General Information

Support and Questions Concerning System Content

System Content

Data Elements

  • Category
  • Control Number
  • Title
  • Recipient
  • Author
  • Date
  • EPA Regions/Offices
  • Subpart
  • Reference
  • Abstract
  • Letter
System User Interface
  • Free-Form Text Entries
  • Scrolling Window Lists
  • Point and Click Selections
  • Multiple Selections
Creating Selection Criteria Screen

Selection Criteria Created Screen

Example Queries

Resulting Determinations Screen

Download Summary Screen



The Applicability Determination Index (ADI) is a Web-based database that contains memoranda issued by EPA on applicability and compliance issues associated with the New Source Performance Standards (NSPS), National Emissions Standards for Hazardous Air Pollutants (with categories for both NESHAP, Part 61, and MACT, Part 63), and chlorofluorocarbons (CFC). There are also separate categories for asbestos (Part 61, Subpart M) and woodstoves (Part 60, Subpart AAA). Recently issued determinations are added to the database on a quarterly basis. The Office of Enforcement and Compliance Assurances (OECA), Compliance Assessment Media Programs Division (CAMPD) maintains the database.

ADI allows users to search for determinations by a combination of categories, control numbers, subparts, regulatory citations (references), issue dates, EPA Region or office, author name, and word search strings connected with an "AND", an "OR", an "AND NOT", or an "OR NOT". Users can then view information from the determinations found including the header (which gives basic data about the determination), the determination abstract, and the full text of the determination. ADI users can select one or more determinations to download to their computers. The downloaded information will be in an ASCII text file that contains all of the selected determinations. The ASCII text file can be read or printed using a word processor or a text editor.

For additional information on ADI or on a specific determination, please contact your EPA Regional Office.



The ADI allows you to search for determinations by any combination of category, subpart, regulatory citation (references), issue date, EPA Region or office, author name, and word search strings. Additionally, if the user knows the control numbers of the determinations in which they are interested, the ADI allows users to query for those control numbers separately. These capabilities enable individual users to easily create powerful queries that result in a list of determinations. Individual search criteria can be connected with either a logical "AND", an "OR", an "AND NOT", or an "OR NOT" operator. The ADI software also allows the user to group search criteria using parenthetical expressions in order to best describe the query that is to be issued.

For example, a user wanting to search for determinations containing the word barium issued between March 4, 1983 and April 5, 1984, would create a query to locate records containing the word barium "AND" with dates FROM March 4, 1983 TO April 5, 1984, while "OR" would find all records that either satisfied the date range criteria or contained the word barium.

Users may also search for determinations added to the ADI in the most recent quarter or in quarters prior to that by following the link for "Recent ADI Updates".


The ADI search results page displays search information about each determination found in a search (including control number, title, date, office, recipient, and author). The user may view the full-text (including abstract and letter) of the determination on screen by pointing to and clicking on the control number of the given determination.

To ensure data integrity, the ADI allows only the EPA-designated system administrator to modify or add ADI data files. Users are granted read-only access to files.


Printing screens (pages) within the Web-based version of ADI is browser dependent. Each browser will provide the user with the capability to print the current page of data. For instance, within either Internet Explorer or Netscape Navigator, the user may print a determination letter by pointing to and clicking on the "Print" icon appearing at the top of the browser window, or by selecting "Print" from the "File" drop-down menu. Most, if not all, browsers provide a similar feature.


Users may download one or more determinations to their local computer by clicking the check boxes appearing in the download column next to the desired determination. The determinations will be in an ASCII text file for all selected determinations. The ASCII text files include the record header, the abstract, and the complete determination text, and may be opened using any word processor or text editor.


If you have any questions about a determination or need additional information, please contact your EPA Regional Office.


Data Elements

Each determination record in the ADI contains data fields for control number, category, EPA office, date, title, recipient, author, subparts, references, abstract, and letter.

Control number: The identifier of the determination record. For determinations issued prior to 1993, the control numbers were assigned on the basis of various EPA identifying methods in use at the time. Beginning in 1993, determinations have been assigned control numbers based on the calendar year in which they are entered into the system. This number is used for reference only.

Category: The regulatory category of the determination (e.g., MACT, NSPS, CFC, Asbestos, etc.)

