Read Me file for May 2007 version of SCC List

     The file "codes3_1_a00.mdb" is and MS Access 2000 file which contains all of the tables
needed by the NIF Basic Format and Content Checker (BFCC).  One of those tables is
"SCC_0900" which contains EPA's current listing of all source classification codes (SCCs) and
their descriptions, as of May 1, 2007. These codes are used as a primary identifying data element
in EPA's National Emission Inventory (NEI), National Emission Trends (NET) database, Factor
Information and Retrieval database (FIRE), and many State agency emissions data systems.  The
current file contains  9760 SCCs.  This list contains only the Active SCCs.  Some earlier posted
lists also contained "retired" SCCs.  We will consider adding these retired SCCs, along with
additional columns to identify them, when the re-designed Emission Inventory System (EIS) is
on-line late 2008.

     SCCs for Point sources are 8-characters; SCCs for the other four sectors are
10-characters.  For each SCC, the file contains all four levels of the description for that code.  
Unlike earlier versions of this list, the "standard" thruput units are no longer included, because
the NEI allows the data reporter to specify thruput units.  This version of the list has fields for
"Date_Added" and "Source".  These fields are not usually populated and should not be used.

ORGANIZATION OF SCCs

     The four levels of source descriptions for SCCs are associated with the first 1, 3, 6, and 8
characters of the point source codes, or the first 2, 4, 7, and 10 characters of the codes used for
the other four NEI sectors.  The first level uses only the first character and provides only the most
general information on the category of the emissions.

     The second level of description is associated with the first three characters, and
subdivides the five major categories above into major industry groups.  For example, 1-01
indicates External Combustion in Utility Boilers, and 1-02 indicates External Combustion in
Industrial Boilers.  The Manufacturing Processes category (3-) is currently divided into 21
industry classes, such as Chemical Manufacturing (3-01), Food and Agriculture (3-02), and
Primary Metal Production (3-03).

     The third level of description requires the first six characters to be specified, and it
identifies a specific industry or emission source category, e.g., Cotton Ginning (3-02-004), or
Primary Copper Smelting (3-03-005).  The three characters which have been added to the
industry class description (the first three characters) usually indicate the major product, raw
material, or fuel used.

     The fourth level of description is associated with the full eight character code.  The
addition of two more characters beyond the third level specifies the particular emitting process
within the third-level source category.  For example, SCC 3-03-005-06 specifies the Ore
Concentrate Dryer emission source at a Primary Copper Smelting facility (3-03-005). 

     An eight-character code may correspond to a particular boiler type, process heater,
process vent, or fuel.  A single emission point may have two or more SCCs if it uses more than
one material or burns more than one type of fuel, but most emission points will be described by
one SCC.