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  2. New Source Review (NSR) Permitting

Secondary Emissions

Date Title EPA Office Author Issues Addressed
02/11/1998 Feb. 11, 1998 Letter to Terry Godar on MSW Landfills (pdf) (108.79 KB) Region 3 Morris, Makeba Addresses question of whether emissions of NOx, SO2, PM, etc., from a control device at a municipal solid waste landfill are “secondary emissions,” among other issues.
06/13/1978 Impact of Secondary Emissions in NSRs OAR Hawkins, David Explains that offsets are to be obtained for certain secondary emissions resulting from the construction of a new source (e.g., ship or train emissions), if the secondary emissions are specific and can be accurately quantified. Also states that consideration of the indirect impacts of motor vehicle and aircraft traffic is not required, since EPA's authority to perform or require indirect source review relating to mobile sources regulated under Title II of the Act has been restricted by statute.
04/12/1979 Emissions from Ships Unloading at a Dock SSCD

Reich, Edward

Addresses whether ship emissions, which occur while a ship is tied up at dock, are considered primary or secondary emissions from the docking facility.
01/08/1990

Clarification on "Secondary Emissions" as Defined in the Code of Federal Regulations (CFR)

OAQPS Calcagni, John Addresses whether any emissions from a vessel are considered secondary emissions. Also addresses an error in the secondary emissions definition in the 1988 CFR at 40 CFR 52.21(b)(18).
03/17/1981 PSD Evaluation of Secondary Emissions for Houston Lighting and Power OAR Tuerk, Edward Addresses how the emissions of a nearby mine under different ownership must be taken into account in a PSD evaluation.
07/15/1977 Interpretative Ruling: Allowable Emissions Baseline (pdf) (17.45 KB) OAQPS Barber, Walter Addresses mechanisms under the interpretative ruling which can be used to ensure that offsets are “real.” This memorandum also discusses the requirement that secondary emissions from electrical power generation needed to supply a new source obtain offsets.

Related Topics: Limiting Potential to Emit (PTE) & Synthetic Minor Sources | Fugitive Emissions

Return to Policy & Guidance Document Index

The “Relevant Guidance” index includes a collection of documents issued by EPA organized by topic area. These documents include memoranda, letters, orders, and other types of EPA actions that may provide guidance in one or more forms, such as an adjudication, statement of policy, interpretation of statutes or regulations, or technical information. Each collection is intended to be representative of EPA statements on the topic, but it may not be a complete listing of such statements. The collection does not reflect topic-specific statements that have been expressed by EPA though published rule preambles and Title V petition orders, nor does it include EAB decisions. Each document in the collection speaks for itself, and the inclusion or exclusion of a document in the collection is not intended by EPA to communicate anything more than what is expressed within each document. EPA makes no independent representations on this website as to the extent to which any document in the collection reflects EPA’s current views on the topic, is a final action by EPA, or has any legal effect or precedential weight. Readers are advised to review the documents in the collection and conduct their own assessment of such considerations based on the content of each document and other documents in the collection. Some of the information or views included in the documents may be affected by subsequent changes to the referenced statutory or regulatory language or by court decisions. In addition, many of the statements in these documents are based upon the federal regulations which may differ from rules that govern federally-approved programs. Permitting authorities are advised to consult with their EPA Regional Offices if there is a question as to the relevance of a particular statement to their NSR program.

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Last updated on April 3, 2025
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