EPA Region/Office: An abbreviation for the EPA office with primary responsibility for the determination. Appendix A contains a list of the offices referenced in the system.

Date: The date the determination was issued. Users can track determination responses by date, thereby highlighting trends in regulations or EPA compliance policies.

Title: The title or single line description of the determination content or subject matter.

Recipient: The recipient's name and office. The recipient often is the State official, Regional official, or private company representative who requested the applicability determination.

Author: The name of the person who issued the determination. Most authors are current or former EPA Headquarters or Regional officials.

Subparts: Identifies the 40 CFR 60, 61 or 63 subpart letter(s) addressed in the determination. Many searches are conducted to identify determinations addressing a particular subpart.

References: The specific regulatory reference(s) for the determination. Most references refer to a specific section of the Clean Air Act (CAA) or Clean Air Act regulations.

Abstract: A short summary of the determination. The abstract is prepared from information on the questions posed and answers given in the letter.

Letter: A full text verbatim transcript of the determination.


Free-Form Text Entries. Text-based entries are made within certain search query criteria fields by clicking within the window and typing the desired criteria once the text cursor appears within the window.

Scrolling Window Lists. Several query criteria allow the user to select from a predetermined number of possible entries appearing within a scrollable window. The user can scroll up or down within the window by using the arrow keys that appear to the right of it. Some scrolling windows contain a long list of possible entries. Selections are made by clicking on the desired entry.

Point and Click Selections. Many selections within the ADI system are made by simply pointing to items that appear underlined (or within buttons on screen) and pressing the left mouse button (for a normally configured mouse). This is, in fact, the method that was used to access this User's Guide.

Multiple Selections. The scrolling windows will allow for multiple entries to be made. Additional entries are made by holding down the <Ctrl> button and then clicking on the desired criteria. Criteria appearing in windows of this sort include: category, EPA Office, subparts, and references. The user can select a range of entries by holding down the <Shift> key when making the second of a pair of entries. For example, if the user selects the first entry, then holds down <Shift> and selects the fourth entry, the first through fourth entries will be selected. In comparison, had the user held down the <Ctrl> key while selecting the fourth entry, only the first and fourth entries would be selected. Regardless, when making multiple entries from a scrolling window, the user is indicating a logical "or" condition between the selections. In other words, multiple selections within the "Reference" scrolling window indicates that the user wants determinations containing any of the selected references (as opposed to all of the selections).


The "Create Query Selection Criteria" screen appears as the first screen of the ADI website. If a query were to be submitted immediately upon entering this screen, or following the pressing of the Clear Entries button, the result of the query would include all determinations in the database. The purpose of this screen however, is to allow the user to define criteria to be used in searching for only the determinations of interest. The user may scroll within this screen by selecting the up and down arrow keys that appear on the scroll bar at the far right of the window.

Of particular note are the buttons appearing on the top and bottom of the screen. The "Display/Submit Query" button is to be used once the user has selected all of the criteria that are to be included within the query. Once this button is pressed the query will be displayed and the user will be allowed to edit it prior to the query being submitted. The "Clear Entries" button allows the user to remove any entries that have already been entered and start from the beginning.

The user may select criteria from within as many areas as desired. There are no required entries. However, in order to use the system in the most efficient manner, the user should try to create a set of selection criteria that is as detailed as possible. This will limit the time that the user expends in scrolling through, reviewing and/or downloading the resulting determinations.

Selecting Criteria from Lists. The first criteria appearing on the Create Selection Criteria screen allows the user to search within a specific category of determinations, relating to either the Asbestos, CFC, NSPS, MACT, NESHAP or Woodstove regulations. Selections are made through the use of the scrolling window appearing beneath the "Category" heading. Users make selections from similar scrolling windows within the EPA Office, Subpart, Reference, and Control Number scrolling windows.

Using Date Range Criteria. To define a range of search dates, the screen provides two entry boxes. The first box FROM limits the search to determinations issued on or after the date selected and the second box TO limits the search to determinations issued on or before the date selected. Search for determinations issued on a particular date by entering the same date in both boxes. Leaving either the TO or FROM box empty will cause the system to include all determinations prior to the FROM date, or all determinations after the TO date, respectively.

