Facility Identifications
The Facility Registry System (FRS) is a centrally managed database that provides Internet access to a single integrated source of comprehensive (air, water, and waste) environmental information about facilities, sites or places. The FRS ID is used to identify facilities, sites or places subject to environmental regulations or of environmental interest. Additional information regarding FRS can be found at:
http://www.epa.gov/enviro/html/facility.html. You can search the system to obtain FRS IDs using any combination of facility name; geographic location; facility industrial classification; affiliated organization and contact; program category; and national system at: http://www.epa.gov/enviro/html/fii/fii_query_java.html.

Air Facility System
The Air Facility System (AFS) contains compliance and permit data for stationary sources regulated by EPA, state and local air pollution agencies. The environmental regulatory community uses the information in the database and the AFS ID to track the compliance status of point source facilities with various regulatory programs under the Clean Air Act. Additional information regarding AFS can be found at:
http://www.epa.gov/oecaerth/data/systems/air/afssystem.html.

Tribal ID
"Tribal ID" is a general term used to refer to identification codes assigned by American Indian regulatory entities (e.g., the Cherokee Nation Facility Registry System, the Navajo Nation Environmental Management System) to facilities located on tribal lands.

Source Classification Codes
The EPA uses Source Classification Codes (SCCs) to classify different types of anthropogenic emissions activities. Each SCC represents a unique source category-specific process or function that emits an air pollutant. The SCCs are used as a primary identifying data element in EPA’s WebFIRE, the National Emissions Inventory (NEI), and other EPA databases. The SCCs are also used by many regional, state, local and tribal agency emissions data systems.

There are several types of SCCs: those for point, nonpoint, mobile, biogenic, onroad and nonroad sources. WebFIRE primarily uses the point source SCCs to link emissions factors to an emission process. Point source SCCs have eight digits and follow the pattern 1-22-333-44.

SCCs use a hierarchical system in which the classification of the emissions process becomes increasingly more specific with each of the four levels (moving from left to right). The first level of description provides the most general information on the emissions category. The fourth category is the most detailed and describes the specific emissions process. For example, the 8-digit SCC 3-03-013-09 (entered without dashes, as “30301309” in WebFIRE searches) has the following designation:

You can search for emission factors and reports and reports in WebFIRE using partial or complete SCCs. To conduct an emissions factor or report search using a partial SCC code, you do not need to use an asterisk (*) after the partial code.