 hours or the nextS:\wp11\PERMITS\Issued.c\C30992.ISS.wpd PERMIT #C30992.000

(4/12/10) OWENS CORNING - ELOY 24 business day, whichever is later, of the time when the owner or operator first learned of the occurrence of excess emissions, including all available information require d under subparagraph b. below. ii. Detailed written notification within 3 working days of the initial occurrence containing the information required under subparagraph b. below. b. The excess emissions report shall contain the following information: I. The identity of each stack or ot her emission point where the excess emissions occurred. ii. The magnitude of the excess emissions expressed in the units of the applicable limitation. iii. The time and duration or expected duration of the excess emissions. iv. The identity of the equipment from which the excess emissions occurred.

v. The nature and cause of such emissions. vi. If the excess emissions were the result of a malfunction, steps taken to remedy the malfunction and the steps taken or planned to prevent the recurrence of such malfunctions. vii. The steps that were or are being taken to limit the excess emissions. To the extent this permit defines procedures governing operations during periods of start-up or malfunction, th e report shall contain a list of steps taken to comply with this permit.

viii. To the extent excess emissions are continuous or recurring, the initial notification shall include an estimate of the time the excess emissions will continue. Continued excess emissions beyond the estimated date will require an additional notification. 2. An "emergency" means any situation arising from sudden and reasonably unforeseeable events beyond the control of the source, including acts of God, which situation requires immediate corrective action to restore normal operation, and that causes the source to exceed a technology-based emission limitation under the permit, due to unavoidable increases in emissions attributable to the emergency. An emergency shall not include noncompliance to the extent caused by improperly designed equipment, lack of preventative maintenance, careless or improper operation, or operator error. 3. An emergency constitutes an affirmative de fense to an action brought for noncompliance with such technology-based emission limitations if the conditions of the following subparagraph are met. 4. The affirmative defense of emergency sh all be demonstrated through properly signed, contemporaneous operating logs, or other relevant evidence that:S:\wp11\PERMITS\Issued.c\C30992.ISS.wpd PERMIT #C30992.000

(4/12/10) OWENS CORNING - ELOY 25 a. An emergency occurred and that the permittee can identify the cause(s) of the emergency; b. The permitted facility was at the time being properly operated; c. During the period of emergency the permittee took all reasonable steps to minimize levels of emissions that exceed ed the emissions standards or other requirements in the permit; and d. The permittee submitted notice of the emergency to the Control Officer by certified mail or hand delivery within 2 working days of the time when emissions limitations were exceeded due to emergency. The notice shall contain a description of the emergency, any steps taken to mitigate emissions, and corrective action taken. 10. Facility Specific Data A. Equipment Equipment for which emissions are allowed by this permit are as follows: 1. Glass batch raw material and mixed glass batch storage silos with eight (8) Mikropul Pulse Jet cleaned bin vent filters 2. Three Fiberizers, forming section with C-V cyclonic scrubber 3. Oven (4,000,000 btu/hr) 4. Riser/channel/forehearth, with burners (1,500,000 btu/hr) 5. 3 - Fiberizer burners (5,250,000 btu/hr total) 7. 2 - Furnaces 1100 kva with MikroPul pulse jet cleaned dust collectors. 8. 1-6,000 gallon resin storage tank 9. 70,000 pound urea storage tank with Hosokawa Mikropul baghouse 10. Cooling section with screen filter and loose fill insulation system with screen filter 11. 1- 8,000 gallon starch resin storage tank. 12. 1-500 gallon citric acid storage tote. B. Insignificant Activities (Code §3-1-050.E) Permittee has disclosed the following insignificant activities in the application for this permit: 1. Resin, emulsified oil, silane, dye, ammonium sulfate sodium hydroxide storage 2. Binder preparation and storage 3. Wash water system 4. Backing, cutting, and packaging operations 5. Dry urea storage C. Emission Inventory Table See the engineering analysis for a discussi on of point specific emissions and pollutants.Appendix A Semi-annual Report

Permit C30992.000 Abstract This constitutes a semi-annual report, documenting emissions and use of emission-generating materials during the subject reporting period. Facility - Owens Corning Insulating Systems - Eloy Facility 1825 W. Battaglia Rd., Eloy, AZ Reporting Period - January-June or July-December Year Material Usage Tons of glass pulled during reporting period - tons Resin used during reporting period - Pounds Product shipped - tons. Consumables used containing VOCs and HAPs - pounds. Natural Gas Usage - therms. Monthly averages of batt moisture content (%) 1 stmonth ______ 2 ndmonth _______ 3 rdmonth ______ 4 thmonth ______ 5 thmonth _______ 6 thmonth ________ Did all monthly calculations of the rolling average of glass-pull-rates pursuant to §6.A.1.a show compliance with the permit limits? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Yes No Did all monthly calculations of the rolling average of binder solids use rates pursuant to §6.A.1.b show compliance with the permit limits? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Yes No Did all monthly calculations of the rolling average of LOI pursuant to §6.A.1.e show compliance with the permit limits? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Have the required micro pulse filter inspec tions been conducted pursuant to §6.A.1.f? . . . . Yes No Have the required baghouse inspections b een conducted pursuant to §6.A.1.f? . . . . . . . . . Yes No Did all scrubber operation parameters measured pursuan t to §6.A.2 show compliance with the permit limits, as defined in either §5.C.2.b.ii or §6.E.1.c.ii? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Yes No Have the required scrubber flow and pressure drop records been maintained? . . . . . . . . . Yes No Have the required semi-annual Method 9 opacity te sts conducted pursuant to §6.E.5? . Yes ____ No _____ Certification by Responsible Official I certify that, based on information and belief formed after reasonable inquiry, that the statements and information in this report are true, accurate and complete.S:\wp11\PERMITS\Issued.c\C30992.ISS.wpd PERMIT #C30992.000

(4/12/10) OWENS CORNING - ELOY 27 Signed Printed Name __________________________

Title

Date

Mail to - Pinal County Air Quality Control District PO Box 987 Florence, AZ 85232