Source Classification Codes (SCC's)

SCC List.  The Source Classification Code (SCC) list has been updated for 2015 to ensure consistency with EPA SCCs (the changes are minor). SCCs are the way the U.S. Environmental Protection Agency categorizes sources of air pollution. The file below is a spreadsheet with all valid Source Classification Codes in eDEP.

Source Classification Codes (SCC's)  xls format of Source Classification Codes (SCC's)
file size 2MB (Revised in January 2015)

How to select an SCC for your emission unit:

  1. Download and open the list of SCC in the spreadsheet above.
  2. Using the auto filter feature, in the column labeled SCC Level One click on the down arrow ? to display the industrial category options. Pick one that is right for your facility and unit. Click "Select All" once to clear the check boxes, and then check the one you selected. This will filter out all of the other types and display only the one you want.
  3. Click on the down arrow ? in the column SCC Level Two to refine search for the emission unit. Pick one as you did for Level One.
  4. Follow this procedure using the auto filter feature in the other two columns to retrieve the appropriate SCC.
  5. If you cannot find a good match this way, then you could start by selecting Level One and then a fuel in Level Four, and then selecting the closest possible in Level Two and Level Three. Getting the fuel correct is most important for combustion sources.

To undo your filtering and start over, click on the ? in the columns you have already filtered and check "Select All" - this will clear all of the filters.

NOTE: this may work somewhat differently in older versions of Excel or other spreadsheets programs.

NOTE: Each SCC has a units field assigned - this will be the units in which you will need to report your throughput amounts.

NOTE: The column labeled "Category" indicates whether or not auto calculation of emissions is available for that SCC on the AP1 form. If the Category = COMBUSTION, then auto calculation is available.

If you are not successful in finding an appropriate SCC and would like help, contact MassDEP via email at: for assistance.

The source for SCC is the U.S. EPA EIS system at: Emission Inventory System (EIS) Gateway.  You can find the SCC list in this Access database file on that web page: "EIS Code Tables (Including SCCs)".

Emission Factors

eDEP on-line Source Registration uses a subset of the emissions factors available from the U.S. EPA to calculate combustion unit emissions in the AP1 form. These come almost entirely from EPA's WebFIRE system.

If you wish to find what factor eDEP used to calculate emissions on an AP1, look at the emission section of the form after you validate - the emission factors for each pollutant will be displayed.

If you wish to find emission factors to perform your own emission calculations, go to the U.S. EPA's latest list at (see Emission Factors/AP-42 and WebFIRE): Clearinghouse for Inventories & Emissions Factors


The North American Industry Classification System (NAICS) was developed jointly by the U.S., Canada, and Mexico to provide new comparability in statistics about business activity across North America.

The NAICS system has replaced the U.S. Standard Industrial Classification (SIC) system.

If you are looking for your company's NAICS code, you can look at recent Federal Tax Return documents. This code is now required by the IRS for federal tax returns as your: Principal Business Activity Codes.

You can also search web based databases, using your SIC code or key words to find the best NAICS that describes the main activity at your facility (use 6 digit codes only in Source Registration). Below are links to two NAICS sites:

   North American Industry Classification System