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  2. Air Emissions Factors and Quantification

TANKS Emissions Estimation Software, Version 5

Alerts

2/13/2026 - On February 13, 2026, the Environmental Protection Agency (EPA) released TANKS 5.2 - an updated version of the TANKS 5.1 application. This updated version includes improved and additional features such as enabling users to generate a pdf version of the Routine Losses Report, a Frequently Asked Questions section in the User’s Guide, as well as bug fixes. To receive notifications related to application updates, sign up for the CHIEF Listserv by sending an e-mail to join-chief@lists.epa.gov. 

10/9/2024 - On October 9, 2024, the Environmental Protection Agency (EPA) released TANKS 5.1 - an updated/final version of the TANKS 5.0 Beta application. This updated version includes improved and additional features, as well as bug fixes. To receive notifications related to application updates, sign up for the CHIEF Listserv by sending an e-mail to join-chief@lists.epa.gov. 

TANKS 5.2

Release Date: 2/13/2026

On This Page:

  • What Is TANKS, Version 5? 
  • Audience 
  • TANKS, Version 5 Features 
  • TANKS Update Log
  • How to Access TANKS 5.2

What Is TANKS, Version 5?

TANKS, Version 5 is a browser-based application that estimates volatile organic compound (VOC) and hazardous air pollutant (HAP) emissions from fixed- and floating-roof storage tanks. TANKS is based on the emission estimation procedures from Chapter 7 of EPA's Compilation Of Air Pollutant Emission Factors (AP-42). The most current version of TANKS is 5.2, and the  TANKS 5.2 User Guide (pdf) (2.1 MB, 2/5/2026)  explains each screen and defines the parameters entered into TANKS 5.2. 

TANKS, Version 5 does not store your data within the application; data are stored within your browser's local storage. The data can be saved to your computer for longer term storage. 

The TANKS 5.2 application is located here: https://TANKS.app.cloud.gov. 

Audience

TANKS, Version 5 is designed for use by local, state, and federal agencies, environmental consultants, and others who need to calculate air pollutant emissions from organic liquid storage tanks.

TANKS, Version 5 Features

TANKS, Version 5 uses chemical, meteorological, roof fitting, and rim seal data to generate emissions estimates for several types of storage tanks, including:

  • Vertical fixed roof tanks
  • Horizontal fixed roof tanks
  • Internal floating roof tanks
  • External floating roof tanks
  • Domed external floating roof tanks

See the TANKS FAQ for additional information about TANKS.

The TANKS, Version 5 application employs a chemical database of over 100 organic liquids, and a meteorological database of over 250 cities in the United States. TANKS, Version 5 is capable of calculating individual component emissions using user-defined speciation profiles for mixtures and petroleum liquids. 

New features include the following:

  • TANKS, Version 5 is a browser-based application so no downloads are required;
  • TANKS, Version 5 does not require a user-name or a password;
  • TANKS, Version 5 allows for the addition of meteorological data for new cities;
  • TANKS, Version 5 allows for the addition of custom organic liquids, custom mixtures, and custom petroleum liquids;
  • TANKS, Version 5 includes calculations for floating roof landing losses; 
  • TANKS, Version 5 includes calculations for tank cleaning emissions;
  • TANKS, Version 5 allows export of tanks information into an Excel spreadsheet format that can be saved to the user's computer;
  • TANKS, Version 5 allows the Excel spreadsheet to be imported into the application to make changes to the tanks or calculate emissions; and 
  • TANKS, Version 5 allows calculation of standing and working losses for multiple tanks at once and the emissions are output to an Excel spreadsheet.

TANKS Update Log

TANKS 5.2

The TANKS 5.2 updates were results of items identified by the EPA and help desk questions and comments from the general public since TANKS 5.1 was released. A brief list of updates made can be found below.

Application Updates:

  • Updated EPA’s description to match recent reorganizations
  • Added a new Error Message that has been cited by users through the Help Desk, “Cannot read properties of undefined (reading ‘components’)”
    • Liquid height greater than shell diameter: "This is a required field. Values must be greater than zero, less than or equal to the tank shell height, and rounded to the nearest thousandth"
  • Added a PDF report generation option for the Routine Losses Report
  • Number of deck legs added to Routine Losses Report
  • Minimum tank height and diameter changed to 0.5 feet
User's Guide Updates:
  • Added a section discussing how to generate the pdf report
  • Expanded the Definitions section to include more detail and additional definitions used in AP-42 Chapter 7 and TANKS 5.2
  • Added an FAQs section, especially for questions we have received multiple times through the Help Desk

TANKS 5.1

The TANKS 5.1 updates were the results of items identified by the EPA as well as comments from the general public that were sought out during the TANKS 5.0 public beta period. A summary of those documents and the EPA's response can be found here: https://www.epa.gov/system/files/documents/2024-10/rtc_tanks_final_v2_clean.pdf. 

  • TANKS 5.1 routine losses report updated.
  • Report now includes speciated chemical results by chemical name as well as all inputs and intermediate calculations.
  • Report now breaks out routine losses into deck fitting losses, deck seam losses, or rim seal losses.
  • TANKS 5.1 now has an exportable cleaning and landing losses report ("Non-Routine Losses Report").
  • TANKS 5.1 includes bug fixes for custom meteorological data validation (issues with negative temperatures) and general data validation issues in the TANKS 5.0 - Beta version.
  • TANKS 5.1 now includes multiple Alaska locations in the meteorological locations database.
  • TANKS 5.1 now allows for mole fractions up to 5 decimal places.

How to Access TANKS 5.2

The TANKS 5.2 application is located here: https://TANKS.app.cloud.gov. 


 

Air Emissions Factors and Quantification

  • Basic Information
  • AP-42
  • Emissions Estimation Tools
Contact Us about Air Emissions Factors
Contact Us about Air Emissions Factors to ask a question, provide feedback, or report a problem.
Last updated on March 4, 2026
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