UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

REGION III

	1650 Arch Street

	Philadelphia, Pennsylvania  19103

DATE:	February 22, 2011

SUBJECT:	Technical Support Document - Delaware, 7 DE Administrative Code
1125 – Requirements for Preconstruction Review, Section 3.0 –
Prevention of Significant Deterioration of Air Quality

			/s/

FROM:	Sharon McCauley, Environmental Protection Specialist

Office of Permits and Air Toxics (3AP10) 

TO:		File

			

THRU: 	Kathleen Anderson, Associate Director

Office of Permits and Air Toxics (3AP10)

I.	BACKGROUND

This State Implementation Plan (SIP) revision request governs the
permits for constructing and significantly modifying major stationary
sources of air pollutants in Prevention of Significant Deterioration
(PSD) areas located in Delaware.  This regulatory revision was made
effective as a legislative rule in Delaware on April 11, 2010.  These
current Delaware regulations can be found in Regulation 1125, Section
3.0.  This SIP revision, as proposed, will only replace the current
regulations found in 1125 which establish NOx as a precursor to Ozone,
but will keep in tact the formally approved Delaware SIP increments for
NOx found in the Federal Register notice for Delaware dated July 27,
1993.  

Delaware’s proposed SIP submission addresses changes needed in the
part C PSD permit program.  This SIP submission also corrects
deficiencies identified by EPA in the March 27, 2008 Federal Register
notice entitled, “Completeness Findings for Section 110(a) State
implementation Plans for the 8 hour Ozone National Ambient Air Quality
Standards (1997 Ozone NAAQS)”, (73 FR 16205).  EPA’s proposed
approval of this SIP submission addresses Delaware’s  compliance with
the portion of Clean Air Act (CAA) Section 110 (a)(2)(C) & (J) relating
to the Part C permit program for the 1997 NAAQS Ozone NAAQS, because
this proposed approval would approve regulating  NOx as a precursor to
ozone in Delaware’s  SIP in accordance with the Federal Register
notice dated November 29, 2005 (70 FR 71612) that finalized NOx as a
precursor for ozone regulations set forth at 40 CFR 51.166 and in 40 CFR
52.21.  

EPA has determined that the current amendments to Delaware's PSD permit
program at 7 DE 

Administrative Code 1125 – Requirements for Preconstruction Review,
Section 3.0 – Prevention 

of Significant Deterioration of Air Quality, as submitted on April 1,
2010, meet the minimum 

requirements of 40 CFR 51.166 and the CAA. This SIP proposal is being
proposed as a full approvable revision to the Delaware SIP.  No other
changes to the currently approved SIP are being proposed for approval at
this time.   

II.	SUMMARY OF ACTION

This rule establishes a state construction permit program consistent
with the federal Clean Air Act’s Title I program and implementing
regulations at 40 CFR §51.166, “Prevention of Significant
Deterioration of Air Quality.” 7 DE Administrative Code 1125 –
Requirements for Preconstruction Review, Section 3.0 – Prevention of
Significant Deterioration of Air Quality is part of the SIP and sets
forth the criteria and procedures for major stationary sources to obtain
a permit to construct, operate and/or modify a major stationary source.

As required by 40 CFR Part 51, Subpart I - “Review of New Sources and
Modifications,” this rule adopts criteria and procedures for the
prevention of significant deterioration of air quality that are
consistent with the governing federal regulation at 40 CFR §51.166.
Promulgation of this rule by the Legislature is necessary for Delaware
to fulfill its responsibilities under 40 CFR Part 51 and the CAA, as
amended. Revisions to the Delaware rule are simply adding new references
to include NOx as a precursor to Ozone to comport with federal
counterpart language. The Delaware Department of Natural Resources and
Environmental Control has now submitted a final rule 7 DE Administrative
Code 1125 – Requirements for Preconstruction Review, Section 3.0 –
Prevention of Significant Deterioration of Air Quality as a proposed
revision to the SIP.

III.      INFRASTRUCTURE 

Delaware’s proposed SIP submission addresses changes needed in the
part C PSD permit program.  This SIP submission also corrects
deficiencies identified by EPA in the March 27, 2008 Federal Register
notice entitled, “Completeness Findings for Section 110(a) State
implementation Plans for the 8 hour Ozone National Ambient Air Quality
Standards (1997 Ozone NAAQS)”, (73 FR 16205).  EPA’s proposed
approval of this SIP submission addresses Delaware’s  compliance with
the portion of Clean Air Act (CAA) Section 110 (a)(2)(C) & (J) relating
to the Part C permit program for the 1997 NAAQS Ozone NAAQS, because
this proposed approval would approve regulating  NOx as a precursor to
ozone in Delaware’s  SIP in accordance with the Federal Register
notice dated November 29, 2005 (70 FR 71612) that finalized NOx as a
precursor for ozone regulations set forth at 40 CFR 51.166 and in 40 CFR
52.21.  

IV.	PROGRAM REVIEW

A.	Delaware Submittal

The Delaware submittal includes new references which were added to the
State rule to include NOx as a precursor to Ozone to comport with
federal counterpart language.

B.	Public Notice

Public notice was provided and a public hearing was held in the State of
Delaware on January 5, 2010 and no comments were received regarding the
changes made to Regulation 1125.

C.	Regulatory Review of Proposed SIP 

DNREC Regulation 1125 Section 3.1 Definitions

The following is a brief summary of the changes.

Regulation 

3.1	Modified	Definition of Major Stationary Source was modified to
include NOx as a precursor to Ozone along with volatile organic
compounds.



DNREC Regulation 1125 Section 3.7.7.1Review of Major Stationary Sources
and Major Modifications – Source Applicability and Exemptions

The following is a brief summary of the changes.

Section	Status	Description

Regulation 3.7.7.1	Modified 	No de Minimus air quality level is provided
for ozone….



DNREC Regulation 1125 Section 3.11.1.5Air Quality Analysis

The following is a brief summary of the changes.

Section	Status	Description

Regulation 3.11.1.5	Modified	Modified to include NOx as precursor to
ozone.



Note:  While reviewing the proposed SIP submittal it was noted that the
previously approved NOx increments as approved in Federal Register
notice 58 FR 40065 dated July 27, 1993 were not found in the current
submittal of Delaware’s regulation under 1125, Section 3.0 and Section
1.9.  EPA will propose approving the addition of NOx as a precursor to
Ozone to the regulations noted above, and will in effect, maintain the
prior SIP approval of the NOx increments, as previously approved in
1993.   

V.	RECOMMENDED AGENCY ACTION

EPA recommends approving the revision to Delaware's SIP to include
changes to 7 DE Administrative Code 1125 – Requirements for
Preconstruction Review, Section 3.0 – Prevention 

of Significant Deterioration of Air Quality. As previously noted, this
revision will establish NOx as a precursor to ozone in the State of
Delaware SIP. 

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