If the dates entered exclude all determinations or if the field boxes are filled incorrectly (i.e., the FROM date is chronologically after the TO date), the system will alert you.

Using Letter Author Criteria. We recommend searching for the letter author using this author's name search field and entering the EPA author's last name. The word search feature does not necessarily produce accurate results for author's name.

Using Word Search Criteria. To define the scope of a word search, enter up to 10 word or character strings, separated by commas. The word and character string may consist of alphabetic and numeric characters. The ADI will search each of the determination letters for the string. The string you enter will be found only if the entire string appears in the determination letter. Therefore, the user should always enter the root string. For instance, if the user entered the word "woodstoves", the system would not return determinations including the word "woodstove". The word search is not case sensitive. Word searches are performed against a word index which is generated from scanned documents. The quality of the scanned documents can affect the accuracy of the index of the words. Better search results will be obtained by using more specific keywords or using additional search criteria.

Control Number List. Users wishing to query based upon control numbers only may do that separately from the other query criteria that are displayed on this default query screen. If the user wishes to retrieve determinations based upon control numbers, they may click on the link "Search by Document Control Number" that appears at the top of the screen. The user can then select the control number(s) of interest from the scrolling window. You cannot query using both control numbers and standard query options.


Once the user has selected the criteria that the query will use in selecting determinations, the "Selection Criteria Created" screen appears. This screen not only gives the user a chance to review the criteria that have been selected, but it also allows the criteria to be grouped and connected in order to query the database more efficiently. Groupings are created by using parentheses. The logical operators "AND", "OR", "AND NOT", and "OR NOT" are used to connect the criteria into one efficient search algorithm.

Users should remember that "AND" has logical precedence over "OR." Therefore, without the use of any parenthetical expressions, any grouping expression will have all "AND" conditions evaluated prior to any "OR."

The selected criteria appear on the screen under the "Criteria" heading. Each search criteria is assigned a number by the search engine. The user must use these numbers when defining the logic used by the search algorithm. The criteria, connectors, and any groupings are entered into the window entitled "Grouping Expression".

Several useful examples are provided below:

Example A

Assume that the user decided to search for all determinations concerning Part 60, Subpart Db and selected References 60.14 and 60.15. On the Selection Criteria Created Screen, Part 60, Subpart Db would appear as criteria 1 and References 60.14 and 60.15 as criteria 2. The user could decide whether all determinations containing either of the criteria should be returned (either Part 60, Subpart Db or both references), or only those determinations that had both (both Part 60, Subpart Db and both references.) In the first case the user must use the "OR" operator. Therefore, the criteria displayed and the entry in the grouping expression window would look like this:

1. Part and Subpart = Part 60 Db
2. Reference = 60.14, 60.15

Grouping Expression:
1 OR 2

In the second case, the "AND" operator must be used and the grouping expression would read:

Grouping Expression:
1 AND 2

Example B

Assume that the user has selected the "Asbestos" category; the date January 1, 1985 "FROM" date, and the search string "residen*". The selected criteria, once submitted, will be displayed as it appears below:

1. Category = Asbestos
2. Date range beginning January 1, 1985
3. Key word: residen*

Grouping Expression:
1 AND 2 AND 3

The "residen*" string while appearing to be nonsense, points to the power of the string search capability. The asterisk (*) is a wildcard which specifies zero or more alphanumeric characters. The string "residen*" will match all determinations containing the words: residence, residences, and residential. (Note: The asterisk may not be used as the first character in a search string.) Users should try to keep word search strings to the shortest root that applies to the desired query. As is the case in the previous example, the default grouping expression uses a logical "AND" between each criteria allowing the user to query for determinations containing all of these criteria. The user may change the default value to a logical "OR" condition if desired.

The question mark (?) is another wildcard. The question mark specifies a single alphanumeric character.

Example C

Assume the user has selected both Part 60, Subparts NNN and RRR from the "Subpart" scrolling window, as well as Region 6 from the "region" scrolling window. The criteria, once submitted, will appear as follows:

1. EPA Region/Office = Region 6
2. Part and Subpart = Part 60 NNN, Part 60 RRR

Grouping Expression:
1 AND 2

As explained in the previous section, the multiple selections made from the "Subpart" scrolling window are both grouped under the same criteria number. Therefore, determinations will be selected which contain both of these Subparts. In effect, this is the same as a logical "OR" condition between the values selected. Again, the grouping expression defaults to an "AND" condition between the two criteria, but that can be modified as desired.

Example D

Parentheses add a considerable degree of power to the search engine capability. Assume that the user selected the MACT category, Part 63, Subpart CC, and had entered the strings "hon" and "socmi." The criteria selected will appear as follows:

1. Category = MACT
2. Part and Subpart = Part 63 CC
3. Key Words

Grouping Expression:
1 AND 2 AND 3

Key Words:
1. hon
2. socmi

Key Words Expression:
1 AND 2

As noted above, parentheses are a powerful enhancer of the search engine capabilty. Assume that the user selected the MACT, NSPS and NESHAP categories, and wanted to search on the string "organic chemical" but did not want to return determination with the string "volatile organic chemical" or "synthetic organic chemical." In the Word Search box the user would enter the search strings "organic chemical", "volatile organic chemical", "synthetic organic chemical". The criteria selected will appear as follows:

1. Category = MACT, NESHAP, NSPS
2. Key Words

Grouping Expression:
1 AND 2

Key Words:
1. organic chemical
2. volatile organic chemical
3. synthetic organic chemical

Key Words Expression:
1 AND 2 AND 3

In order to retrieve only those determinations with the "organic chemical" string but not the "volatile organic chemical" strings, the user would have to modify the Key Words Expression to read as follows:
1 AND NOT (2 or 3)


The "Selected Determinations" screen displays information from the determinations found in a search. If the results of your query contain more than 100 determinations, only the first 100 will be displayed. You may move through the determinations 100 at a time by clicking on the text that says "Next," or "Previous," or by clicking on specific page numbers. Once all of the desired determinations on a page have been checked, clicking on the "Download Checked Determinations on Page" button will initiate the download process.

The data that is displayed includes control number, title and record header information. The user may select to view the full-text (including abstract) of a determination on screen by pointing to and clicking on the control number of the given determination.

Only the checked determinations from the current page (up to 100 determinations) will be downloaded when the user clicks the "Download Checked Determinations on Page" button. For instance, if the user selected 3 determinations from the first page of determinations and then moved to the second page of determinations and selected two more determinations prior to clicking the "Download Checked Determinations on Page" button, only the two determinations from the second page would be downloaded. The user must then return to the first page in order to check and download the first three determinations.

One or more determinations may be checked for download to your computer. This is done by pointing and clicking the check box appearing in the download column next to the desired determination. Each check box acts as a toggle. Initially, all determinations will be unselected. When the user clicks the check box for a given determination for the first time, a check mark will appear within the box indicating that the determination has been selected for download. If the user clicks the box again, the determination will be unchecked and the check mark will disappear. Multiple determinations may be downloaded. The downloaded information will be an ASCII text file that includes all checked determinations. The ASCII text files can be read or printed using a word processor or a text editor. The filename of the file that is downloaded is a uniquely named, generated file name.

When selecting determinations the user may click the "Check All on Page" button in order to download all the listed determinations. The "Uncheck All on Page" button allows the user to deselected any determinations that may have already been checked.


The "Download File" screen displays the determinations that are to be downloaded. Click on the "Download Text File" text to begin the download. An ASCII text file which contains the selected determinations will be downloaded to a uniquely named file. The downloaded file has a file extension ".adi". The file may be opened using a text editor such as Windows Notepad or word processing software such as Corel Wordperfect or Microsoft Word.


AED Air Enforcement Division
CCSMD Chemical, Commercial Services and Municipal Division
CAMPD Compliance Assessment and Media Programs Division
DOE Department of Energy
DSSE Division of Stationary Source Enforcement
EMAD Emissions, Monitoring, and Analysis Division
EMB Emission Measurement Branch
ESD Emissions Standards Division
ESED Emission Standards and Engineering Division
HQ Headquarters
OAQPS Office of Air Quality, Planning and Standards
OAR Office of Air and Radiation
OECA Office of Enforcement and Compliance Assurance
OECM Office of Enforcement and Compliance Monitoring
OGC Office of General Counsel
OPTS Office of Pesticides and Toxic Substances
Regions 1-10 EPA Regional Offices
SSCD Stationary Source Compliance Division